Radial Arm Saw Operation Question
kenewald | Posted in Power Tools and Machinery on
Question: The blade’s teeth point away from me when I stand in front of the machine. Am I supposed pull it towards me to cut or push? I seem to recall my dad holding the work with his left hand and pulling the saw towards him to cut.
If I pull it towards me, it seems very dangerous – like it could run away on me, on the other hand, holding the piece and pushing the saw towards your hand doesn’t feel very comfortable either. And threading the piece through doesn’t seem right either.
Could I have something mounted backwards?
Your thoughts will probably save me a finger or two .. Thanks in advance.
-Ken
Replies
Ken,
The saw pulls towards you. You have to be careful of this when dadoing. If you take too much stock, the set up has a tendency to climb at you. The new craftsman saws have a cable on them that controls the max feed rate so this doesn't happen. I'm new to this feature and not sure if I like it yet or not.
Don
OK, I thought you pull to cut. Just seems strange, since the blade will tend to bite off more than it can chew...
radial arms you pull, whereas sliders you push
Ken,
I believe that blades for radial arm saws have teeth with low rake angles. Some are zero degrees, even negative angles, to minimize the blade's tendancy to pull itself into the work.
Rich
Ken,
I've only read the first five or six posts here, and Rich is correct.
PULL the saw toward you, but make sure that you have a blade for a RAS. Anything with a positive rake angle will feed the saw toward you at a rate of knots. Not pleasant and limb/life threatening
Cheers,
eddie.
ps: How's things Rich
pps: just saw that this is the same discussion as a year ago
Edited 4/16/2003 5:40:17 PM ET by eddie (aust)
at first, lock your elbow, and pull by rotating your shoulders, you'll get the feel .
no turn left unstoned
Get a cut-off blade (opposite to a rip blade) made for radial arm saws. My old Monkey wards RAS has an adjustable clutch mechanism that is kept tight enough so that the blade won't lurch forward, but loose enough to still pull forward.
Basically, RAS are dangerous as HE-double-L. NEVER try to rip with one. Been there, done that and won't do it again.
I use mine primarily cause it has a third spindle that turns at 20,000 rpm that is great as an over-arm router.
PlaneWood by Mike_in_Katy
PlaneWood
Ken,
If you are new to using a radial arm saw, do like has been suggested, pull the saw toward you to make the cut. Practise on some fairly soft wood, no thicker than 4/4 (3/4" thick) till you get the feel for it. You have to develop a feel for pulling the carriage toward you and holding it back at the same time, to avoid the saw's aggessive tendancy to aggressively overfeed in thick wood.
But, you can avoid this (overfeed) completely, even in thick hardwoods by the method of pushing the saw through the work. I was reluctant to try this at first, because it seemed so unnatural. (Sort of like kissing your dog on the lips.) But it works; the tendancy of the saw to overfeed (to try to climb over the work) is completely eliminated. It feels like using a skilsaw. Also the finish cut is smooth as cutting in the normal way, if not smoother. But it's not a method to use for production cutting because it would not be safe to move the wood along the fence between cuts, behind the running saw. GP.
toss a newbie a bone.... isn't 4/4 1" thick?
Like all professional groups, woodworkers have developed certain arcane, counter-intutitive code so that (i) outsiders can't understand what they're saying, and (ii) they sound smarter than they really are at cocktail parties. You'd think 4/4 meant 1, because it does, but it doesn't. It means 3/4. The 4/4 is the "nominal" dimensions of the rough timber before milling.
I've been using a RAS (for crosscutting only) for many years. In my opinion Mr. Jennings is right about pushing the saw across the stock - you eliminate one danger but create a different one, which is worse. I know of no scientific evidence to support this opinion, however.
But you have to be carefull as h*ll pulling the blade toward you, especially if the board is thicker than 4/4, is harder than pine, or has knots. I always hold my breath and hang onto the handle very firmly, and even so have experienced the "climbing" phenomenon more than once, which is not really dangerous, as long as you don't have your fingers anywhere near the blade, but frightening nonetheless. The phenomenon is less likely to occur if you have the right kind of "negative rake" blade, if the blade is sharp, and if the saw is well-powered. My own saw has been having more and more trouble recently and I don't know why. I've had the blade sharpened and checked the brushes on the electric motor - maybe the motor is just wearing out somehow with age, like me.
Thank you friends for your thoughtful comments.
I was sure all these weird forces indicated that something was very wrong... just seemed very unnatural and terribly unsafe .. a little unnerving.
I made a bunch of sawdust last night and I completely understand your comments today. By the way, never stand on the side of the saw-dust blower thingy when turning the machine on .. doooh.
I'll stick to the table saw for ripping and small stuff (w/ sled) and leave the cross-cutting to the RAS.
Thanks again,
-Ken (Go Huskers!)
Hi tschmaling,
Yes & no.
4/4 is 1" green sawn = approx 15/16" dry = 3/4" dressed (surfaced).
Hope this clears up your confusion.
Cheers, eddie
Holy Cow! I got so much done this weekend with my new (good clean used one-owner) RAS .. and I love it! It's like going from Kakhi's to blue jeans .. feels funny at first, but before you know it .. it's what you feel most comfortable in.
It's so easy to go from a straight cut to 45 deg. and back again without cranking, measuring and cutting a test piece and measuring again on a table saw.
I noticed another interesting thing. I can cut a slightly thicker piece of wood on the RAS because the table is not between the piece and the blade.
Thanks for your well thought input on the feeding issues. Both sides have their merits -- correct me if I've totally missed the point. Push gives you better feed control (a consistent feed control will yield a cleaner cut), and pull gives you a better margin of safety (what's your vector, Victor?).
Now I've got a REAL dilemma: work vs. wood shop
I love this stuff.
Just don't assume that when you go from 90 to 45 and back again, that you'll be back at a true 90. My experience that you have to tweak it each time. But my RAS is pretty cheap (Riobi) and maybe the better saws go back more accurately.
Good point. The 2 boxes I've created so far have been right on.
It's got a machined slot that has put it right on the mark so far. Apparently the previous owner calibrated it well.
-Ken
Mark and Ken,
Don't have a RAS now, wish I did. When I did (old Craftsman 10"), I set it to 90 degrees and locked it there, never to move because it NEVER returned true. I made holding devices (not allowed to use the "J" word any more) to cut other angles.
Rich
Sorry to ask the obvious, but .. was it consistently off by the same amount?
I know... but I just had to ask.
Ken,
No. It was a P.O.S. The arm stop mechanism was totaly inadequate for repeats.
Rich
Rich,
Just got a Craftsman RAS about 56 weeks ago. works great, and repeat of settings IMO is better then average for what is basically in the range of the bottom of the line for RAS'S.
Don
Ken all the professionals use the RAS in the pull through mode this is the way it was designed to be used period.
Bart,
I always wonder why some people find it necessary to insist that there is one "true" way to do something, period! That is just silly. What "professionals?" Where is it cast in stone that pulling a RAS is the way it was designed to work and that any other method is "wrong?" Why do you find it necessary to insist on one, and only one way to work?
A craftsman or an artist uses a tool to best match his or her needs. Methods of work have eveloved that are diametrically opposite to accomplish the exact goal. An example is the fact that respected "elders" of our craft cut dovetail joint tails first, before pins, while other, equally respected teachers do it the other way, each insisting that his or her method is the best. It is, for each.
There is nothing inherently dangerous about pushing a RAS, in fact, it is less dangerous than pulling. As pointed out, it does not lend itself to production because it IS dangerous to put your hand behind a spinning blade to position work.
I agree that the original designer, and most manufacturers expect their saws to be pulled. So what?
Rich
You'll think so until the saw grabs the wood & flings it up behind the saw possibly doing injury to you in the process. Between my Dad who is 81 & myself we have about 99 - 100 years experience-using RAS's both in construction & cabinet making. He started in the trade at 16 & I started working with him using the RAS at 15. We have both seen people injured by RAS's because they either didn’t know how to use the saw or didn’t care to give it the respect it absolutely requires. Remember that saw doesn’t have any respect for you.
"A craftsman or an artist uses a tool to best match his or her needs. Methods of work have evolved that are diametrically opposite to accomplishing the exact goal. An example is the fact that respected "elders" of our craft cut dovetail joint tails first, before pins, while other, equally respected teachers do it the other way, each insisting that his or her method is the best. It is, for each. "
Does the Dovetail saw have a 2 hp motor connected to it - no I didn’t think so. Ways of using electric tools have been established so that you & I can safely enjoy the use of them & hopefully the insurance will not need to be used.
You have received advice from people who have a combined experience level of about 200 –300 years. I realize we don’t know anything. My daughter used to think that way but just lately that has changed all of a sudden Dad is a little smarter than he used to be.
Well maybe your time hasn’t come yet.
I still have all my fingers.
Use guards & your head (for something besides a hat rack) or you may not need gloves.
No opinion hee on the topic at hand, but your post reminded me of what Mark Twain use to say.
He left home at 16 and returned at 18. He was surprised how much his dad had learned in just two years! ;^)
Don
Don,
That's a great quote, as are all Mark Twain's. I wonder if that really was his, or did it predate him? The version I heard was, "When he was 16, he thought his father a fool. By the time he was 18, he was amazed at how much the old coot had learned in 2 years!"
Bart,
it's your insistence that only one way is right that bothers me. I don't buy it. I have as much experience as you, apparently more. I have all my digits. And my head serves as quite a fine hat rack, thank you as well as for other uses.
Now as to the safety of a RAS. The woodworking literature is FULL of accounts of workers losing their left hand or fingers from that hand, using the saw "as it was designed to be used." Why they got their hand in the path of the blade is pondered every time. But it has happened over and over. The RAS used as it is intended to be is the most dangerous power tool in the shop. Some shops refuse to have one. Whether that's good thinking or not, I don't know, but that's a fact.
How many times has it been reported that injuries have occured as a result of pushing the saw? I don't ever recall one. The fact that in my experience none has happened is not all that important, but the incidence of that kind of thing is very low.
Pushing the saw, the left hand sits on the work to the left, holding it tight down on the table. The front edge of the work is against the fence, where the saw forces it tightly. What are the mechanics of danger if precaution equal to that used pulling the saw is observed?
If everything is done correctly, only sawdust and chips are thrown. No work pieces. It's certainly no more dangerous than the saw used "as it should be."
Do you rip on a RAS? Now THERE'S a nice, safe operation, fully supported by the manufacturer. Ripping on a RAS is grounds for immediate firing in my shop.
If your sage advice about pushing the saw were valid, then circular saws should be banned. At least with the RAS, the fence prevents the work from being thrown. What then, stops the kind of danger you insist is inherent in pushing the RAS from occuring with a circular saw?
Rich
Ripping with a RAS, what's so wrong with that?no turn left unstoned
nothing as long as you have no problem getting your daily allowance of dietary fiber from a board in the face... lol
A gun is designed to shoot with the barrel pointed away from the shooter. Is it equally safe to point the barrel at yourself and then pull the trigger?
A gun can be fired pointing away from or toward yourself. A RAS can be pulled or pushed - but in each situation there is only one safe way to point a gun about to be shot and like a gun there is only one safe way to use a RAS.
Quoting yourself -"I always wonder why some people find it necessary to insist that there is one "true" way to do something, period! That is just silly. "
To each his own.
I use an old Delta Side-Kick which is similar to a ras as to cross cutting and mittering. I alwasy push on it with the right hand while pushing the workpiece AGAINST the fence and downwards. While the blade is being pushed into the board, the fence actually supplies the counter forces of the blade and the left hand is doing only a steadying work. Things to watch are that one is fully pushed against the fence and that the board is not warped. Do feel verys confident about this aproach.
Now, as to differences between a ras and the Sidekick. The Sidekick as used cuts the board fully all the time across its thickness. The height can not be changed so it is always about 1/16" of teeth on the bottom side of the workpiece.
1. RAS if it does not cut fully would actually be TRAPPING the wood between te blade and the table surface. So it is a good idea to make sure that for cross cutting or mittering, the blade is positively cutting the thickness.
2. The Delta Sidekick uses an 8" dia blade, which is sufficient for most jobs. If 10" or 12" or even bigger blades are used on RAS, then the forces and dangers increase highly. Would say if blades diameters are kept as low as possible, much risk is reduced.
3. As to vectors showing the board being lifted when RAS is pushed, that is only true at the very minute beginning. The complete picture would have vectors also pushing the board DOWN at the teeth closer to the operator. If the borard is fully being cut across, any trapping and tendency to toss the board would be much lessened. Therefore, making sure that the blade cuts fully through the board by say 1/2 tooth height or so is a thing to insure as part of the setup.
4. On pulling a RAS, the fence technically should be right next to the operator to oppose the force of the blade being pulled. On that case, the advantage of production flow with the blade not stopping between cuts would be lost.
5. When the fence does the stopping of the cutting thrust, obviously more accurate cuts will result.
6. As far as a blade in a RAS cutting deeper than when mounted on a table saw, that would be true only if the arbor of the RAS is offset from the RAS's motor's circumference (as with a small belt inside). Otherwise, the fat motor itself may even waste more cutting capability than on a table saw, where small spindles are driven by a belt and to that one would add the thickness of the table.
7. Dado cutting with a RAS will always be trapping wood between blade and surface, so the bite depth and the through speed are key factors to offset that, plus clamps on the workpiece.
8. Pulling the RAS favors climbing of the balde into the wood, definitely, and that's what it will want to do if it can't cut it.
I also have a Comet RAS, very heavy and precise, but use only an 8" diameter blade on it and 6" dado. It uses a small rubber belt, so it slips on overloads, which is a good design. I use 8" because that's the smallest I can get for it.
Read post 47
I agree with Chas' sentiments if not his choice of words.
The vector analysis given earlier is complete, only pull a RAS towards you and then only with a negative or neutral angle blade specifically sold as being suitable for a radial arm saw.
I sincerely hope that you never experience a kickback and that you retain full function of your left hand when you retire from the game.
ps: I'm a former senior engineer and teacher of woodwork to high school students. In both roles, safety is foremost. Please heed the advice.
Cheers,
eddie
Edited 4/16/2003 7:04:26 PM ET by eddie (aust)
Dear friends,
Vector analysis is too complex to call it complete as discussed. However, if one follows the movement of just one single tooth in the blade, it can be seen that:
1. When pushing the RAS to cut, the tooth forces vary in magnitude resulting throughout the cut in forces both towards the fence and upwards. The upwards force of a tooth is only totally vertical when a tooth is horizontally level with the horizontal center-line of the blade bore. Since a blade can not possibly cut to that depth, in the push-mode there will always be a resultant vector that combines a force towards the fence and slightly upwards. To that force towards the fence of the rotating teeth, we add the force of the right arm of the operator pushing the RAS towards the fence. To that force, add also the force of the left hand pushing forwards towards the fence. All forces towards the fence are desireable. The only force not desireable is the upwards force which is countered by the left hand pushing down on the board, AND the natural static force of the blade as it is OVER the board, supported by the radial arm (verify this support force by stopping the RAS in the middle of the cut and see that the board is trapped and can not move up). The other force to counteract the teeth upwards force is the WEIGHT of the board itself.
3. So, to cut by pushing, the force to offset is the resultant upwards force of the teeth, which is never a vector totally upwards. That force, actually, is not a very difficult force to offset. For instance, depending on their weight and geometry, it is possible to cut boards with no other downwards force other than their own weight, at the proper push speed, of course.
4. To the downwards forces discussed, it is very easy to add the 'infinite' downwards force of a vertical clamp (will see about posting a photo on the set-up I use. With this setup, one can put the left hand behind the waist absolutely, and achieve safe and accurate cross-cuts by pushing the RAS forward.
5. When cutting by pulling the RAS, there are no resulting upwards forces. But, UNFORTUNATELY, we now have BACKWARDS forces TOWARDS THE OPERATOR and now, rather than lift, the teeth want to flip the board by pushing down on the forward edge of the board, so the left hand still has to push down. A vertical clamp, therefore, is not precluded whe pulling on the RAS.
6. With either aproach, if the teeth cut the board as intended, no problems would be experienced. However, would say that the actual problem comes when the wood, acting as a disk brake, grabs the blade from its walls. The factors that lead to that situation are many, and none have to do with whether the direction of the blade is pulling or pushing, but more with the force/speed of doing the pulling or pushing, wood imperfections, improper support of the cut piece, improper settings on the RAS, or worse, the lack of a setting such as not locking one or more handles, dull or incorrect blades; RAS not designed for the task presented to it, etc.
I am fully aware of the many accidents relating to RAS and have very carefully selected my methods of work with it and duely respect the right of others on their elected means.
I have an acquaintance professional woodworker, for instance, who does no other thing for a living. He goes by tradition, even to where he will hand the shop to his son, as a family business. So by tradition, he pulls on the RAS. But, guess what? A long time ago his small delta RAS motor burned up and the repair man not only could not fix it, but lost it. So he hang a common hand-held circular saw from the arm of the RAS. He's got it so that the handle of the hand-held is away from him, just as if someone were to cross-cut towards him with it. Of course, the saw cuts well, as no fundamental modifications were done to the hand-held. However, the rotation of the blade is opposite to that of a RAS and so his pulling actually tends to lift the workpiece, which he has no problem dealing with. We all know that all hand-held circular saws tend to lift the workpiece, of course. When I told him "Your blade is backwards", he said "Yes, I know, but I already flipped THE BLADE over and it just WON'T cut".
Now, please no one try to cut wood by pulling on a hand-held circular saw, EVEN IF all the mecanics of rotation are the same as those of a RAS. Please, specially now with the small battery-operated hand helds, even a minute backing, so as to adjust the direction of cut, can result in serious damage. And even if they are light enough for some to use with only one hand, please hold them with both hands wherever possible. If not, please keep the other hand far from the cut line, neither in front NOR behind it.
May everyone find his best way.
None so deaf as those that will not hear.
Dear eddie,
Even a deaf person can read.
So reading a manual for a RAS, as suggested by another member, will only confirm that it will not say "CAUTION: do not cross-cut by pushing blade towards the fence".
If the manual does not say it, then WHO is saying it?
Much cost has been incurred into by RAS manufacturers to implement safeguards for them, such as guards, cables, interlocks, etc.
But not even one penny has been spent by them to stick a label on any RAS saying "DO NOT CROSS-CUT BY PUSHING", much less to put a mechanism that prevents it. And that mechanism would not be too difficult to implement, by the way.
In my ancient Comet saw, as in many others, however, there is a red label on the handle side of the blade that says "CAUTION: DO NOT RIP OR GOUGE FROM THIS END". That ought to mean to a good reader, even if deaf, that the climbing effect at that end is IN ITSELF the hazard that relates to most RAS accidents, not the cross-cutting direction.
Edited 4/20/2003 1:59:43 AM ET by mbl
mbl,
I'm not going to get into an argument with you on this.
I spent a little bit of time on google and came up with the following hits from authorities regarding radial arm saw safety and operating instruction. I suppose you could say that they are the ones who say to do what is recommended.
http://www.safetyline.wa.gov.au/pagebin/pg003568.htm Accident with RAS
http://files.owwm.com/PDF/Dewalt/1952-GR.pdf Dewalt RAS operating manual, 1952, p10. What you are proposing warranted a bold 'never', even in those days.
http://www.safetyline.wa.gov.au/PageBin/guidothr0019.htm et al. Safety guide to RAS
http://www.selu.edu/Administration/Depts/Safety/safe2.html#RulesforWoodworking Safety Guide for RAS
http://www.mtea.net/PDF%20Files/Pennsylvaniasafety.pdf p142 dictates how the RAS is to be used in all government departments
http://www.epcc.edu/safety/safety03.pdf Section 6.20 gives clear safety rules for RAS
http://www.trialbehavior.com/articles/Theme%20Development%20and%20Jury%20Selection%20in%20Product%20Liability%20Litigation.htm
http://www.law.washington.edu/lawschool/students/sba/walsh_torts_1999.doc
Do a search on 'radial', interesting point it brings up on the above two sites
http://www.law.emory.edu/1circuit/june98/97-1988.01a.html Law case against Sears
http://www.safetyline.wa.gov.au/imagebin/nail.gif Nail gun accident - image, as an aside.
You're missing something simple in your justification to yourself that you are working safely, that is that there is no resultant vector when the blade has cleared wood out and is whistling happily through the (now empty) kerf that is full of nothing but thin air. There's nothing for it to push against so it won't.
The safety problem to be avoided is that the wood can be lifted off the fence and pushed into any random direction, taking your hand with it if it's holding down the wood, perhaps into the blade, as well as the saw running toward you (for which reason, you must use a blade with a neutral or sligtly negative (?) rake angle, the one where the included angle of the tooth is greater than 90 degrees, like an aluminium blade).
The reason why you don't rip on a RAS feeding wood backwards into the blade (ie: in a climb cut) is that there is no fence for the wood to be pushed against. You feed into the teeth to avoid this, and always with anti kickback pawls in use. But, there are other, better ways to rip, ie: ripsaw or table saw, even straight edge and circ saw.
I can't comment on trenching because 'dado' heads or drunken saw blades are not popular with our safety authorities and I've never seen one, let alone use one. From what I know, I'd still cut this by pulling the saw away from the fence as usual, just with depth set and job firmly clamped, but I've never come across this..
But, by all means, use this saw however you see fit.
Above all, stay safe.
eddie
Edited 4/20/2003 4:10:39 AM ET by eddie (aust)
Dear friend,
Thanks for the links on the "correct" way to cross cut and use of the RAS, and on safety.
In the link of the instruction book of an early RAS, the fellow in the picture advises us to hold the specimen with the left hand while pulling to cross-cut with the right hand.
However, on the link from a government safety recomendation, the drawing illustration tells us to pull with the LEFT hand, while holding the specimen with the right hand.
Now, which would be the 'absolute' best way? Or would one be wrong?
...
Another link describes the case of an unfortunate 18 year old who injured his hand with the RAS while doing angled mittered cuts free-hand instead of supporting the work agains the fence. We all know that is incorrect whether one were to pull or push the RAS.
...
In the instruction book linked, where the picture refered to above is shown, the fellow showing how to cross-cut is doing what many would consider unsafe. He is cross cutting a board only as wide as his hand (5"?) and is cross cutting it along the longer dimension which is maybe a foot long. That geometry of board would call for ripping, rather than cross-cutting. Not the best examples for an instruction book, would say.
In another photograph, the old instruction book also shows a method of ripping which is not the one I use. And why I do it differently is for safety reasons.
That manual for the old RAS does say "you should never push the blade into the material". It needs to be realized, however, that earlier RAS's did not have auto blade brakes which stop the blade in seconds after the switch is flipped to off. As it may be known, on some of those saws it may take up to 2 minutes, or even longer, before the blade completely stops spinning, and the larger the blade the longer they free-spin. If one wants to chop several segmets from a long board, it is not practical to cross cut by pushing because after the first cut, it is not safe to pull the spinning blade and relocate the workpiece to cross cut the next segment by pushing. To the newer RAS's, most of which have auto-brake for the blade, that issue would not apply, and tradition may be dropped.
Edited 4/20/2003 11:49:53 PM ET by mbl
Edited 4/20/2003 11:52:37 PM ET by mbl
Edited 4/20/2003 11:58:34 PM ET by mbl
Hi MBL,
The book's 50 years old, I'd stick with the modern practice, reflects 50+ years more experience. I think in one of the references, they referred to 'cross arming' as a no-no, which is what was described 50 years ago in the manual you refer to.
As the 'correct' instructions state, always pull the saw to cut. This has to do with keeping the board flat on the table and avoiding wrenching the wood out from under your hand, as happened to the 18 y.o. when he tried to cut away from the fence. The blade brake is a welcome safety feature.
Glad the info helped.
I stand to the right, hold with the right hand and pull with the left hand on the infrequent times I use a RAS now (on which, in each case, the motor has been to the right of the blade, I'd reverse this if the motor was on the left of the blade, on each occasion standing on the same side of the blade as the switch/handle). I don't put any part of my body in line with the blade on any saw.
cheers, eddie
Edited 4/21/2003 2:17:08 AM ET by eddie (aust)
Dear Eddie,
As you just said, you chose a method of holding the wood with the right hand while pulling with the left hand and hiding behind the motor, even if it may deviate from the instructions of manufacturer and from convention.
I personally find that method of pulling with the left hand a little cumbersome as I don't like to have the the motor above the hand. Also, it reduces visibility and in the event of a board jumping up, the motor above the hand would be undesireable. Would also say that, given a risk choice, most righ-handed persons might put the left hand in the riskier area.
As to the motor being on the left side of the blade for cross-cutting, I wouldn't do it on mine since the guard would be upside down and no way could I mount it elsewhere. There may be RAS built like that but don't know where.
Best wishes.
Edited 4/22/2003 1:59:33 PM ET by mbl
Hi mbl,
I asked around a few people I know that were classically trained as well, and it depends upon where in the world you were trained as to which hand holds the wood.
I was trained to keep the arm out of the way as you're pulling the blade toward you and if a sleeve snags on the saw casing, you're in trouble
Others were trained to stand where they could see the progress of the cut.
Both are valid options. As always, advice on any internet forum is free and comes without liability. Choose whichever one you feel safe with. Glad you saw what I was saying and hope I saved your hand from a horrible accident.
Probably the last word that needs to be said on this topic. Hope the thread slowly buries itself again.
Cheers, eddie
Dear friend,
Thank you for your reply and all the research you've done and offered. May all of that be of benefit and may no benefit be limitted to a single individual.
One is to realize, though, that no effort of any single individual is ever complete, definitive, or absolute.
On that light, am posting the following extract from a book published by TAUNTON PRESS, from the series The Best of Fine Woodworking, called POWER SAWS AND PLANERS, the chapter on Radial Arm Saws, page 39, USING A RADIAL ARM SAW:
===============
"Cutting with a radial: Once a radial saw is correctly adjusted and cutting smoothly, there are a few tricks I've learned that can help the job go more quickly and accurately. First, I prefer PUSHING the blade throut the cut rather than puling it -the more traditional method-. The advantages to push-cutting are that the blade ends up on the other side of the fence after the cut, farther from harms way. Also, pushing prevents the blade from 'self feeding' towards you (the tendency of a blade that's climb-cutting) and stalling in the cut or jerking the saw out of adjustment." The entire chapter (and book) are highly recommended.
===============
In that chapter, one can also see the unorthodox Inca 810, among other traditionsl RAS's surveyed. The Inca 810 was originally prototyped and built by the employees of Inca as a birthday present for the company president. That small, light saw could cross-cut to 27" inches (the largest of the ones surveyed by the author of that chapter) because it was a push-to-cut design. By push-to-cut, it also had the benefit of an unusual kerf-splitter that prevented blade binding in BOTH cross-cutting and ripping. The president of Inca liked it and made it commercially available, the article says.
Of course, If anyone wanted to use that Inca to cross-cut by pulling, he'd have to remove that kerf-splitter and put an auxiliary fence closer towards the operator.
However, for me and my RAS: the same end that cross-cuts is the same end that rips.
May all be well with everyone.
Ken,
First off, Don't ever push the carriage through the work on a RAS; the rotation of the blade can cause the work piece to lift off the table, very dangerous condition. When you pull the carriage through, the work piece will be held down and back towards the fence.
Climbing can be significantly reduced or eliminated entirely by using a negative hooked blade, as others have mentioned.
Personally, I don't consider the RAS to be any more "dangerous" than the TS; any tool can be dangerous when common sense is not used...FWIW.
Dano
Dano,
Pushing a radial arm saw thru the cut is no more dangerous than pulling it, as long as you start the cut with moderate feed pressure (don't jam it into the cut), and are not trying to cut something higher than it is wide, such as a 2 X 4 on edge. Why would it be more dangerous than using a portable circular saw? The saw travels the same direction, the blade turns the same direction, and and the teeth point the same direction. The fact that the circular saw has a base that rides over the wood is compensated for by your off hand (well out of the blade path, of course) holding the leading edge of the workpiece down on the saw table surface, with only moderate hand pressure needed. I was leary of this procedure also till I tried it a couple of years ago. I had a wide piece of 12/4 oak that I knew would cause my saw to over feed and possibly stall in the wood if cut by pulling the saw through. I clamped the wood to the table, turned the saw on and pushed it through. It gave a very smooth cut with predictable, constant resistance through the entire cut, sort of like using a super powerful Skil saw. I've been using it since when cutting thick wood, though I've done away with the clamps, just using my left hand to hold the workpiece as you would do on a normal cut.
As I said before, I wouldn't recommend using this procedure in production cutting because it's not effecient to shut the saw off between each cut and its is definitely not safe to be shifting the workpiece along the fence behind a saw that's running. But for the infrequent cutting of thick hardwood, I think it's much safer than pulling the saw through the cut and dealing with the overfeeding, in which the blade tries to aggressively climb thru or over the workpiece, while travelling toward the operator.
Your experience and opinion are always valued, Dano, but in this case I disagree with you. GP
GP,
No need to apologize for disagreeing, GP. But I will explain in detail.
Firstly, a hand held circular saw is a lot different than a radial arm; not only does one hold down the work piece but the saw itself is "held down" as well, as I beleive you alluded to. Ever experience a kick back with a hand held circular saw? Instead of the work piece coming back at you the whole saw "jumps" out of the wood and comes back.
Any who, because the blade on a radial arm rotates clockwise the teeth enter the work piece from the back top edge and the forces are vectored down and back towards the fence when pulled; the resulting kerf offers relief of any further resistance on the blade. As the blade moves through the board, the downward vector does not change but the vector to the back does ( depending on the width and thickness, it moves up towards the top of the fence).
When pushed, the blade again enters the workpiece at the front top edge but the thrust of the blade is vectored up and back which can cause the workpiece to lift. Since the resultant kerf is now in front of the blade, it offers no relief and the lifting condition will be prevelant through out the cut. I consider this to be a very dangerous condition.
While you may have been successful in pushing the carriage without injury, that in itself does not mean that it's a safe operation. What it means is that you have been lucky. I've attached a rough sketch of the thrust vectoring of an RAS blade....
Dano
"Form and Function are One" - Frank L. Wright
Edited 8/25/2002 8:52:03 AM ET by Danford C. Jennings
Push or pull a RAS? Which is the safer?
Try this experiment then post your opinion.
Lay a board of whatever reasonable widith (from minimum to maximum of the RAS if you desire) against the RAS stop/fence.
Without using your hand or a hold down on the board - now PULL THE RAS TOWARD YOUR SELF BEGINNING NEXT TO THE RAS POST AND CUT THE BOARD IN HALF.
Without using your hand or a hold down on the board - place the RAS on the side of the board closest to your body - now PUSH THE RAS TOWARD THE POST OF THE RAS and cut the board in half.
If you have continue to have doubts about which is the safest - pull or push - and since a factor influencing your opion will be the weight of the the board being cut - then take a board of equal width and thickness to the above test but only 2 to 6 inches long and repeat the cross cut tests above.
You be the judge as to push or pull being the safest.
Legacy39,
"Without using your hand or a hold down on the board - now PULL THE RAS TOWARD YOUR SELF BEGINNING NEXT TO THE RAS POST AND CUT THE BOARD IN HALF."
What in the world does that prove? You've set up a straw man, and think that because he falls down, it proves your point?
The saw is NEVER meant to be used without holding the work firmly in place.
Your gun analogy has nothing to do with this situation.
Yes, to each his own. That was my point. Thank you for making it.
Rich
you guys could totally get past the problem and any safety concerns by just using a tablesaw instead...
-that ought to stir up the natives ;)
(i suggest you not pull your stock thru it, though...)
I tend to side with the guy who throw his saw the farthest!
I tried to throw the RAS but there was a guy there that was supposed to help me throw it pushing the blade back through the wood the ignoramus cut his hand off & couldn't help throw the saw. Besides that the saw & floor in front of was all red & slick with blood.
Precisely the type of a response I expected from an individual who is not able to determine the difference between safe and unsafe practices. As to the gun scenario - merely an example again of safety.
The no nothings who don't know which end of a gun the bullet comes out and hence do not know how to safely use a gun create the accidents which kill people. Surely the connection with safety could not have been that difficult to perceive!
The no nothings in wood working don't know how a RAS was designed to be used hence they think nothing of unsafe practices.
And if you are so deficient that you do not know how to test for safety features then perhaps you should cease and desist from woodworking. Since you apparently are not going to run the test I will give you a clue. you are an accident waiting to happen.
A board no matter how wide Inch or less to whatever the maximum width of the RAS.
A RAS which is pulled without a holddown on the board will nearly every time cut the board cleanly without moving the board more than fractionally . There are exceptions of course and the shorter and narrower the board being cut, the more prone the board is to jump, but will almost invariably be driven down and into the backstop/fence - hence safety. A hold down merely insures added safety in an already marginally safe manuver
On the other hand - pushing the RAS into a board without a hold down will always attempt to raise the board due to the upward direction of the teeth, hold down or no hold down - and either twist and or throw it over the fence resulting in often times a kickback throw back or whatever. A hold down such as a hand does not insure safety, in fact given the right set of circumstances such as a loose or careless grip and too fast a push can even result in serious damage to the hand or in a worst case situation the complete loss of future hand functions.
Dig you own hole!
The suggestion of no hold down was for safety testing only. No sane person would cut a board without holding same down by hand or mechanical means. Surely you are sufficiently perceptive to grasp that simple fact. Also no sane person would push a RAS into a board as opposed to pulling the RAS through a board.
And for your personal edification I add this.
If someone injures themselves because they followed advice which provides unsafe procedures, whether that advise was posted on this forum, in person or writing as in a book, regarding the incorrect method of using a RAS or any power tool - the individual injured as the result of following unsafe advice can sue those who provided unsound and unsafe advice.
Forewarned is forearmed! Beware. You had best hope that I don't sit on a jury for the plaintiff that injures him/her self after following bad poor advice as to the proper method of using a RAS or any power tool. I will find for the Plaintiff.
I suppose the correspondents to this forum will now be subjected to a diatribe of vulgarity and "wisdom" from yourself?
Just for the sake of the argument I went out to our small RAS (16" Dewalt) and found a 3/4" x2" x 36" scrap of plywood and proceeded to do a few test cuts. Unfortunately our saw has a negative hook but I will do the same test with a positive hook next week. I didn't even hold the board which I normally do in all cases. With the negative hook blade the piece didn't move whether I pushed or pulled the saw carriage. It's funny how no one even mentioned the url I posted about using a compound miter saw and those are recommended to be pushed. As far as I see it no one has given any real proof that you can't push a RAS. I've been running and fixing machines for thirty years and cringe when I see someone doing something risky but pushing a RAS isn't one of them. With a positive hook blade I think it's even safer to push it. Try it before you knock it!
I don't want anything to do with this argum****discussion, but I'm curious of your miter saw analogy: because of the insert, for lack of a better word, in a miter saw, the bottom of the blade is not being used. It works more like a tablesaw with the blade raised max all the time. The center of the blade is always used. I've never seen instructionsdirections on using a sliding miter saw for cuts that aren't thru cuts. But the RAS and SMS always have the tool pressure on one side, the bottom in terms of gravity, of the blade. If my writing makes sense, does this make any difference?
Don
To push, to pull - suit yourself.
It is your folly if you encounter an accident. It is you that will do the bleeding and you who will feel the pain, not I. I have been there and have no desire or intention to revisit my past carelessness and foolishness - even with the care I always tried to excercise.
I bought my first RAS about 1962 - a Sears model. I used a RAS from about 1962 until about 1989. Twenty seven years more or less. During those years I must have encountered nearly every type of accident that can occur with a RAS. I used it for both cross cut and ripping.
Now when I say "I used a RAS" I mean by that - only brief and occasional use during those 27 more or less years. The saw was so dangerous, even in the hands of a very careful person - which I am - that I eventually restricted my use of the RAS to an occasional cross cut and primarily for mitre type cuts. I eventually became wise enough to make a sled and use it for cross cutting on a Unisaw and other bench saws I have owned.
Early on in the 27 years and shortly after purchasing the RAS, I bought a bench saw and later a mitre saw and more or less retired the RAS. In 1989 I sold it at an auction, informing the buyer that the RAS was the most dangerous power tool in the workshop, including a few suggestions as to the sort of safe use of a RAS, because it looks so deceptively easy to use.
Occasionally, and always without thinking first, I would push the saw into the wood. Always by accident never by intent. Unless the board was wide and held firmly down as in careful versus careless, I could usually count on an upward movement of the board when the saw pushed into the board. Of course there were successful cuts right along with the kick ups when I got careless and in a hurry.
When pushing the RAS, I also had the misfortune of the saw kicking back at me to the arms stop
Pushing the RAS into the board, I have witnessed kick ups, twists of the shorter wood pieces, excessively bruised hands from flying short boards, short pieces sailing across the room and you name it. Pulling the RAS into the wood, I don't ever recall encountering wood movement of a dangerous nature to myself.
On the other hand, pulling a RAS from the post into the wood is also an extremely dangerous manuver but not from flying wood. The danger in pulling a RAS is that if an exceptionally hard knot or foreign obstruction is encountered or a fast unthinking pull is made, the RAS can grab the wood and because the wood is prevented by the fence from moving, the RAS can ride up on top of the board and shoot itself backward to the arms end stop. Of course depth of cut has much to do with the ability of the RAS to force the Radial arm high enough to allow the saw to climb up and over the board. That manuver can result in a broken or sprined hand, wrist and even injury to the arm holding the saw handle. Worse if you are foolish enough to wear long sleeves or flapping clothes or perhaps you are one of those types who in a moment of carelessness had something sitting on the table in the way of the moving saw. It happens!
As to ripping, that is perhaps the most unsafe type of cut that a RAS can be used to make. I suspect that I bore some of the hot dogs who know all there is to know about how to "use a RAS" so I will confine my comments about ripping with a RAS to merely saying - don't do it - there will probably come a day when you regret it.
I don't know why but it seems that on the various forums that it is always the self proclaimed - "experienced woodworker with years of experience" who always shouts the loudest and is the first to put down the safe use of power tools.
It is your hand, finger, eyesight or hole in the body that is lost, not mine. So quite frankly I could not care less about your flamings and your putdowns of safe practices. Howl, whine, ridicule to your hearts desire, while you continue to tell us how wrong we, who offer safe suggestions, really are. It is you and not myself who may some day pay the piper with pain, blood and missing body parts because of your self assured conceit.
Read some of the absurd responses to safety practices which have been posted.
Leg...
You highlight what I consider to be one fine, long overdue feature of my new Craftsman RAS. It has a cable that is triggered and run by a separate motor controls the speed the saw can be pulled towards you. If you let go of the trigger the saw returns to the reststop position. You cannot pull the saw without using the trigger. The cable prevents the saw from moving along the arm without the cable operating. Hope you can follow that. It's not a cureall for potential dangers, but it's a big step.
Don
I do follow and recall, although not the year, that the feature about which you speak was introduced. At that time I seriously considered purchasing a Sears RAS with that feature. However, my previous experience with a RAS during the years I owned one prevented me from again buying one. Between the table saw, a sled I built myself and the mitre saw I feel that I have much safer equipment than a RAS, even one with the Sears feature.
I do give a lot of credit to the designers of that hold back/pull back feature for improving the safety of the RAS.
I should have mentioned in one of my previous posts that I have also witnessed the initial torque, when a RAS was turned on, actually driving the RAS with it's spinning blade into the arms end stop. Don't recall how I accidentally turned it on but I do recall that I wasn't holding the handle of the RAS.
I guess the - to push - to pull - is one of those things that will never be settled.
Wow, this turned into a real pissing contest. In my reply to GP (message 14) I not only explained the cutting dynamics but provided a sketch as well.
Using circular saws and sliding compound saws as analogies is preposterous; they are totally different in their cutting characteristics, i.e. the thrust vectors are completely different.
Like any machine, the radial arm saw has it's strengths and weaknesses and, like any machine, it's safe operation should be in accordance with understanding the "dynamics" of how it performs and the use of common sense.
Whether one chooses to take "good" advice or "bad" is their decision and their's alone; getting pissed because one's advice isn't taken serves no one. In the past I've been very vocal on issues of safety; it's a "pet peeve" but I've given up on this one. In over 40 years of working with wood I've seen some pretty severe accidents and one fatality; so push to your hearts content...the odds will catch up to you. FWIW.
Dano"Form and Function are One" - Frank L. Wright
Dano, I haven't read this whole thread but I take it that there must be some idiot who is a proponent of pushing a radial arm saw.
What a f****** moron he must be.
Now when I say "I used a RAS" I mean by that - only brief and occasional use during those 27 more or less years.
It was better that you did get rid of the RAS because you were scared of it. Someone that is scared of a tool should not be using it. A scared person is a nervous person & is setting themselves up for an accident.
Where as someone that is careful & operates a tool the way it was meant to be operated & with respect will most likely operate it for years without any problems or injuries.
You all can argue how to use a RAS until the cows come home & it won't change what is the right & proper way to operate the RAS.
Read your manual!!!
Remember the manufactures are more than likely liable for how they tell you to operate any tool.
Edited 4/19/2003 3:07:50 PM ET by Bart
Ken, you're blade is mounted correctly. I have heard that in Europe, the proper method is considered to be pushing but I think you'll find that on this side of the pond the proper method is considered to be pulling. The best way to find out for sure is to read your manual and follow the manufacturers recommendations. I've used a RAS for a year or so now and find it to be a valuable addition to my shop. I too did not like the way it seemed to climb at me. I found that I was able to adjust the slide detent and achieve a more comfortable climb rate.
There are also blades available now with 5 deg negative rakes that will help with the problem but that doesn't help much for dados and rabits which is where I think the RAS really shines.
In summary, read the manual and practice. Its a great tool.
I'd say you were incorrectly informed somewhere no one. As an European with European furniture making training I can say quite categorically that any one of my instructors would have done just a bit more than frown at me and go, "Tsk, tsk," if they'd seen me 'pushing' rather than 'pulling' as I'd been instructed to, and as they had demonstrated. Part of my instructions included a reasoned argument of why pulling was the preferred method. This thread has been, er, well---interesting from an onlookers point of view, a position to which I'll now return, ha, ha. Slainte, RJ.RJFurniture
Thank you. I've come to enjoy using it. Seems like I'm only using my tablesaw for ripping now.
I feel more comfortable pulling small stuff and pushing the bigger boards. Seems like it would be easier to back off when pushing.
I've used my Craftsman RAS for 30 years now but for the last 20 years, it has been relegated to the rough crosscutting of boards too heavy to handle on the TS. This due to accuracy and safety reasons mentioned by others.
I just went to the shop to envision pushing the blade through the board and what I envision is the teeth lifting the front edge of the workpiece up and back until it is standing on edge and somehow wedged firmly in some unknown position. I don't want to think about where my left hand would be at this point. As for experimentation, I couldn't even muster the courage to try it. When pulling, I envision the blade (teeth) pushing the workpiece down to the table and back against the fence, a much safer scenerio. Just seem like common sense to me.
Incidently, when crosscutting thick boards, say 8/4, I feel more comfortable raising the blade, taking half, then lowering the blade for a second pass. It's a lightweight saw and I don't expect too much from it.
Ian Cummins
I know how to use a Radial Arm Saw & that is the way I'll use it. If I were to use it as some on the forum suggest I would be the one to pay the hospital bill because the insurance would investigate & would refuse to pay the hospital cost.
Ignorance is nothing more than untaught innocence,
but stupidity is a choice.
There are non so blind as those who refuse to see.
If the shoe fits wear it.
Edited 4/14/2003 12:58:57 PM ET by Bart
Dear friend,
for cross cutting in light pases, we can remind ourselves of when we use a hand-saw to cut a board, or a hack-saw to cut a piece of metal.
With metal, the effects are more notorious. To cross cut a piece of wide metal, it is by far less strenuous to cut from the edge. The same holds for cross cutting wood by hand: by the edge at a slight angle. Of course narrow pieces like tenons are not the case.
Cross cutting a well supported, thick wide board in a single pass, by pushing at a controlled rate is probably faster and more accurate than making several pull passes on the top surface, since it avoids having to unclamp the arm, lower the blade, and re-clamp the arm for every pass.
Would say that the more passes and the more adjustments needed to make a single cut, the more risk, too.
Edited 4/19/2003 12:58:41 PM ET by mbl
Edited 4/19/2003 1:00:52 PM ET by mbl
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