A few months back I posted a question about my old Sears Craftsman 10 inch radial arm saw. The overload switch went bad and I thought the saw had finally died, but after advice from this forum I replaced the switch and resurrected it. It now works as it did before, which is to say that when crosscutting an 8/4 board or possibly even a 6/4 board of something hard like oak, the blade gets stuck and it stalls out. I have been using a Freud 60 tooth finecut crosscutting blade. I have to advance the saw very very slowly, almost scraping away at the wood to complete a cut in anything over 4/4. Is there any way to enhance the power of the saw?
The unit is probably 20 years old. I own it for 14 years (second owner). I use it mostly to cut boards to approximate size from boards that are too long for the table saw. I then do the final cut on my table saw with a crosscut sled. Should retire it and I just get a miter saw instead? Replace the saw with a new one? If I can make it work better without spending an arm and a leg, that would be best.
Thanks.
Jay
Replies
If it were me I'd retire it and buy a new SCM saw, they're really nice. I have a 10" makita but I've heard the hitachis are better. I have trouble with my fence once every month or so. If you do come across a 12" or 14" used comet for about $500.oo, let me know.BTW, SCM=sliding compound mitre.
What kind of "trouble" do you have with your fence? Anyone else have recommendations re a sliding compound miter saw?
Jay
Jay, I just scanned the thread and saw that comment about the fence and wondered what he was talking about. I have a DeWalt 12" SCMS. I have a Forrest Chopmaster blade and it is wonderful. I bought clamp and crown guide when I bought it new. I can cut almost perfect crowns and the clamp is great for settion short stops.
The only problem I have is that the left side is perfectly 90 degrees with the blade while the right side is slightly off 90. As you know the base is cast aluminum and there is no adjustment I can make to remedy that. I work mostly from the left side and the problem with the right side is not enough to consider a new saw. I noticed it early when cutting a dead flat piece which covered all the base. I notice at the end of the cut that the piece would "break" back slightly. I checked it out and discovered the problem. I have had that saw for 7 years now and have gotten along fine by just working around the problem. When I need a 4' piece, I usually cut it about 1/4 long so I can be sure to square both ends using the left side.
I do have to adjust my saw on occasion, because the base and blade will get off square or vertical. That happens infrequently and I always notice it very soon because I usually check the cut for square since things can sometimes get between the workpiece and the fence causing it to be off square.
Would I buy another DeWalt?? Probably not.
Edited 12/24/2006 10:39 pm ET by coolbreeze
Why can't you add a face to the fence and shim the right side so its angle is the same as the left side? If you use one piece that's long enough for both sides, attach and shim it before cutting at the center. Start at the widest angle from one side, cut the 0ยบ angle and remove the piece (watch out for it to fly out) and then cut the other side's widest angle (that you will ever cut). The last piece may go out the back side so watch out for it and wear safety glasses. You can also make the left (or right) cut and just cut the rest out in small slivers.As long as the piece is shimmed properly, you should have the same angle on both sides of the blade and the face doesn't need to be very thick but it needs to be strong enough.
"I cut this piece four times and it's still too short."
No i dont know that your saw can be rewired. I had one that could and it clearly stated that in the manual. I have worked with my Brothers (he picked it up in a yard sale) and it is a little smaller and can not be. Both are 10" Sears Craftsman saws. So go figure.
I dont know the model that we had but i would recognize it when i see it. That being said the one I had was made (I think) by the company that went on to sell Ridgid tools at HD and for a while they had a version that looked very close to what we had.
Doug Meyer
Emerson Tool Co. (ETC) made those saws.
I really dont remember who made them even though thier was an artical about 5 or so years back that they released an upgrade to the blade gaurd and they sent it to everyone that asked for it. It even included a new top for the saw (wood parts and metal attachments)
I do know that when Ridgid first started at HD they had one that look almost identical. Nice say (the old Sears) but it had all the limits of a RAS still I loved if for cross cutting.
Doug Meyer
Yeah, I got that same free retro kit for my Sears and it was great. It was from Emerson.That free kit is still available for anyone who needs it: http://www.radialarmsawrecall.com/
Ok, I will take your word for it. That being said did they have anything to do with the first generation Ridgid? Also do they still sell/make this saw for anyone else?
Doug Meyer
Yes, you're on the right track. I seem to recall the Ridgid looking exactly like my Craftsman except for the different paint. I remember some years ago finding a MFR plate on the Ridgid and it did say something about Emerson Tool Co.
Ahh, that explanes much (well not really but it explanes why it looked like the old craftsman)
Doug Meyer
Jay,
I had the 9" predecessor to that saw. It may have been the same motor. I used Craftsman HSS hollow ground Planer blades. I cut a lot of 8/4 ash on it, some 8/4 oak. I could never take a full cut. I used to take about a 3/4" cut at a time, lowering the crank after each pass.
It worked well. The cut line was perfectly straight. It just took a little longer than if the saw could have powered the blade through in one pass.
As I remember the bearings were just slip variety. Yours are probably worn which robs the saw of power. I would think the 60 tooth blade is more than the saw can handle. Also, carbide teeth, while they last much longer than HSS are not as sharp as a new HSS blade. That's also a problem for that little motor.
A smaller blade should help. You might find that a 9" HSS blade works better than the one you're using.
Rich
Edited 12/22/2006 2:52 pm ET by Rich14
Well the 10 Inch Craftsman that my dad had could be rewired to run on 220 vs the 110 it came with and that was a HUGE impovement. That saw was bought in about 1977 or 78. This was a big help to it.
Doug Meyer
Rewiring a saw that can run on either 120 or 240 does not result in more power at the 240 configuration unless there is a significant current limitation in the 120 line which causes a voltage drop at the saw.
Rich
You know i have heard that for a long time but that being said i have personally used the saw both ways and the difference was noticable. I dont know if this is due to the fact that most house in the US have an issue or what but thier you have it, we rewired it and it was like haveing a differnet saw. It spun up a lot faster and it never slowed down durring a cut again.
Doug Meyer
Doug,
By all means, then run the saw in its 240V configuration. If you're ever curious, though, wire it up for 120. Then check the voltage at the 120 outlet before running the saw, and while it's running.
According to the behavior you describe, there should be a voltage drop from 120 (or whatever the nominal, no-load voltage is) with the saw running.
If there is no drop, and the saw has less power at 120, there is simply something wrong with the motor wiring in the 120 configuration.
The point is, there is no advantage to running a motor at 240 vs 120, if the power lines supply adequate current at both voltages. A motor that can be configured for either voltage has 2 windings and it doesn't care if you configure then in parallel and apply 120V or configure them in serial and apply 240V.
Rich
There is very likely to be a noticeable difference at high loads between running a saw on a 110 volt, 20 amp circut an a 220 volt, 20 amp circut. The wire size is probably the same but with half the current draw on 220 volt the voltage drop in the house wiring will be half.
Ohm's law applies to losses in house wiring. It's not a simple matter of whether the wire can supply sufficient current or not.
David,We are saying exactly the same thing. If the 120 wiring can't supply the needed current at the highest load the motor has to handle then the saw will not perform as well in its 120V configuration as it will in 240V configuration - IF THE SAME KIND OF WIRING IS USED FOR BOTH. But that's an anomaly of poorly-wired houses.The oft-repeated "wisdom" that running a motor, that has dual voltage capability, at 240V vs 120V results in higher power (or torque) simply as a consequence of using 240 is simply wrong.If your point is that most houses do NOT have adequate wiring to supply saw motors in their 120V configuration, I might agree with you that the consequence of changing the motor taps and plugging the thing into a 240 outlet ALWAYS results in better performance.My house is 2 years old and has quite adequate wiring as have most houses of recent construction due to better building codes in most residential areas. But it's probably true that any equipment motor that is pushing anything close to an advertised power of 1.5 hp is straining 120 V circuits if the motor is not very efficient.Rich
I agree that whether the motor is wired for 110 volt or 220 volt it will perform the same everything else being equal. The current will be cut in half with the higher voltate. But there is a real world consideration which keeps everything else from being equal when that motor is used in a building with residential wiring.
Most 120 volt outlets in houses have wiring based on what's required by code for 20 amps or in older houses 15 amps. If a 220 volt outlet is installed then it will generally be on a 20 amp or higher circut. (I've never seen a 200 volt, 10 amp circut in the US.) The required wire size is based on the current, not the voltage. So both 110 volt and 220 volt 20 amp circuts will have the same size wire. By switching the motor from 110 volt to 220 volt the losses in the circut supplying the motor will almost always be less. That's why a table saw or other stationary tool will frequently run better configured for 220 volt.
The size of the wire does not determine how much current is available. Rather it determines the resistance. If the current is halved the voltage drop is also halved and the power loss is one quarter. The So by switching from 110 volt to 220 volt with the same size and length wire in the circut supplying the motor the power losses in the supply circut will be one quarter.
Thanks for the advice. Casn anyone tell me how I would go about re-wiring the motor for 220V. Do you know with certainty that it is possible to do this on a Sears Craftsman saw? If you cannot descibe the exact steps, can anyone suggest a source?
Thanks.
Jay
If it can be rewired for 220v. Most motors have a label on the inside of the motor connections cover to show the new connection.
Two things with these saws. Check the size of the wiring feeding the socket you are plugged into. Many sockets were/are wired with #14 and this will cause volt drop.
The tooth angle on the blade will affect the way the blade cuts. Negative hook angle will tend to push the blade away from the cut and prevent the blade from climbing the work piece, when climbing your not cutting.
Thanks. My 60 tooth Freud finecutting blade definitely climbs into the cut which is what jams the tooth/teeth into the workpiece, stalling the motor. I will try a negative angle blade. I recently had the cover off to replace the overload switch and did not see any re-wiring diagram.
Jay
Thanks. By the way I did not see any re-wiring diagram inside the motor when I had the cover off. Any way to tell if it can be reiwired?
Jay
One of the guys I work with said he got a radial arm saw for free but it didn't work and I could have it if I wanted. It was an old Rockwell Beaver 9" that's 30 or 40 years old. When I got it home I plugged it in an hit the switch just to see what it would do. It screamed to life and worked fine. The garage it was in was very old with corresponding wiring, and the wires on the saw were original too. There was too much resistance with that combination to run the saw. I told the guy when I went to work and he said to keep it anyway. New wire and plug and the saw is good.Before you try anything drastic make sure the shop wiring and the saw's cord and switch are good first as others have suggested. Try a different cord bypassing the switch, on a different circuit and see if that makes an improvement.
I read somewhere,not sure where, that some manufacturers have shipped motors that actually do produce more horsepower when wired for 240V. It was something to do with the winding configuration. They know that many homes and small shops have wiring for 120V, rated for 15-Amps. But, those shops for 240V, were wired for at least 15-Amps. So the motors would draw 15 Amps at 120V, and 10 amps at 240V.
As to whether Jay's motor can be wired for 220-V, the name plate on the motor should tell the amp draw at both voltages if it can be wired for 220-V.
The manual should also have the wiring diagram if it can be wired for 220-V. If you don't have the manual, they are usually available from the Sears Parts website.
My thoughts on the low power: If you have an induction motor with a centrifugal start switch, it might not be cutting out, and thus lowering the horsepower of the motor. If it is a dual capacitor motor, the run capacitor could be breaking down. Since the motor protection thermal breaker was bad, you may have degraded insulation in the windings.
If it is a universal motor, look at the brushes.
The bearings could be bad with either type.
I never thought about it but my new dust collect worked only the first time I tried it and every time after that it would start to spead up and befor it ever hit even half spead it would pop the breaker. This was on a brand new house with a 20amp breaker with nothing else on the line (dedicated to the dust collector) and only a run of about 25' From panel to outlet and directly plugged in. I could run anything else i tried on that circuit with no issues. Took the collecter back the local company I bought it from looked at it, ordered some new part and installed it and everything was great. It was something to due with the slow start system. It would not let it go into the full speed mode (how ever that works, i am not an electrition)
Not that I think this is to likly on an old Sear RAS as the ones I have used (a couple of them over the years) just go from off to full on. Still one never know. My brother Sears has an issue that sometimes it will not start. If you turn it off and move the blade about a half inch and turn it back on it works fine. I think it has something going wrong in the motor. IF he used it more then once a year and for something other then cutting a board for the garden I would worry about it but he does not. So strange things do happen sometime.
Doug Meyer
Had a radial arm saw lose power on a remodeling job several years ago. We traced it to an extension cord that was too long. Here is another story. I sharpened saw blades for a guy once who brought them back and told me that they would not cut. After questioning him , we decided that his helper had needed a longer cord so he picked up an available lamp cord and plugged it into the circuit. When he went home and got rid of the lamp cord, his saw cut fine.
Good thought but I'm, not using an extension cord. The original cord on the saw (which I am using) is only about 4 feet long. I may try a blade with fewer teeth (although most blades labelled as croisscutting are at least 50 teeth) and I will also try a 9 inch diameter blade. Still, it is a 10 inch saw and it should work properly. Could there be anything else wrong with it where some maintenance item would restore what I would consider to be normal power? Thanks.
Jay
The 9" blade will make it stall even faster because the cutting tip speed will be much slower than that of a 10". The bigger the blade diameter, the faster the teeth hit the wood.RPM x Diameter x (Pi/12) = SFMIt sounds like you simply have an old motor.
Mumda,A smaller blade will REDUCE the possibility of stall. You are right that the circumference of the smaller blade will be traveling a bit slower than the larger. But that's inconsequencial. The angular velocity is the same, even a bit higher because the motor can move the snaller mass of the smaller blade faster.The most important factor is that the smaller blade has a shorter lever arm with which to act on the motor as the teeth engage the wood.To get more cutting ability out of an underpowered saw, use a smaller blade or a thin-kerf blade, or both.Charles from Freud blades was kind enough to post on this subject a few years ago here.Rich
From the physics standpoint you are exactly right. It's the lever arm that is the key. For those non scientific types, take it to the extreme, and imagine if the blade were 12 feet in diameter. You could hold a tooth with your fingers and prevent it from rotating. Same idea why a 3 inch diameter Forstner bit requires more power than a 1/8 inch twist bit.
But do I need a whole new motor? If I am going to have to spend money, what about another radial saw vs a miter saw?
Jay
Go for a sliding miter saw. I did and have been happy about it.
Actually, a 10" will stall faster because the friction is acting on a longer moment arm. The same principal as putting a long pipe on a wrench to add torque is in effect when a larger diameter blade is used.Sorry, I hadn't seen the other post about the same thing I wrote about. "I cut this piece four times and it's still too short."
Edited 12/24/2006 10:03 pm by highfigh
Has anyone suggested that the brushes in the motor may be worn out? It sounds like that could be a possibility.
Alan, Merry Christmas to all.Alan
Started Learning, Still Learning, and will never know enough!
"worn out brushes" Yes, post #21.
Jay: Check the plug and receptacle for excess warmth after giving the saw a good workout. They could be the weak link in the electrical supply to your saw. Loose fit of the blades in the slots or loose wiring inside either could do it. I'm seeing some excellent electrical advice from others, not always the case on electrical questions I've seen here at Knots. It pays to install industrial spec or Federal spec receptacles in the shop. They will grab the plug better and last longer with repeated insertions.
Duke, 30 year retired electrician, novice woodworker.
"... Buy the best and only cry once.........
Edited 12/25/2006 10:31 am by dukeone
You could take it to a motor rebuilder and have them look at it. They'll need the cord, switch, motor and anything else that is electrical. They won't need the mechanism, though.
Have you thought of checking the plug, all connections and the cord? What about the outlet it's plugged into? They will all have a cumulative effect on how well it works. It could be as simple as the brushes on the motor. If you don't remember changing them, they probably never have been.
I think the motor may just need a good cleaning and maybe brushes. If the blade has bound too many times, it may have some problems caused by the heat. If the motor goes away completely, you'll know it. There's either no response or in the cases I have personally, seen, a lot of white smoke.
"I cut this piece four times and it's still too short."
Edited 12/24/2006 10:05 pm by highfigh
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