There has been several discussions on band saws so I’ll chime right in with something I have been experiencing with my 14″ Jet:
I have been reswaing with a carbide tipped 3 tpi blade on 6″ stock. As i begin the feed, the wood smokes. There are no burn marks on the wood so I continue. After a few inches, it either rattles or screams, then it acts as if it were to bog down but continues. I pull back and restart and the rattling goes away – for a little while. I think I am pushing in a straight line, not bending the blade. What is the problem? Is my technique what is causing it? or blade tensioning? or dull blade? I would apprecieate any insights on this. Thanks.
Replies
TMARCELLO,
I would suspect need for blade lubrication, increasing tension, wheel alignment, adjustment of blade guides (which about covers the mechanics of a bandsaw).
Rich
Jeff, Rich:
I have the Tube Lube I use to wax the blade before each cut. The wheels are aligned, the guides are within tolerance. I supposed that leaves the tension in question. I have been using the gauge on the saw as a guide. I have heard is not always reliable - how much over the 3/4" mark can I go safely? I can't tell the difference when the right tension is set when I try the "twang" method - I have nothing to judge it against. Flexing a blade to check the tension doesn't sound like a very consistent method. I should probably invest in one of those Ittura tension gauges until I get familiar with the amount of tension required per blade thickness. Thanks guys.
I hate to use too much tension and have that 3/4" blade snap on me. It happened once and it startled the crap out of me.
edit: No, the tires are not worn, maybe they need a little cleaning of the wax from the lubrication but that is about it. The screams and rattles come from the wood being cut.
Edited 10/26/2002 12:57:02 PM ET by TMARCELLO
T,
I don't think you can possibly break the blade with the tension spring on the saw. The gauge on a bandsaw is notoriously poor in showing the real tension on the band. I would slowly increase the tension until the blade either performs well or you run out of adjustment.
If increasing the tension to maximum does not help that leaves two possibilities: Either increased tension is not the answer, or you aren't able to apply sufficient tension with your current spring and you need a new spring.
I think that your problem most likely is insufficient tension.
Rich
Rich,
Sounds like the tension to me. Is there any chance the tires are worn out and the carbide blade is catching the wheel as it pulls back during the cut?
Jeff
Have you checked to make sure all the carbide teeth were in alignment?
I had a similar problem and it turned out a few teeth were out of alignment which caused the vibration and a loud noise. I never experienced any smoke.
"Have you checked to make sure all the carbide teeth were in alignment?"
Dog,
How do I do that? Do I need to have full tension on the blade before I check it? If the Jet can't achieve that much tension with the supplied spring as mentioned earlier, it may be a little difficult. The blade does not waver when it is running, so warpage is not an issue. How did you correct your problem?
Marcello
Mr. T
I could'nt see anywhere in these posts if you had installed a new blade or not, or if the type of blade you are using has ever given you trouble in the past.What about your cooling blocks. ARE THEY OK.AND SET RIGHT.
"I could'nt see anywhere in these posts if you had installed a new blade or not, or if the type of blade you are using has ever given you trouble in the past.What about your cooling blocks. ARE THEY OK.AND SET RIGHT."
No, it is not a new blade, although I did changed blades from a 3/8" to the 3/4". I have used the 3/4" blade before without any trouble. The cooling blocks are about a paper thickness away from the body of the blade - no trouble there. As I mentioned to Rich R., it may be the spring that has lost some of its resiliency causing low tension at the 3/4" setting.
Be careful about tightening the tension spring beyond what the scale reads for the 3/4" blade. Don't compress the spring completely or there will be no shock resistance and you'll put excess strain on the saw frame and wheel bearings. The stock spring on my Delta is about shot, too, and I need to get one of those after market ones.
Dennis in Bellevue WA
[email protected]
"Be careful about tightening the tension spring beyond what the scale reads..."
It is only 2 or 3 turns past the mark, not too bad. I will not compress the spring all the way, it won't spring back to its original shape if that is done. I get nervous every time I think about weather the blade has the appropriate tension - over tension is bad, under tension is bad. What is the right amount? -- I need to get that tension gage and relax a bit.
Iturra Designs sells both the tension springs and the tension gauge.
He wants $135 for the gauge he makes. He also sells Starret and Lennox ones for a couple hundred bucks more. Order one of his catalogs. It's a good read even if you don't buy anything. The guy knows his bandsaws. He makes some good points regarding those supposedly 'low tension' blades on the market.
Getting his catalog and buying one of his gauges was a real eye opener for me.The proof is in the puddin'
I do have a couple of their catalogs laying around. Great source of supplies. I will be calling them in the next couple of days to order something. I am not sure what yet. Their catalog is like a candy store for me: I want that...and that...and that....and....
He makes some good points regarding those supposedly 'low tension' blades on the market.
I don't have their catalog & don't know him. But how many blades has he designed & how many patents does he own on blades. Does he supply blades to the lumber & furniture industry?
This sounds primitive but it worked for me.
I put full tension on the blade then I set the rip fence 1/2" from the blade. I then take an adjustable Combination Square (CS), placing it on the rip fence, setting the length of the rule so the teeth just pass by.
I am turning the upper wheel on the BS in segments at a time, just like twisting off the lid to a jar apple sauce. So by twisting the wheel back and forth in this manner roughly 6" to 8" inches of BS blade is passing by the CS. Once the CS is set I continue the twisting action until I have turned the wheel 360 degrees.
In my case, I found four teeth which needed to be adjusted.
MSD
Now don't take this wrong but did you just install the blade before you started this round of resawing? If so, check to make sure that the blade is on the saw with the teeth pointed down. I am just asking because I have a coworker who put one on backwards and the exact same thing you described happened Joe
Joe,
It is physically impossible to put a bandsaw blade on a bandsaw with the teeth pointed any way BUT down. Unless the blade is put on so that the teeth point away from the operator. In which case no cutting action would take place at all.
R
Would that be true if the blade were twisted inside out which is easy to do with a bandsaw blade.
There is no way a 14" jet will tension a 3/4" blade.
My 14" Delta has trouble tensioning a 1/4" blade with the stock spring.
You'll be very lucky to be able to use a .025 1/2" blade on that saw.
Buy a 4 tpi 3/8" blade. It'll work fine. Buy a new spring from Iturra Designs.
Better get the $150 tension release accessory too, because your saw won't be able to take the stress.The proof is in the puddin'
There is no way a 14" jet will tension a 3/4" blade.
Well then I sure am glad I purchased a Grizzly G1029 because a 3/4" blade is the only size I have & I cut 6" 8" 10" & 12" soft & hardwood all the time with absolutely no problem.
Maybe you need a better saw or maybe you need to send it to me because unless there is really something wrong with it I can get it to work with no problem.
Or you could talk to Suffolk Machinery & purchase a Timberwolf low tension blade.
Easy to do?
Rich,
Depends on how you store your blades. If you twist them so they fold up into the 3 loops, when undoing them, the will often turn inside out.
Don
I've been twisting blades into loops for storage for as long as I can remember. I've never had a blade turn inside out.
For those of you who have, is it "stable " in that state or does it want to pop back? I just went out to the shop to TRY and turn some blades. Can't do it.
R
It is perfecty stable . It all depends on how you unfold the blade. I don't think it will happen with smaller blades as with 3/4" + blades. This is why I brought it up . Unfolding larger blades is sometimes like playing with a rattlesnake. I wouldn't want to get bit, would you? Joe
Actually it is possible and I have seen it.If you turn the blade inside out it will be backwards Sorry Joe
Rich -
I certainly don't mean to dissagree with you since you've been so helpful to me on many occasions but - you *can* turn a bandsaw blade 'inside out' and put it on backwards if you're not paying attention. The reason I know is I've been practicing coiling blades (one of those zen things I thought I should master) and found that it could be turned so the teeth pointed down when held with the teeth facing me.
Should I submit this to Riply's believe it or not? (grin)
Dennis in Bellevue WA
[email protected]
Dennis,
Gees, don't apologize for disagreeing. This is totally new for me. I have never seen it happen. I've tried to make some of my blades turn inside out - 1/4, 1/2, 3/4. Nope. We're having no inside out here. fascinating.
R
I increased the tension on it tonight and the cuts were perfect. The screaming subsided. Thanks to all.
I tried to twist a blade inside out and ended up with a warped blade. I think I'll just store them unfolded and not worry about putting the teeth in backwards.
TMARCELLO,
Was the problem low tension, or a frozen thrust bearing? Or both?
R
"Was the problem low tension, or a frozen thrust bearing? Or both?"
Seems like it was low tension. I backed up the lower thrust bearing because it was gauged and was not rotating. Slowly increased the tension untill the rattling subsided. I may need to purchase the tension gage and a more resilient spring.
Ok Rich: I just walked out into my shop and picked up the first blade I came to (1/4") and shook it out. It came out the way it was supposed to, which I expected. Then just for giggles I grabbed the blade in the center and rolled it inside out and (Drum roll please) teeth pointed up. I did not hurt the blade in any way and I even returned it to it's original state and coiled it back up again.I don't know, maybe you just have to experience it once to figure it out.
ps. Coil your blades up. It make them a lot easier to store. Joe
Joe,
As I said before, I DO coil my blades. I always have. I just don't get the inside out thingy going here. It must be a property of one type of blade vs another. My current blades don't do it. I guess I'll just have to keep on trying with each new blade I get. I really must be missing out on something.
NOT!
R
Heck you must not be bassackwords enough Rich. I'll bet you can't turn 1 arm in one direction while turning the other erm the other way right in front of yourself either.
Hmm wonder if he can walk & chew gun either, well you never know. Chuckle !!!
Rich -
The way I was shown to coil a blade was to hold it, teeth facing away from with both hands holding the blade a little above the centerpoint of what would be the circle formed by the blade. Bringing the hands together in front of you and pushing in, twisting the blade while 'folding' it, so to speak away from the body. The bring your hands together twisting the right hand counterclockwise and the left hand clockwise until you get a coil going.
In practicing this contortionist move I kept forgeting which way to make the initial twist; I was pushing the back of the blade to the outside instead of the inside. The blade would flop over, I'd try to bring my hands together to make the coil and whamo - I'd come close to getting a face full of bandsaw teeth and the blade would be "inside out".
You've probably coiled so many blades in your experience that it's harder to do it wrong than right. In fact, I should have gone out and re-coiled a blade just to make sure I got the directions straight this time.
I *don't* think you'll be a lesser person for not being able to turn a bandsaw blade inside out, though. (grin)
Dennis in Bellevue WA
[email protected]
Dennis,
I'm losing so much sleep over this! Every night, I'm out in the shop trying to turn those blades inside out. Will they cooperate? Noooooo!
R
You can always cut it and then re-weld it.
I always knew that band welding kit would come in handy.
R
I don't take it wrong, I would like to look at all the options. The teeth are pointed down.
You can lubricate your blade with "Pam" (spray-on vegetable shortening), I use that and I have good results on my bandsaw, you can have information on the website: http://www.suffolkmachinery.com/sixrules.html , there is lubricate information.
Good luck and happy woodworking!
If you have a bad thrust bearing, it can produce significant noise. If it is very bad, it will get hot, a possible source of the burning.
For what it's worth: I've been using a bandsaw to make all kinds of cuts for quite a while and I've never had to resort to lubrication. Personally, I'd be rather worried about the Pam, wax, or whatever contaminating my wood. Also, it certainly is possible to turn a bandsaw blade inside out and then install it with the teeth pointed up. Yea, it's a silly mistake.
"If you have a bad thrust bearing, it can produce significant noise. If it is very bad, it will get hot, a possible source of the burning."
Well, I just checked the bearings, the bottom was as stiff as a crow bar. I lubricated it and got it to spin somewhat freely again, but soon it stuck again. I reversed it with no luck. I'll have to replace it on Monday.
One thing that is often recommended after installing a new blade is to ease the back edge of the blade--the non-cutting surface.....I have always assumed that this is to remove any burrs that might hinder smooth passage of the stock past the blade; and a burr certainly can cause a screaming sound............I do this by lightly running a whetstone against the back corners of a running blade, keeping the whetstone down against the table while doing so. ( to keep it from 'slamming' down which might crack it and will surprise you in any case.)
Also I didn't see any other postings highlighting dealing with 'blade lead'-how the blade wants to lead or influence the line of the cut. This is unique to every set-up, owing to many factors, but you said you thought you were cutting in a straight line, and not twisting the blade:
You can be more sure that you are not , if you take these steps that have been taught in several books: take a piece of wood, something such as a piece of 3/4" scrap plywood, maybe 4" wide, 20" long--not critical but it MUST have a straight, true left edge. Mark a pencil line parallel to this straight left edge, full length of the board. Now start saw, cutting carefully along this pencil line for some 2/3rds the length of the board.......WITHOUT changing position of the board, stop cutting, and turn off saw. Next take a pencil or better a magic marker and mark the table surface along the left edge of the board. This is the general angle that you should use to feed stock into the blade. You can take a bevel and copy the marked angle, and then use that to set up your fence for a great match to the blade lead of your current blade. You may be surprised at how 'not square' the angle tourns out to be...but it doesn't matter, it's just relative to your blade, the prime dictator of straightness. You will need to check this for every blade change.
MAYBE you knew all of that, if not , hope it helps!
Lil' acorn
"...is to ease the back edge of the blade" --- Yes that is done.
'blade lead' -- I am aware of it. When I wrote it was running straight, I meant the back of the blade was not touching the wood sides from the top of the cut, as I could see.
Thanks for the input.
Another tidbit regarding the upside down teeth thing...Consider the INCA bandsaw (got one) ..... it has the blade to the left of the support, so backwards to it is really correct.
Thanks to all who posted and helped me with this issue. As a follow up, I ordered and received in the mail from Iturra Design a pair of sealed thrust bearings and a spankin', brand new, yellow, high tension spring. I installed them this last weekend, put in the 3/4" resaw blade, and went to town. I resawed, resawed, and resawed. No more screaming from the blade. Low tension induced harmonics from the blade hence the screaming.
I had saw dust everywhere. Need to invest on a dust collection system but that is a different topic. Thanks again.
Marcello
You talked to the right people.
I bet you're happier with your saw now!The proof is in the puddin'
Marcello,
Ain't a well-tensioned bandsaw a great thing to operate!
BUT!!!
No dust collection!! Holy Cow. I can put up with dust from the table saw, chips from the joiner. But band saw dust, ESPECILLY from resawing. That is the WORST! It's like fine powder and it goes everywhere. Before my dust collection, I got to the point where I just avoided using the bandsaw. I don't know how shops put up with it before dust collection became so common. (It's hard to remember pain)
If you think that the tension spring made the saw enjoyable to use, wait 'till you get a proper dust collection system. It makes a world of difference.
R
Yes, I can imagine. I have dust collection budgeted for the first quarter of next year. If I get a decent commission, I'll move it up. In the mean time I have my Darth Vader dust mask I am very fond of. After resawing I feel the need to take my skiis out and try out the new powder.
This forum post is now archived. Commenting has been disabled