Band Saw Blade Coming Off Pulley

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Steffin T
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Re: Band Saw Blade Coming Off Pulley

Post by Steffin T » Sun Sep 04, 2011 9:20 pm

I had a similar experience when cutting a 4" round piece of 6061 Aluminum with the cheapy HF saw. My first attempt was cutting it dry - didnt work out too well. Once I tightened up the blade, set the "back-tension" on the arm so it rested on the round - then just used a squirt bottle with WD-40, it cut like a champ. Now whenever cutting AL, I have a squirt bottle handy and give a few squirts on the blade as it contacts the stock - no problems.

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steamin10
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Re: Band Saw Blade Coming Off Pulley

Post by steamin10 » Sun Sep 04, 2011 11:36 pm

Two things about these small Chinee based saws. They need a little tension spring for the wheel setting, and if the blade sticks, it is off in a second.

Often a wood blade of 5-6 teeth per inch will put your 14 tooth inna dirt for speed. A little motor oil, or water coolant helps keep the chips from sticking, which is the real base of the problem. ( I cut heavy bar and plate on my table saw, with close spaced carbide tips. I used the one that came on my chop miter saw, when it got dull. I just made a stop on the grinder for a swing arm and ground every other tooth, flip, and do the other way. Just stay out of line with the blade when sawing, the chips come very hot.)

The other thing is the tension varies too much after just a little cutting, the blade heats up and expands, effectively loosening the tension. Punch out some rubber washers and put them on the tension adjustment, to help steady the preload, and take shock out of the blade loading. Belleville washers of a small size may not be sensative enough.

My opinion.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
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spro
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Re: Band Saw Blade Coming Off Pulley

Post by spro » Sun Sep 04, 2011 11:52 pm

Lot's of variables and good suggestions. Of course the gas can doesn't stay there. If that is the piece of stock it should be turned on its side. That would reduce the downward pressure required, then the blade wouldn't flex as much to ride under the crown. The noticible click or thump is about the weld. It can be a little too thick but often there is an interrupted gullet. It is almost impossible to manually elect-weld a blade and have the spacing excact(for me). So there is a fat tooth or huge gullet there which sets a rythm. A little dressing with a Dremel type can relieve that.

stevec
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Re: Band Saw Blade Coming Off Pulley

Post by stevec » Mon Sep 05, 2011 8:04 am

spro, ole bud, which side? it's 3x3 stock, lol. I'm with ya on the weld gullet though.
phil, I believe some kinda lube or cutting oil is really the answer, even for the "too fine" blade, (if it's a 1 or 2 off sorta job).
Keep it cool and lubed and maybe put a little brush against the blade at the exit of the cut and you should be good.
Last edited by stevec on Mon Sep 05, 2011 1:16 pm, edited 1 time in total.

thekrutch
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Re: Band Saw Blade Coming Off Pulley

Post by thekrutch » Mon Sep 05, 2011 1:01 pm

A friend of mine had the 'blade jump off' problem which I corrected by dressing the blade wheels. They had become worn by years of use and the blade would 'track off' the blade wheels. I turned them on my lathe, taking off as little as I could get away with. He never had the problem again.
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stevec
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Re: Band Saw Blade Coming Off Pulley

Post by stevec » Mon Sep 05, 2011 1:15 pm

I had to turn both my wheels and replace the shoulder on the drive wheel. I machined a step on the rear of the wheel and then cut a ring of 1/8 sheet which I bolted on with 3 (I think) 6-32 flathead hex socket screws.
But then, in it's years of abuse, I've also had to replace the worm gear and bearings in the gearbox.

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Falcon67
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Re: Band Saw Blade Coming Off Pulley

Post by Falcon67 » Mon Sep 05, 2011 3:47 pm

This is a common problem with those HF saws. You can usually fix it with some judicious adjustments. Mine actually runs fine with the blade just a little off the wheels. There is a Yahoo forum for these saws and you can pick up a lot of info on them there.
http://groups.yahoo.com/group/4x6bandsaw/

Join the group, then look for the Basic Blade Adjustment and Tracking PDF in the files section.
Chris -
http://raceabilene.com/kelly/hotrod
"Check all parts for proper condition before operation; if normal safety precautions are noticed carefully, this machine can provide you withstanding of accurate service."

Mr Ron
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Re: Band Saw Blade Coming Off Pulley

Post by Mr Ron » Mon Sep 05, 2011 5:44 pm

I'm surprised about the "thump" with a Starrett blade. I have Starrett blades and you would be hard pressed to find where it was welded.
Mr.Ron from South Mississippi

spro
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Re: Band Saw Blade Coming Off Pulley

Post by spro » Mon Sep 05, 2011 6:53 pm

Phil. Yeh OK except now that you have the cut, if you turn that to the side toward the motor. The piece becomes another blade guide.

oldbrock
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Re: Band Saw Blade Coming Off Pulley

Post by oldbrock » Tue Sep 06, 2011 1:04 pm

Of course everyone checks to see the teeth are pointed in the right direction. DON'T WE?
Difficult done right away, impossible takes time.

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Falcon67
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Re: Band Saw Blade Coming Off Pulley

Post by Falcon67 » Tue Sep 06, 2011 1:17 pm

oldbrock wrote:Of course everyone checks to see the teeth are pointed in the right direction. DON'T WE?
Unless we are cutting sheet metal roofing material, in which case you can flip the blade around backwards in your circular saw and slice right through it. :D
Chris -
http://raceabilene.com/kelly/hotrod
"Check all parts for proper condition before operation; if normal safety precautions are noticed carefully, this machine can provide you withstanding of accurate service."

spro
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Re: Band Saw Blade Coming Off Pulley

Post by spro » Tue Sep 06, 2011 8:22 pm

Good points. Sometime way back I traveled to see a Carolina cutoff saw for sale. It was fairly large . I was checking it out and definitely no Kalamazoo. Welded up stuff but American!!!! So he's demonstrating it cutting some bar to us (me and gf) and its rattling etc. and he's talking it up. We just had to go. The blade was backwards the whole time.

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