Bandsaw 1/2" blade problem

azarcher · Post by **azarcher** » Sun May 06, 2012 8:24 pm

I was resawing some 2x5 cherry wood and when I finished the cut the blade
rolled off the front of the wheel. The blade was new old stock from the package.
When I reinstalled it the back of the blade was about 1/8" from the guide bearings. Turning it by hand it would not move back. The upper wheel will move back and forth when holding top and bottom of wheel 1/8". Could there be a bad upper bearing or just a bad blade.

Thanks in advace for any help

Bob

charlese · Post by **charlese** » Sun May 06, 2012 8:36 pm

azarcher wrote:I was resawing some 2x5 cherry wood and when I finished the cut the blade
rolled off the front of the wheel. The blade was new old stock from the package.
When I reinstalled it the back of the blade was about 1/8" from the guide bearings. Turning it by hand it would not move back. The upper wheel will move back and forth when holding top and bottom of wheel 1/8". Could there be a bad upper bearing or just a bad blade.

Thanks in advace for any help
Bob

Hi, Bob! Sounds like you upper wheel bearings are shot. The upper wheel should not move back and forth at all. There should be no play between the axle post and the wheel. It should just spin (rotate) freely. Also if set correctly, when a straight edge is layed across the upper wheeel, (as close to the center as possible) the straight edge should pass about 1/4" in front of the lower wheel.

azarcher · Post by **azarcher** » Sun May 06, 2012 8:44 pm

Thanks Charlese The upper wheel is behind the lower wheel by about 1/8" is there a way to move it forward.
Bob

JPG · Post by **JPG** » Mon May 07, 2012 12:16 am

The clearance is created by the difference in the angle of the wheels, not the in/out position. The top wheel should be canted such that the top is closer to the frame than the bottom.

1/8" bearing slop seems excessive. However the upper wheel behind the lower wheel seems to indicate the shaft may not be angled properly. The bearing shaft creates the cant angle.

Your description seems like an attempt to 'align the wheels' co-planer has been undertaken. OK for all but a SS bandsaw.

I think some pix of the straight edge against the wheels would be prudent at this point before some drastic corrective action is suggested. Also pix of the needle bearing and shaft would be helpful.

Although the wheel may be moving 1/8", what else is moving other than the wheel itself? Shaft? Tension arm pivot? ...?

azarcher · Post by **azarcher** » Mon May 07, 2012 9:26 pm

I put new bearings in the upper wheel today and here are the after pictures. Level is clamped to lower wheel. About 1/8" gap on top.

Same picture as above, checked with degree meter, and it is 1 degree tilt.

Level is just touching the wheel most of the way around.

I tried the same blade as before and it came off again. So I tried a different 1/2" blade that I had and it seems to turn just fine and rides alot further back on the wheel against the guide bearings. So much for the new blade!

The Power Pro setting for 1/2" blade in hardwood says 950 rpm. The bandsaw book that I have says 700 rpm. Which one do we go by? The wood I'm resawing is 4 1/2" cherry.

Does this setup look like it will be okay?

Thanks for your help!

Bob

JPG · Post by **JPG** » Mon May 07, 2012 9:50 pm

I be used to thinking a straight edge held against the UPPER wheel and observing the distance from the straight edge to the top of the lower wheel(about 1/4" ? IIRC)

That cant can sometimes be increased(temporarily?) by grasping the top and bottom of the top wheel, and pushing in at the top while pulling out on the bottom. Do not overdo this nor do it often. The arm will fatigue and become weak.

The saw blade back MUST ride against the blade tracking bearing(s).

azarcher · Post by **azarcher** » Mon May 07, 2012 10:08 pm

The blade contacts the lower blade guard bearing first, not the tracking bearing.
I haven't found a way to move either one of those brgs.

Bob

JPG · Post by **JPG** » Tue May 08, 2012 2:45 am

azarcher wrote:The blade contacts the lower blade guard bearing first, not the tracking bearing.
I haven't found a way to move either one of those brgs.

Bob

They are NOT adjustable!

If the blade is not settling on the upper guide, then the wheel is not canted properly.

azarcher · Post by **azarcher** » Tue May 08, 2012 9:52 am

Thanks for all the help JPG

Bob

billmayo · Post by **billmayo** » Tue May 08, 2012 11:32 pm

PLEASE DO NOT GRAP THE UPPER WHEEL AND TRY TO BEND THE UPPER ARM.

This can bend/warp the upper wheel. I remove the upper wheel and use a piece of pipe on the axle to bent the upper arm. Remount the wheel and check that the upper wheel edges track outside the lower wheel edges as described above.