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Re: Wobble in Lower Bandsaw Tire

Posted: Sun Mar 13, 2016 12:13 am
by JPG
1) The wheels are beveled. The back od is greater the the front od. That is illustrated by the pix above with the square.

2) The lower wheel axle is horizontal.

3) The upper wheel is canted(top tilted in toward the base casting).

4) If the cant is insufficient, the back of the blade will ride too close to the back rim and if way off, the blade will tend to slide off the front rim.

5) If the cant is too much, the back of the blade will ride too far from the the back rim.

Actually the blade back is positioned by the rear guide bearing, and the wheel cant positions the wheel relative to that.

In the past we thought a straight edge laid against the upper wheel should clear the top of the lower wheel by at least 1/8". That 1/8" was sourced I know not where.

More recently CS was 'quoted' as saying the back of the blade should ride 1/8" from the back edge of the tire(the front edge of the rear rim).

What matters is that the back of the blade travels in a flat plane. Slight in/out wobble I do not think will affect that much. Since the blade moves in/out on the wheel, I think that indicates the plane is adhered to as the wheel wobbles. A bump will not either, but could alter the vertical path of the blade between the wheels and if great enough could possibly cause it to 'jump the groove'.

Furthermore Jim McCann considers a slightly(very) wobbly wheel 'defect free'.

It matters not how 'many' things one has done, but rather how much is learned while doing them. ;)

Re: Wobble in Lower Bandsaw Tire

Posted: Sun Mar 13, 2016 1:00 am
by ERLover
I dont want to dismiss anyone or all here, but after reading all here my head is a spinning and not from a liquid influence.
I like things to be perfect, but IMHP, now the blade is staying in the guide bearing, vibration seems to be acceptable, so what difference does it make where it is riding on the rubber? the blade is not coming off, not jumping out of the guide bearing, maybe it is all about the rubber which is new and yours are a bit used/broken in, and/or a bit different angle on the tilt of the upper wheel then yours, which no one here has given that degree of tilt, and the blade rides a bit different on the wheel.
No disrespect to all that have spent time here analyzing this and yours as a comparison.
I have a Delta 14" with a 6" riser block and SS free stander, and my nephew has a SS on his greenie, that I have set up for him, he is not mechanically inclined, all bought used, his was bought at the same time as the SS, I think about 1954, and have non of the problems here, with the original tires and wheels, and on both SS the tension is not taking of in between occasional usage. Maybe just lucky.

Re: Wobble in Lower Bandsaw Tire

Posted: Sun Mar 13, 2016 9:03 am
by gatheringsplinters
All

Thanks for all the advice and troubleshooting questions.

I think at this point my original concern regarding my lower wheel has been answered. Yep, there is a little wobble but it's not going to affect anything.

I also mentioned that the blade was jumping the groove and originally thought this was because of the wobble. After removing all the wheels and bearing and reassembling the bandsaw the blade travels just fine in the groove of the backup bearing.

At this point I think we can consider this post closed.

Re: Wobble in Lower Bandsaw Tire

Posted: Sun Mar 13, 2016 9:21 am
by dusty
Not Quite. The original problem was that the band saw blade would periodically jump out of the groove between the two backup bearings.

It now no longer does that. What do you believe resolved that issue?

Re: Wobble in Lower Bandsaw Tire

Posted: Sun Mar 13, 2016 9:29 am
by gatheringsplinters
dusty wrote:Not Quite. The original problem was that the band saw blade would periodically jump out of the groove between the two backup bearings.

It now no longer does that. What do you believe resolved that issue?
Honestly, I think that I did something differently when I put together and installed the backup bearing the second time. That's the nearest I can figure. I can't see the reinstall of the wheels changing much since their seating positions are fixed.

Perhaps the gremlin in the machine decided to move on. I just hope it wasn't into one of my other tools :P