Band Saw Tires

[RobLund]

How do I get in touch with Bill Mayo?

[jsburger]

Bill, So that I'm sure I understand correctly: You lay a straight edge vertically on the upper wheel and measure 1/8 to 1/4 gap at the top of the lower wheel?

This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:

With the cover removed and the table tilted as far as it will go:

Lay a straight edge across the ends of the two hubs (upper and lower wheel hubs),
measure the distance from the rims of the two wheels to the straight edge. The distance from the rim (at 0° and at 180°) of the lower wheel should be equal; this indicates no cant on the lower wheel. Mine measures about 1/16". The distance from the rim (at 0° and at 180°) of the upper wheel should be different. The distance at the top of the upper wheel to the straight edge should be greater than the distance at the bottom of the upper wheel to the straight edge. This difference is, in my understanding, the cant. Mine measure 1/8" and 3/8" or a 1/4" cant.

I know nothing about the "cant angle" of which JPG speaks. Yes, there obviously is an angle but how that angle relates to the "rim angle" is in the fog. This is one of those times when I'll just keep on doing what has been working for me for a couple decades++ now.

OK Dusty I am not sure how that method would work without thinking about it more.

Having said that, this is not rocket science, it is very simple and a matter of basic physics. Everyone is over thinking this and over reacting. Tracking adjustments are made on all belt/blade machines in the same way. The powered drive wheel, roller or what ever runs 90 degrees to the motor shaft and can not be changed. To accomplish tracking the idler wheel angle compared to the drive wheel has to be adjusted in either the vertical (band saw) or horizontal (belt sander) plane so the belt/blade runs true. As a result the two wheels are not parallel. If you adjust the tracking knob on a SS strip sander you can see the large upper idler wheel tilt back and fourth in the vertical plane. If you adjust the tracking knob on the SS belt sander the idler roller angle changes front to back in the horizontal plane. If I adjust the tracking knob on the upper wheel on my Powermatic 14" band saw it moves the vertical angle of the upper wheel front to back.

Now enter the SS band saw. There is no adjustment to cant the upper wheel to adjust tracking. It was probably manufactured at the factory with a set amount of cant and the backup bearing on the left side of the saw keeps the blade from running off the back side of the upper wheel. My Powermatic band saw does not have a backup bearing on the left side but it does have a knob to adjust the upper wheel cant to provide proper tracking just like the SS strip and belt sanders. As long as the top of SS band saw upper wheel tilts back (away from the operator) it should work fine not withstanding really bad tires and excessive tilt. The actual numbers of the measurements don't make any difference unless maybe they are excessive.

My band saw runs the blade 1/32" from the back edge of the upper tire. That is without measuring to see if the tire is centered on the wheel. That would effect the measurement. The cant measured at the top of the bottom wheel is 1/16". These dimensions are different from what others have said they "should be". I bought my band saw new in 1994 and have never had any problems and never leave the tension on it. It works perfectly.

The bottom line is that SS decided to have a fixed cant to the upper wheel and put a backup bearing on the left side of the saw to keep the blade on regardless of the amount of cant or the blade. If the cant needs to be tweaked the only way is to SLIGHTLY bend the upper arm/wheel assembly.

OK, let the flames begin.

[ChrisNeilan]

I can not relate to the tire coming off. The tires are so firmly attached to my two old bandsaws that I am concerned about how much work it is going to take to get them off when I do need to replace them. But those are my problems.

Since yours are already loose, I would probably replace them. It sounds like you are going to 'need to' anyhow.

As for the blade "tracking off the back" - this should not happen and I would not suspect wheel cant as the primary cause until after I was certain that the tracking bearings were all properly adjusted.

Unlike most other bandsaws, the Shopsmith blade does track in the center of the wheels. The upper wheel is suppose to be canted so as to cause the blade to move back on the wheels. The bearings are to be adjusted so as to limit that rearward travel.

The procedure for adjusting these bearings begins on about page 13 in the manual (re this link):

http://www.shopsmith.com/ownersite/manuals/845539.pdf

I was starting to replace my bandsaw tires this evening. They were the glued on rubber tires and were more than FIRMLY attached! I was able to do the lower wheel in about 20 minutes, probably less. My secret was to use my trusty Black & Decker heat gun designed for paint removal! That and my secret cleaner (available at REAL paint stores. ) When most of the wheel is off, use the cleaner and a red scotch brite pad. Not much work, but the cleaner is like sniffing glue! Since I gave up alcohol for lent, was that a good substitute???!!!

[JPG]

Bill, So that I'm sure I understand correctly: You lay a straight edge vertically on the upper wheel and measure 1/8 to 1/4 gap at the top of the lower wheel?

This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:

With the cover removed and the table tilted as far as it will go:

Lay a straight edge across the ends of the two hubs (upper and lower wheel hubs),
measure the distance from the rims of the two wheels to the straight edge. The distance from the rim (at 0° and at 180°) of the lower wheel should be equal; this indicates no cant on the lower wheel. Mine measures about 1/16". The distance from the rim (at 0° and at 180°) of the upper wheel should be different. The distance at the top of the upper wheel to the straight edge should be greater than the distance at the bottom of the upper wheel to the straight edge. This difference is, in my understanding, the cant. Mine measure 1/8" and 3/8" or a 1/4" cant.

I know nothing about the "cant angle" of which JPG speaks. Yes, there obviously is an angle but how that angle relates to the "rim angle" is in the fog. This is one of those times when I'll just keep on doing what has been working for me for a couple decades++ now.

I do not see how a straight edge against the hubs does anything but obfuscate the details. One hub is on a horizontal axis and the other is 'not'.

The rim bevel(s) cause the blade(band) to tilt from vertical. Since the second wheel must match that tilt angle(with it's beveled rim), it's axis must be two times the bevel angle. That is the 'cant' angle of the upper wheel.

[JPG]

. . .

The bottom line is that SS decided to have a fixed cant to the upper wheel and put a backup bearing on the left side of the saw to keep the blade on regardless of the amount of cant or the blade. If the cant needs to be tweaked the only way is to SLIGHTLY bend the upper arm/wheel assembly.

OK, let the flames begin.

All correct except the underlined word.

The cant angle and bearing position together establish the position of the blade on the upper wheel. The lower guide bearing does the same on the lower wheel.

[dusty]

Bill, So that I'm sure I understand correctly: You lay a straight edge vertically on the upper wheel and measure 1/8 to 1/4 gap at the top of the lower wheel?

This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:

With the cover removed and the table tilted as far as it will go:

Lay a straight edge across the ends of the two hubs (upper and lower wheel hubs),
measure the distance from the rims of the two wheels to the straight edge. The distance from the rim (at 0° and at 180°) of the lower wheel should be equal; this indicates no cant on the lower wheel. Mine measures about 1/16". The distance from the rim (at 0° and at 180°) of the upper wheel should be different. The distance at the top of the upper wheel to the straight edge should be greater than the distance at the bottom of the upper wheel to the straight edge. This difference is, in my understanding, the cant. Mine measure 1/8" and 3/8" or a 1/4" cant.

I know nothing about the "cant angle" of which JPG speaks. Yes, there obviously is an angle but how that angle relates to the "rim angle" is in the fog. This is one of those times when I'll just keep on doing what has been working for me for a couple decades++ now.

I do not see how a straight edge against the hubs does anything but obfuscate the details. One hub is on a horizontal axis and the other is 'not'.

The rim bevel(s) cause the blade(band) to tilt from vertical. Since the second wheel must match that tilt angle(with it's beveled rim), it's axis must be two times the bevel angle. That is the 'cant' angle of the upper wheel.

The function of the straight edge is not at all confusing and, in my opinion, obscures nothing. Using a straight edge against the hubs provides a reference edge to which the measurements can be made. The hubs, relative to one another, should be positioned very close to the same on whatever machine one might be working on. Accuracy of the measurements is not the issue. It is the relationship of these measurements, one to another, that shows what the cant is (positive or negative).

[JPG]

As an 'indicator', absolutely.


As a measurement step, unpredictable.

As you say, we do not know the 'proper' dimensions anyway.

What is relevant is the effect. I consider the back edge of the blade to the rear edge of the tire(which should be tight against the rim raised lip) to be the only thing 'critical'. Only recently has that insight from CS indirectly arrived to this forum.

Makes all the other earlier 'stuff' interesting, but not 'important'.

[RobLund]

I have measured the CANT on my band saw at 5/16" by putting a straight edge across the upper wheel and measuring the space between the straight edge and the front edge of the lower wheel. Is 5/16 a correct cant for the upper wheel or does it need adjusting?

[jsburger]

. . .

The bottom line is that SS decided to have a fixed cant to the upper wheel and put a backup bearing on the left side of the saw to keep the blade on regardless of the amount of cant or the blade. If the cant needs to be tweaked the only way is to SLIGHTLY bend the upper arm/wheel assembly.

OK, let the flames begin.

All correct except the underlined word.

The cant angle and bearing position together establish the position of the blade on the upper wheel. The lower guide bearing does the same on the lower wheel.

OK, the backup bearing keeps the blade from running off the back of the wheel. The amount of the cant determines how close the back of the blade is to the back of the tire. Less cant means the blade is closer to the back of the tire edge (as you said in another post) and more cant means the blade runs farther from the back edge of the tire. As I said, the backup bearing keeps the blade on the wheel regardless of the cant. Unless you have no cant or negative cant or possibly way too much positive cant.

The point is you need some cant. The amount is not important as long as the the blade stays on the wheel. If the blade stays on the saw the actual measurements don't matter.

[JPG]

I have measured the CANT on my band saw at 5/16" by putting a straight edge across the upper wheel and measuring the space between the straight edge and the front edge of the lower wheel. Is 5/16 a correct cant for the upper wheel or does it need adjusting?

If it ain't broke, it don't need fixing. Take a look at this cant stuff IF it not working properly. Otherwise ignore it.