Re: Band Saw Tires
Posted: Wed Feb 25, 2015 8:09 pm
How do I get in touch with Bill Mayo?
A woodworking forum for woodworking hobbyist and woodworking projects related and unrelated to the Shopsmith MARK V
https://forum.shopsmith.com/
OK Dusty I am not sure how that method would work without thinking about it more.dusty wrote:This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:paulrussell wrote: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?
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 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.dusty wrote: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 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'.dusty wrote:This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:paulrussell wrote: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?
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.
All correct except the underlined word.jsburger wrote: . . .
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.![]()
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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 wrote: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'.dusty wrote:This is not the procedure that I have understood for measuring wheel cant (both upper and lower). I measure mine as follows:paulrussell wrote: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?
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.
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.
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.JPG wrote:All correct except the underlined word.jsburger wrote: . . .
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.![]()
![]()
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.
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.RobLund wrote: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?