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Re: Band Saw Tires
Posted: Mon Feb 23, 2015 11:43 am
by RobLund
My band saw blade tracks about 1/32" from the back of the tire. I measured the cant as you describe and it is 5/16". I don't know what it what it should be. The idea of using a pipe to twist the support arm seems a bit risky in terms of wreaking my saw. What should the cant actually measure?
Re: Band Saw Tires
Posted: Mon Feb 23, 2015 11:53 am
by dusty
I feel the same way about the added leverage you get when using the pipe. Fortunately. I have not had the need. I don't know what the cant "should be" and no one else does either. Shopsmith does not divulge that sort of information. The best that any of us can be is tell you what our "working machines" measure.
I don recall the numbers on my two band saws but I'll search past posts to determine what they were. There have been two of three threads on this subject.
Re: Band Saw Tires
Posted: Mon Feb 23, 2015 1:00 pm
by wa2crk
Did you check the bearings in the upper wheel. Just a thought.
Bill V
Re: Band Saw Tires
Posted: Mon Feb 23, 2015 3:30 pm
by jsburger
FWIW, I am in the shop right now and measured my band saw. I bought it new in 1994 and have never had any problems with it or had to "realign" it. It does have the double backup bearing upgrade and the Carter bearing blade guides. The blade runs 1/32" from the back edge of the tire and the cant is 1/16" measured at the top of the lower wheel.
Re: Band Saw Tires
Posted: Tue Feb 24, 2015 11:08 am
by RobLund
I have measured the cant at 5/16". Is that correct? I don't know what the cant should be.
Re: Band Saw Tires
Posted: Tue Feb 24, 2015 1:05 pm
by JPG
RobLund wrote:I have measured the cant at 5/16". Is that correct? I don't know what the cant should be.
As Dusty said, 'we' do not know what is 'correct', and how to measure it.
We in the past laid a straight edge against the upper wheel and measured the amount that straight edge 'cleared' the top of the lower wheel.
A recent thread included quoted comments from CS that stated cant is correct if the back of the blade is 1/4"(IIRC) from the back of the upper wheel. I
assume that means from the edge of the tire.
That makes sense as it more directly relates to the blade positioning controlled by the rear guide bearing(s).
Blade tracking closer to the back of the tire implies 'insufficient' cant, but, if it works, it don't need fixin.
The reason for the pipe approach is that it is a better method than push/pulling on the upper wheel. That tends to bend/warp the wheel. The amount of force applied is not big, so the arm is not likely to be harmed.
Opinions vary, but, leaving the blade tension set will tend to cause insufficient cant due to the arm twisting over time.
If the 5/16" is from the back of the tire, the cant is likely barely too much. Again,
If it works, it don't need fixin!!!
Re: Band Saw Tires
Posted: Wed Feb 25, 2015 1:02 am
by billmayo
I have always set the upper wheel cant using a straight edge to be 1/8" to 1/4" offset at the lower wheel. I was given this measurement at the factory many years ago. The cant can decrease with use so should be checked yearly.
Re: Band Saw Tires
Posted: Wed Feb 25, 2015 8:57 am
by paulrussell
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?
Re: Band Saw Tires
Posted: Wed Feb 25, 2015 11:23 am
by JPG
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?
Yep!
Bill: Thank You for
additional info from gleaned from CS. Unfortunately we need to filter it sometimes. That said, both reported responses are
not self contradictory.
Unquestionably the cant angle will cause both 'measurements' to vary.
That angle needs to be twice the rim angle on the wheels.
Re: Band Saw Tires
Posted: Wed Feb 25, 2015 7:02 pm
by dusty
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?
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.