Bandsaw Blade Tracking Adjustments Etc.

[JPG]

Estimating the distance from the square to the bottom of the wheel to be around 3/16" indicates an angle close to 2 degrees.

IIUC you placed a wixey(or whatever) on the top and with no other support the angle gauge indicated 4 degrees. That means the 'bevel' angle is 2 degrees and that implies the wheel cant angle is 4 degrees.

I will do a rough measurement of the cant angle on one of my BS and get back.

Well I attempted that, but have zero faith in any 'results'. My iGauge has had a stiction issue since day one and these angles are too close for repeatable results.

[jsburger]

Estimating the distance from the square to the bottom of the wheel to be around 3/16" indicates an angle close to 2 degrees.

IIUC you placed a wixey(or whatever) on the top and with no other support the angle gauge indicated 4 degrees. That means the 'bevel' angle is 2 degrees and that implies the wheel cant angle is 4 degrees.

I will do a rough measurement of the cant angle on one of my BS and get back.

Well I attempted that, but have zero faith in any 'results'. My iGauge has had a stiction issue since day one and these angles are too close for repeatable results.

That is exactly what I did. The reference surface surface was the bench and the angle gauge was zeroed to that. So why is the bevel half of the measured angle?

Now you are going to make me look up the formulas for a triangle since I don't have all of them on the top of my head. That is actually a good thing. The 3/16" measurement is pretty close although I didn't measure it. But you still need to have the length of the other side. Remember the square is touching the top of the hub casting not the center of the shaft.

As far as having faith in digital measuring tools, remember we designed the SR-71 (fastest airplane in the world still today 1960), all the space capsules and probably the space shuttle with a slide rule. I know you know what that is but how many youngsters don't know. A lot of engineering students say "Yeh I have heard of it but have never seen one."

[JPG]

Estimating the distance from the square to the bottom of the wheel to be around 3/16" indicates an angle close to 2 degrees.

IIUC you placed a wixey(or whatever) on the top and with no other support the angle gauge indicated 4 degrees. That means the 'bevel' angle is 2 degrees and that implies the wheel cant angle is 4 degrees.

I will do a rough measurement of the cant angle on one of my BS and get back.

Well I attempted that, but have zero faith in any 'results'. My iGauge has had a stiction issue since day one and these angles are too close for repeatable results.

That is exactly what I did. The reference surface surface was the bench and the angle gauge was zeroed to that. So why is the bevel half of the measured angle?

Now you are going to make me look up the formulas for a triangle since I don't have all of them on the top of my head. That is actually a good thing. The 3/16" measurement is pretty close although I didn't measure it. But you still need to have the length of the other side. Remember the square is touching the top of the hub casting not the center of the shaft.

As far as having faith in digital measuring tools, remember we designed the SR-71 (fastest airplane in the world still today 1960), all the space capsules and probably the space shuttle with a slide rule. I know you know what that is but how many youngsters know. A lot of engineering students say "Yeh I have heard of it but have never seen one."

Wonder if they know what a "log" is.

I estimated the length of that 'leg' of the triangle to be 5.5"(half the wheel od). Also at small angles one can interchange the 'hypotenuse' and the 'adjacent side' for (arc)tangent calculations.

As for the angle 'doubling', the bevel on the bottom of the wheel causes the wheel to lean. The bevel at the top of the wheel 'leans' the same direction(i.e. more).

[jsburger]

Estimating the distance from the square to the bottom of the wheel to be around 3/16" indicates an angle close to 2 degrees.

IIUC you placed a wixey(or whatever) on the top and with no other support the angle gauge indicated 4 degrees. That means the 'bevel' angle is 2 degrees and that implies the wheel cant angle is 4 degrees.

I will do a rough measurement of the cant angle on one of my BS and get back.

Well I attempted that, but have zero faith in any 'results'. My iGauge has had a stiction issue since day one and these angles are too close for repeatable results.

That is exactly what I did. The reference surface surface was the bench and the angle gauge was zeroed to that. So why is the bevel half of the measured angle?

Now you are going to make me look up the formulas for a triangle since I don't have all of them on the top of my head. That is actually a good thing. The 3/16" measurement is pretty close although I didn't measure it. But you still need to have the length of the other side. Remember the square is touching the top of the hub casting not the center of the shaft.

As far as having faith in digital measuring tools, remember we designed the SR-71 (fastest airplane in the world still today 1960), all the space capsules and probably the space shuttle with a slide rule. I know you know what that is but how many youngsters know. A lot of engineering students say "Yeh I have heard of it but have never seen one."

Wonder if they know what a "log" is.

I estimated the length of that 'leg' of the triangle to be 5.5"(half the wheel od). Also at small angles one can interchange the 'hypotenuse' and the 'adjacent side' for (arc)tangent calculations.

As for the angle 'doubling', the bevel on the bottom of the wheel causes the wheel to lean. The bevel at the top of the wheel 'leans' the same direction(i.e. more).

Yes, it came to me last night while I was laying in bed.

[everettdavis]

The bevel became somewhat obvious to me but maybe we aren't talking about the same thing.

Does this image of my band saw wheel depict the way you measured the bevel?

Oh bother, I forgot to attach the picture. Looks like the angel is about the same.

Yes we are talking about the same thing. It is very obvious to me when the wheel is removed from the saw just by looking without the square but not obvious at all when the wheel is installed even if you know it exists.

The Lip on the front and back of the wheel are not the same size. Dusty discusses this in another post. http://www.shopsmith.com/ss_forum/viewt ... 81#p179981

Review the photo with the notes below.

Bandsaw Wheel photo from jsburger.jpg (203.58 KiB) Viewed 8064 times

[JPG]

Are you calling attention to this statement?

"Take my word for it, the wheels have a larger od at the back than at the 'front'. Yes it is slight!!! They are flat across that slanted face."

If so it refers to the rim thickness that infers a larger od at the back rim.


It is not referring to the od of the inner and outer rim.

Granted the rear lip could cause the wheel to 'tilt' as shown in your pix, but the lip does not extend beyond the rubber tire so the wheel bevel is indicated through the constant thickness tire and the square.

The upper wheel axle is canted causing the top of the upper wheel to lean inward towards the base.

Both wheels are beveled so as to create a larger od(of the tire)at the rear or inner edge. They are beveled at half the wheel axle angle(about 4/2°)

The lower wheel axle is parallel to the SS drive train/earth etc.

The The blade travels in a plane that matches the wheel bevels.

P.S. The upper axle is canted which makes the upper wheel cant.

......The wheels are beveled which allows the blade to rest firmly against the tires as it travels in that tilted plane.

[everettdavis]

Are you calling attention to this statement?

"Take my word for it, the wheels have a larger od at the back than at the 'front'. Yes it is slight!!! They are flat across that slanted face."

If so it refers to the rim thickness that infers a larger od at the back rim.

Yes I was pointing exactly that out. If the lip on the front and back were identical, then standing it on the table as illustrated in the photo, would be (far more) square. Since they are not the same, it tilts.

Some time ago I placed the upper wheel flat on a piece of MDF with a hole I made with a hole saw that allowed the flange the bearing was on to recess into the hole, which placed the back Rim flat on the MDF (or should have).

I also do this with bandsaw blades laid out on MDF. It is amazing the things you find comparing new blades, especially the inexpensive ones, and I cannot imagine the issues that come from welding broken blades back together. Used blades are also a trip at times.

I had accumulated a few of them through the years, and some wheels were warped slightly, perhaps from being left under tension for a long time as was discussed also. As stated, the early manuals made no mention of backing off the blade tension when stored etc.

I did locate several that were flat against the MDF all the way around.

Looking across the wheel from the side, where the tires track (tires had been already removed for replacement), one can see the profile of the surface the tires ride on better.

I wish I had taken pictures back then, and will the next time I take one off (if I can remember to). I am not as disciplined in memory as I once was I fear.

One of the most relevant articles I read was at the http://shopsmith-tool-hunter.blogspot.c ... d-few.html article, which discusses the differences between a Shopsmith and all the other bandsaws out there with some illustrations.

In it at the end he states "If all these things are in place you should be the proud owner of the best bandsaw on the market today."

I really like mine. I have several and like others tend to leave one set up just for resawing, and use the newer one with the aluminium table for more of the work requiring me to adjust the saw for varying operations.

I really appreciate all the insightful and thoughtful analysis and comments folks have contributed in this thread.

My point in commenting was in confirmation solely to the statement "the wheels have a larger od at the back than at the 'front'", and the picture helps illustrate that especially if the tire was off. They are different. They are supposed to be different.

Everett

[jsburger]

Are you calling attention to this statement?

"Take my word for it, the wheels have a larger od at the back than at the 'front'. Yes it is slight!!! They are flat across that slanted face."

If so it refers to the rim thickness that infers a larger od at the back rim.


It is not referring to the od of the inner and outer rim.

Granted the rear lip could cause the wheel to 'tilt' as shown in your pix, but the lip does not extend beyond the rubber tire so the wheel bevel is indicated through the constant thickness tire and the square.

The upper wheel axle is canted causing the top of the upper wheel to lean inward towards the base.

Both wheels are beveled so as to create a larger od(of the tire)at the rear or inner edge. They are beveled at half the wheel axle angle(about 4/2°)

The lower wheel axle is parallel to the SS drive train/earth etc.

The The blade travels in a plane that matches the wheel bevels.

P.S. The upper axle is canted which makes the upper wheel cant.

......The wheels are beveled which allows the blade to rest firmly against the tires as it travels in that tilted plane.

Actually, that is a picture I took. It is from a previous post in this thread. You are exactly right JPG. The lip on the back of the wheel does not extend above the tire. In that picture the wheel is sitting solely on the tire. The lip on the back of the wheel is not touching the table. As such that picture illustrates the bevel of the rim of the wheel.

[JPG]

I had not seen the patent drawing until today.

One 'error' in toolhunter's description. The lower wheel is not 'flat', but also 'conical' like the upper wheel. Conical = beveled.

Notice the angle descriptions. 90° - a and 2a.

The 90 - a is the angle the back of the blade makes to the axles. That is the bevel angle.

The 2a is the cant angle of the upper wheel axle.

71 and 72 are the blade guide bearings.

References are to the rightmost drawing.

[everettdavis]

Actually, that is a picture I took. It is from a previous post in this thread. You are exactly right JPG. The lip on the back of the wheel does not extend above the tire. In that picture the wheel is sitting solely on the tire. The lip on the back of the wheel is not touching the table. As such that picture illustrates the bevel of the rim of the wheel.

Indeed it is your picture. That's why I named it
"Bandsaw Wheel photo from jsburger.jpg"

I had noted the issue I was discussing would have been better visible in the picture without the tire on the wheel (it is sitting on the tire as you state), and I will try to get one without the tire the next time I replace a set of tires.

It would really be nice if Shopsmith could produce a CAD drawing for the two wheels that we could reference that illustrated the dimensions of the upper and lower bandsaw wheels. I feel certain they have them, as someone has to produce the production wheels for them, whether internally or externally.

I just got off the phone with Shopsmith Customer Service and was told that the 2° Bevel was added in April 1984 to the upper wheel. Prior to that, they said they were flat like the lower wheel. That may answer some of the questions since many of us have Bandsaws from early and later production.

Everett