Band Saw Misbehaving

[JPG]

Strange indeed.

Using the metal casting rib as a reference,(the raised part that the plastic cover overlaps) I get the distance to a straight edge laid on the lower wheel to be 1 1/4" at the top of the wheel and 1 1/2" at the bottom(the rib is further away than the rest of the way around). The distance to a straight edge placed on the upper wheel measures 5/8" at the top, and 1 1/4" at the bottom of the upper wheel.

A straight edge laid against the lower wheel just touches the bottom of the upper wheel. A straight edge laid against the upper wheel clears the top of the lower wheel by about 1/8".

Yes the top of the upper wheel is inset further into the casting.

Measurements taken on the one bandsaw I currently have access to with a 1/4" properly tensioned blade. FWIW the back of the blade appears to be 1/8" below the back of the upper wheel at the top.

What does yours measure? There be a mystery afloat here. I wonder if the support arm for the upper wheel is bent???

[JPG]

After sleeping on this, I believe the upper wheel is on backwards.

That reverses the bevel and would explain the reverse cant, the 'inset of the wheel'(the hubs have different projection) etc. etc.

You will have to reset the cant.

[dusty]

After sleeping on this, I believe the upper wheel is on backwards.

That reverses the bevel and would explain the reverse cant, the 'inset of the wheel'(the hubs have different projection) etc. etc.

You will have to reset the cant.

You better go back and sleep on this again!

The upper wheel can not be installed backwards. It is a physically impossible. It can be mounted backwards but the retaining washer and c-clip can not be installed.

[JPG]

You better go back and sleep on this again!

The upper wheel can not be installed backwards. It is a physically impossible. It can be mounted backwards but the retaining washer and c-clip can not be installed.

What prevents that?

No I did not actually remove mine to determine that.

Got a better explanation for the weird stuff??

Wheel might interfere when on backwards.

We know nothing of what a PO might have done.

Shot gunning fer sure!;)

[JPG]

OK unaltered it cannot be secured on backwards.

It interferes with the arm.

So a close examination of the wheel is in order! If on backwards, it would need to have shim washers to allow clearing the arm. That would mean the other end of the hub was truncated. Not likely.

So tis still a puzzlement.

[dusty]

OK unaltered it cannot be secured on backwards.

It interferes with the arm.

So a close examination of the wheel is in order! If on backwards, it would need to have shim washers to allow clearing the arm. That would mean the other end of the hub was truncated. Not likely.

So tis still a puzzlement.

You are trying to confuse me now.

If the upper wheel is on backwards, the shaft does not protrude far enough to allow the washer and c-clip to be installed. Putting in shims would make that even more impossible.

[dusty]

Makes sense, but not easiest to determine.

Tensioned, same as the 'official' method.

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.

That resultant angle is only a degree or two.


The same forces that cause the blade to ride against the autotrack bearing are in effect when rotated in reverse, but there is no guide bearing in the front, so it does walk towards the back. I know inconsistent use of front/back. Front of the bandsaw, back of the wheel.


Now i'se cornfuzed? Left/right from what vantage point?

Sorry but I can't do that. As I measure the upper wheel, it is 11" in diameter on both sides. It is a nominal 11 1/8" measured on the outside of the rubber wheel. The thickness of the tire is visibly inconsistent around the wheel which accounts for the variations in outside diameter.

The face of the wheel (where the tires meet the metal) is square to the plane of the wheel itself. There is no crown (slight or otherwise).

Now the wheels that you are measuring may be different than mine but I can judge only on what I can touch and feel.

I don't see the mystery to which you have alluded.

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Additional Comment Posted March 5, 2015 -- Despite the photographic evidence, there does appear to be a slight difference in the diameter of the upper wheel when the front side measurement is compared to the rear side measurement. I must have jumped to conclusions that supported my beliefs when I did this original post. What now confuses me is that it appears that the upper wheel is slightly (1/8") larger on the rear side than on the front. This would imply a bevel of approximately 1/16" which is consistent with comments made by JPG. This confuses me because that would indicate to me that the blade would "tend" to move to the front of the which it does not. I am revisiting this discussion because I am attempting to make a decision on new tires. The diameter (11"), the crown (if there is one) and the bevel are critical, in my mind, to choosing the correct tire. Some of the tires are advertised for bandsaws with crowned wheels. I see that the Shopsmith tires are now a bright orange - who sells bright orange tires besides Shopsmith?

[algale]

My wheels are not on backwards. In addition to Dusty's observation which would require modification to mount backwards, the wheels have a single raised rim which goes to the rear and that is where mine are. I also agree there is no observable or measurable taper on my wheels.

[JPG]

My wheels are not on backwards. In addition to Dusty's observation which would require modification to mount backwards, the wheels have a single raised rim which goes to the rear and that is where mine are. I also agree there is no observable or measurable taper on my wheels.

Then how/why does the upper wheel need to be canted etc.....

Look at the rims in Dusty's pix above. 'Back' rim is thicker. Wheel is flat and beveled. Front/rear od varies by about .1".

[dusty]

[quote="JPG"]Then how/why does the upper wheel need to be canted etc.....]
The upper wheel needs to be canted in order to make the blade ride inward (against the tracking bearing) on the wheel.

Yes the wheels are not shaped the same (inside and outside). But the rim is the same diameter both inside and outside. Notice also that the inside of the wheel has been drilled for balancing.

Read the ruler in the pictures. The ruler displays the diameter of the wheels. The first two pictures are the front side of the wheel and the next two are of the rear side. The aluminum blocks are against the tire on both sides.