Bandsaw Bearings

[dusty]

dusty,

I noticed, and was confused by the terms used for the bearings. I'll use yours:

Auto-Track Roller Bearing

Lower Blade Guide Roller Bearing

Upper Blade Guide Roller Bearing.

One thing, you said "If your bandsaw has not been modified to change the bearing configuration, the Auti-Track Roller Bearing is a two bearing arrangement and the two Guide Roller Bearings are each single bearings. Some have modified this configuration to utilize a pair of bearings (different bearings) at each of the Guide Roller Bearing positions".

I'm looking at 2 saws, and both have single bearings in all 3 positions. And they are different styles of single bearings.... The auto-track roller bearing, being a single, was the main reason I was interested in the upgrade to duals.

Another question: my single auto-track bearing never makes contact with the blade (misses by a hair). Since it's not adjustable forward and back, should I try a shim? When I lightly touch the back of the blade while it's running, it really smoothes things out (much less eccentric blade movement).


BillV,

Good info. I've done almost all of what you said, and things are looking better.

Thanks!

Fred

As long as the blade is tracking on the wheels properly, I would not do a thing to change that. The bearing is there to prevent the blade from creeping back farther onto the wheels and eventually off the backside.

The blade tracks where it is because of how the upper wheel is canted as limited by the tracking bearing.

In the way of possible clarification, the Auto-Track Bearing has always been a two bearing set. The guide roller bearings have been modified by some (myself included) to be a two bearing pair. Quite frankly, I am not certain that I gained anything in the way of performance by doing that.

[fgrule]

As long as the blade is tracking on the wheels properly, I would not do a thing to change that. The bearing is there to prevent the blade from creeping back farther onto the wheels and eventually off the backside.

The blade tracks where it is because of how the upper wheel is canted as limited by the tracking bearing.

In the way of possible clarification, the Auto-Track Bearing has always been a two bearing set. The guide roller bearings have been modified by some (myself included) to be a two bearing pair. Quite frankly, I am not certain that I gained anything in the way of performance by doing that.

Well then it makes sense that my "auto-track" bearing doesn't quite touch if it's function is to prevent the blade from going off the back.

Are you sure the auto-track bearing has never been a single as I'm looking at a 1980 and a 1982 model 500 with single bearings there. Not trying to be argumentative, but that seems odd. Also, my parts list in the manual shows the exact same setup at all 3 positions.....same part #502578 for all 3.

In any case, I plan to replace it with a double!

Thanks for your help!

Fred

[dusty]

Well then it makes sense that my "auto-track" bearing doesn't quite touch if it's function is to prevent the blade from going off the back.

Are you sure the auto-track bearing has never been a single as I'm looking at a 1980 and a 1982 model 500 with single bearings there. Not trying to be argumentative, but that seems odd. Also, my parts list in the manual shows the exact same setup at all 3 positions.....same part #502578 for all 3.

In any case, I plan to replace it with a double!

Thanks for your help!

Fred

No, I cannot say that I am certain it has never been a single bearing. Furthermore, if you have documentation from a manufacturer that states otherwise, I am dead wrong.

With regard to making a decision to change it, be aware that alignment may be effected. You want to keep the blade running in the same relative position on the bearing surface. In this case, that is likely to be the groove between the two bearings. What you want to make certain of in that the blade tracks there naturally (not pulled out of natural alignment to get there).

[fgrule]

No, I cannot say that I am certain it has never been a single bearing. Furthermore, if you have documentation from a manufacturer that states otherwise, I am dead wrong.

With regard to making a decision to change it, be aware that alignment may be effected. You want to keep the blade running in the same relative position on the bearing surface. In this case, that is likely to be the groove between the two bearings. What you want to make certain of in that the blade tracks there naturally (not pulled out of natural alignment to get there).

Yes, I was concerned about the alignment when I read the posts explaining how to do the "mod" to dual bearings. I just took it for granted that I'd need to use whatever spacers necessary for correct alignment.

Fred

[JPG]

I am not sure re the dual bearing 'auto track' bearing, but IIRC, originally all the 'bearings' were sleeve bearings, not ball bearings. I believe they were all single bearings.

The lower 'blade guide bearing' should contact the spine of the blade. It serves the same function for the lower wheel as the auto track for the upper wheel(That is why it is not adjustable front to back) in addition to backing up the blade.

The upper 'blade guide bearing' should be adjusted to 'almost' contact the spine of the blade under no load. However since it can be raised and lowered, it must be adjusted to align so at all 'elevations'.

The spine of the blade will be slightly off 90° and can be made 'square' only by shimming the table to the trunion. That is 'intentional', not a defect.

The table is adjustable to square to the blade from the sides of the blade.

I am glad you rephrased the side to side deviation to include from top guide to lower guide. One or both blade guides(the square rod thingies) are out of line!

Remove the blade guides(they 'almost' contact the sides of the blade), or make sure they are moved completely away from the blade.

The blade should now be running straight from the top wheel to the lower wheel. Lay a straight edge against the wheels and the blade should follow that edge. i.e. The blade should 'naturally' be straight along a line tangent to both wheels. Adjust the upper and lower blade guide bearings left/right so as to center the blade to the bearing. Finally adjust the blade guides to just clear the sides of the blade. A '$20' bill wrapped once around the blade makes a good shim. $20 so you will not forget to remove it. If you tend to be forgetful, make it a $100!. Make sure the guides do not touch the blade teeth(set).

Now check the table squareness to the SIDE of the blade. The stop screw is under the table towards the rear.

You asked if you should be following a post of mine. If you are referring to a thread I posted, then yes(reserve a full weekend). If you were referring to something else, I need clarification.

[JPG]

Yes, I was concerned about the alignment when I read the posts explaining how to do the "mod" to dual bearings. I just took it for granted that I'd need to use whatever spacers necessary for correct alignment.

Fred

The bearing mounting bracket is adjustable to allow centering. However it is also a sloppy slot, so care must be taken to ensure the sides of the bearing are parallel to the blade. Otherwise the blade will skew as it rotates the bearing and tend to squeal.

[fgrule]

The bearing mounting bracket is adjustable to allow centering. However it is also a sloppy slot, so care must be taken to ensure the sides of the bearing are parallel to the blade. Otherwise the blade will skew as it rotates the bearing and tend to squeal.

That makes sense.

You said: "I am glad you rephrased the side to side deviation to include from top guide to lower guide". I think you misunderstood what I was trying to say. The side-to-side deflection occurs as the blade leaves the lower wheel and travels to the upper wheel. I was asking if a dual bearing (the auto-track) to replace my single bearing, might help this issue, since the blade rides in a slot between the 2 bearings. I'm now guessing that "auto-track" means dual bearings, not a single.

And, yes, I was referring to your thread on aligning the bandsaw. I'll set aside adequate time to do it....I'm slow! But I think this is where I need to start (a complete alignment).

Thanks for all the info! This is all becoming more clear now.

Fred

Fred

[JPG]

That makes sense.

You said: "I am glad you rephrased the side to side deviation to include from top guide to lower guide". I think you misunderstood what I was trying to say. The side-to-side deflection occurs as the blade leaves the lower wheel and travels to the upper wheel. I was asking if a dual bearing (the auto-track) to replace my single bearing, might help this issue, since the blade rides in a slot between the 2 bearings. I'm now guessing that "auto-track" means dual bearings, not a single.

And, yes, I was referring to your thread on aligning the bandsaw. I'll set aside adequate time to do it....I'm slow! But I think this is where I need to start (a complete alignment).

Thanks for all the info! This is all becoming more clear now.

Fred

Fred

"Auto track" is referring to the total lack of a 'tracking' adjustment. The tracking refers to the positioning on the wheel. Most other bandsaws require the blade to run centered on the wheel. The SS has the spine always running at the same location on the wheel. Thus the guides will always stay positioned to the spine.

The dual bearings prevent the spine from moving side to side on the bearing, thus preventing the blade from twisting. The dual bearings are more useful when backing up the blade at the blade guides. I think the dual bearing tracking bearing prevents the squealing I mentioned earlier.

[dusty]

"Auto track" is referring to the total lack of a 'tracking' adjustment. The tracking refers to the positioning on the wheel. Most other bandsaws require the blade to run centered on the wheel. The SS has the spine always running at the same location on the wheel. Thus the guides will alwaysstay positioned to the spine.

The dual bearings prevent the spine from moving side to side on the bearing, thus preventing the blade from twisting. The dual bearings are more useful when backing up the blade at the blade guides. I think the dual bearing tracking bearing prevents the squealing I mentioned earlier.

I am not sure I agree with this statement. I do not believe that Shopsmith endorses this dual bearing arrangement. If I recall correctly, I believe the dual back up bearing configuration was introduced here on the forum'. Thisis Shopsmith's current catalog selection for these bearings.

If this is a function of the bearings, what are the cool blocks there for?

[JPG]

I am not sure I agree with this statement. I do not believe that Shopsmith endorses this dual bearing arrangement. If I recall correctly, I believe the dual back up bearing configuration was introduced here on the forum'. Thisis Shopsmith's current catalog selection for these bearings.

If this is a function of the bearings, what are the cool blocks there for?

The dual bearings at the blade guides are more functional with larger blades.

They will not keep the entire blade from moving sideways(in/out).

True they are not a ss option. That idea originated elsewhere and was implemented by many who frequent here.

If you are using cool blocks tight against the sides of the blade, the dual bearing probably is not much of an improvement.