Realigning a rebuild bandsaws' wheels?

[Doc Nickel]

I'm closing in on the rebuild of my Wellsaw horizontal bandsaw. Here's a "before"...



And here's a current pic:



I've gotten it far enough it's time to try installing a blade and aligning everything. I'm a little stuck on that point, though- the manual is of little help, as it assumes the alignment is close, and just needs fine-tuning.

But I had this thing apart down to the last screw, and both wheels have options for tilting the wheels in both axis. So I need to get the wheels coplanar- if that's the correct term - in both tilt and skew.

I'd originally planned on using a couple of chunks of angle iron or angle aluminum as a straightedge, but unfortunately, parts of the support frame are in the way:



So you can't really even eyeball down the faces. So any other ideas? Clamp a couple carpenter squares to each one and eyeball down the 90 degree face?

Doc.

[Andrew R Stewart]

Place risers or blocks of equal dimension on the pulley sides as sighting surfaces? Andy

[danlb]

First I'd spin the wheels to determine whether the outer rim (like in that last picture) is a good reference edge. I'm assuming that it is.

Then I'd put a 2x3 bar across the edge to establish a surface that is parallel to the rim but 2 or 3 inches higher. I'd do that for both wheels.

Then I'd put a long carpenter level (or other straight edge) across the span. It should go all the way to the outside edge of your wheels. That would let you know which is higher, whether they are tilted, etc.

Dan

[BCRider]

As mentioned use spacers of some sort to allow a long straight edge to extend over to the idler wheel. Keep in mind that the tilt setup will mess with your head but if you take the far and near distances from straight edge to rims of the idler and find the average that should be the same as the height of the spacers you used to allow the straight edge to clear the frame/housing. If not space the driven wheel in or out on the axle to make it match.

And hey, nice job on the re-build. Looks spiffy and ready to rock!

[Doc Nickel]

After checking several YouTube videos, yeah, it seems a reliable straightedge that can span both wheels is virtually a requirement.

I think what I'll do on Monday is go buy a chunk of 1/4" x 2" or 3" bar long enough to span the wheels, and just mill some notches where it'd interfere with the frame. I'll have to double-check afterward to make sure the milling didn't release some tension and cause it to warp or twist, but I think that'll be a lot easier than having to handle extra spacers or blocks. Especially since this is all overhead.

If anyone's interested in the nitty-gritty on the rebuild, I have it up in my Projects Pages, including fixing this terrible prior repair, from this:



Which looked more like this when ground down:



To this:



You'll also find a more complete write up- albeit not as tongue-in-cheek- of my motor shaft repair that I posted here last summer.

Doc.

[bandsawguy]

can you measure from the rim of the wheel back to the head at four points around the rim to get the rough alignment. That would get each wheel square to the frame and roughly in line with each other.

[rkepler]

I think I'd find a chunk of 3/16 or 1/4 stock long enough to span the wheels and tack some to the edge to reach into each wheel. So maybe 10' of stock to start? You might be able to just clamp things together but it's likely as easy to tack weld it for the job.

[J Tiers]

This is what parallels are for.... that will help in one direction.

In the other, it gets more complicated, unless you have a rigid frame with two crosspieces (known to be parallel) that can be laid on the wheels and used to check the direction perpendicular to the cut.

I do not think it could be "sighted" very accurately from one to the other, but maybe.with three parallels, so that with two on one wheel and one o the other, the two would establish a line of sight. Both this and the previous assume (possibly wrongly) that the wheel surfaces are well aligned vs the blade.

Another way more directly connected to the action of the wheels (assuming they are NOT crowned), would be to clamp parallels or similar to the actual blade surface of the wheel, so they stand up parallel to the axle. Then turn both wheels to bring the parallels to the same position, right where the blade starts the contact the wheel. The parallels should be fairly obviously actually parallel or at different angles, so they can be adjusted to be parallel, taking care of the most difficult direction.

[Doc Nickel]

can you measure from the rim of the wheel back to the head at four points around the rim to get the rough alignment. That would get each wheel square to the frame and roughly in line with each other.

-That's just it, the frame is a weldment, and has had a rough life. I can't really assume the ends of the frame itself are anything like coplanar.

I think I'd find a chunk of 3/16 or 1/4 stock long enough to span the wheels and tack some to the edge to reach into each wheel.

-Tack weld to balanced cast-iron wheels, eh? I think we'll save that one for a "last resort" attempt.

[...]unless you have a rigid frame with two crosspieces (known to be parallel) [...]

-Again, the frame's a welded assembly, and the whole saw has been treated badly over the years (best guess is this thing's pushing 50 years old.) I have no common datum point to measure anything from- I can measure from the wheel to it's own end of the frame, but I have no way of telling if that reference is in any kind of alignment with the other end of the frame. Well, apart from the Mk I Mod. 0 eyeball, but that's been known to fall out of calibration on occasion.

Doc.

[wierdscience]

Doc,from having done it a few times on a couple different model Wellsaws it's pretty simple.Just make sure the drive wheel is parallel to the frame casting,that;s pretty much it.

[nickel-city-fab]

I used to align bike rims by using a chunk of bent wire as an indicator pointer, sharpened on one end and fasten the other end to the frame somehow. Duct tape even. Spin it and align your rim till it has the same gap between the rim and the wire all around. Keep reading, it gets better --

You could do the same with an indicator and a mag base: stick the mag base somewhere on the frame, setup and pre-load your indicator on the rim. Adjust till it stops moving the needle. Undo the magnet and move it to the other rim. Repeat till you got the same numbers as the first rim. Done.

[wierdscience]

Dumb question,have you tried just putting a blade on it and making a cut?

[Doc Nickel]

Dumb question,have you tried just putting a blade on it and making a cut?

-At the very least, I still need to rebuild the gearbox and wire the VFD.

But really, half the reason I decided to "rebuild" this thing is because it didn't cut well. I mentioned in a thread here several years ago, that with this saw, depending on how thick the material was, the blade would almost always jam at some point during the cut, and if you weren't right there to catch it, the blade would pop off the wheels.

The guide rollers were improperly aligned- and couldn't be properly aligned in part because the adjuster screw on one of them had broken off at the boss- one of the guide arms had been broken and badly rewelded, and overall, the machine had been beat to hell in some industrial shop- or series of industrial shops.

If I'm going to spend all this time and effort rebuilding the thing, I don't want to just throw it together and hope for the best. I want to know it's properly aligned, both for maximum blade life (and wheel life) and for the best possible cut.

Doc.

[Bruce Griffing]

Can you do the job by removing the saw from the base, jigging it up so you can use a level (with 123 blocks)?

[shampine1]

Clamping a long extrusion across a wheel would let you sweep it back and forth across the other one to detect mistakes alignment. If your wheels have shoulders, you should make a matching set of spacers so your extrusion is perpendicular to the shaft.

I would set the frame on a table, wheels up to do the alignment.

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