Help! Jet JWBS-14OS not co-planer by 2 inches!

So I got a big problem here with this Jet 14" BS. When to change the 1/4 to 1/2 blade, and the blade won't even ride the bottom wheel, the wheel is so much further back than the top wheel. When I put a straight edge flat across the top wheel, the bottom wheel is 2 inches further back from the straight edge. No matter how far in either direction I bring the tension, nor no matter how forward or backward I tilt the top wheel, the bottom wheel is 2 inches further back. I've had the 1/4" in there forever, and really haven't noticed "major" issues in sawing, other than the blade sometimes hunting, but I never really cared or noticed. None of the wheels have shims on them. Shimming the bottom wheel would bring it so far forward the bottom guides wouldn't reach it. It's important to note this has the 6" riser block, but the riser block appears to be well centered according to a Starrett square. Moving the top back on the riser 2 inches would look pretty odd. Not sure what's going on here, or how to fix? I'm less concerned about what the second photo is showing than I am about being able to a)get the blade to even ride the bottom wheel and b)get the blade "mostly" centered on both wheels. I don't do a lot of precision cutting, just rough cutting, I do all my finish milling with a hand or power plane. Wheels appear to be well balanced.

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Was this a problem before you added the riser block?

Your test of the alignment with the straightedge and with the square are not really the same thing. The straightedge measurement is affected by cant in the wheel, while the square shows where the blade is positioned relative to the table. The cant you have to put in the wheels to get the blade to track can be affected by tire wear and gunk built up on the tire, among other things.

I'm not sure I can really tell where the problem starts from the pictures, but if there is no solution using existing adjustments, you could shim the right side of the riser block. Do it with a softer metal so you don't ding your casting. Might have to be thick enough that you'd want to file a taper into the shim to give a substantial seating area and avoid stressing the casting.

While you have your riser block off, you might want to check to be sure its two faces are coplanar. If they are not, could have that addressed at a machine shop.

Best,

Dave

I bought it used with the riser block, and only noticed the problem when I decided to put the 1/2 blade on. 1/4 inch blade works, but rides pretty close to the front of the bottom wheel when it's centered on the top. The tires are pretty sloppy, just ordered some new ones.

Thomas there is something really wrong with this saw. My guess is the alignment of the wheels is "twisted" as well. I own a Delta with a riser block that I installed. I remember playing with it for a while,to get it all lined up. I would pull the blade and take it apart. The riser block should be cleaned to bare cast iron on the machined surfaces that meet the saw frame. Once this is done check the block to make sure both surfaces are parallel to each other. Some riser blocks have steel pins to align things. Put it back together and tighten up enough to check but still be able to move things and adjust from there.

I wonder if one wheel is mounted backwards or if a bearing was not pushed in far enough, or maybe pushed in too far. A closeup of the arm joint might help us see if that looks correct.
Bil lD.

As mentioned. Use your bottom wheel as your reference surface. It is common to rip a piece of plywood long enough to rest against both wheels, cut out a section to miss the table and guides, and place this against both wheels. The top wheel's plane varies to allow tracking adjustment. Use the bottom wheel as your reference plane, force the top wheel to that plane and then judge your variance.

There is a good example of this in the Grizzly G0513 / G0514 manual available on Grizzly's site, page 51. If it were me I would quickly pull the table, make a couple of the gauges shown and go through the process. Fiddling around trying to do it other ways can be a big waste of time and never really get you where you are trying to go. I am not bashing setting wheels via plumb bobs a-la Northfield but, for a 14" saw in a home shop . . . just rip some plywood strips and grab a few clamps.

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Originally Posted by glenn bradley

As mentioned. Use your bottom wheel as your reference surface. It is common to rip a piece of plywood long enough to rest against both wheels, cut out a section to miss the table and guides, and place this against both wheels. The top wheel's plane varies to allow tracking adjustment. Use the bottom wheel as your reference plane, force the top wheel to that plane and then judge your variance.

There is a good example of this in the Grizzly G0513 / G0514 manual available on Grizzly's site, page 51. If it were me I would quickly pull the table, make a couple of the gauges shown and go through the process. Fiddling around trying to do it other ways can be a big waste of time and never really get you where you are trying to go. I am not bashing setting wheels via plumb bobs a-la Northfield but, for a 14" saw in a home shop . . . just rip some plywood strips and grab a few clamps.

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I did the plywood 'C' shaped gauge for an older Grizzly saw I had. Worked very well. Get all 4 surfaces (top and bottom of each wheel) touching the plywood and they should be coplanar.

There is much debate on whether the wheels should or should not be coplanar (probably on the level of religion and politics). I don't know which is best, but mine are coplanar & the saw cuts with absolutely no drift & the blade is square to the table. Hard to be sure from the photo, but it looks like there is quite an angle between the wheels.

With a straight edge on the bottom wheel, it should at least point close to the hub of the top wheel. Getting the bottom wheel right would be a good place to start.

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Originally Posted by Frank Pratt

There is much debate on whether the wheels should or should not be coplanar (probably on the level of religion and politics). I don't know which is best, but mine are coplanar & the saw cuts with absolutely no drift & the blade is square to the table. Hard to be sure from the photo, but it looks like there is quite an angle between the wheels.

With a straight edge on the bottom wheel, it should at least point close to the hub of the top wheel. Getting the bottom wheel right would be a good place to start.

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There is absolutely no debate left for me. They need to be coplaner if your goal is to have a saw that works extremely well. I spent two days tuning a Steel City saw that was made with adjustments possible on everything including the guide post. I went as far as making my saw coplaner with the blade size most used under TENSION. Table square to the blade in both planes,guide post square in both planes,Miter slot parallel with blade.The fence parallel to miter slot and square to the table. The result is a saw where "blade drift" is non existent,you can set the fence and cut straight lines effortlessly. This of course includes a sharp blade that is properly tensioned. I still have my plywood alignment jig on my shop mezzanine. I agree with Glen that is the place to start.

This is all great stuff! I ordered two carter wheels, cool blocks, and the yellow tension spring (all of which needed to be replaced due to wear) gonna wait for those to get here next week before I try all these great ideas I'll post back. Guess I should be paying more frequent attention to saw tuning and alignment! Usually I buy a tool, set it up, and don't open the cover....ever......

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Originally Posted by Thomas Colson

This is all great stuff! I ordered two carter wheels, cool blocks, and the yellow tension spring (all of which needed to be replaced due to wear) gonna wait for those to get here next week before I try all these great ideas I'll post back. Guess I should be paying more frequent attention to saw tuning and alignment! Usually I buy a tool, set it up, and don't open the cover....ever......

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I sure would have found the problem with the major alignment issue before ordering parts. Have you fully inspected the frame? With a 2" issue, that thing could have been dropped sometime in it's history!

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Originally Posted by Richard Coers

I sure would have found the problem with the major alignment issue before ordering parts. Have you fully inspected the frame? With a 2" issue, that thing could have been dropped sometime in it's history!

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Richard’s advice is spot on. None of the parts you ordered will impact the alignment of the wheels themselves (to any great extent). I’d sure want to find out what the problem is before dumping cash into the saw. At the very least, don’t open or install the parts until you have tackled the alignment issue. If the frame is bent/cracked no accessory is going to make it markedly better.

Have you made sure the bottom wheel is not moving on the shaft ? Or for that matter that the shaft is not shifting ? I have seen weirder things. keep us posted.