Bandsaw table upgrade issues - Blade hits the insert

[joet]

I have a 1981 bandsaw and just installed the table upgrade. All went well until I installed the round table insert. The blade hits the inside (left) edge of the slot. It looks like the entire table is about 1/4" to far to the right, based on how the slot lines up with the blade. I reached out to SS but no reply yet. Reading through this forum I see that the trunnion setup was changed when the aluminum table was introduced. I'm wondering if this is my issue. The simple fix is to widen the slot or make a custom insert. Any thoughts on the cause or the solution?

[HopefulSSer]

Something's obviously not right. I did the cast iron to alloy table upgrade on mine a few years ago and everything lined up properly. You shouldn't have to modify anything.

I'll go to the shop later today and look at mine but I don't recall running into anything tricky. I don't recall how the trunnions go together but is it possible something to do with the trunnions is flipped 180º around?

[chapmanruss]

joet,

You are correct about a change to the Trunnions when the Bandsaw went from the Cast Iron Table to the Aluminum table. For the Trunnions themselves it wasn't a big change and they are interchangeable. If the Trunnions are causing the problem, it would have to be caused by them being bent somehow. It was the mounting bolts and sleaves through the Main Frame Casting that really changed and they are not interchangeable. There is very little adjustment room between the Trunnions and the Table Bolt Holes. Most of that adjustment room is for squaring the Table to the Blade.

I would first suspect the Bandsaw's Upper and Lower Guides and are they are aligned correctly. In your picture it appears the Upper Guide Block is "pushing" the Blade to that side. It should not have needed a change going from the CI Table to the AL Table. I would suggest backing out the Guide Blocks in both the Upper and Lower Guides. Check that the Blade is properly tensioned and see how close to center it is without the Guide Blocks in place. If it centers up sufficiently re-align the Guide Blocks and enjoy using your new Aluminum Table features. If that does not solve the problem, we will have to find other possible causes.

[joet]

Thanks for the insight. I had already tried adjusting the table as far to left as possible, but that didn't help. I had also checked to make sure I had the blade tension correct for the 1/4" blade I have installed. I backed way off on the upper and lower blade guides so there was absolutely no pressure on the blade and that allowed for about 1/16" clearance on the left side at the insert. So the right side bottom guide was a bit too tight. I think I'll be OK with that clearance. If not I'll enlarge the slot a bit.


Thanks!

[jsburger]

Maybe the camera angle but... The blade does not appear to be parallel front to back with the opening in the insert. The back of the blade seems to be in line with the back end of the slot in the back of the insert. The front of the blade looks twisted to the left by the lower guide. Looking at the groves in the table behind the blade it looks like the blade is not square to the table front to back. Also if the table is not square to the blade (left to right) the blade will be closer to one edge of the slot depending which way the table is off. There is a stop screw on the back left of the table to set it at 90º.

[JPG]

IIWM, I would first remove all blade guides so as to eliminate any contribution from them. Also back away the 'upper' back up bearing.

Then address table alignment.

The stop screw controls the tilt angle. It should be square the the wide edge of the blade.

Squaring the blade to the miter gauge slot is done by moving the table on the trunions. Very little adjustment is possible there.

The blade should be in a path tangent to both wheels(vertical). The top back of the blade should tilt slightly due to the upper wheel cant etc.( exclusive to the SS bandsaw)

If this does not place the blade in the center of the table insert hole, something else is causing the misalignment, although off hand, I cannot think of a cause.

[chapmanruss]

joet,

From your last picture below the arrow points to the location of the Blade close to the one Guide Block Mounts. This is the point I was concerned about in my last post. Is the horizontal Block pushing the Blade to far over towards the angled Block Mount.

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After backing off the guides - joet BS arrow.jpg (49.55 KiB) Viewed 7200 times

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Compare that to the picture below of one of my Bandsaws where the Blade is more centered between the Guide Block Mounts. You can see the Blade is pretty much centered going through the Table Insert hole. This one is a 2006 Bandsaw that came with the Aluminum Table.

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Blade Path 2006.JPG (306.99 KiB) Viewed 7200 times

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If the Upper Guide Blocks are not pushing the Blade to the side, I then wonder if the entire Upper Blade Guide Assembly is aligned properly when going from raised to lowered. The entire Assembly should not change the Blade path when raised or lowered to any position. That includes left to right or front to back. To check that alignment you could back off the Guide Blocks and raise the Upper Blade Guide Assembly to the top and back down to the Table observing the location of the Blade side to side and front to back through the entire vertical range. The Blade should remain the same distances from the Guide Blocks and the Roller Bearing.

As it looks now the blade is not hitting the Table Insert so it looks okay to use. Even when the table Insert is slightly rotated so the leveling screws are seen through the holes it should maintain that clearance.

While we are talking about alignment there was a change at some point adding a nylon bolt to the Guide Column Bracket to help eliminate side play in the Blade Guide Column Post and aids in alignment. The picture below shows that nylon bolt on the Guide Column Bracket.

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Guide Bracket.JPG (75.17 KiB) Viewed 7200 times

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If your Bandsaw has that Nylon Bolt great but if not, it can easily be added. It only takes drilling and tapping a hole in the bracket as seen below.

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Guide Bracket 2.JPG (51.56 KiB) Viewed 7200 times

[joet]

Russ,
Thanks so much for all the detail and insight. I installed a wider 1/2" blade and then re aligned the table for square and perpendicular. It was off a bit in both axis. I backed off the guides and noticed that the blade was hitting right side the lower guide block assy. The upper block assy did not interfere with the blade at all. (Mine does not have the nylon screw.) There is some adjustment in the lower guide block assy. and I was able to get the blade to clear the guide casting sufficiently. All in all, the blade is tracking left of center in the insert slot, but with more clearance then I had before. I made a few cuts to check for square and no issues with it hitting the insert. In the process I saw that my blade has some noticeable twists in it so I ordered a new blade.

[chapmanruss]

Adding the Nylon Bolt to the Bandsaw Upper Guide Retainer part number 5025499 is relatively easy as long as you have the correct size tap to thread the hole. Drill a hole in the location as shown in the picture below and thread it. The Nylon bolt, I believe, is 1-1/2" long and either a 1/4" or 5/16" Nylon Bolt should work. I am not sure which size Shopsmith uses. I would have to remove one from a Bandsaw to check the size.

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DSCF1609sc.jpg (46.06 KiB) Viewed 6403 times

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Your other option is to buy the Bandsaw Upper Guide Retainer (seen above) part number 5025499 from Shopsmith for $27.95 and the Bandsaw Upper Guide Nylon Guide Bolt part number 517908 is $6.95. If looking the Nylon Bolt up in the online parts catalog for some reason it shows a steel bolt.

[joet]

Russ,
I'll consider adding the nylon screw at some point. But for now I decided to go through the complete alignment of the upper guide assay because the upper guide roller was quite a ways away from the blade and not the same distance at its high position vs the low position. I found the tension adjust screw for the upper guide assy would only turn not even a 1/4 turn in either direction. So I took the entire upper guide assy off and found some sort of locktite or something on the threads of the tension adjustment screw. After removing most if it and cleaning it up, I reassembled everything and went through the complete upper guide assy alignment. The blade is tracking in the center of the guide rollers and there is plenty of clearance between the blade and the blade guide housing. All is looking good!!! Thanks again.