Perpendicular Blade changes when height above table changed

[pfallert]

Ed in Tampa wrote: On my Shopsmith I adjust the table to be perfectly perpendicular to the blade. I then push in the table stop and adjust the adjusting screw so that stable stop keeps the table perfectly perpendicular. Once done it is steel against steel and I trust it. From then on I just push in the stop tilt table against it and consider it perfectly perpendicular to the blade. Also I never use the main table as a handle to move the ShopSmith around. I'm convinced that using the table instead of the bench tubes to move the SS will slowly work the alignment out of alignment."

I will summarize the defects and repeat for those not willing to read through this long thread.

1) Main tables can warp. My shop is in an unheated garage and temperature changes can cause castings to warp. Check your entire table for high spots. Find a flat section to base your square when adjusting the table perpendicular to the blade.

2) My main table (when totally lowered) sits on the headstock. This causes the table to cock, causing table settings to not be consistent.

3) The dust collection system on my machine is plastic and it has warped causing interference when fully extended (opened to max). This caused interference when raising and lowering the table, which caused the table to be knocked out of alignment sometimes, but not always.

4) My SS OEM saw blade is tapered near the outside edge. Not big deal unless you try to adjust the errant table (see #3 previous) with only 1" or 1-1/5" sticking up above the table. Obvious operator error or ignorance? To make an adjustment with the table near the top of its range (eg 1" or 1-1/2" blade exposure), remove the table insert and measure down from the table or as I did (see above), make a straight edge with two magnets to hold the straight edge against the blade and rising above the table for more accuracy and use that to align to your square sitting on the table.

5) Observe Ed's precaution about not tugging on the main table, because it does move out of adjustment due to manufacturing tolerances and maybe a design defect/failure to use a heavier support structure). As was mentioned above, the 510 (and later?) models went to using outrigger tables and tubes to help support the main table. In this regard, when you DO use the outrigger tables (in my case) when you have to raise/lower the main table, you will find that unless you are very careful aligning the tables and tubes, these tubes will CAUSE the main table to go from being adjusted to being out of adjustment.

6) Not a defect, but a "setup" problem nonetheless, you must TIGHTEN the table rising lock BEFORE making the table perpendicular. Not believe me? Try this as suggested above - put a level on the main table. Loose the table rising lock. Watch the level bubble move. Re-tighten the lock. The table moves again. Lock, lock, lock.

Since the main table is inherently unstable Example: a heavy piece of work without the outrigger tables/tubes connected for stability) when you need to frequently change the height of the blade AND the extension tables, you will discover many opportunities to knock you main table out of adjustment without even being aware of it; leading to lousy joinery. Does anyone have a procedure/system to make this easier/quicker?

[dusty]

Just a couple comments.

If you could measure them all, I don't believe you would find a main table that is perfectly flat. They were not manufactured to tight a specification.

When you lower the Main Table simply do not go so low that it contacts the headstock. We would allbe in the same situation if we all lowered the table til the headstock interfered with flatness.

The warped plastic in your lower saw guard is similar to all lower saw guards that I have seen. Simply do not open the lower guard quite so far. As part of my dust collection improvement effort, I have secured my lower guard so that it only goes about half way. Occasionally, it interfers when tilting the table. If that happens, I just take it off for duration of that task.

I don't use my 15' extension tubes for the very reason you cite. I use the shorter tubes along with some wooden dowels that I turned to fit inside the extension tubes. When I need to adjust table height, I simply pull the extension tubes apart, adjust the table(s) and get on with it.

Yup, the locks MUST BE SECURE if you expect accurate and repeatable cuts.

As you previosly stated, thge problems are for the most part not the hardware but rather the procedure.

[JPG]

Coming late to this party, but, I think the initial cause was stated way back towards the first post. Zero clearance insert.

I have difficulty understanding how all the 'causes' discussed could add up to 1/16" in 3/4". That is almost 5°!

Yes stops(clamps) need be tightened down when both making setup adjustments and when actually 'cutting'. That is not a design defect nor an inadequacy.

So many things were brought up that I am confused by them. I am not sure some of them were very meaningful relevant to the initial problem.

As I see it, a saw blade that is not flat sided is an exercise in failure. I prefer the sanding disk for that reason. Once done, any fine measurements between the table(not a surface plate mind you) and the side of the blade(possibly tapered and warped) are meaningless. A warped blade will rip with the closest tooth determining the width. I do not think the table support tubes etc. can create much tilt variance(certainly not 5°).

Any thing that 'interferes' is an obvious culprit.

[dusty]

Paul; thanks for the ride. I enjoyed it all the way through even if others did not. This thread shows, I do believe, that simple things can cause great consternation. Main Table alignment is relatively simple but only if you understand all of the simple issues that can contribute to improper alignment.

I am glad you resolved all your problems. Now, go make sawdust but do it safely.

BTW, you never mentioned the blade being parallel to the miter tracks. I am assuming that was simply not an issue and did not need to be discussed.

[algale]

I also enjoyed the post thoroughly and I'm glad you figured out what you needed to do to get the results you wanted.

The best thing about this forum is that there are members who will spend the time to try to help you diagnose and solve any issue you may be having.

[Ed in Tampa]

Ed in Tampa wrote: On my Shopsmith I adjust the table to be perfectly perpendicular to the blade. I then push in the table stop and adjust the adjusting screw so that stable stop keeps the table perfectly perpendicular. Once done it is steel against steel and I trust it. From then on I just push in the stop tilt table against it and consider it perfectly perpendicular to the blade. Also I never use the main table as a handle to move the ShopSmith around. I'm convinced that using the table instead of the bench tubes to move the SS will slowly work the alignment out of alignment."

I will summarize the defects and repeat for those not willing to read through this long thread.

1) Main tables can warp. My shop is in an unheated garage and temperature changes can cause castings to warp. Check your entire table for high spots. Find a flat section to base your square when adjusting the table perpendicular to the blade.

2) My main table (when totally lowered) sits on the headstock. This causes the table to cock, causing table settings to not be consistent.

3) The dust collection system on my machine is plastic and it has warped causing interference when fully extended (opened to max). This caused interference when raising and lowering the table, which caused the table to be knocked out of alignment sometimes, but not always.

4) My SS OEM saw blade is tapered near the outside edge. Not big deal unless you try to adjust the errant table (see #3 previous) with only 1" or 1-1/5" sticking up above the table. Obvious operator error or ignorance? To make an adjustment with the table near the top of its range (eg 1" or 1-1/2" blade exposure), remove the table insert and measure down from the table or as I did (see above), make a straight edge with two magnets to hold the straight edge against the blade and rising above the table for more accuracy and use that to align to your square sitting on the table.

5) Observe Ed's precaution about not tugging on the main table, because it does move out of adjustment due to manufacturing tolerances and maybe a design defect/failure to use a heavier support structure). As was mentioned above, the 510 (and later?) models went to using outrigger tables and tubes to help support the main table. In this regard, when you DO use the outrigger tables (in my case) when you have to raise/lower the main table, you will find that unless you are very careful aligning the tables and tubes, these tubes will CAUSE the main table to go from being adjusted to being out of adjustment.

6) Not a defect, but a "setup" problem nonetheless, you must TIGHTEN the table rising lock BEFORE making the table perpendicular. Not believe me? Try this as suggested above - put a level on the main table. Loose the table rising lock. Watch the level bubble move. Re-tighten the lock. The table moves again. Lock, lock, lock.

Since the main table is inherently unstable Example: a heavy piece of work without the outrigger tables/tubes connected for stability) when you need to frequently change the height of the blade AND the extension tables, you will discover many opportunities to knock you main table out of adjustment without even being aware of it; leading to lousy joinery. Does anyone have a procedure/system to make this easier/quicker?

Thanks for the great summary! I too enjoyed this thread.