Perpendicular Blade changes when height above table changed

[dusty]

Again very simple raise main table to it's highest position and put a level on it side to side. Adjust the level until it is perfectly level ( shim between it and the table) now lower the table if the level changes you have bent table support tubes. If it doesn't change then something you are not mentioning is happening to change the perpendicular relationship between the blade and table.

Ed,

This is a neat trick!! I must spend some time in the shop checking this out.

However, I have a question or two. Have you ever experienced table legs that were bent enough to be detected by this test???

Why do you have to shim the level. Why can you not tilt the table to achieve that same level condition and then lower the table?

[Ed in Tampa]

Dusty you could adjust the table to start with, I was just trying to do it fast and easy.

The only thing that moves when you raise or lower the table is the table. For the angle of the table to change by just lowering it, could only be bent table support tubes. Unless there is something else done that was not yet mentioned.

If the level stays level in this test, then we know something else got moved/changed/effected. Then the question would be what and how.

[pfallert]

I used a dial indicator with the tip against the side of the main table. The table was not connected to the side tables for this test.

I checked first and determined that all of the locks were tight and needed no further tightening than what I found.

The blade was centered in the zero clearance insert.

I tried to move the table left-right and with reasonable force I got +.005 and -.005. This does not seem to be excessive.

Next I used an angle indicator on the vertical table tubes. They were at zero aka perpendicular to all of the horizontal surfaces.

[dusty]

I am unable to draw any conclusion. This recent information would indicate that "all is well".

Does the main table still move out of horizontal as a function of raising and lowering the table???

You did not comment on binding. When you raise and lower the main table, do you experience any binding? If not, I would conclude that the tubes are NOT BENT.

[pfallert]

"BINDING". There was binding, but it was entirely the dust collector system. I adjusted the dust collector nearer to the blade and the binding ended, but now I get a lot more sawdust dropping. It is definitely not a tight system with large openings. Is there a thread about how to "fix/improve" the dust collector?

"TABLE SHIFTING". Drew a line on the main table (left to right) in line with the center of the axis of the spindle. This line I planned to use as the only place to measure if the blade was perpendicular. I placed a 2 foot level (tested accurate by reversing it on a level workbench). I followed the instructions (above) raising and lowering the table while observing the level. To those instructions I added an observation of the "locked" and "unlocked" change in level. The level had to be shimmed .013" higher on the right side when the hand wheel is unlocked than locked. Locking the hand wheel definitely shifts the table. I noticed that the bottom of the table on the left side was resting on the headstock casting, so I used the micrometer-stop vertical tube accessory to keep the front vertical tube lifted 1/4" above "bottom".

"LOOSE VERTICAL TUBES" - not loose when locked, not sticking now that the dust collector was moved. Tubes look like new. BTW, I bought this DEMO from SS as a 510 and it has been upgraded to a 520. It has not had a lot of use since I have had it.

"SETTING PERPENDICULARITY". With the table riser locked in the bottom location, the table was adjusted to 90 deg to the blade. Made a "test cut". Good. Raised the table, watching the level and locked the table riser. It is then the I realized that there was a problem with method I used to check if the blade (sticking above the table by 1") was perpendicular. As someone had noted, there is some taper in the blade (.001") at the outer edge. I then removed the zero clearance insert and held a straight edge down to the blade hub securely against the blade and with my third hand, place the square against this straight edge. It was good. Checked the protractor/pointer on the front trunion. It was "off" by one line. Aha! Now we are getting somewhere.

"TABLE NOT FLAT" Discovered that the table is not flat. There are high spots. One of them is located on the right side of the blade and it is the right side of the t-slot that is raised, measured to be .002" above the rest of the table. When a straight edge is placed from left-right to the right of the blade and it is pressed down, it rocks and when it is (in PLAN view) shifted, the point of rotation is at this spot. Also found another similar spot to the left of the blade and nearer the operator. This table, btw is the replacement table.

"TRUNIONS AND CROSSBAR" no cracks or tightness.

"New tool" I took a straight 3/4" x 5/8" x 8" birch-ply stick and added to high strength magnets. Used this against the blade to hold it there while using a square to gauge perpendicularity. "Patent Pending" You'll see this in the next ShopSmith ad !

Is there a thread that discusses a method of minimizing the changeover hassle with the outer table when changing table height?

I want to thank everyone for their ideas and suggestions. Every suggestion helped a lot. Thank you all!

Paul

[jsburger]

"BINDING". There was binding, but it was entirely the dust collector system. I adjusted the dust collector nearer to the blade and the binding ended, but now I get a lot more sawdust dropping. It is definitely not a tight system with large openings. Is there a thread about how to "fix/improve" the dust collector?

"TABLE SHIFTING". Drew a line on the main table (left to right) in line with the center of the axis of the spindle. This line I planned to use as the only place to measure if the blade was perpendicular. I placed a 2 foot level (tested accurate by reversing it on a level workbench). I followed the instructions (above) raising and lowering the table while observing the level. To those instructions I added an observation of the "locked" and "unlocked" change in level. The level had to be shimmed .013" higher on the right side when the hand wheel is unlocked than locked. Locking the hand wheel definitely shifts the table. I noticed that the bottom of the table on the left side was resting on the headstock casting, so I used the micrometer-stop vertical tube accessory to keep the front vertical tube lifted 1/4" above "bottom".

"LOOSE VERTICAL TUBES" - not loose when locked, not sticking now that the dust collector was moved. Tubes look like new. BTW, I bought this DEMO from SS as a 510 and it has been upgraded to a 520. It has not had a lot of use since I have had it.

"SETTING PERPENDICULARITY". With the table riser locked in the bottom location, the table was adjusted to 90 deg to the blade. Made a "test cut". Good. Raised the table, watching the level and locked the table riser. It is then the I realized that there was a problem with method I used to check if the blade (sticking above the table by 1") was perpendicular. As someone had noted, there is some taper in the blade (.001") at the outer edge. I then removed the zero clearance insert and held a straight edge down to the blade hub securely against the blade and with my third hand, place the square against this straight edge. It was good. Checked the protractor/pointer on the front trunion. It was "off" by one line. Aha! Now we are getting somewhere.

"TABLE NOT FLAT" Discovered that the table is not flat. There are high spots. One of them is located on the right side of the blade and it is the right side of the t-slot that is raised, measured to be .002" above the rest of the table. When a straight edge is placed from left-right to the right of the blade and it is pressed down, it rocks and when it is (in PLAN view) shifted, the point of rotation is at this spot. Also found another similar spot to the left of the blade and nearer the operator. This table, btw is the replacement table.

"TRUNIONS AND CROSSBAR" no cracks or tightness.

"New tool" I took a straight 3/4" x 5/8" x 8" birch-ply stick and added to high strength magnets. Used this against the blade to hold it there while using a square to gauge perpendicularity. "Patent Pending" You'll see this in the next ShopSmith ad !

Is there a thread that discusses a method of minimizing the changeover hassle with the outer table when changing table height?

I want to thank everyone for their ideas and suggestions. Every suggestion helped a lot. Thank you all!

Paul

So what was all this about? Seems like you have a no problem. You are talking 10 thou or less. That is nothing in wood working. What have I missed? This seems a lot of angst about nothing.

Do you really think your Birch ply tool will be more accurate than 10 thou?

[dusty]

We are not all as sharp as you are, John.

I learned a lot while following this thread.

[dusty]

Paul, yes there is some discussion here on the forum regarding dust collection and how to improve it.

This may help with your dust collection issue. It did mine.

http://www.shopsmith.com/ss_forum/viewt ... ion#p70908

http://www.shopsmith.com/ss_forum/viewt ... ge#p108456

[pfallert]

You asked...what is all this fuss about, .010" ? In short, "NO", that's what is wasn't about.

The cause was not excessive looseness or a bend in the vertical pipes, since the TIR = only .010".

This SS 520 has several defects and if it is not aligned in a way that minimizes these defects, when ripping a 3/4" board, the edge of the board will not be square by 1/16" in 3/4", making for really lousy joinery ! And that was a big deal, because I can do better than that with a handsaw.

Thanks to all of those who patiently and intelligently helped track down the actual defects and more importantly helped to avoid replacing stuff that was not broken.

Finding the actual defects made it possible to develop a simple procedure to avoid the defects during setup and get repeatable square cuts.


Aside: As far as the birch 7-ply stick is concerned, although it sounds crude, it is extremely stable and straight. Because it is long, it magnifies any error in the table angle. It could have been made from a piece of UHMW plastic with the embedded magnets, but I needed to make a quick prototype as a proof of concept and it worked in that capacity.

[Ed in Tampa]

You asked...what is all this fuss about, .010" ? In short, "NO", that's what is wasn't about.

The cause was not excessive looseness or a bend in the vertical pipes, since the TIR = only .010".

This SS 520 has several defects and if it is not aligned in a way that minimizes these defects, when ripping a 3/4" board, the edge of the board will not be square by 1/16" in 3/4", making for really lousy joinery ! And that was a big deal, because I can do better than that with a handsaw.

Thanks to all of those who patiently and intelligently helped track down the actual defects and more importantly helped to avoid replacing stuff that was not broken.

Finding the actual defects made it possible to develop a simple procedure to avoid the defects during setup and get repeatable square cuts.


Aside: As far as the birch 7-ply stick is concerned, although it sounds crude, it is extremely stable and straight. Because it is long, it magnifies any error in the table angle. It could have been made from a piece of UHMW plastic with the embedded magnets, but I needed to make a quick prototype as a proof of concept and it worked in that capacity.

Could you summarize what you found? You mention defects that you found and I'm wondering what they are. I realize you found your table was not flat and that the blade itself has taper.
But was here anything else?
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.