Saw Kerf with respect to the insert centerline

[dusty]

Hi,

Table stability was given a major upgrade with the addition of the front/rear rails and tubes. You now can have 4 or even 6 vertical tubes. To see this major improvement you need to add an extension table then a set of bars to connect the main table and extension. BINGO major improvement.

Keep in mind you are after getting a blade to center line on an insert while my work was done to obtain repeatability, they just happen to have overlapping areas.

I guess if I felt compelled to center the cut rather then have a kerf edge on the center line I might visit the washer that Red mentioned. They were once upon a time changed out and thus could account for portions of your "misalignment".

The second change could be caused by how the main table is aligned. We have a 1/2" hole and a 3/8" bolt, if they happened to be centered in one direction in the design then when adjusted could be a 1/16" off with no problem at all (either way). So the next time you have the main table loose for alignment it is likely you will need a new spacer.

Have you had time to see what effect your offset has with splitter alignment alignment?

BTW I did look at the standard table insert and yes it slot is centered.

Just a few more things to think about.

Ed

I understand your comments regarding repeatability. Due to that factor, the kerf cut in an insert WILL NOT remain pristine. It will become ragged as a result of the blade running slightly different each time the table is raised, lowered, locked and unlocked and moved.

I don't think the sp[litter will have changed but I'll check on that. Thanks for that comment. It could certainly be a safety issue.

[dusty]

Some one here on the forum said this and I chose to disregard it. However, I am now beginning to think that he was absolutely right or at least there is a much better than even chance that he is right.

Drilling out the holes in the trunnion just might have led to this centerline issue that I have been chasing.

I began thinking this way while I was using the drill press. I have the drill scribed in the side of my 520 rip fence. Today, after drilling three or four holes that were "off", I came to realize that the drill line (on the rip fence) is now improperly located.

Moving the table on both the x and y axis could conceivably have caused those changes.

[algale]

Some one here on the forum said this and I chose to disregard it.

I think that would be me, as I had just drilled my trunnions and gone through the alignment dance when I you posted about the problem. So it was on my mind..

However, I am now beginning to think that he was absolutely right or at least there is a much better than even chance that he is right.

Drilling out the holes in the trunnion just might have led to this centerline issue that I have been chasing.

I began thinking this way while I was using the drill press. I have the drill scribed in the side of my 520 rip fence. Today, after drilling three or four holes that were "off", I came to realize that the drill line (on the rip fence) is now improperly located.

Having trouble visualizing what you are describing.

Moving the table on both the x and y axis could conceivably have caused those changes.

Sure. The 1/2 inch holes front and back of the trunnion will allow movement in both directions. And if you are trying to get parallel without paying attention to centering, this could easily happen.

[JPG]

I posted this over on the arbor thread thinking it was this blade/slot alignment thread.

It really belongs here, so here is a link to it! https://forum.shopsmith.com/viewtopic.php?p=110573&postcount=8

[dusty]

I think that would be me, as I had just drilled my trunnions and gone through the alignment dance when I you posted about the problem. So it was on my mind..


Having trouble visualizing what you are describing.



Sure. The 1/2 inch holes front and back of the trunnion will allow movement in both directions. And if you are trying to get parallel without paying attention to centering, this could easily happen.

Without drilling the holes but with all four trunnion bolts loose, you have very little movement of the table other than left/right. After drilling the trunnions the table readilt moves (with limitations) in all directions.

I suspect that I moved the table to the outfeed side and to the left when I did the alignment after drilling the trunnions and have maintained that position ever since.

Until a short while ago that is. Reacting to a recent post about table alignment, I loosed all four bolts and did a table alignment using my short cut procedure. Table was aligned to the blade without concern for movement infeed to outfeed direction.

If this is the case, returning the table to the exact location in all directions could be a real bear.

[algale]

Without drilling the holes but with all four trunnion bolts loose, you have very little movement of the table other than left/right. After drilling the trunnions the table readilt moves (with limitations) in all directions.

I suspect that I moved the table to the outfeed side and to the left when I did the alignment after drilling the trunnions and have maintained that position ever since.

Until a short while ago that is. Reacting to a recent post about table alignment, I loosed all four bolts and did a table alignment using my short cut procedure. Table was aligned to the blade without concern for movement infeed to outfeed direction.

If this is the case, returning the table to the exact location in all directions could be a real bear.

I'll bet you will also find that the extension table is no longer properly aligned to the main table on the Y axis either, which will confirm what you found by accident when your fence scribe line no longer accurately showed the Y axis location of the quill relative to the table in drill press mode.

As you say, getting the main table back to some theoretically ideal X/Y location (saw blade centered side to side and front to back in the blade slot) is going to be very hard to do while maintaining parallelism of the blade to miter slot. I'd just re-align the extension table to the main table and call it a day. The most the trunnion "fix" could cause the table to drift out of the hypothetically ideal X/Y position is 1/16th left/right and 1/16th front back. I can't see how this would have any impact on the functionality of the machine. In contrast, being out of parallelism by 1/16th can be a problem.

[dusty]

I'll bet you will also find that the extension table is no longer properly aligned to the main table on the Y axis either, which will confirm what you found by accident when your fence scribe line no longer accurately showed the Y axis location of the quill relative to the table in drill press mode.

As you say, getting the main table back to some theoretically ideal X/Y location (saw blade centered side to side and front to back in the blade slot) is going to be very hard to do while maintaining parallelism of the blade to miter slot. I'd just re-align the extension table to the main table and call it a day. The most the trunnion "fix" could cause the table to drift out of the hypothetically ideal X/Y position is 1/16th left/right and 1/16th front back. I can't see how this would have any impact on the functionality of the machine. In contrast, being out of parallelism by 1/16th can be a problem.

These issues have NO IMPACT on functionality - you are correct in that statement.

The initial centerline issue was also really just an annoyance.

BUT - I will eliminate those annoyances OR understand the reason why I cannot. This is just my nature. It is a good thing I have two Mark Vs and that I am retired (have time to spare).

I think I understand why you say that movement of the table is limited to 1/16" but it sure seems that when all four trunnion bolts are loose the table can be "moved all over the place".

I'll start this endeavor in the drill press mode. I want to verify that I can correct that alignment to the mark I previously scribed on the rip fence. If I can move the table enough, toward me, that issue is resolved.

Then it is on to a full table alignment.

Once the normal alignment is finished, I'll create reference points (lines) so that I can return to that position later.

THE QUESTION BEING ANSWERED now is "Did drilling the trullions allow enough movement on BOTH the x and y axis to create this situation"?

[algale]

Perhaps i should have said at most the trunnion fix could have permitted an additional 1/16th movement in any direction. The total amount of movement is a function of the difference between the trunnion hole size and the cap head bolt diameter divided by two. Keeping the same diameter cap head bolt and increasing the trunnion hole from 3/8ths to 1/2 is an extra 1/8th clearance divided by 2 gets an added 1/16th movement over what ever there

[dusty]

Algale: To you I am indebted. Your comments sent me off on an excursion that really paid off. I now much better understand the Mark V table alignment.

If you had not commented on the trunnion bolts, I would still be battling my centerline issue and would have added to that the drill press issue.

By loosening all four trunnion bolts and then repositioning the main table while taking into consideration both parallelism and drill press centerline, I have resolved both issues.

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I now have spare rubber bumpers coming from Shopsmith. With the carriage slid up against the old bumper, the saw blade is centered on the insert centerline. Mystery one solved - solution: correct the table positioning before alignment. Pushed table toward the headstock and pulled the table to the infeed side simultaneously and then aligned for parallelism while taking care to move the table no more than absolutely required.

[robinson46176]

Having fixed that issue the motor will probably now fall out of it.


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