What's wrong with my table?

[JPG]

Good point! I did not include that above since it adds an ADDITIONAL thing that does not contribute to solving the current problem.

For sure it needs to be checked prior to use and any adjustments will not alter the current fix(almost since table shims will affect everything(maybe).


Everything I said above is very much easier said than done!

[DLB]

It seems appropriate to point out that Double Tilt machines don't seem to exhibit any way tube assembly 'twist' and have no means of correcting for it (No 'big set screw.'). Knowing this leads me the conclusion that I don't understand twist. There is very little difference in the Base between the traditional and DT bench, essentially the DT Base Arm hinge holes are open rather than a full circle, allowing the Arm to separate vertically. Then a second Base assembly is used in lieu of the Headrest. Therefore, if the Base is the source of twist, it can only be because the hinge pin path is more constrained compared to the DT.(?)

Getting back to the basics here, the question is why the way tubes (upper) are not level front to back while the bench tubes (lower) are, and why the OP is having issues correcting it. IIWM I'd check that the Base Arm is level on the top of the casting directly above where the way tubes seat. I'd check this both with the Headrest locked and unlocked. If that is good, I'd check that the way tubes are reasonably straight by rolling them across a flat surface.

In looking closely at the OP's first pictures, I think I see damage to the Base. It's difficult to be sure because I'm losing the detail in shadows and photo resolution as I zoom in. But I'd guess it was damaged at some point by attempting to swing the machine vertical with an extension table or similar mounted. This may just be cosmetic, or my error, but I'd check the Base either way.

- David

[JPG]

The DT way tubes have the reference of the hinge pin at both ends. MV way tubes only have that at the hinge end. The headrest casting is not as precise so the big set screw allows adjusting twist out. Then there is the head rest clamp that can skew things if not properly adjusted.(it should not be pulling things other than merely securing)

I do not recall the Meng88 mentioning table front to rear tilt, however that will vary IF the way tubes have a twist.

Where do you see the base damage?

[lahola1]

Is the garage floor level? I had a similar problem of twist (tube assy not sitting flat on the base; like OP pic #4) on my MKV. I found that I had it sitting on a non level section of my garage floor. Move the SS to a different part of the garage and the twist went away.
Just a thought.

[JPG]

I think that would also cause the bench tubes to be twisted as well.

[DLB]

...
Where do you see the base damage?

This is where I think I see damage, circled locations. At the back, in this view, of the pass through holes for the extension table. It's in the shadows, so I'm uncertain. And it is superficial if present, but suspicious.

a1.jpg (97.71 KiB) Viewed 1077 times

- David