Mark 5/V Extension Table Alignment

[dusty]

From the bottom up, a pair of bench tubes, a pair of way tubes, an idler shaft and at top the quill shaft.

I am not sure why the way/bench tube angle is being measured. Perhaps to establish the bench tube/way tube/quill shaft relationships. The spt bores are what is relevant from this perspective.

In the second pix, the way tubes appear to be 'twisted'.(IIUC)

Keep in mind, the way tubes will only affect the main table.

Yes, they do appear to be twisted. but that is because I do not have the display set properly. Go fire up your Sketchup and play with a drawing prepared in 3D an presented in two point perspective. My fault. Poor draftsmanship. They are not twisted.

[JPG]

So the second pix indicates the way tubes are 'tilted'.(left appears higher than right)

[dusty]

For those of you with the Double Tilt Upgrade, be aware that the Pivot Arms are not necessarily centered or even positioned the similarly between the wings on each side of the Base Casting. I became aware of this while attempting to isolate the cause of my Extension Table issue. This condition will most likely not cause a problem and most of you can ignore this tidbit of information but I won't. I am going to cut shims to fit on either side of the Base to center it.

It is the small stuff that counts when attempting to isolate an elusive problem like "Lack of Interchangeability of the Extension Tables".

[dusty]

Another day and still another observation.

Shimming the Pivot Arm Assemblies so that they are positioned the same at both ends of the Bench/Way Tubes has eliminated the variability at the four corners. I have the tubes all positioned p[roperly with respect to one another. It may soon become time to check table interchangeability again.

[dusty]

The quest is over. Never let it be said that an Extension Table that has been aligned at the right end cannot be relocated to the left end and used as is when it gets there.

I'll not belabor this but it has all been procedural. I did nothing that has not been discussed here on the forum except that I did it all on one machine. I did it on a Mark V Model 520 that has been upgraded with the Double Tilt kit. Now that I understand the idiosyncrasies of the the table system, I am going to attempt all the same on my Shorty. I don't need swappable tables on the Shorty because I never use it that way but it is here so I am going to use it as a test bed.

I also plan to install the lift assist while I am doing that.

[algale]

Hooray! But I'd like a little more explanation of what was done and some photos (including of the shim locations)! Does this give you any better insight on how to accomplish the same on a standard 520 (without the double tilt upgrade)?

[dusty]

The appropriate pictures have already been posted. I took no additional pictures when I finished and I have the Mark V back in its normal position with the jointer mounted.

However,I do believe (as I said) that this same thing can be done on a standard Mark V. The issue on the standard Mark V I believe in with the headrest lock. The tubes (way AND bench) must be in proper position with respect to one another. The sketchup of the tubes (discussed yesterday or the day before) depict what I believe is the proper positioning. Symmetry is the issue and not dimensions. Drop a plumb bob off the ends of your machine and check for distance to the string from the tubes. It must be centered.

I previous post by another member discussed using lathe centers and the headrests at both ends to verify that alignbment.

It all plays together.

Main Table must be properly aligned and level. Hear that!!! Level! That means perpendicular to the blade (not horizontal) - perpendicular to the blade which is synonymous with parallel to the tubes. Nothing new! Just picky!!

[Ed in Tampa]

Curious! When I said my aux table worked on either end of my Shopsmith I think someone said I was full of crap. Now you say you got yours to work. Curious!

[JPG]

IIUC you gained success by minute alterations to YAW while making no adjustments to either ROLL or PITCH.

I can see that making the 'four corner' measurements the same, but fail to understand how such small 'shims' made success possible when it was elusive before.

This implies the casting bores are very accurate re 'perpendicularity' and the upper portion accurately registers on the hinge 'pin' which is itself 'perpendicular'.

[dusty]

I've been doing all of this on my garage floor. I have had no yaw, roll or pitch to deal with. Maybe, is I was working on a cabin cruiser.

Just lack of attention to all of the details not just the obvious ones.

The shim, by itself is not the issue that has caused all of this. It is all of the piddly things put together. As I said from the beginning, it has been procedural.

I am sort of surprised though that the Pivot Arms do not center themselves when locked down.