Typically after careful adjustments to the aux table mounted on the right end to align it to the main table, it will not be so when mounted to the left end.
The Mark 7 has been hailed as not having this problem. The reason for that is the end castings are identical due to the dual tilt capability.
It has been my contention that a Mark 5/V can achieve that as well if the base is adjusted correctly. The critical alignment has to do with the lack of the way tubes twisting, and the end castings being parallel to each other front to rear.
A culprit is the 'leveling' setscrew that provides a resting surface for the tiebar. To add to the confusion, adjusting that rest has been touted as a solution for related alignment issues. Blindly adjusting that screw without consideration for where it actually needs to be can create other problems.
So, I offer the following as a way to shed light on how it should be adjusted.
I preface this with the admonition that the main table must be properly adjusted to be perpendicular to the saw blade vertically and the miter gauge slots parallel to the outer face of the saw blade. Without that all else is not likely to achieve left right compatibility anyway.
Also ALL clamps need be tightly secured when making ANY measurement etc.
The methods to so align the main table have been repeatedly covered elsewhere in this forum and will not be repeated here.
It is my intention to address a neglected/misunderstood alignment of the base assembly that makes the left/right compatibility possible. It essentially achieves the same left/right alignment of the end castings similar to that accomplished with the mark 7 design(identical left/right parts).
So the first step is to acquire a gauge that can be mounted to either spt mount and provide a reference relative to the spindle.
Aux table mounting tubes are a convenient source. The mounting base is marked so as to locate the center mid way between the vertical spt mount tubes. A 1/2" router chuck and a counter sink bit with a 1/2" shaft works as a 'pointer' that coincides with the axis of rotation of the quill.
The first two pix show the base mounted in both orientations. That illustrates that it matters not how the base mount is oriented.
The router chuck and countersink bit are mounted on the quill shaft, and the quill extended so as to reach the base mount at its midpoint.
- centered right a.jpg (396.92 KiB) Viewed 2756 times
- centered right b.jpg (490.3 KiB) Viewed 2756 times
That alignment should be automatic. i.e. I did nothing to make that alignment happen. Since the end casting cannot impart a twist to the way tubes at that end, the quill axis should always project to the mid point between the spt mount tubes. The only adjustment I made was to set the height of the mount and attach stop collars so as to achieve the same height repeatedly.
So now how about the left end? Move the router chuck with countersink bit to the upper shaft on the back of the headstock. Move the spt mount to the left end. Slide the headstock to the left until it is barely short of reaching the mount.
The next two pix show the rest setscrew is not adjusted correctly.
- off center left rear low.jpg (553.49 KiB) Viewed 2756 times
- off center left back high.jpg (329.23 KiB) Viewed 2756 times
Now for the difficult part. That setscrew is humongous and not easily turned. The newer Mark V has a hex head socket screw. The older Mark 5 has a slotted head screw. A large bladed screwdriver is needed for that.
Now this tweaking must be done accompanied with other tweaking that assures the tie bar actually comes to rest both at the front on the casting, and the set screw at the rear. Moving the set screw alters the tightness of the clamp. Raising the set screw causes the clamp to become tighter. The inverse is true when the screw is lowered.
The clamp MUST assure the tie bar rests firmly on the casting and setscrew with no slop. The clamp has a tapered head(like a flathead screw) that nests into a tapered(similar to a counter sink hole) hole that makes the clamp center the tie bar to the screw. That occurs both laterally(front to rear) and vertically. It is the vertical clamping that becomes critical. If there is vertical play, the tie bar will not rest tight to the casting and setscrew.
So the clamp screw must be continuously readjusted as the rest setscrew is adjusted. It should not be so tight as to bind when the clamp handle is lowered, but also the tiebar must not move vertically when pulled up with the clamp secured. A lot of adjust/test/repeat necessary.
I did not take a pix of the left with the setscrew properly adjusted, but it would look essentially the same as the right.
There is rotary flex in the way tubes so the tiebar must be tightly secured.
Hoookay that takes care of the 'twist' issue.
We ain't done yet.
The following will apply to the Mark 7 as well(I say that with no hands on with the Mark 7 hardware).
The second criteria is the spt tube mounts being parallel to each other front to rear. Lack of that parallelism will cause the rip fence to not be parallel to the miter gauge slots on both ends. The 'fix' is to rotate the end castings on the bench tubes.
No pix, but that is accomplished by loosening the screws on the bench tube clamps and rotating the casting. When the end to end distance between the spt bores is the same at the front and rear the fence should work at either end. I measured that distance by inserting the 'gauge' in one end and the aux table at the opposite end and measuring the distance between the tubes both at the front and at the rear. A final fine tuning can be done by measuring the fence to miter slot the same as when adjusting the aux table at the right end.
My results last night are illustrated here.
http://www.shopsmith.com/ss_forum/viewt ... 99#p193899
