Shopsmith Forums

For some time there have been lamentations regarding the inability to achieve alignment of the aux table so as to use it on either end(right/left).

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.

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.
I apologize! The pix description is incorrect. reverse 'low/high'.

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

Thanks for posting this. I'll have to take to the shop and check this out. As I have said, my set screw is inconsequential (on my machine). This may lead to an explanation of why.

I have been to the shop and it was an enlightening effort. I don't know exactly where I go from here but these two images show what I have to start with. It is important to know that I have two Extension Tables that do not maintain table top alignment if I swap them from end to end. Used where they were aligned, they are as close to "right on" as I need them to be.

It is also important to know that the set screw in the tie bar (on my machine) is not being used. It is screwed in where it touches nothing.

JPG has offered a procedure that is intended to correct the problem that I have. It looks to be very viable.
I would normally consider what we are seeing here as "close enough" but given the circumstances I am not going to do that.

Where is the set screw? It is in the tie bar (on the left end) on the outfeed feed side. If I use the set screw, what will it do? I THINK it will move the pointer on the left side toward the infeed side of the machine. This appears as though it would correct the problem with the pointers. I don't know what it would do for table top alignment.

I wonder why that set screw is located in such a difficult position?

See third and fourth pix. They are taken from below. I noticed in the video yesterday, that it was inverted(socket up). Another thing 'wrong' with the video.

http://www.shopsmith.com/ss_forum/viewtopic.php?t=3823

I now consider the method posted here to be a better more accurate way to 'level the way tubes'.

Keep in mind it is imperative to assure the tie bar is actually against the end casting/setscrew when clamped down. Otherwise ye be resting on air.

Raising the set screw moves the mount towards the front. Yours is already too far forward. That is why I repeated the need for the tie bar to be in contact with it clamped. It MUST be tight against the casting/screw. It takes considerable force to make that happen. The clamp needs to be adjusted very carefully. Too tight and it binds. Too loose and it does not accomplish the 'tightness'. Pulling up/rocking the way tubes should not cause any movement off the casting/setscrew.

What this corrects is the table tilting front to rear differently on left.

Do not overlook the need to rotate the end casting to provide rip fence/left = rip fence right.

I have no 'fix' for the side to side tilt of the aux table. I be suspicious of rails when using tubes. Shimming the way tubes may be an option.

The mounting tube clamps are another potential source of consternation.

JPG wrote:Raising the set screw moves the mount towards the front. Yours is already too far forward. That is why I repeated the need for the tie bar to be in contact with it clamped. It MUST be tight against the casting/screw. It takes considerable force to make that happen. The clamp needs to be adjusted very carefully. Too tight and it binds. Too loose and it does not accomplish the 'tightness'. Pulling up/rocking the way tubes should not cause any movement off the casting/setscrew.

What this corrects is the table tilting front to rear differently on left.

Do not overlook the need to rotate the end casting to provide rip fence/left = rip fence right.

I have no 'fix' for the side to side tilt of the aux table. I be suspicious of rails when using tubes. Shimming the way tubes may be an option.

The mounting tube clamps are another potential source of consternation.

I am not following what you say here. Please explain "rotate the casting".

However, I came here now to say thank you. You have done an excellent job with this explanation and I am here to say that it does work. All of it. It was not easy to make myself do some of what I did simply because of years of habit (many years).

I modified the procedure for adjusting the Extension Tables slightly but I did that only after I had worked on the set screw issue. My tie bar now touches down on both sides of the casting (one side bei9ng the set screw). Long ago I backed the set screw off and have worked with that way for many years. I now believe it was tolerable because I seldom move this machine. Once it was aligned, it pretty much stayed that way. I still won't move it much but it is good to know that alignment will probably not be effected if I do.

As for the change in procedure. I aligned both Extension Tables to mate with the Main Table on the right side. This is where the Main Table can be moved right up against the edge of the Extension Table. I clamped the straight edge (in my case a level) to the top of the Main Table and then adjusted the Extension Table to bring it firmly against the straight edge (minimal light gap).

The completed Extension Table was then moved to the left side and the procedure was repeated for an extension table on the right side. Both being aligned in the same location was my way of convincing myself that other forces were causing the alignment phenomena.

Low and Behold, when I swap Extension Tables back and forth from end to end there is very little difference is table top alignment. That is to say that the table tops are all is the same horizontal plane (almost). To approach a condition where I could rightly use the word "precisely" in the same plane I would have to tweak on the set screw adjustment.

I chose not to do that right now because I am about to remove the lift assist from that machine and install it on the other. When I remove the lift assist, I expect some changes in alignment.

Again I say Thanks JPG. Good Job, Well Done.

I am pleased that this has resulted in 'co-planarity'.

As for rotating the castings, that is to insure the rip fence is consistent when the table/fence is mounted on either end. I assume setting the fence to the miter gauge slots, then the aux table/fence is common procedure for you. You may may be doing that with the rails/tubes(indirect but adequate if all else is correct). <<<< edited

However moving the table to the left will not produce miter slot to fence parallelism unless the castings(spt mount bore center lines) are parallel to each other.

To rotate the left casting involves loosening the screws securing the BENCH tubes to the casting. Then twisting the casting(leg and all) about a vertical axis.

Measuring from fence to miter gauge slot at front and rear will indicate when the fence is parallel(just like on the right side, but the table/mount is NOT adjusted, but rather the 'whole end'.)

The parallelism can also be checked by measuring end to end the distance between the spt mount bores at both front and rear. Using table legs in the bores make that possible to measure otherwise the headstock/carriage get in the way.

Another edit:

The lack of parallelism should also be apparent with the rail/tube fit/alignment. However I think the tubes can deflect enough to disguise it. The single clamp in the center etc.

I must be thick unless you are saying to verify that the rip fence remains parallel to the blade (miter slots) no matter where it is installed along the rails, even on the Extension Tables. If so, I understand.

Anytime I mount the rip fence on either the floating tables or the Extension Tables, I verify proper rip fence alignment before I make any cuts. There is a real good reason for that which we really do not need to discuss. It is one of the reasons why I have a cross cut sled.

What I am attempting to say is that the rip fence will not align correctly to the miter gauge slots when mounted on the same extension table at both sides unless the spt mount castings are parallel to each other.

Since I align the Extension Tables with their rails attached to the Main Table using extension tubes, I believe I achieve rip fence alignment by default. The Extension Table rails are simply an extension of the Main Table rails and therefore are perpendicular to the miter slots. When the rip fence is mounted on that rail, it will be perpendicular to the rail and therefore parallel to the miter slots.

Yes, those are a lot of assumptions and the conclusion that I draw is dependent on the accuracy and repeatability of all associated alignments.

I do understand now what you are saying and warning against. You are absolutely correct in all regards.