Raising Shopsmith Taller

[DLB]

As you probably already know, there are several versions of the involved parts that are both older and newer than yours. I have an older one that is similar, and to be blunt it does not really lock to the carriage very well. Unlike mine, your arm looks like it is removable from the post with a setscrew that also allows rotation. The low budget improvement is to get the newer type of post that does not have 'rack gears' going all the way around it, more similar to the table post but for the tool rest. This will mechanically limit rotation to a few degrees. Here is an example of what it would look like: https://www.ebay.com/itm/Tool-Rest-Hold ... SwzLVe0WH4 I don't see any of these posts available by themselves right now though. The only post by itself is the same or similar to yours. There are other choices of getting either a complete '500' style tool rest or a 510/520 two position tool rest.

I'm deferring to anyone on which tool rest is better with the small (500) carriage, I have never used a two-position tool rest like that.

There are two or more versions of the larger 510/520/M7 carriage and in my opinion the later one does a lot more gripping of posts. I've never looked close enough to know if older carriages could be modified to match or whether it could also be used on a 500. This might be something to search older posts for. The short version is that the casting is 'cut' (perhaps not how it is done) vertically on one side of the mounting holes. I think this allows the clamping system to clamp the casting down on the post, more like how the quill is locked. If this can be retrofit to a 500 carriage it might work for you. I'll go see how my old quill locks up in a 520 carriage and report back.

You make a good point that it might make sense to start a new thread on this, it is a bit of a departure from the subject. It will be easier for someone to find with a new title.

- David

[JPG]

Let us speak of the parts that affect 'clamping'.

aaatemp.jpg (7.23 KiB) Viewed 7118 times

In the center is a long square cross section rod. The far end has a groove and a clip. The clip presses against the rear pinion gear. The 'part' pointed to by the arrow presses against the front pinion gear. The pinion gears are free to slide on the rod. When the wing nut is tightened, the front 'part' moves the front pinion gear inward. In tightening the effective length of the rod is decreased so a similar(inward from the back) motion is imparted to the rear pinion gear. The pinion gears have a bevel on the outer side that put a squeeze on the table or lathe post. IF the posts are not present, the flanges on the outer ends of the pinion gears squeeze the carriage casting. That force from tightening the wing nut MUST NOT be impeded by anything. The 'part' must be free to move along the rod. That part should be the clover leaf shaped thingie that allows alternate lever location.

BTW I have never noticed a rusty version before.

The sleeve that the lever screws into must NOT interfere with the wing nut pressing against the 'part'.

The front pinion gear appears to NOT be bottoming out in the bore, but rather is pressing against the post. So I do not see why it is 'loose'.

The only clamping action being accomplished is the front pinion bevel against the tool rest post. Small area of contact.

Assuming all the parts are functioning correctly,(no interferences) perhaps help from a gorilla is needed. Never thought I would say that!!!

[shoe4hire]

Full disclosure: I just finished a 50+ year career as a chemical/mechanical design engineer. In some of that time my dear SS endured 15 years in Saudi Arabian salt air while I wrestled dragons of many kinds in that blessed place. My SS Mark V was a gift from my wife in '82 - THE BEST GIFT EVER!!

Many thanks for the detailed replies. I've had my SS apart numerous times and do not see any but basic design faults for the movement in the tool rest post (for instance, a rectangular post with a wooden handled all-thread set screw might have been a better design - I think the 510 and a tool rest upgrade had something like this (thanks DLB) - I am considering something like this as a solution to my problem to include a set screw in the threaded post, although that might fix tool height).

The table height and the lathe tool height function is faultless. But, the tool rest post rotates even when using gorilla level force (I've been called an ape and worse) on the T bar (wing nut). I'm concerned that I might break something... Many posts on this...

I've scanned through 45 of 93 pages of the forum search of "loose tool rest" tonight and am near concluding that the UTR is my only reasonable solution, although possibly outside the current budget (today is my birthday...). I did find a post about building a tool rest that might have legs... I'll finish the 93 pages and decide on a plan...

Thanks again!!! This forum rocks!!

[shoe4hire]

Thanks for the reply !

To get through the current project (a walnut trimmed bowl on a faceplate with a walnut vertical inclusion) I have chosen to use a clamp to secure the post from rotation.

It's not easy to see but the graphic shows how the clamp can (crudely) prevent the rotation of the post for this turning. May not work in all cases.

[DLB]

My old tool rest is a bit better in the new style carriage, but with moderate force that old style post can still rotate in the bore.

The 'newer' style post with the rack on just one side is prevented from rotating by the mechanical design in all carriages, won't rotate more than a few degrees even with the lock loose. It's like a "D" shaped peg in a "D" shaped hole.

- David

[JPG]

I gotta ask - does the 'rusty'/clover leaf shaped part extend beyond the sleeve the handle screws into so the wing nut directly applies force to the rusty part? i.e. the sleeve is free when the handle is removed.