Don't you need an arc to set the top slide over for an angle?

With the toolpost far over to the left will you be able to get enough tailstock extension when turning between ctrs? You may find the tool won't come far enough to the right to start the cut

Further to Jasons concerns.

There seems no reason why the idea wouldn't work just as well with a single tapped hole in the bas plate to simultaneously hold both spacer and toolpost. Does that way It would be relatively simple to add another tapped hole for the stud close to the centre of the base block so the assembly can easily be moved on the (rare) occasions it might be necessary.

Although the 4 bolt mounting via the Tee slots makes turning the whole base round simple I suspect this would just shift any access problems from tailstock end to headstock end with no net gain.

Clive

Well it works well for the WM250 (as per the article you linked to) so I see no reason why it should not work for the WM290 with suitable amendation of the dimensions.

I note you have opted for a rectangular base-plate with the tool post front and centre. This will limit options as to tool position. The square with post at the corner (as per original) allows for rotation of the assembly so the toolpost can be in one of four locations as required. The whole base-plate can be slid back and forth in the T-slots to further aid getting the most suitable position.

John

The only proviso is that if the tool post is moved to the right will you get close to a large chuck's jaws

Jason

I agree with what you are saying and what you have drawn.

 had assumed that fitting the carrier plate via the tee slots would let the whole set up be pulled towards the outside of the cross-slide sufficiently far to avoid the situation you have sketched. Ideally the toolpost needs to be far enough out to run past the side of the tailstock casting. A situation I'm not always able to arrange with my S&B 1024 so even high end machines can suffer.

Extra mounting positions, as you show in your third post are clearly a sensible option for dealing with this sort of thing. But down the centre of the plate may not be the best location. If the situation in your pervious sketch occurs then off centre towards the outer edge may be better.

CAD makes it so much easier to deal with this sort of clearance issue. 2 hours on the computer has saved me lots of grief several times in the past.

I still see no advantage to the separate fixings for the block. A single stud and locating pin will do just as well and make moving much easier. When dealing with a sufficiently similar situation I made the stud with a ring drilled with pin spanner holes partway up it and counterbored the top of the block so the ring was beneath the upper surface when tight. Applied to this case the upper part of the stud behaves as normal to hold the toolpost. If it ever becomes necessary to move the block the stud can be undone with the pin spanner.

Clive

Edited By Clive Foster on 25/02/2023 21:16:27

I should think 8mm bolts would do the job. I was thinking I might add a couple of dowel pins between the base and the round turret for positive location though. Or at least countersunk screws coming up from the bottom so they locate on the angled countersinks. I would not rely on clamping force there because any tiny movement will affect finish, chatter, precision etc.

On the vaguely similar fabricated one I made for my Myford, I welded those two pieces together to form in effect one solid block. Solid is the object of the whole exercise with such a toolpost.

Edited By Hopper on 26/02/2023 03:03:04

Jason

I fear we have gotten at cross purposes. Again!

As I understood things the issue is avoiding this situation:-

where the tailstock barrel is undesirably extended to clear the toolpost. There is a considerable gap between tailstock base and cross slide.

If the toolpost mount is moved outwards it can clear the tailstock casting like this :-

considerably reducing barrel extension and bringing the tailstock base close to the cross slide.

I think it inevitable, most especially with a smaller lathe, that one toolpost position suits all is pretty much impossible without work arounds involving undesirable tooling arrangements such as long stick outs or tool shifting mid job. Accepting that it seems sensible to not only provide several alternative positions for the toolpost and its mounting block but also make it easy and quick to move. If it's not quick and easy you won't shift it and struggle to do the job with things as is taking three times as long with worse results and considerable profanity. Human nature, Been there, dunnit, got the tee shirt and wrote the book.

I would use a simple stud of suitably hefty dimensions and just drop the block on relying on a locating pin to ensure it always goes back where it should. I'd also fix a locating pin to one of flat sides of the toolpost to either engage with the teeth of a flat gear affixed to the top of the block or drop into a one of a ring of holes drilled in the top of the block. Best to drill and tap the toolpost for couple of screws to either hold the locating pin directly or via a tube so it can be slid up out of the way when using the toolpost on the compound slide. Having the pin you may wish to consider whether some sort of rotational indexing can be arranged when using the compound.

Clive

Edited By Clive Foster on 26/02/2023 10:24:25

Why not make it square as per the 250-222 tool post [if you can]?

Tony