How I hooked up way too big QCTP to my lathe

[PekkaNF]

I have an old capstan lathe waiting for a resurrection, but now I have one another lathe I use pretty much. These two lathes are quite different size, but I want to have some common tooling between them. I was playing with the numbers figured that I could mount the bigger one in the smaller lathe, if give up the top slide. Since this flipping threading too seems to work, I can live with it.

So I ordered a QCTP with some spares that was perfect for the big lathe.

Had to fudge measurements and finally I came up with a plan that has a spacer on the smaller lathe, that is turned to thickness to make it possible to change tool holder between lathes without too much adjustment.

Another criteria was that it had to be easy to remove to use original tool post with the topslide.

Anyway 80 mm by 110 mm by 25 mm hot rolled steel section was surfaced and markked.

Then I pinned it and clamped to the milling machine to drill the pilot for counterbore, drill 6,8 mm hole for M8 thread (this goes to cast iron cross slide) and finaly a couterbore for M8 cap screws.

Notice my crap-o-Z-set.

Notice my ATC

Pekka

[PekkaNF]

Then next consideration was where to place the TP on the relation of the foot?

Figured that because I'm going to use that big chunky TP for purposes the original poxy TP is no good, I better place it to gain maximum rigidy.

I can punch another M16 thread later where I want, internal turing was my concern.

I drilled start hole with a stub drill, then 14mm drill for M16 tap. Nothing special.

Had to use as it is to turn the spacer.

Pekka

[PekkaNF]

Now the spacer.....

Only purpose of it to bring the TP in such a height that I can use smallest internal boring tools and normal lathe tools. So I had one tool holder adjusted such that when I subtract from centre height the measured height I'll get spacer thickness.

Only problem was that only piece I had proper size steel available was marked all over with permanent marker "tool steel". Changed a new blade to band saw and proceed slowly, it went down really slow and generated a big mess. But came out perfectly straight.

Only thing left to drill pilot, square, and bore hole.

Works out fine, I have to work it and see what to following items:
* Needs a bolt down, need to see local bolt shop if they have one with ratchet handle or make one
* I have to figure out where to put another M16 hole for an alternative place for large diameter boring.
* needs camfering and cosmetics, after I know where to hack off the extra metal.

Now I only need a threading holder and one contraption to mount one spindle to QCTP to test how much power I need for a sptting drill and then I can get to real spotting drill spindle building!

Pekka

*phfff! Picture DSCN0093 lies. The 16 mm tool holder cutting edge will align completely middle of the leading cross slide shear (bearing surface of the slide to apron guide).