Help me buy a QCTP

[Vinny]

From the MSC catalog (page 676), the range from the top of the compound to the height of the top of the tool:

http://dirxion.mscdirect.com/ukbigbook/2...Id=6.5.7.5

AXA 7/8" - 1 5/8"
BXA 1 1/16" - 2 1/8"
CXA 1 1/4" - 2 1/4"
CA 1 9/16" - 2 3/4"

Aloris has a table of lathe models and what fits them on page 31.

http://www.aloris.com/aloris_cat/31e970.pdf

Hope it helps.

[Pete O]

Thanks for those links Vinny. The maximum centre height of the CXA looks okay at 2 1/4" as my lathe's centre height is 2 1/8 above the compound, it becomes a problem with boring bars as the tool tip is halfway down the bar- I'm thinking I can put a machined plate under the toolpost to eliminate that problem, as long as I can still get a turning / facing tool low enough.
Another problem I'm going to face (no pun intended) is that the carbide insert holders I'm using are a 32x32mm shank, i.e. approx 1 1/4" square, (MTGNL and MTGNR 32x32) I already milled them down to fit in my SCTP, perhaps I can reduce the shank some more and open up the slot in a couple of the toolholders.
At present I'm having to put a plate under the toolpost to get a boring bar up to centre height, then remove the plate to get a turning tool low enough. Adds another annoying stage to changing tools with the 4-way toolpost. I really do not want to have the same problem with a QCTP!

My lathe does not have a T-slot in the compound, just a 3/4" threaded hole. The 4-way holder rotates on a 1 1/2" spigot that is part of the bolt that holds it down
   
I think I'm going to have to mill a couple of flats on that thing to get it out.

I'm also wondering if there's enough metal there to mill a T-slot, the top of the compound is 1" thick.

The odds of my Kobe lathe appearing in the Aloris chart was pretty slim, I've never even been able to find a photo of another one!

[Vinny]

Another possibility... On my mini lathe I replace the compound with a piece of T-Slot, in your situation you could probably just mount a piece of it to your compound. That would add the height and you could size it appropriately (height wise) so you could adjust the the tool height for both the boring bar and regular tool bits.

[Mayhem]

Pete - your current set up resembled mine before I put the QCTP on. There are pics and a description in the thread on my clean up of that old girl. That link should take you to the right post (#12).

[Pete O]

Vinny- any chance of a photo to help me understand what you mean by a 'piece of T-slot'? I'm picturing a strip of metal with a slot milled in it, bolted to the top of the compound?
Also, what is the advantage of having the toolpost mounted in a T-slot rather than fixed in one position? (This question founded in my ignorance and inexperience!)

Darren- thanks for the link, I hadn't waded that far through the Lathes section. I slid the top of my compound off and from the underside I can see that the hole is threaded and appears the same as the top part of the stud, so I think the stud is one piece with the fat section in the middle. I can't actually see a join where the fat section meets the top surface of the compound, so it may hold some surprises yet when I come to remove it.

[Vinny]

I used this exact piece, but I had to cut a couple of inches off of it. Remember, this was on a mini-lathe. I liked it because I could slide the tool post all the way to the back and cut threads running the machine in reverse. I prefer it that way, especially with internal threads.

[Mayhem]

Unscrew the stud and then mill off the boss. Then depending on the remaining thread (if any), you can either use/modify the stud that comes with the QCTP or turn up a new one.

If you ever wanted to return to the 4-way TP simply turn up a boss that will slip over the stud and all will be fine.

[Pete O]

(04-21-2016, 07:29 PM)Vinny Wrote: I used this exact piece, but I had to cut a couple of inches off of it.  

Was there supposed to a photo attached to this Vinny?

[Vinny]

There was supposed to be a link attached to it. Seems I forgot to paste it!

http://www.littlemachineshop.com/product...4&category=

[Pete O]

It all suddenly makes sense!
I'll be able to determine what sort of height, if any, I need to add etc once the toolpost set arrives from Arvid so will give that idea some consideration then.