Dorian BXA Tool Post Index Question

[bretthl]

I recently purchased a Dorian BXA tool post used off of ebay. It came with a T-nut which does not fit my compound. I ordered the OEM T-nut from a local tool supplier but have not yet received it. According to Dorian, the nut that I ordered will not be machined however is drilled and tapped for the post and indexing pins. My question is about the indexing pins. What should I use? My thought initially is just 3/8" cold roll protruding about 1/4" above the T-nut. Is there a better way to do this?

 

[ddickey]

You don't need to use them.
If you want to I'd just buy a couple dowel pins the appropriate size.

 

[Dabbler]

Using indexing pins on a QCTP is, well in the way. I've never used indexing pisn in my AXA, and don't plan to use them in my BXA...

 

[westerner]

don't plan to use them in my BXA...

Useful, I suppose, for squaring a cut-off tool. Other than that, I would think they would take some of the "quick" out of the name!

 

[Dabbler]

I square my cut-off tool using the jaws of the chuck and it seems to work well, and quickly also. I should add that my QCTP is on my lathe about 50% of the time, the rest taken with my 4 way and Rocker toolposts - yes I still use the rocker for some jobs, it can be faster and easier to reach into troublesome places....

Anyway, I will be upgrading my 4 way to indexing, as that really makes it much more useful. I just find myself angling my QCTP a lot, and the pins would get in the way.

 

[darkzero]

My Dorian QCTP came with dowel pins. As said you don't really need them. Rather for indexing I believe they're more used to prevent the QCTP from slipping during heavy turning. For a small lathe the motor would probably stall before moving the tool post.

I have a BXA and the only time I ever had the QCTP slip was during a heavy form knurling op on Ti. I installed the the pins & got the job done, haven't used them since.

 

[westerner]

Rather for indexing I believe they're more used to prevent the QCTP from slipping during heavy turning.

Ah, yes. Good call, DZ. I doubt verrry seriously I will ever feed so hard and fast the post will rotate.
My Chinese BXA has no pin provisions, and for good reason, I suspect

 

[bretthl]

All points well taken. Not related to indexing - I just destroyed an Accusize tool holder about 3/4 of an inch into a part off in 4130. I found the post had moved and the post lock nut was loose. Did I not tighten enough?

One thing I did not consider is this; with the compound set at 45 degrees and the tool post square to the lathe axis (one face parallel to the chuck face) the index holes in the QCPT are 45 degrees off from those in the T-Nut. I wonder if I can drill two additional like shown below without damaging the QCTP?

 

[mksj]

I have the same BXA Dorian, which came with the ground pins. The T -nut is not finished because the T-nut slot varies from lathe to lathe. It needs to be milled for the specific lathe, also be sure the the top of the T--nut surface is a few thousandth below the top of the tool post slide, otherwise it will not lock down the QCTP. My T-nut also has two small set screws for locking the T-nut in place. On the alignment pins, I used them once, but not since then which seems like a familiar comment. More often they just get in the way, I typically have my QCTP/tool post slide oriented at 60 or 45 degrees, not 90. Thought it would be nice to have the QCTP indexed with pins or a mechanism, but I do not recommend drilling the bottom as you have outlined. A quick way to align the QCTP to the chuck is hold a 123 block against the face of the chuck, bring your tool holder flush up against the block and then tighten the QCTP nut keeping pressure against the 123 block. Very quick, doesn't matter what the angle the tool post slide is set to, the tool holder will always be parallel to the chuck. If you want to cut an angle use a similar method against the angle you want.

On a similar note, the stock Dorian QCTP threaded post was poorly threaded (see areas in red) and a bit undersized relative to the hole in the QCTP. I made a new threaded post out of O1 drill rod that was slightly larger in diameter and with a step for locking it against the T-Nut. Felt a bit more sturdy and a tighter fit with the QCTP, but then one always thinks it is better when you make something.

 

[Janderso]

Just bought a new Aloris CXA set. I didn't see any pins. Is this a Dorian specific idea?
Rigidity I would guess?
Sounds like a PITA.