Quick Change Tool Post Size For 12" Lathe

I purchased a AXA for my Atlas 10" and when I sold it and bought a 1340, I simply moved it over. On my lathe a BXA would be border line. The height of the top slide is going to call out which toolpost you can use as others have stated.
Pierre
 
Bob nailed it in post no. 4

My 12x36 gap bed lathe is 1.22'' from top of compound to axis of spindle. BXA size is best for me.
 
I just measured my 12 Atlas, 101.7403, it's 1.22" also. The AXA is what I use.
 
Another issue is what size tools you normally used in your holders. A BXA might hold 5/8" tools, or even 3/4" tools with an oversize holder, but what if you typically use 1/4" tools? What about your boring bar setups and cutoff setups? There is more to this than what it initially seems to be, and what works for one person might not work at all for another. There is also some overlap, as noted, so it is worth looking at how all your anticipated tooling setups will work on YOUR lathe with YOUR tooling doing YOUR kind of work. Saying a 12" lathe takes a BXA, or an AXA, and no others, and leaving it at that, is like wearing blinders on purpose...
 
There are a couple of other issues that could influence you.
Just consider them before you make your choice.

Some topslides have holes drilled in them to enable pin location of the toolpost at 0 and 90 degrees.
On my Harrison M250 (Clausing something), the BXA does not fully cover the holes used by the original Dicksons toolpost.
Every time the BXA is rotated, these holes are uncovered, then covered, with the inevitable result of swarf/lubricant being dragged under the toolpost with subsequent scarring and looseness.
This is a real problem not anticipated and I will have to deal with it in some way.

Then there is tool reach.
Most of these toolposts expect tools to be inserts carried on a holder that is then mounted into the toolpost adapter.
But, if you try to use HSS tools directly in the toolpost adapter, the cutting edge may not reach out far enough tp prevent the topslide itself coming into contact with the job or chuck, or the topslide contacting the tailstock on small diameter jobs.

John
 
When I bought my QCTP tool post from Dorian, they told me there is no additional rigidity gained by going to a BXA vs AXA QCTP, they said the weak point is the lathe compound and carriage, both will flex long before any of the tool post will. The real benefit is the ability to use larger tools, without modifying the tool blocks. I have open many AXA blocks out to hold 5/8" and 3/4" shanked tools, probably buying the larger larger size, might have been the easier way to go. Not better, but easier.
 
Oh boy you guys brought up a bunch of stuff I hadn't considered! Thanks, will make me go back to the drawing board. As far as tooling the biggest bits I have are 1/2" and don't own anything smaller then 3/8". The top of the cross slide to the centre of the headstock on the lathe is 1.250"
This is the one I am thinking about getting http://www.ebay.ca/itm/281990113312?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
It says it suitable for a lathe swing of 10-15" with a measurement from the cross slide to spindle centre from .7-2.2 so it should work ok? Or possible to large? Thanks again
 
This has been interesting reading. I have a Enco 13x40 lathe & didn't have a good feel on which size of new tool post to buy for it....wound up with the bxa 200 size.....seems a little big, but we'll see after I get the foot machined to fit my T slot (which is huge by comparison to the original post foot that came with the lathe). I just received the post set a couple days ago & will be working on it this week.
Mike S
 
Armourer said:
Oh boy you guys brought up a bunch of stuff I hadn't considered! Thanks, will make me go back to the drawing board. As far as tooling the biggest bits I have are 1/2" and don't own anything smaller then 3/8". The top of the cross slide to the centre of the headstock on the lathe is 1.250"
This is the one I am thinking about getting http://www.ebay.ca/itm/281990113312?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
It says it suitable for a lathe swing of 10-15" with a measurement from the cross slide to spindle centre from .7-2.2 so it should work ok? Or possible to large? Thanks again
Click to expand...

Armourer, why would it be too large?
 
Last edited:
The actual size of the post means that you cant get the tool down below centre. So depending on the physical height of your cross slide and compound a BXA may or may not be suitable. As Bob said earlier, its not the swing of your lathe, its what you can pass over your saddle.

Cheers Phil
 
You must log in or register to reply here.
Back
Top