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AXA or BXA Tool Post
- Thread starter Janderso
- Start date
- Joined
- Nov 25, 2015
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- 8,303
bigger is always better, more rigid.
you should minimally do a BXA, You might even consider a CXA, since it is 13" up to 18"
you should minimally do a BXA, You might even consider a CXA, since it is 13" up to 18"
- Joined
- May 10, 2014
- Messages
- 819
The Aloris catalog shows the height of bottom of the tool post (which is top of the compound) to spindle centre is
BXA = 3in
CXA = 3 1/2in
The Southbend spec sheet shows the distance from the top of the compound to the spindle centre is 1 5/8in.
You should be able to work with BXA or CXA, depending on the thickness of your tools.
BXA = 3in
CXA = 3 1/2in
The Southbend spec sheet shows the distance from the top of the compound to the spindle centre is 1 5/8in.
You should be able to work with BXA or CXA, depending on the thickness of your tools.
- Joined
- Jun 7, 2013
- Messages
- 10,089
The CXA might be the better choice, but on the other hand, the BXA is going to be cheaper, and the holders also cheaper; the 13" SB is not exactly a heavy duty machine ---
- Joined
- Oct 3, 2015
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- 983
An AXA will only work if shim it up about 3/8" from the compound. I have a heavy 10" that came with an AXA, and when I got a 13", I wanted to have interchangeable tools so I made a shim spacer that took up the difference in height and used another AXA. That way I could interchange tools without adjusting the individual tools for each lathe. If I only had a 13", I would go with a BXA.
- Joined
- Mar 26, 2018
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- 8,407
That's why the Chinese tool post that came with my SB had a square washer under it. I wondered why it was there. I must have an AXA, cheap no name.
I ordered the Phase 2 BXA. There are some good reviews and some not so good. As long as it works I will live with it. Mine is almost unusable.
I ordered the Phase 2 BXA. There are some good reviews and some not so good. As long as it works I will live with it. Mine is almost unusable.
- Joined
- Nov 16, 2012
- Messages
- 5,596
Careful folks: If just enough is just right, then is too much even better?
A BXA works fine on most modern 14” machines with 3/8, ½ and 5/8” tools. With some 13” machines, a 5/8” tool and BXA holders cannot be set low enough to function. ½” tools will just about bottom-out the holder. With a CXA on a 13” machine, you might be fairly close to limiting yourself to 3/8 tools or worse yet, need to trim down your ½ or 5/8 tools. I often do machining at friend’s shop on a 16x60 lathe and a CXA fits comfortably. I personally think CXA is way over-kill for a 13” machine. I keep envisioning my 325lb uncle who drove around in a 1968 VW beetle. It literally leaned to the driver side as it went down the road.
Another issue with large QCTPs on smaller machines, is that the drop-down projection of cutter position is very close (or possibly over-hanging) the left-most edge of the carriage. This can cause really nasty cases of chatter –even when taking light cuts. Ideally, the cutting action should take place as close to the center of the carriage as possible. This puts all the forces straight downward on the carriage. With all the forces happening on the left side, the right side lifts up, leading to a chatter condition. Been there, done that –and scratched my head a good long while to solve that mystery.
Finally, a really large QCTP can create impossibly tight quarters when using the tailstock with a live center. Most live centers are about 2.25” diameter. You will not be able to get your cutter close to the workpiece because the QCTP body will hit the body of the live center. Since you'll be limited to smaller size tooling, you now just shot yourself in the foot.
Summary: 13” machine + CXA is WAY too big.
Ray
A BXA works fine on most modern 14” machines with 3/8, ½ and 5/8” tools. With some 13” machines, a 5/8” tool and BXA holders cannot be set low enough to function. ½” tools will just about bottom-out the holder. With a CXA on a 13” machine, you might be fairly close to limiting yourself to 3/8 tools or worse yet, need to trim down your ½ or 5/8 tools. I often do machining at friend’s shop on a 16x60 lathe and a CXA fits comfortably. I personally think CXA is way over-kill for a 13” machine. I keep envisioning my 325lb uncle who drove around in a 1968 VW beetle. It literally leaned to the driver side as it went down the road.
Another issue with large QCTPs on smaller machines, is that the drop-down projection of cutter position is very close (or possibly over-hanging) the left-most edge of the carriage. This can cause really nasty cases of chatter –even when taking light cuts. Ideally, the cutting action should take place as close to the center of the carriage as possible. This puts all the forces straight downward on the carriage. With all the forces happening on the left side, the right side lifts up, leading to a chatter condition. Been there, done that –and scratched my head a good long while to solve that mystery.
Finally, a really large QCTP can create impossibly tight quarters when using the tailstock with a live center. Most live centers are about 2.25” diameter. You will not be able to get your cutter close to the workpiece because the QCTP body will hit the body of the live center. Since you'll be limited to smaller size tooling, you now just shot yourself in the foot.
Summary: 13” machine + CXA is WAY too big.
Ray
- Joined
- Oct 13, 2014
- Messages
- 6,703
I have a Phase-2, it works well enough for my and I assume most hobby, maintenance and non-production, shop work.
The height adjusting screws on the tool holders need good tightening before adjusting and locking the nuts.
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- Jan 20, 2018
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- 5,629
+1 on that. The screws on all of the tool holders that came with my Bostar AXA needed tightening.
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- Apr 28, 2014
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- 3,590
+1 to what RayC states. a CXA is just too darn big for 13" - Bigger is not always better.
I had a CXA that came with my 14" and I'm sorry you just can't take full advantage of the size tool bits a CXA can handle so there's the first compromise.
The Aloris BXA that I finally scored recently seems to me to be as Goldilocks stated - Just right.
And if you're hampered with budgeting issues a BXA is a lot cheaper to tool up...
I had a CXA that came with my 14" and I'm sorry you just can't take full advantage of the size tool bits a CXA can handle so there's the first compromise.
The Aloris BXA that I finally scored recently seems to me to be as Goldilocks stated - Just right.
And if you're hampered with budgeting issues a BXA is a lot cheaper to tool up...