Which QCTP do I need?

[PHPaul]

The Toy Fund is healthy enough to cover an import QCTP for my Seneca Falls lathe.

I'm confused by the AXA, BXA, OXA nomentclature. How do I know which one I need for my 9/10 (depending on who you believe) inch lathe?

Also, are the t-nut slots standard or will I need to make one to fit?

 

[4ssss]

The letters are the sizes. An AXA will fit your 9/10 lathe, and you may have to mill the T-nut depending on which company you buy from. It will not be a T style, just a flat plate with a tapped hole.

 

[PHPaul]

The letters are the sizes. An AXA will fit your 9/10 lathe, and you may have to mill the T-nut depending on which company you buy from. It will not be a T style, just a flat plate with a tapped hole.

Perfect, just what I needed to know. I assumed it would be a flat plate based on the slot in the compound and also that's how my lantern style tool post mounts.

Any particular advantage to wedge or piston type?

 

[projectnut]

I have a Seneca Falls Star #20 lathe that uses an AXA. My tool post is a Phase II like this one:
https://www.travers.com/quick-change-tool-post/p/55-400-100/

I chose the piston style simply because back 20+ years ago it was less expensive. It's proven to be a good investment and still works great today. The plate that fits in the compound is just a flat piece of steel not a T nut. If I recall correctly I had to thin it up a bit to get it to fit in the slot.

My lathe was originally sold as a 9" model, but the actual swing is 10 1/4"

I also have a Phase II BXA on my Sheldon 13" machine. This one is the wedge style. After many years they are both accurate and repeatable.

Here's a picture of the AXA on the Seneca Falls:


Here's the BXA on the Sheldon:

 

[PHPaul]

Again, perfect. Exactly what I needed to know.

I love this place...

 

[BROCKWOOD]

It is said that the wedge version is more repeatable. This saves on setup time. Once initially adjusted, just drop it in, cinch it & go - this is what we all want. In my limited experience, the lathe 'swing' is not the number to focus on though. Clearance above the cross slide is much more important. Let's just say there are many people looking up 'how to lower the tool holders to get them on center' because of this. If your cross slide is like Projectnut's, you should be fine with the manufacturer's charts for correct size.

 

[PHPaul]

@BROCKWOOD - Yes, that's the exact cross slide I have. Thanks for the confirmation. Ordered from Shars with their Black Friday 20% discount.

I'll report back when it comes in and I have a chance to play with it.

 

[RJSakowski]

It is actually the distance from the top of the compound to the spindle axis that is the determining factor. The tool holders can't go any lower than the top of the compound.

Measure that distance. It should be greater than the distance from the bottom of the tool holder to the floor of the tool holder slot plus the thickness of the tools that you wish to use. For example the Shars AXA tool holder 250-101 measures .431". Add a 1/2" tool for a total of .931". Your top of compound to spindle axis should be greater than .931" If you are close, Shars and some of the majors players offer an XL version, the purpos being to permit using an oversized tool bit. However, the upshot of this is that the floor is lowered slightly. The Shars 250-101 XL distance measured at .417" and .409" on my two XL tool holders which gave me just enough clearance to use 1/2" tooling on my G0602 lathe.

Different manufacturer have slightly different values for the bottom to floor measurement. Shars and the major name brands all list this measurement in their specifications.