Useful Lathe Accessories?

[Spokerider]

How deep [ width ] is the tool cut in an OXA tool holder? Good thot.
I bought this;
https://littlemachineshop.com/products/product_view.php?ProductID=3112

Quick Change Turning & Facing Tool Holder, 0XA 3114

QCTP Tool Holders 3114 Tool Bit Capacity of Up to 1/2"; Hardened and Ground; Compatible with 0XA, or Series 000, Tool Post; Turning and facing tool ho...

littlemachineshop.com

Have yet to measure it. The ad doesn't actually state what the optimal size tool to use is. I'm guessing that is not advantageous to have the tool wider than the width of the slot.....

 

[pontiac428]

Or in other words, how deep is the slot in a 001 or 002?

May be different from Aloris, but Shars has the capacity.

 

[wa5cab]

OK. The two drawings reminded me (I've seen them before but with the dimension were for the AXA) that Shars doesn't seem to have an isometric drawing of a 002 or 102. It does not show the location of the groove in the bottom of the slot. And only someone who didn't grow up speaking English and using the Imperial measurements system would use dimensions in increments of 1/24". However, if I didn't know where the holder came from, I would probably assume that the designer intended it for either 1/4" or 5/16" square tooling and couldn't make up his mind which so he/she split the difference. I guess that what we really need is the location of the groove in the bottom of the 002's slot.

In any case, although you can apparently fit 3/8" and 1/2" square tooling in the slot, they will not be as stable as either of the two smaller sizes.

 

[erikmannie]

May be different from Aloris, but Shars has the capacity.

You might want to take that drawing with a grain of salt because the part number on the drawing is 250-101 which is the most common AXA tool holder. I have a lot of these, and you can definitely fit a 1/2” tool bit in there. There is a part called a 250-101XL which will certainly fit a 5/8” tool bit.
I thought that Spokerider was trying to determine the max size tool bit that could fit in an OXA; I am almost 100% sure that 250-101 is AXA. This would be a good time to research further before you start buying a bunch of 1/2” tool bits.
This (“turning & facing”) tool post for OXA is 250-001. For AXA, it is 250-101. For BXA, it is 250-201. For CXA, it is 250-301.
Another fine point would be that a 250-101XL can also be marked 250-101T, and I take T to stand for a taller slot.
One other thing I noticed is that the 250-101 does not have a trough at the bottom. A 250-102 has a trough at the bottom for use with a circular boring bar, but all of the boring bars that I have ever bought are flat on the top and bottom. People use the trough if they buy round HSS tool bit blanks.

 

[erikmannie]

The Grizzly website seems to indicate that you can use a 1/2” tool in an OXA tool post. The value is .512” in this picture:

 

[wa5cab]

Eric,

The drawings may have been inherited from Yuasa who Shars apparently bought the design from. And Shars didn't completely eradicate the Yuasa part number from the drawing when they used it to advertise their OXA smaller holders, I happen to have a complete Yuasa AXA or 250 set purchased new many years ago when I bought my 3996. The drawings uploaded by pontiac428 show dimension C (the depth of the slot) as being 7/24" which I poked fun at earlier. But that is 0.292". The depth of the slot in a 250-101 and 102 is 0.440". So the drawings may be of a 250-101 but the dimensions are not. And after checking the dimensions of my AXA holders, I will say that although you can fit larger ones into them, the OXA holders were made for 1/4" square cutters.

The AXA or 250-101 and -102 tool holders were made to fit 3/8" square cutters. The 0XA ones were not.

On the subject of boring bars and the 250-102 holder, it is made to hold a 1/2" diameter round boring bar. If you lay a 1/2" diameter rod in the 250-102, when it is fitting the groove in the bottom of the slot, it is also touching the back wall of the slot. And almost all of my boring bars are round. Although the diameters vary from 1/4" to I think 1/2", Atlas sold a HSS boring bar set back in the day all of which were round They also sold a boring tool holder that accepted 1/4" square cutters. I forgot to check the diameter of mine just now but it is also round. So some boring bars are not square. It just happens that yours are.

 

[erikmannie]

So what should we figure as the (1) recommended and (2) maximum tool bit heights for OXA and AXA tool posts in the very common 250-001 and 250-101 types? You seem to have said 1/4” for OXA and 3/8” for AXA. That sounds like your answer for (1) recommended height.

I would prefer to work with the size that the tool post was primarily designed for, and only use a larger tool if necessary.

In any case, it sounds like if your tool bit is hanging a lot outside of the tool post (with regard to width (e.g. using a 1/2” bit in an OXA tool post)), then you may be using too large of a tool bit.

 

[erikmannie]

Here are some turning tool holders for a 1/8” square tool bit.

The shank on these holders is an 8mm square. They are intended for use on an OXA or other Mini Lathe tool post.

 

[erikmannie]

 

[Aaron_W]

This is easy enough, I have a Little Machine Shop OXA QCTP, with 1/4" and 3/8" tool bits. Just eyeballing the tool holder is about 5/16" in depth, as a 1/4" bit has about 1/16" to spare, and the 3/8" sticks out about 1/16" or perhaps just a hair under. I don't have any 5/16" bits but they would likely be a perfect fit.

I didn't check 1/2" I think it would fit in height, but obviously would stick out quite a bit (3/16" or so).


Considering the power of a lathe running an OXA tool post (typically 1/2hp or less?) I doubt using a 3/8" tool bit in an OXA would result in any substantial loss of performance. Then again, I'm not sure it would provide any substantial gains, the benefit primarily being the ability to share tool bits between lathes of different sizes or use a random selection of used bits bought in a lot. 3/8" bits are often longer as well which could prove useful in some cases.

1/4" bit in OXA holder


3/8" bit in OXA holder