What is this lathe tool?

[RaisedByWolves]

That's the proper sized AXA for a 10'' lathe. It's what everyone else is using, unless they go BIGGER,,,lol.

Personally I don't follow the crowd, you only get the crowds results that way.

If the tool holder is set at the proper height, this is not what I would use. That compound was designed to have the tool tip much closer to the ways than that toolpost will likely allow.

Or it could just be an issue of forced perspective.

 

[woodchucker]

Personally I don't follow the crowd, you only get the crowds results that way.

If the tool holder is set at the proper height, this is not what I would use. That compound was designed to have the tool tip much closer to the ways than that toolpost will likely allow.

Or it could just be an issue of forced perspective.

I don't understand? What are you saying? 10" would not be a BXA, so AXA would be the correct size.

 

[RaisedByWolves]

I don't understand? What are you saying? 10" would not be a BXA, so AXA would be the correct size.

Based on that pic Im thinking smaller, but again, I don't have nor have I touched this setup.

It looks like overhang of the tool in the holder will be too far out in my opinion.

The round marks are the outline of some washers I just put on there to get clearance.

This is what has me puzzled, clearance for what? As shown it looks like clearance for the tool holder with it sitting as low as it is on the toolpost. This leads me to believe the toolpost is the wrong size, it the tooling is so big that the tooholders need to be dropped to an extreme to get the toolbit on center.

If that is OP's setup, it needs rethinking, there is only roughly half of the wedge engaging the tool holder for starters.

 

[Provincial]

AXA is recommended size for an Atlas 10" or 12" lathe. But recommended is misleading, and as RaisedByWolves noted, makes for a lot of overhang between the center of the QCTP and the cutting edge of the tool. The more overhang, the more leverage against the compound and carriage.

I have used my 10" QC42 for almost 40 years with a QCTP made by a co-worker that is somewhat smaller than an 0XA. The tool holders are made to fit 3/8" square bits. It has been very rigid, probably because of the short overhang. It also enables me to get into tight areas that an AXA cannot fit. A 3/8" bit is actually bigger than a 10" Atlas needs, because of lack of power and rigidity. The only drawback is that the size of boring bars is limited, but I can work around that.

I also have one of the last Atlas 12" commercial lathes. It has the thick ways and all the latest changes to that series. I have an AXA toolpost on that lathe, and it isn't any more rigid, and perhaps less so, than the QC42. I suspect that it would be more rigid with a 0XA because of the overhang issues.

I see a lot of posts talking up big tool holders. Often the argument for going up to a BXA is ability to use 5/8" square shank tool holders. When I was starting out, sweeping the floor of a machine shop, they were using very heavy WWII era lathes and flat top brazed-point carbide tooling. Using a 1/2" tool, the machinists could make a 25 HP motor grunt very hard by using aggressive feeds and coolant. The deepest cut could only be 1/2" on a side, but the production was quite impressive!

If you are only absorbing 1/3 to 1/2 HP, it doesn't take a very large tool bit, and the machine/tooling has to be rigid enough to hold up it's part of the load.

 

[RaisedByWolves]

^^^^what he said!^^^^


I often hear people thinking the bigger the tool post the more rigid it will be, and this is a case of “forest for the trees”.

The tool post and holders will certainly be more rigid, no doubt about it, more is more.

But as the toolpost gets bigger, it also gets wider, and so do the toolholders. Add in a “more rigid” large toolbit and suddenly your toolbit tip is 50-60% further away from the center of the compound than it would be with the next smaller size toolpost.


All of this adds leverage against the ways and even though your toolpost if more rigid, you will actually induce chatter and other issues going this route.

It’s a bit of a head scratcher, but if you have run both large and small machines it becomes immediately apparent.

I spent decades running out large Moro Seiki lathe and when I tried to run my 5” Prazi it was a whole different ballgame .

Now that I have some time on this lil guy I have it dialed and can take much heavier cuts that I initially thought possible.

.120 D cuts are easy and with the right tooling and don’t stress the machine at all. Tiny lil compound, tiny toolpost, tiny tooling.

Here I go from 36rpm to 800rpm without no muss no fuss as I probably only have 5/8” stickout on the toolbit with the OXA toolpost, in 3/8”dia O-1.

Probably 2” stickout on the drill rod from the chuck.

 

[woodchucker]

that is very impressive considering the stick out.

 

[RaisedByWolves]

that is very impressive considering the stick out.

That is due to the material, the chuck and the razor edge on that style toolbit. And well, everything is dialed for rigidity as I was really testing the new drive setup. I think I could go .140-.160, but that’s excessive and I don’t want to hurt it.

The toolbit is 8% cobalt and is only 3/16” wide for scale, and I have more torque than god ever intended in a machine this size.