OXA Tool Holder and Cutoff Bar Woes

[BanjoDude]

I have a new-to-me Emco Compact 8 that I'm trying to get set up for little projects. I ordered an OXA QCTP from LittleMachineShop so I could swap tools easily. I've never run a lathe before, but managed to make a new stud to mount the tool post that worked great with a little time and patience (though it wouldn't win any awards from a real machinist, I'm sure). All of the tools I ordered fit great and can be centered up perfectly using the adjustments on the tool holders. The exception is the cutoff bar. It was above center by 50-75 thou. My great idea was to carefully hone the cutoff bar down so that I'd have a little adjustment room, so I took 100 thou off of it....and now it's too short for the clamp to secure it in the holder. The only solution I can think of to that is to add a shim at the top. Is that safe? The shim I have in there is not what I'd use - just what I had laying around. If it's a safe way to clamp it in there, I'll order some proper shim stock and cut it to size. Any other ideas? Thanks in advance for your help!

Wes

 

[tweinke]

Bummer on the hone job. I think if it were me I would order a new cutoff tool then remove material from the bottom of the tool holder. that may not be possible though due to it looks like the bottom of the holder may already be too thin? Is the holder touching the top of the compound slide?

 

[BanjoDude]

Bummer on the hone job. I think if it were me I would order a new cutoff tool then remove material from the bottom of the tool holder. that may not be possible though due to it looks like the bottom of the holder may already be too thin? Is the holder touching the top of the compound slide?

The tool holder is already really thin on the bottom, so that's not a great option. Yes - it is sitting clear down on the top of the compound slide.

 

[tweinke]

Shoot. Another thought, On my AXA cutoff holder i Needed a shim at the lower part of the parting blade to keep it square. there is no groove for the top of the blade to sit in. Assuming yours is like that, Could you possibly make a shim with a groove for the top of the blade and that will keep the blade vertical. this would go between the blade and the tool holder.

 

[BanjoDude]

Shoot. Another thought, On my AXA cutoff holder i Needed a shim at the lower part of the parting blade to keep it square. there is no groove for the top of the blade to sit in. Assuming yours is like that, Could you possibly make a shim with a groove for the top of the blade and that will keep the blade vertical. this would go between the blade and the tool holder.

Now that could work. I don't know why it wouldn't, really. The blade wouldn't sit back against the back of the holder that way, but would that matter?

 

[BanjoDude]

I ended up making a shim from steel plate and that seems to have worked great.

 

[ChazzC]

The tool holder adjustment screw is set so that the tool is at the top of its travel: if you raise the knurled wheel, the top of the cutoff tool will be lowered.

I ended up making a shim from steel plate and that seems to have worked great.

View attachment 497022

 

[BanjoDude]

The tool holder adjustment screw is set so that the tool is at the top of its travel: if you raise the knurled wheel, the top of the cutoff tool will be lowered.

It is in the picture. I just screwed it back down on there so that it wouldn't fall off. It is still 50 to 75,000 high when flush against the bottom plate.

 

[ChazzC]

I'm confused: I have a 7x16, and would expect that the center height (above the cross slide/compound) of 8x lathe would be higher or at worse similar.

Here are three 0XA cutoff tool holders set to center for my lathe:

The camera was not directly over the holders so there is some parallax effect; however, you can see that for all three holders the knurled knob is well above the top of the QCTP block. I did need to mill some off the bottom of the GTN-3 Holder (red) since at 1/2" the holder is too large for the 0XA; the GTN-2 Holder (silver) is 3/8", so is a good fit as supplied.

Here is a comparison of the regular cutoff tool holder and a 3/8" turning insert tool holder, both set at center height:

Again, ignoring parallax you can see that the knurled rings are at comparable locations.

What turning tools/holders did you buy? If 1/4" the answer may be to remove stock from the bottom of the QCTP itself (or top of the compound). Also, did you confirm with LMS that the 0XA QCTP set you purchased was compatible with the EMCO Compact 8? Per there website, they recommend an AXA Set:

 

[BanjoDude]

I'm confused: I have a 7x16, and would expect that the center height (above the cross slide/compound) of 8x lathe would be higher or at worse similar.

Here are three 0XA cutoff tool holders set to center for my lathe:
View attachment 497061
The camera was not directly over the holders so there is some parallax effect; however, you can see that for all three holders the knurled knob is well above the top of the QCTP block. I did need to mill some off the bottom of the GTN-3 Holder (red) since at 1/2" the holder is too large for the 0XA; the GTN-2 Holder (silver) is 3/8", so is a good fit as supplied.

Here is a comparison of the regular cutoff tool holder and a 3/8" turning insert tool holder, both set at center height:
View attachment 497062
Again, ignoring parallax you can see that the knurled rings are at comparable locations.

What turning tools/holders did you buy? If 1/4" the answer may be to remove stock from the bottom of the QCTP itself (or top of the compound). Also, did you confirm with LMS that the 0XA QCTP set you purchased was compatible with the EMCO Compact 8? Per there website, they recommend an AXA Set:
View attachment 497065

This is super interesting. I would expect that a 7" lathe would be lower on center also, but it is certainly too high with that OXA holder and a 1/2" blade. The EMCO C8 has a compound slide (not sure that's what it's called) that can be angled, and I think I've seen that others have to take that off or mill the plate down to make an AXA set work. Perhaps that's what's going on? I'm not super cracked about modifying a 50 year old machine in great shape if I don't have to.

Also very interesting that the LMC site shows the AXA as the right set. I have an email string from them recommending the OXA, which is why I went that route. I'm using an Edge Engineering alignment tool that I calibrated to my machines, so I'm pretty confident I've got it set correctly.

Here's a pic of the tool post before installation and then installed on the machine. Perhaps that sparks a thought?