Threading on a PM1127 lathe - turning instead of threading

Pcmaker

Pcmaker

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Does anyone have a Precision Matthews PM1127 lathe and has been threading with it? I put it on threading leadscrew, going from right to left. I've tried on A, B, C, speeds. It turns the workpiece instead of threading. I tried different depths of cut from .001 to .010.

I used a carbide threading insert.

I did not mess with the threading gears. I just left it as it was when I received the lathe. I'm just trying out threading and don't care what thread pitch.
 
Pcmaker said:
I did not mess with the threading gears. I just left it as it was when I received the lathe. I'm just trying out threading and don't care what thread pitch.
Click to expand...
You have to mess with the change gears. There's a helpful chart of gear combinations on the gear cover and on page 27 in the manual.

Tom
 
If the factory setting is a fine feed it will look like turning instead of threading. Set the gears for a coarse feed/thread and make some scratch passes to check the pitch. Try threading some aluminum first to get familiar- cutting steel threads takes a number of passes and can try your patience at first
Change gear lathes take a bit of getting used to :) Your geartrain is a hybrid, semi quick-change gears.
Use the slowest speed initially to cut threads
 
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Pick a thread, look it up on the chart and thread it. You won't learn anything by just flipping the lever to "thread".
 
The diagram is so confusing and the manual does not even explain how to read it. There's L1, L2, etc.. but doesn't show what "H" means.
 
Pcmaker
I don't own a PM , but just trying to help. I looked at the manual and The reference I saw is for L and H being the speed pulleys. Could this be what is confusing? It looks like some threads require changing the belt on those pulleys. I agree it is confusing. This is what I am talking about:
294727

Roy
 
Looks to me that H is a gear.
Yeah H must be a gear.
Are there any gears marked H?
 
I didn't see any H gears, but I'll look again. All the gears I've seen are numbered.

Here's a screenshot from the .pdf manual I downloaded from the site, which is a lot better than the paper manual it came with.

PKDUGyP.png


royesses said:
Pcmaker
I don't own a PM , but just trying to help. I looked at the manual and The reference I saw is for L and H being the speed pulleys. Could this be what is confusing? It looks like some threads require changing the belt on those pulleys. I agree it is confusing. This is what I am talking about:
View attachment 294727

Roy
Click to expand...

I don't see any "L"s on the diagram, so I'm not sure if "H" is referring to the high/low speed or not.
 
No I was wrong. L looks like a position. The arrow pointing to L, is that a dual gear like the other, one gear on top of another?
 
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