Logan Threading Dial

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bhusted

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In my work to rejuvenate a Logan 825, I've gotten to the threading dial. I cleaned it up a while back with the rest of the lathe in my other thread, but I just installed and had a closer look at it. I have been impressed with the detail and complexity that went into the design of this lathe overall, but the threading dial looks like they had the blind and drunk apprentice on night shift make it. When the half nuts are engaged, the mark on the body does not line up with anything on the dial. You sort of have to guess the timing. I've also never seen a dial with the opposing numbers like this. Knowing that a PO of my lathe had made some other "modifications" is this really the original dial? Has anyone made a new one? Post pictures of your threading dials please!

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All of the lines are crooked and not evenly spaced. If I line up 1, then the others will not hit the mark.
 
Atleast you can use it until you find a replacement.
The dial does appear to be home made with a chisel and center punch.
My SB9 came to me with a dial with 3 lines.
I had a replacement 3D printed.
 

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I'll probably try making a new face for the dial. This one must come off somehow if the PO was able to make one.

I've never seen a threading dial with an odd number of marks like that. Does the SB have an 8TPI leadscrew? How would that work? I guess you really only need 1 mark as long as you always engage on that one.
 
bhusted said:
I'll probably try making a new face for the dial. This one must come off somehow if the PO was able to make one.

I've never seen a threading dial with an odd number of marks like that. Does the SB have an 8TPI leadscrew? How would that work? I guess you really only need 1 mark as long as you always engage on that one.
Click to expand...
Yes, my leadscrew is 8 TPI.
 
That dial is not a Logan part.

Mine came with a non-standard dial as well, but it was blank. I recently marked the dial by indexing the spindle
on the lathe and scribing the lines. The dial itself is an easy part to turn, though there is a tiny hole at the bottom
for the roll pin that secures the gear that would have to be drilled carefully.

IMG_1169.jpeg
 
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On the threading dial and its markings, most of the time you really could live with only one mark. If you are not in a hurry. Exception would be for multi-start threads.

Since you can't physically make a fraction of a thread, it might not be doable, but how fast the threading dial rotates depends upon the lead screw pitch and the number of teeth in the actual threading gear.
 
Nogoingback said:
That dial is not a Logan part.

Mine came with a non-standard dial as well, but it was blank. I recently marked the dial by indexing the spindle
on the lathe and scribing the lines. The dial itself is an easy part to turn, though there is a tiny hole at the bottom
for the roll pin that secures the gear that would have to be drilled carefully.
Click to expand...

Thanks! I like the look of your dial. Does the face not just separate from the shaft? I've been hesitant to disassemble mine as it sort of "works". Did you take any pictures of yours when you had it apart?

With regard to multi start threads, I actually just did some of that today. I understand that one could do it using the threading dial, but I prefer to swing the compound parallel to the bed and cut the other starts by advancing the compound.
 
On mine, the head and shaft are a single part. Sorry, no pictures, but the shaft portion is simply a straight, uniform diameter with
the larger diameter face. Easy turning job. Of course, you could make it up as a 2 piece assembly, but I'm not sure that would
be less trouble.
 
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