Threading dial for an 11" Logan, differences in drive gear?

As my quest to be able to return my Logan model 1957 to screw cutting abilities progresses, I'm on the lookout for a threading dial. I've found several on eBay, however one thing has me stumped. Of the threading dials listed for sale some have a straight cut drive gear and some have a helical gear on the drive. Why the differences? Don't both drive from the leadscrew, and the leadscrew is 8TPI? Since I don't have one to compare, I'm at a loss. Could one of you vastly more experienced chaps chime in? I would like to purchase the correct one the first time. God bless.
Jon In Tucson

Jon, you bring up a very good point.

If you look closely at the thread chasing dials that have straight cut teeth, you will find that the mounting hole is at a slight angle to the axis of the shaft that runs up the center. This is the way the older Logan lathes were. The one in the photo is on my 10" Logan model 200. You can just barely detect the mounting angle. It is slight, but it is there.

Those that have what appear to be helical cut teeth will usually have the mounting hole perpendicular to the shaft axis.



Your lathe will need the same as shown in the photo here.

Here is a photo of a model 1957 with a thread chasing dial on it. It appears to be a bit heavier than the one on my model 200.

Terrywerm, :man:

Thanks for the clarification as well as the photos. My Logan catalog shows one part number, LA-12-2 and LP-1767 for both 10" and 11" lathes, but throw a little curve ball in with the two different gear styles. Now I can buy "with confidence" on eBay... Well more, or less. God bless.
Jon In Tucson

You are most welcome, Jon. I just did a quick search on eBay for LOGAN THREAD DIAL and it found four, all of which will work with your lathe. My 200 is one of the earlier ones, which used the 'skinny' thread chasing dial. The newer ones would work just as well.

terrywerm said:

You are most welcome, Jon. I just did a quick search on eBay for LOGAN THREAD DIAL and it found four, all of which will work with your lathe. My 200 is one of the earlier ones, which used the 'skinny' thread chasing dial. The newer ones would work just as well.

Click to expand...

Yup, and one of them is on it's way to me... God bless.
Jon In Tucson