1 ½ X 8 threading

wa5cab,
Let me fill you in on whats going on here. A number of years ago I purchased a separate threading supplement because my old age eyes could not read through the cataracts,so in this supplement the item #2 " Place 32 tooth gear and 20 tooth gear on bushing in position B. Tighten so that 32 tooth gear meshes with gear in screw position.The 32 tooth gear is an idler :the 20 tooth gear is a spacer.
Exception : when cutting 8 threads per inch, substitute a 48 tooth gear for the 32 tooth gear. "There are quite a few exceptions listed in this supplement. Does any of this make sense,I'm having a hard time sorting this out. Again Thanks for the assistance.
dgehricke
 
Robert,
A few other items that probably have no bearing on anything but just fyi the lathe came with a Babbit head stock, I purchased a Timken head stock
quite a few years ago from Dave Sobel before he passed. I also purchased a new ( used) bed in very good condition from eBayother then that nothing that would change any threading info.
Hope it helps.
dgehricke
 
The reasons for pointing out the exceptions are that on the threading chart, the "Figures" column says 2 and when you look at Figure 2 it shows a 32T screw gear. Unfortunately, my only lathe is a 3996 so even if I had the gears, I couldn't mock up the settings to see why the exceptions. But logically, they have to be because of something hitting or nearly hitting something else unless you use a larger than 32T Idler.
 
Robert,
Thanks for your help I will be doing exactly what you mentioned I'll have to set up the lathe as the chart says and then set it up with the exceptions and see which is better or which works the way its supposed too. I guess a good excuse to be looking for a quick change gear box.
I'll let you know how it works out thanks again.
dgehricke
 
You must log in or register to reply here.
Back
Top