Tooling and Surface finish

DavidR8 said:
Yes, that’s exactly what that means.
Essentially for each spindle rotation, the carriage will advance by the rate at which the selectors are set.
E8 being .0032” per revolution.

One thing to note is that you have separate feed mechanisms for screw cutting and power feeding. The top one is for threading and should only be used for that purpose to save wear and tear on the half nuts and to a lesser extent on the lead screw.
The bottom one is for power feeding.
I believe that the lever directly above the threading chart controls which feed mechanism you are using.
Click to expand...
Yes sir, you are correct. I have been feeding with the lev er in the feed position. So this means I’m feeding at the slowest rate possible? If so, that would mean I can slow my feed down unless I reduce the RPM of the spindle
 
The feed is in distance per revolution of the spindle, so slowing the spindle RPM does not change the reed rate.
 
Pevehouse said:
So this means I’m feeding at the slowest rate possible? If so, that would mean I can slow my feed down unless I reduce the RPM of the spindle
Click to expand...

Not really. What the gear box does is change how far the carriage travels for every revolution of the spindle. Changing the spindle rotation speed will not change how far the carriage moves per rotation but it will affect how fast the carriage moves.
For example, let’s say your spindle is running at 500 rpm. At the slowest feed rate of .0037 that means the carriage moves .0037” for every revolution. So in a minute the carriage will have moved 1.85” (500 x .0037”)
Double the spindle speed and the carriage will travel 3.7” in a minute.

Run your carriage down to the tail stock end so you aren’t in immediate danger of crashing in the chuck. Then try the various feed rates out to see the differences.
The quickest speed of .0919 will be very fast carriage movement compared to the slowest speed. Just don’t change feed speeds while the lathe is running.
Note the correlation between feed speed and the threads per inch. The 4 threads per inch setting will cut a very coarse thread with only four thread peaks per inch.
 
You must log in or register to reply here.
Back
Top