New 1440 GT Question

[INTJ]

Our new PM 1440 GT arrived a couple days ago at the shop where I work. It is the lathe I recommended. I have had a 1340 GT at home for about four years and love it.

We are setting it up. The only puzzling thing to me is the feed shaft seems to turn with the lead screw. When I put the upper gearbox lever to the "I" position, only the feed screw turns. When I move that lever out of I, both the feed shaft and the lead screw turn.

Is that how it's supposed to work? With my 1340, I select either feed or thread and both don't turn together. I didn't see anything addressing that specific question in the manual.

 

[jbolt]

The feed screw always turns unless you set the feed/lead direction knob halfway between, then both feed/lead shafts will not turn. Lead screw only turns when set to the positions other than "I".

 

[B2]

Yes, mine works that way too. I do find it a bit difficult sometimes to be sure that the lathe is actually in the right lever position.... especially the I position. This feature makes for some interesting differences from other lathes. While you can use the feed shaft to thread on most lathes if you are desperate... for some rather different TPI values. Having the feed shaft always turning adds more possibilities. I tried to document all of the possible TPI, Feed, X-Feed rates as well as the metric versions in my Excel post. Try it out and see! With the standard external PM1440GT gears plus the gear box lever positions there are >6000 possible ways to get potential TPI values! The spread sheet can compute all of these automatically to generate a large table which you can use a provided macro to search or to order/sort the table . Actually the spread sheet is not limited to the PM1440GT. I set it up for both the 1440 and a few other lathes, but could probably be setup for almost any lathe.

TPI Feeds X-Feeds: Generalized Excel file for your Lathe​

Have fun
Dave L.