Cutting buttress thread on pacemaker

[collector]

Hi guys
Had to make a thread gage and nut to thread some lock nuts. The 1942 pace maker was just a treat to use for this with the the lead screw reverse as it was 2 TPI. Here’s some pictures.

 

[Illinoyance]

Years ago I had a 13 x 30 P&W lathe with lead screw reverse and a threading stop on the cross feed. It also had a stop on the feed so you didn't have to manually stop the leadscrew. I really miss those features. I could thread up to about 600 rpm. That is when I could hear the feed clutch bounce.

 

[Cole2534]

Years ago I had a 13 x 30 P&W lathe with lead screw reverse and a threading stop on the cross feed. It also had a stop on the feed so you didn't have to manually stop the leadscrew. I really miss those features. I could thread up to about 600 rpm. That is when I could hear the feed clutch bounce.

My Monarch has those features as well. It's also nice to be able to change speeds without interrupting your threading in case you want to pass a file or sandpaper across it. Just drift the clutch a little as you re-engage the lead screw and you're off to the races.

 

[Mike C.]

Only machine I know of that will change the thread index when you change the speed is the @#$%ing Summit at work. Any other lathe has the leadscrew driven off the spindle gearing. You can change speeds, go to neutral, anything you want to do with the spindle speed, as long as you don't change the repationship of the compound dna cross slide, tool position, leadscrew gearing, or position of the part.

The #$%^ing Summit has three different leadscrew ranges for the corresponding speeds, as is it somehow driven off the leadscrew gearing. That also means that fine pitches like 20TPI can only be cut at 250rpm or more. If you thread left handed, you have to change the leadscrew gearing to match the pitch. The thread/feed chart looks like an open Manhattan phone book printed on the headstock.