View Full Version : Favor Please-Logan Leadscrew measurement

06-17-2012, 11:29 PM
I have a favor to ask. I need to know the depth of the groove in the lead screw on a Logan lathe, one that uses the 3/4 in. dia. lead screw. I'm working up a power feed on a "franken-Logan" and it looks like standard 3/4" dia. grooved shafting with a 3/16 x3/32 groove may not be deep enough for the driving key that is inside the worm drive.


06-17-2012, 11:40 PM
My Logan 850 10" lathe with 3/4 lead screw's groove measures .095" deep at the headstock end where there are no threads, before it enters the QC Gearbox.

J Tiers
06-18-2012, 12:10 AM
On mine it measures more on the order of 0.110 to 0.115 deep and about 0.140 wide

06-18-2012, 12:22 AM
Thanks, I appreciate the quick info. Looks like I might need to get a hold of Joe at Plaza and see about an original Logan leadscrew. The inside of my worm drive bore is .753 and the driving key is .106 so I would need a deeper groove than the standard keyed 3/4 shaft would give. (not going to be a treading lathe so I don't need the threads that the half nut would engage, hence the use of just a keyed shaft for driving the worm)

06-18-2012, 01:53 AM
Logan 912, 3/4" screw. I measure .110 to .114.