I've been making progress on this machine. So here is a quick summary of where I am at. The machine has been disassembled down to the bed, components have been rebuilt (new bearings, paint, repairs as needed), the machine has been repainted. When I was rebuilding the turret, I found a hint in one of the drawings that the turret was compatible with a machine with a leadscrew (it had two part numbers for the cover on the rear of the turret apron that protects the feed rod worm and pinion, one for a lathe with leadscrew, one for a lathe without). So I contacted Scott at Monarch. Scott pulled the drawings for the part, and also made the comment that in his 20+ years of working at Monarch this was the first power turret 10EE he had run across. It turns out that the rear cover for a machine with a leadscrew is identical to one for a machine without, except for two holes bored to allow the leadscrew to pass through. The print gave the dimensions and location of the hole.
OK, great. So I decided to add threading to the machine. I already had some of the parts, the main thing missing being a threading gearbox. With the turret slid all the way to the end of the bed, there is room to thread up to 10-12", which covers 99% of the threading I have done in the last 30 years, and since this machine has both a 2-spd gearbox and a DC motor, it has the low speed capability I have always wanted for threading. So for me the decision makes sense.
So here is what that decision entailed:
1. replace the spindle with one that has splines for the threading reverse gears.
2. install the reverse gears, shift fork, dog gears, idler gears, shafts, bearings, end cover, seal etc. in the headstock.
3. install oil lines in the headstock for the reverse gear bushings.
4. install the fwd/rev/feed shift knob, dial, packing gland, packing, and interlock on the doghouse
5. replace the mfg. gearbox with a threading gearbox.
6. install a leadscrew and bearings.
7. install a threading dial
8. install a chasing stop in the crossfeed dial
9. install half nuts and engagement lever & housing on the apron
10. modify the cover on the turret apron to allow the leadscrew to pass through
The mfg. headstock was already fully machined for the addition of the threading gears and shafts. The spindle I acquired came from a late 60's machine and had what appeared to be nearly new spindle bearings, which was good because the bearings on the mfg. lathe were quite rough. The bearings cleaned up quite well in the ultrasonic cleaner. The rear bearings were the later angular contact variety, and a new cover was included, so the spindle installation went well. New oil lines were fabricated from 3/16" copper line. I had the remaining headstock parts from last year's 59 lathe headstock replacement project, and the shifter installed with a perfect sliding fit, with a good fit between the rack gear and the splines of the shift rod . It is absolutely amazing that Monarch machined all those parts with the precision that would allow me to transfer parts from another lathe without any hitch, 70 years after the machine left the factory.
The only step that entailed some machining was the installation of the fwd/rev/feed shift rod. The hole for the rod was present on the machine, filled with a 2-hole plug and 70 yr. old sealant that absolutely refused to budge. I made a 2-hole spanner, but the pins kept shearing off (hardened dowel pins) when I applied a lot of torque. I ended up drilling a hole in the plug and used an ez-out with a ½" ratchet. Then I found that the bore of the shift rod hole had not been reamed for the shift rod, and the bushing in the dog house had also not been reamed, so most likely those two operations were part of the 10EE assembly line that included the install of the reverse gears, and got skipped on mfg. lathes. Later on, when I installed the half nuts in the apron, I found a similar issue: the bore in the apron for the shaft that actuates the half nuts had not been reamed (or honed), so that operation also got skipped on mfg. lathes. But other than that I found no differences.
To complete the work on the headstock, I installed a lever-operated collet closer on the spindle, since the lathe had one originally. The closer came on the 59 lathe, but I want to use 2J collets on that machine.
Installing the collet closer entailed two machining operations: the spindle needed to be drilled for the setscrews that lock the collet closer in position, and the bracket for the lever needed to be repositioned on the upper headstock cover, so that it would clear the knob that attaches the middle headstock cover. Evidently there was a design change at some point, the original 49 collet closer bracket had a 1 degree tilt and was wider than the later bracket. The later bracket was installed with a 15 degree tilt, and it is a good work height for the lever. That work is described in this thread:
10EE Lever Collet Closer
I am currently rebuilding the threading gearbox, but I will cover that in another post. Here are some photos of the lathe:
New oil lines, just prior to spindle install:
Lever-operated collet closer:
Gearbox apart:
New paint:
