I currently (2017) own the Atlas version of this lathe. Mine came pretty beat-up, so I’ve already had to make some parts for it, and I need to make more. Consequently I’m always scouring the web for specs. Here are a few things I’ve collected so far, and I’ll add items as I find them and time permits.
First off, you may want to check out:
My Atlas 12 is Model # 3996. A nice, clean .pdf of the manual for that model can be downloaded here:
Please let me know if that link becomes broken. Maybe I’ll figure a way to put up my own copy for download. The manual contains exploded parts diagrams, a lubrication chart, and other useful information.
Two-Step Motor Pulley
My lathe came missing the original two-step pulley that connects directly to the motor. It’s part #21 if you refer to page 22 of the manual, or part 10-428 more generally. I need to make a new pulley. Bill Rosselot provided me with a drawing:
Cross-Slide and Compound Rest Nuts
Both of these are made of brass and become worn over time, introducing backlash in your controls. There is a gentleman who makes these and sells them at a very good price on eBay. He gets good reviews. His home page on eBay is here. It’s not me, BTW.
Here are the specs he provides in his ads for the two parts:
- Cross-Slide Nut (Part 537-041): Approximately 3/4″ x 1″ x 1-3/8″ overall, ACME 1/2″ x 10 Left Hand Class 4G Threads, 3/8″ diameter mounting post
- Compound Rest Nut (Part 537-040): 3/4″ Diameter x 1-5/8″ long with a 1/2-10 ACME Right Hand Thread
My machine does not have terrible backlash, which is surprising considering how much wear it has in other areas. When I get to the point where I consider replacing these parts, I’ll likely buy from this fellow rather than invest in the right- and left-handed versions of the ACME taps. It is nice that he provided the information, however, just in case I get ambitious.
Ah, the Atlas gears, made of the infamous ZAMAC material (which was also used to make Hot Wheels toy cars). My gears are shot, so I’ve got to learn to make new ones. To do this, one thing you need to know is the type of gear cutter required. The specs are:
- 14.5 degree pressure angle
- 16 diametral pitch
You’ll have to look elsewhere for an explanation of what those terms mean. It gets pretty complicated, and I can never remember from one reading to the next anyway.
I bought my gear cutters off of eBay and plan to make my own arbor for them. If you want a complete set of cutters together with an R8 arbor, here you go: