My current project is fixing up an antique Craftsman Model 80 6" lathe. Built by AA for Sears in 1949, its model number is 109.21270, sometimes listed as 109-21270. It has a capacity of 6" swing over bed and 18" between centers.

I am slowly removing rust and grime from all the components. It is currently taken almost fully apart to it's basic parts. Rust has been removed with a phosphoric acid solution. I would have used an electrolytic process if the rust was worse, but it's only a surface coating with little to no pitting. I'm currently degreasing the parts with Simple Green, I wanted to stay away from difficult to dispose of degreasers. The next step will be repainting with a color close to the original dark gray.

The lathe was missing some of the change gears and a couple minor parts. It's amazing, but many of the parts are still available from various places - mostly from Home Shop Supply, and a few vendors on ebay. I have purchased original replacements for the majority of the missing gears, and have found (and made) the remaining missing items from my shop.

The 109 lathes are similar capacity to the new Chinese 7x's. Each is better in some areas and worse in others. The spindle of the 109 is one of its weak spots, it's only ½" diameter with ½"x20 threads and a short MT0 taper. The original lathes were sometimes sold with a spare spindle just in case the first one was bent by taking too hard of a cut. The tailstock is also a short MT0 taper, making it difficult to find live centers and drill chuck arbors.

As the project progresses I plan to post pictures of the cleaned up lathe.

Since my threading chart was a little worn I've recreated the threading chart for the 109 series lathes. To the bottom of the chart I've added approximate metric threading setups. Metric errors are typically 0.0125%, the largest is 0.061% for 1.75mm threads. The chart is available as an XLS Spreadsheet, PDF sheet, a high resolution PNG image, and a smaller JPG image. I'm not happy with the figures on the chart and plan to replace them eventually.