Finally decided to add a DRO to the old South Bend Lathe. When looking for info on how to add digital scales to a '40s era lathe, I didn't find much, so I thought I'd share what I came up with. The inexpensive digital scales I chose are not terribly accurate, but they're good enough for the majority of the work I do.
The X axis was fairly straightforward: there's room on the back of the lathe to hang the scale. The Y axis was more challenging: tight clearances on the carriage led to mounting the crossfeed scale behind the carriage. Fortunately, on this SB with the rear-mounted countershaft/motor assembly there was room behind the lathe.
Cheap but decent digital scales
 | ||
| Aluminum angle bolted to the tapped holes for the taper attachment I don't own. |
 |
| 1/8" aluminum extension bolted to the crossfeed carriage. The side of the crossfeed casting was milled flat and holes were tapped in the cast iron. |
 |
| X axis hanger clamped to the rear ways. |
 |
| X axis scale attached to y axis aluminum angle |
