I am a hobbyist and have been working on refurbishing a 1971 SB13 toolroom lathe. Along the way, I have needed to make and repair a few parts. When making a reproduction part, I find it preferable to first create a drawing with all the needed dimensions, then make the part in my machine shop. I have found this "reverse engineering" work to be somewhat more difficult than I had originally imagined. Just taking measurements off a used part with wear and possibly other damage isn't quite what is needed. For example, a part I'm looking at might need to be 1.000", or it may need to be 0.997 for a sliding fit, or it may need to be 1.0025" for a press fit. My point is that you can't just measure the worn part. You need some understanding of the part's function within the machine and then additional information from Machinery's Handbook or similar to complete the picture. Another more subtle issue is the fact that the original part was made to specifications on a drawing that included both dimensions and tolerances. Quite possibly a part that measures 0.997" or 1.003" would best be made to a nominal 1.000". This can be important when the part needs to match up with commercially made hardware like a pin or a bearing.
Having struggled with this a few times, I'm wondering:
1. Is there somewhere that I might find proper drawings of South Bend parts? An online archive or a reproduction set of prints that could be ordered would be ideal.
2. If the answer to question #1 is "no", do other rebuilders feel that a collection of reverse-engineered SB parts drawings would be useful to the community?
3. If your answer to question #2 is "yes", what would be the best way to start such a collection? I have three or four drawings that I could contribute. If there is enough interest I may be willing to spend some time on it as a long-term project.
Thanks in advance for your thoughts,
-- mike
Having struggled with this a few times, I'm wondering:
1. Is there somewhere that I might find proper drawings of South Bend parts? An online archive or a reproduction set of prints that could be ordered would be ideal.
2. If the answer to question #1 is "no", do other rebuilders feel that a collection of reverse-engineered SB parts drawings would be useful to the community?
3. If your answer to question #2 is "yes", what would be the best way to start such a collection? I have three or four drawings that I could contribute. If there is enough interest I may be willing to spend some time on it as a long-term project.
Thanks in advance for your thoughts,
-- mike