Hi Art!! Love your videos, I was wondering can/or do you work on string instruments if someone needed you to? You are very knowledgeable about your craft.
Now that metal lathes can be had fairly inexpensive, wouldn't you think it a good investment? Rather then buying sets of dentballs one can make them as needed. Same goes for many mandrels. Have you given it any thought?
If you can get a band instrument repair manual from Minnesota State College Southeast Technical (formerly Red Wing Technical College), that is very good, but they are very hard to find. There are a few other books out there, but I am not sure of the titles of any of them.
If you but them new, I would guess it would be about $2,000 to $3,000 for the tools in the video. If you can find them used, it would be about half of that.