JPG wrote: ↑Thu Sep 30, 2021 4:51 pm
Do I understand correctly that adding the washer lowered the speed with and more additional adjustment towards slow is available on the speed control dial? I am curious how thick the washer was.
JPG, I have been carefully reading your previous journey through this same exact process here:
viewtopic.php?f=10&t=13906
Sounds like I was starting down the same path and considering the same potential solutions. I never thought to just push the eccentric in a bit as opposed to using a washer, and I see you tried both. I could have saved some time disassembling. Anyway, I am not likely to find a new-old-stock Shopsmith 507490 belt as you did. The 29.5" length is counter-intuitive to me at this point, but I am going to try to find a 14mm (0.55") X 750mm (29.52") which should be a close match if the advertised dimensions are true. I'm considering adding the idler/rack protection as well.
Yes, I am going to go remove the washer now and measure it. I ran about 6 RPM tests last night and they were all right around 710. I am not using a digital laser RPM meter, I am using an old Starrett 104, so RPM is based on how fast you can react to a stopwatch. When I remove the washer I am going to take another RPM reading and if it is back to 820 RPM than I will know I am not going crazy.
Yes, in one of my previous pictures you can see the speed cam is completely max'ed out
without the washer. I will take another pic of the position before I remove the washer but I am sure it displays more exposed cam at the end. Note though, that it is not really possible to rotate that cam any further without likely damaging the plastic cam. There is one additional available detent left on the dial, but it cant be turned.
Also note, that the first set of pictures in this post are from my first Mark VII, and the others are from a backup headstock. I see that could be confusing.
Thanks, Mike -