I picked up a 2003 Model 510 for rehab, it is in fairly rough shape for its age. The main issues inside the Headstock appear to be caused by the Idler Shaft Eccentric slipping part way out of the casting. The Drive Belt had severe wear, down to less than 0.40 inches width remaining, and pretty much everything inside the Headstock is full of Drive Belt residue. The unit has what I think of as the new style Eccentric Bushing, with a split and a screw that prevents the bearing from slipping out of the Eccentric. What it did not have is the screw that goes into the casting and prevents the Eccentric from slipping out of the Headstock (SS PN 514324).
I initially assumed that the screw and washer had been left out by a previous owner. However, the hole in the Headstock shows no evidence of ever being threaded. Now I think that it is a latent manufacturing defect:
- Headstock missing threads
- Incorrect Unthreaded.jpg (668.79 KiB) Viewed 4901 times
For contrast, here is a normal Headstock both with and without the screw:
- With Retention Screw
- Correct (2).jpg (663.56 KiB) Viewed 4901 times
- Threaded Hole
- Correct threads.jpg (696.36 KiB) Viewed 4901 times
Moral of the story: If one was made incorrectly, as I assume, then probably more than one was. I encourage you to check for the presence of the retention screw the next time you have your belt cover off for any reason (say, lubricating the motor shaft for the floating pulley). This unit presumably ran good for years until one day the clamping force was insufficient to retain the bushing. It would be much easier to correct this condition prior to failure.
If you find a missing retention screw, I found the following on the SS website. Note that it is targeted at the early Greenie community, but is enlightening and relevant:
https://www.shopsmith.com/mediawiki/ind ... Mark_V_500
The relevant part is entitled Gilmer Mark V 500. (I did not create the title, I know it is a Mark 5, neither V nor 500 is correct. Also, it only applies to some early Gilmers.) I presume it tells us what we need to do to correct this condition in the field (I haven't tried it yet, but I can confirm that the hole is not 1 inch deep as required. I'm hoping that it is of the correct diameter for the threads.)
- David
