Hi Ken!

The is the exact subject I've been meaning to post and already had my pictures ready!

I also asked this question over at DFO and got only an answer that made no sense. Like you, I honestly don't see what this screw does. Looking at the mechanical drawing by Joe Thompson, it is part #77. But when looking at it, I still can't see what it really does. All I can come up with is that it acts as a stop, should you turn the post to the extreme in either direction. But, why would you even do this? I also watched those YouTube videos, but there is no real explanation about screw #77! So, if there are some really knowledgeable Swivo Pedal people out there...Tommyp?!!...please chime in on this issue!

-Mark

I found the complete patent description, as written up by Joe Thompson, and found the reference to mystery screw #77. Here's the answer:

“Lateral movement of the tilt arm 75 is prevented by a flat-headed retaining screw 77, which bears slidably against the edge 73e of the collar 73.”

I'm guessing this proved to be a non-issue and was soon dropped. What do you think?

-Mark

Mark!

I have a small collection of Swivo's, and do indeed have ONE that has screw #77! The other six of them do not. The one I have with the screw is my earliest model .. early 60's .. so yes, I think you're right! It was not needed, and was done away with! Excellent investigative work as always Mark! :)

Tommyp

Thanks Tommyp!

This is, again, one of those issues where we obsess with the minutia of our vintage equipment. I've seen people looking for these first generation Swivo pedals and will only accept that version...or nothing!

Most of us can agree that Joe Thompson was a perfectionist in everything he designed. In regards to screw 77, it was probably determined that it offered no real benefit to the functionality of the pedal, and would certainly save money by not having to add that screw!

Each generation of Swivo pedal was pretty darn good...well, except when they used the bronze "oilite" bearings. But, as we know, just punch them out, insert a B-68 and you're good to go!

-Mark

Tommyp,

Looking at the mechanical drawing, it appears that bearings 71 and 72 are different lengths. If they were the same length, I would expect to see the same number for each bearing. Have you ever disassembled your first-generation pedal to see if this is the case? Would really be interested to find out. Thanks!

-Mark

To me it looks like the screw prevents bearing creep/waking. If I'm seeing this correctly? Screw seated against the bearing face yes? Pretty common the see in the printing press world.

Glenn!

Look closely and you'll see that screw #77 has absolutely nothing to do with the bearing. If you have a Swivo pedal, with or without this screw, you'll be able to see for yourself. I've verified this with my 2 Swivo pedals!

-Mark

Mark don't have a Swivo pedal. Just looking at the pics it appeared to overlap the bearing. I see in the drawing there's no relation. Wasn't 100% clear if the drawing shows true size and placement Thanks for clearing that! So safe to assume this screw is a good clue in a true 1st gen pedal? I've had one on my bucket list for some tome. Thanks!

Mark .. Glenn .. kenshireen!

I took a moment to take a few pics of the earliest Swivo-Matic in my collection .. ( there are 7 of them in this collection .. but sequential and slightly different/changes as the years went by .. two of which are my MAIN gigging and practice pedals. Anyway! ... this one is around a 1962/64, and does indeed have screw #77. This pedal is NOS, and has never been played that I can tell. Everything is correct including all the PatPend markings, etc. Have a look! Truly ...don't know what JT was thinking with this screw! It literally .. does .. nothing. At least it certainly looks like it does absolutely nothing! None of the other 6 have this screw .. so .. it appears to have been eliminated quickly! :)

Tommyp