Cutter physics/mechanics question...

[strdsk]

Hey all....first post here! Nice to meet you! Question. When you have a blank record/plate/CD...and you begin a cut...what makes the cutter arm move towards the center of the record and prevents it from cutting over each revolution's previous cut? Is there a mechanism in the arm that draws it towards center...or do the physics of a spinning circle (record) self right the arm toward center naturally? Thanks much!!!

[rsimms3]

Hey all....first post here! Nice to meet you! Question. When you have a blank record/plate/CD...and you begin a cut...what makes the cutter arm move towards the center of the record and prevents it from cutting over each revolution's previous cut? Is there a mechanism in the arm that draws it towards center...or do the physics of a spinning circle (record) self right the arm toward center naturally? Thanks much!!!

Welcome!

A feedscrew, just like a nut on a bolt goes in and out as you turn the head of the bolt. The pitch of the feedscrew (or the speed which a single screw is turned) determined how close each groove is cut in relation to the previous groove. I would recommend watching some YouTube videos.

[strdsk]

Thanks for the welcome and info! Watched a bunch of vids, but cannot ever see how this works on a Wilcox Gay or Recordio unit. But there IS something that moves it, huh? Not just the arm willfully toward center on it's own driven by cut? I bought two of these units, have been ripped off by one tech after another, and am close to trying to fix it or build one myself. Thanks!!

[rsimms3]

Yes, those recorders used a feed screw system too but it's located underneath the platter. I'm not sure on the exact workings for those models but there is a system with a feed screw that maintains the distance between the grooves. The Cutting arm is coupled to a gear underneath the platter, you can see it sticking out on the right side of this picture below.

[strdsk]

Very helpful....thanks!!!!!