Let's see... 1982... but really lighting say in 1984... darn, I loose...
Fiber washer between
yoke and clamp where I work does the two
hand adjust type of focus needs sufficiently. As for lock washer throwing out or
cone washer (expensive), to each his or her own. Somewhere over 1,000 fiber washers per year all custom stamped to USS 1/2" washer specifications and they work sufficiently to ensure that no matter how much you tighten the 1/2"
bolt securing the clamp to
yoke, you with two hands will still be able to adjust the
fixture without un-loosening either the lock washer or regular washer which would tend to loosen or tighten. Wrong placement of one's intent to provide a swivel
point in my reading. This especially in ensuring that those focusing still also re-tightien the main
fixture locational
bolt or don't over tighten it.
By way of spring lock washer dirctly onto aluminum or even steel
yoke, one can do better I agree and rarely do so. On the other
hand the lack of lock washer of any type by way of hex
nut head of screw offers limited to no locking in place ability. Best would be a internal or external tooth lock washer between that of the hex head and
yoke in dispersing the pressure on the
yoke. Otherwise, normally when doing a
yoke to
C-Clamp, I would do a washer against the
yoke and spring lock washer against the head of the
bolt.
Believe it's the "
Jesus Wrench" or "Jesus
Nut" we are discussing and a search into those key words of the past would lend further info onto the subject.
For record, when possible, I always first choose this 5/16-18x3/4" square head set screw as a primary adjustment part to focus with. When it slips by way of some gorilla's in the past having over tightened it - so it don't move, I grumble at them especially when I need to have to remove it so as to make the clamp into a studio/spud mounted clamp. You replace such damaged things.
No excuse for a rusted
bolt of any type, nor one that's stuck or slips. On the
stage and under a controlled - this is the only use of it type of thing, this should never happen either over tightened and than grooved for locking T-fittings or broken Jesus nuts. What's wrong with adding a
bit of oil to the
bolt during the yearly maintinence anyway?
My most favorite
C-Clamp is one where someone installed a
yoke knob in place of the set screw. While the
bolt on the knob is most likely to be a lesser grade of steel, this knob in place of a cup
point alloy grade set screw is by far the easiest solution for the problem of focusing the light. No stuck
nut or need for a tool to adjust it. Expensive solution but the
hand knob is possibly the better solution for this focus in doing it properly type of way.
Yea, by way of past gorillas too lazy to adjust by way of the Jesus screw and especially in the cases of a slighly loose one, the inner T-shaped part it screws against gets channeled and won't lock very well at an assigned position. Once the gorilla of the past is done with this, do you work around this past person or replace the damaged part? There is a reason this part is there, don't know it other than it's a better thing to have than clamps without it.
Beyond this a fiber washer or teflon washer between clamp and
yoke is often easier to adjust with, but that's getting into more expensive add on parts to supplement those who would intent to just focus on the quick. Doing so properly is still the right method where possible.