proper use of arc protractor ?


For about a week now I have been talking with some of you here and trying to determine if my set up an the Mint protractor I purchased are compatible.Never once did I consider that I might be doing something wrong. If someone could walk me through best practice in as much detail as they can stand it would be very helpful.I am a my wits end after a week of messing around please help.
128x128wilson667

Showing 2 responses by markd51

Yip's Instructions that accompany the Tractor were IMO well written, and easily-clearly understood.

As was mentioned in your other thread, the goal of correct overhang is to get the stylus to precisely trace the Arc from start to finish of Arc.

It is permissible to rotate the Tractor to accomplish such, as this is not a Sight Line Tractor, like a Geodisc, or the Turntable Basics Mirror Tractor (as two examples).

It is a lot of fidgeting, no doubt about it, and I almost took two hours to use my Mint Tractor to properly set up my Cartridge.

You must achieve proper overhang first. Then you lastly move on to achieving correct Zenith Angle.

This is the adjustment, of insuring the cantilever tube of the Cartridge is in alignment with the two null grids on the Tractor. These are actually microscopic, and almost an impossibility to do by naked eye. A magnifying galls, and a Loupe (Yip calls it a Lupe) will surely ease the process of this alignment.

But as you slightly nudge the cartridge within the headshell to adjust Zenith Angle, you most likely will also nudge the overhang, and it will again be slightly off.

This is what causes the Mint Tractor to be a lengthy process, going back, and forth, double, triple, quadruple, etc etc checking, to insure both adjustments are dead on.

Then one must finally snug the headshells screws reaonably snug, then check again. Then the final finishing tightening of the Cartridge to headshell, and again, another check must be done again.

One you see that the Stylus will perfectly trace the Arc with headhsell screws finally tightened, and that Cantilever alignment is nuts on to the null grids, you are then finally done! Whew!

The Mirror itself can also be used as a decent check of azimuth angle of the Stylus itself, by viewing from the exact front of the cartridge as the Stylus carefully rests on the mirror, that you want to see the Stylus, and a reflection of the Stylus, that both images look perfectly symmetrical, like an hourglass shape. Again, use a magnifier, or loupe to aid you.

Since the Mint Tractor is an overlay onto a sheet of (real) glass, you might note some scratching of the surface, caused by the Stylus. This can be lessened be wiping the surface of the Tractor with a little alcohol on a clean piece of Kleenex. Mark
No, one should not then rotate-move the tractor when going in between inner, and outer points of the arc of protractor.

Only initially, if the protractor itself is grossly off the mark. If one cannot trace the Arc perfectly, one could possibly have the Protractor positioned slightly incorrectly.

One can then move the protractor, but then must start all over again with the overhang adjustment.

I think I have this right. Mark