Tool for measuring pivot to spindle distance?

Holly has a Teres 160 table with a few upgrades. The
armboard on that table swivels and when you move it, it
changes the pivot to spindle distance. I was the one that
moved it several times when we were trying to figure out
what was wrong with her system. The armboard was very
loose, so I wasn't really to blame, (that's my story and I'm
sticking to it) :-)

I told her the first thing that she would need to do is
remeasure the pivot to spindle distance, (she knows the
correct distance), then lock down the armboard very tightly
before she installs her new cartridge. I think the armboard
loosened up over time and she hadn't used it for quite
awhile.

I think a good solid, thin metal ruler would be fine, but a
digital caliper would work too.

I have a very old original manufacture Dennesen Protractor. If I need to locate the pivot of a tonearm I want to mount, I take a piece of clean white paper and make two pen marks on it, at a distance from one to the other that is equal to the desired P2S distance. Then I set the spindle hole of the Dennesen centered on one of the two dots and line up the vertical steel pointer at the other end of the Dennesen with dot number 2. Then I lock in the Dennesen at this distance. I then place the Dennesen over the tt spindle, and the vertical steel pointer tells me where the tonearm pivot point needs to be. So, I recommend a Dennesen or Dennesen type protractor to kill 2 birds with one stone, as they say. (Because once you've mounted the tonearm, you can use the Dennesen again to set pivot to stylus distance.) Dertonearm offers an accessory attachment to his protractor, exclusively for setting P2S, but it costs several hundred dollars over and above the cost of the protractor.

I think I am confusing folks, or I am confused myself, lol, I know what the spindle to pivot distance is supposed to be, just looking for a tool that will give me a reasonably accurate measurement.

I have a Teres turntable with the original acrylic armboard; my Moerch DP-6 (with a 12" armtube) is already mounted in the armboard. The arm board is loose because the hex screw was not tightened down. The tone arm manufacturer says the spindle to pivot distance should be set at 294.1mm (11 9/16".) I am assuming, perhaps incorrectly, that I need to move the armboard until the spindle to pivot distance matches, or gets very close to, the manufacturer's recommendations, then I can tighten down the screw to keep the armboard in place and go on to align the cartridge with a protractor.

Am I going about this wrong? Doesn't the mounting distance need to be basically correct and the armboard secured in the right place before you use the protractor to align the cartridge? Or do you align the cartridge with the protractor and once the null points are correct, that means the tonearm pivot to spindle distance is automatically correct and you tighten down the arm board then?

I have been looking at that Neiko caliper, too, Banquo. I would think that it would be accurate enough for use in turntable set up - and the price certainly works for me!

I am assuming, perhaps incorrectly, that I need to move the armboard until the spindle to pivot distance matches, or gets very close to, the manufacturer's recommendations, then I can tighten down the screw to keep the armboard in place and go on to align the cartridge with a protractor.

Correct. The tonearm must be mounted with the correct S2P distance before the cartridge is mounted using an arc protractor specified for 294.1mm S2P distance.

Also, when using the caliper to measure the S2P distance, take the arm wand off and measure to base pivot point. This will eliminate the possibility of damage, plus you will create a more level measuring distance (if the spindle point and pivot point are not level, your measured S2P distance will be slightly off)

Sorry, Mofi and Lewm - for some reason didn't see your posts when I wrote my last one. Mofi has the situation correctly described, and, no, I can't blame him for the unsecured state of the armboard. :-D

Mofimadness has a Dennesen protractor/Soundtraktor, too, Lewm, and I would love to have one, but, they don't seem to come up for sale/auction very often anymore, and the Nerve Audio protractors, which appear to be a copy of the Dennesen Soundtracktor, is almost $200, so out of my reach.

So, I need to get a good metric ruler or an acceptable pair of digital calipers; I may go the Harbor Freight route; their Pittsburgh calipers get decent reviews.

Holly