Tool for measuring pivot to spindle distance?

My new cartridge is on its way. I am making sure I have all the necessary tools for setting up the tonearm and cartridge, and realized that I don't have a decent tool for measuring the pivot to spindle distance for the tonearm. All I have is a plastic ruler with mm measurements - not ideal to say the least!

I would love to get something like the Clearaudio Protractor or the Dennisen/Nerve Audio Protractors, but such tools are beyond my budget. Is there a less expensive alternative? For example, would a set of 12" digital calipers (with mm readings of course)work?

I see some calipers costing around $35 - great price - are they accurate enough at that price point? No doubt most of these are made in China, which may or may not be a problem.

My budget is not much - less than $50 would be ideal. Any advice would be appreciated.

You already have everything you need to set the Pivot-to-Spindle *and* align your cartridge.

1. Use your ruler to set the Pivot-to-Spindle. Take your time. Tighten the articulated armboard (tight, but not too tight).

But what if it isn't perfect? Don't worry, and proceed to Step #2.

2. Go the Conrad Hoffman website and download his free cartridge setup protractor. Enter your arm’s spindle to pivot distance and print out a customer arc protractor template. Pull out that ruler and double check what you print out to make sure your scale is correct.

3. Carefully cut out the hole for the spindle, and begin to align the cartridge per the instructions that come along with Conrad's tool.

4. If your cartridge won't align perfectly at both points on the arc...guess what? Your Pivot-to-Spindle is beyond the acceptable margin of error, and you go back to Step 1.

There is only one Pivot-to-Spindle and one Effective Length that will allow the stylus to perfectly touch both points on the arc. If all align, you *know* it's set up correctly.

Read the README.TXT that comes along with Conrad's tool. It explains the process far better than I just did (and I tested and gave feedback on many of the early versions of this tool).
Well, just saw a Dennesen Soundtraktor on the US Audio Mart site that sold for $39 at the end of December! Darn it! And one that sold on eBay for $120, a more likely price. Sounds as if a good metric ruler is what I had best get for the time being - back to square one. There may be a Soundtraktor in my future, though!

I have a tool that I am looking to sell. its made by acoustical systems Germany. I can list it if you would like.
Holly, I've replied to your post on VE. You don't actually need to know the P2S distance if you can easily adjust at the base, just a two point protractor.

Simply adjust the board with your protractor to set up the cartridge, like the SME. Just mount the cartridge square anywhere in the headshell and then adjust at the base until the nulls are correct.

If you want more tech info as to why this is the case, see point 2 in
this link here: common misconceptions about tonearms