Mint Protractor for the Classic Toneram 10.5i-SE

258 mm

Yes agreed mine is 258mm as well Classic 3. There is a caveat, if you completely remove the tonearm base, there is a bit of play with the 3 screws and the Plinth, you could move it one way or the other by 1mm or so. I think that is where the 1mm confusion comes from. But that is about it. About 1mm of play based on the pressure you put on the tonearm base as you tighten up the 3 tonearm base screws against the plinth. So based on the pressure you could get 259mm instead of 258mm by applying pressure as you tighten up the screws and you apply the pressure.

Actusreus,
I suggest the absolute best way to be sure is to measure yours, that is what I did. Ensure that you account for height, you want the pivot and spindle to be at the same height as much as possible. I measured from the center of the spindle to the point of the pivot, with the tonearm off of the pivot. Mine was 258mm. But like I said in my post, it is possible to get a 1mm difference based on pressure applied during the tonearm base install to the plinth. Since I have taken my tonearm base off a number of times, I ensure that when I re-install, I use a ruler to ensure I get 258mm, as I am tightening up the 3 tonearm base screws. Yip will make the protractor based on your specs, the only measurement he needs is the Spindle to pivot distance, the rest is derived.
He uses the Baerwald (identical to Löfgren A) - minimizes and equalizes distortion at the three weighted tracking error peaks resulting in moderate distortion between the inner and outer grooves.
If you type in your Spindle to pivot distance on this website and look at Baerwald this is what you will get from Yip.
http://www.vinylengine.com/tonearm_alignment_calculator_pro.php

BTW, I have the MINTLP from Yip configured at 258mm, Baerwald, and think it is well worth the investment.

If your measurement is yielding 262mm then I would go with that for the protractor, since it is quite possible the holes in your plinth were drilled differently than mine resulting in the bigger difference from spindle to pivot. The most important is your measurement, accounting for height, not what a database says, since your plinth holes might be drilled a little differently than mine.

Interesting, I optimize my VTA the realign with the MINTLP. For my cartridge I have 9 turns on the VTA tower. I then realign with the MINTLP with the 9 turns on the VTA tower, that ensures I am right on with the arc protractor at my optimal VTA. I just checked the Jig, with the same 9 turns, and the stylus is still within the dot, but towards the back of the dot, towards the pivot. It is not centered on the dot. Of course if I lower the VTA the stylus moves up, so I could change the VTA and make it come right on. Bottom line, when the MINTLP is right on, with my 9 turns on the VTA tower, I am towards the back of the dot on the VPI jig.

The VPI jig wants more overhang. Using the calculator:
MINTLP uses Lofgren A (Baerwald) the overhang is 15.025mm. Maybe the VPI jig is using Lofgren B the overhang is 15.422mm

Löfgren B - minimizes distortion between the inner and outer grooves resulting in the lowest average RMS distortion at the expense of slightly higher distortion close to the inner and outer grooves

I've convinced myself that the MINTLP uses IEC standard Lofgren A (Baerwald), which at 258mm results in 15.025mm. The Lofgren B IEC standard comes out to 15.422mm which might be the difference between the MINT and the VPI jig. It looks pretty close to a half a mm. The VPI jig wants more overhang which is consistent with Logren B.
Of course non of this solves your problem of 262mm spindle to pivot. Might I suggest you download Conrad Hoffman's program and print out IEC Lofgren A at 262 and compare it to your MINT protractor. I suspect your MINT is either 258mm or 259mm, since both of those numbers were used in the past. You could also print out a 258 and 259 and check those against your MINT and then you would be sure of what you have. Ultimately though you might consider using Hoffmans printout at 262, since that is you spindle to pivot distance.

On the VTA question I convinced myself that the MINT protractor is the thickness of a standard record. Therefore with your VTA set and alignment to the MINT your standard records will be "on the arc". Based on my measurements you need 50 units on the VTA tower UP to compensate for 180 gram records. So for standard thickness records you are good, for 180 gram raise your VTA tower by 50 units.

One more point about MINTLP and classic spindle. The spindle gets a little fatter as it meets the platter the last half mm or so. That is why my MINTLP never was flush on the platter, also why it seems thicker than it really is. What I did was countersink the back of the spindle hole of the protractor with a bigger hole, using my drill and drill bit. You have to go about half way through the hole, once you do that, the protractor will sit flush on the platter. It takes a while because it is glass, but it worked for me without cracking the glass, and I just used a standard bit. With that complete and the protractor sitting flush you can convince yourself it is the thickness of a standard record.

Great news I am glad it is 258mm, yes the height makes a big difference. The spindle to pivot distance should be measured on the same horizontal plane.
As another point, after you dial in your VTA, realign with the MINT, otherwise your stylus will not be on the ARC. And all that work to get your stylus perfect is in vain. VTA changes make a big difference on the MINTLP, as you increase the VTA height, you will need to pull the cartridge forward to compensate, and keep the stylus on the arc.

There was a question brought up about the Effective Mass of the VPI tonearm. I did receive information directly from VPI that the effective mass of the Classic 3 tonearm is 11.1 grams. That arm is called the JMW-Classic 3 damped stainless steel tonearm. At the time I received this information I tested it. I computed the resonant frequency with the calculator based on my tonearm, cartridge compliance and weight. I then then tested it with a test record and the frequencies came out very similar. I therefore convinced myself that the effective mass information for the classic 3 tonearm was correct.