I would argue that an arc protractor produced on thick paper is superior to the best two point protractor produced on mirrored plexiglass, laser etched stainless, etc. I won't name names to protect the guilty.
Is a paper protractor as good as a precision tool like the MintLP? You'll have to answer that question for yourselves.
I checked the above site and took a look at the excellent FAQ he wrote (the readme file). He points everyone to the fact that his protractor should be in perfect agreement with John Ellison's spreadsheet. He strongly recommends playing with the Ellison spreadsheet, so we're in complete agreement here as well.
I need to play with this a bit. Don't get confused by his inner groove radius and outer groove radius entry boxes. He is NOT talking about the null points (i.e. 66.0 and 120.9 for Baerwaald). I'll play with this and verify it against the the ones I've drawn for the Tri-Planar, and of course, against my MintLP.
I encourage everyone to play with this program. Read his excellent FAQ, and play with the Ellison spreadheet as well.
Another nice stiff paper you can use in place of photo paper is called "card stock". You can pick it up at places that sell an assortment of printer paper (e.g. Office Max).
Hint about cutting a nice record spindle hole. Use a straight edge razor and cut pie shaped wedges (8 of them) to form the record hole.
Start slicing from the circumference of the spindle hole and work your way toward the center. Cut 8 radial lines to form 8 "pie slices".
This will not only get you real close to "nuts on", but the hole will also be self centering if your spindle is a bit wider than the circumference of the hole.
After I sent samples made this way to many of my customers, they became true believers.
The only risk you are taking is that you might learn something (grin).
Cheers,
Thom @ Galibier
