Here's a link to a page that has a waaay cool, free downloadable custom arc template generator for phono cartridge alignment that also prints strobe discs. IMO these are the finest protractors and strobe discs I've yet come across online.
http://conradhoffman.com/chsw.htmThe download is a very small computer program that simply runs from whatever folder it's put in. It can print Lofgren A/Baerwald, Lofgren B, and Stevenson alignments and allows you to set inner & outer groove radii or use standard DIN, IEC, or typical radii. 200mm reference lines are printed on the protractor which you must measure to verify your printer is printing accurately. You can enter x,y printer correction factors to correct your printout if need be. The x,y correction factors can also be used to vary the size of the strobe disc, which even have a radial line marked on them so you can count revolutions and compute your percentage of speed accuracy. The center of the printouts are marked with a circular hole you can punch out with a pin, and also with a rectangle you can cut out. (For me, the rectangle always seems to work easier and better).
Instructions are in the Help tab, and there's a whole lot more in the readme file. Please read the entire readme before you print. The upper section of readme just lists updates to the program, but scrolling on down you find there is a TON of info there which I found captivating to read. Enjoy!
