Grace G-707 Alignment Protractor

[Qwin]

A friend needed an Alignment Protractor for his Grace G-707 and couldn't locate the original Grace Protractor, so I did the CAD work for him.
Other Grace owners might find this useful.

The Grace G-707 and G-707 mkII Arms use Alignment Geometry similar to Stevenson's.
Like Rega and Technics, they are all similar, but not exactly the same as Stephenson's, or each other.

I used the numbers from the Vinyl Engine data base and John Ellinson's spread sheet and this is what the Grace comes out as:



Using this I made the drawing and PDF file linked below.

Grace, like Rega use an Effective Length of 237mm and a Spindle to Pivot of 222mm.
The offset Angle however is 21deg, compared to Rega's 22deg.

Using the Grace Alignment Geometry, with their own Null Points, as I have done, mounts the cartridge well into the headshell and square to the fixing slots, no twist.

https://www.jkwynn.co.uk/Pics/Z_038_G707_Protractor.pdf

[drSM]

Print it and make sure the big rectangle actually measures 100 x 220 mm, cut out hole for spindle and it should align as intended ?
Thanks Ken this is very convenient
Awaiting armboard

[Doctor Fuse]

Thanks, Ken, I look forward to trying this out soon! I used the two null point protractor from the HIFI News TEST LP, with excellent results. But I am very curious how yours compares.

[Qwin]

Thanks, Ken, I look forward to trying this out soon! I used the two null point protractor from the HIFI News TEST LP, with excellent results. But I am very curious how yours compares.

Look forward to some feedback.

[Doctor Fuse]

Well I finally found the time to print your protractor off, and check it with my alignment. Looks like my cartridge aligns almost perfectly with it! Now I have to find some good card stock to print a good copy off with. Awesome job!

Thank you so much, a nice tool to have in the arsenal.

[Doctor Fuse]

Also, looking forward to swapping cartridges more often, on the Grace now. Your protractor should make it a breeze!

[Qwin]

Once you have the null points, effective length and Spindle to pivot distance, anyone with a CAD system can easily produce a template.
You don't need the overhang or offset angle as these are the result of the other elements, always nice to check they are correct though.