Ah -- you're right, John....  dang these Senior Moments anyway!

Ken, "Perfection pegs" are made by Knilling.   That's their brand name.  And "Pegheds" are made by an different company.  As are Wittner "Fine-Tunes", I believe.

Is it "wise" to replace the McSpad friction tuners with Whittner pegs?  Probably.  There are other "planetary tuners which look more traditional -- Perfection and Knilling.  Geared pegs will not affect how the instrument sounds.   

One thing to know is that the McSpadden tuning shaft holes are parallel, not tapered, and the Whittner pegs are tapered.  For proper fit and function you should reame the holes with a standard 1:30 tapered instrument reamer.

The Whittner website WITTNER® - Finetune-Pegs, Made in Germany (wittner-gmbh.de) gives you the necessary tech specs for each of their models.  At a glance it appears that their models for 4/4 and 3/4 violins are the size you'll want.   Similar information is available for Perfection and Knilling planetary tuners of course.

updated by @ken-hulme: 07/08/21 06:11:59PM

I acquired a 1973 Mc Spadden M12 it has non-geared tuners where the tuning tension is adjusted by tightening or losing a screw the the knob.  I find these tuners difficult to use.

  My brother gave me a junk shop find three string and no 6 1/2 fret hourglass dulcimer with a broken and repaired by splint head.  It had wooden pegs which were a difficult to use.  I replaced them with Whittner finetune pegs.  They work very well and very easy to install.  The dulcimer sounds very good (as good or better than the McSpadden - I tune CGg), and has a label inside "MADE ESPECIALLY FOR JOANNE M.   WITH LOVE AND CARE MICHAEL".  I have no idea who Joanne or Michael are but the dulcimer was found in Minnesota.

Now to my question - Is it wise to replace the tuners on the Mc Spadden with Whittner tuners and if so what size should I use, the peg hole is about 8.27mm.  Also the McSpadden does not sound bad but not as good as I thought it would.  It may be me, the tuning, my playing noter style using my fingers or are there some other recommended changes.

Jim