Top and Back thicknesses?

pzwinakis

Hello All,

I have measured a couple original Selmers. An early "D" hole and a Later Oval hole. Tops on both were approximately 3mm but I assume many Selmers have differing thickness tops. I have read in this forum that people making reproductions recommend much thinner tops. The forms I have made for top arching have an approximate 9.5mm top arch beneath the bridge as per the Oval-hole I measured...

I am looking for recommendations for what a good starting point for top thickness on a non-pliage top in Engelman or Alpine Spruce? Also what thickness are you Luthiers out there using for solid wood backs (Mahogany or Rosewood)? What are the trade-offs as far as sweetness of tone, volume, projection? Are you thinning the top and/or back plates around the lower-bout perimeter?

Any information and opinions greatly appreciated. Thanks, Peter

richdaigle

I've only had my hands on a Dupont md50 to reference and It seemed to be a pretty even 2mm...I recently finished a dhole and oval with that as my top and was very happy with them both (Alaskan Sitka)...on my current build I went with M.Collin's book measurements where there are variances from 1.7mm, 1.9mm and 2 mm around the perimeter...he claimed to have taken off a selmer, ...I'll let you know how it goes.

As far as backs go, I ply qtr sawn 1/16 mohog, then a standard veneer mohog aprox 1/32 (cross grain) then the rosewood veneer...it all figures out to around <or>.90 inch I think. I use a vacuum press for the making the veneers the sides are same way, except I use 2 standard mohog veneers and the rosewood...thin, but remarkably strong sides.

Good luck and feel free to contact me
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Ken Bloom

I've built a lot of instruments but only one guitar, my 7 string Selmac. The top is Sitka spruce and is a uniform .078". The back and sides are solid rosewood and are .080. I made a lot of mistakes but it sounds good, plenty of volume and all the sustain that I wanted.
One bit of advice. Then next time I do this I will thin the side down more where that very severe bend for the cutaway goes. That was the only bending problem I had. It came out fine thinning at that spot would have made it a lot easier.

Ken Bloom