Acoustic side height calculation

[mac007]

Hi,

Does anyone have a tip on calculating side height contour for various back radiuses?

I have seen a spreadsheet (Dooling guitars) which is pretty tedious.

Or is it common practice to approximate and then scribe the sides while the braced back is in the radius dish and fine tune with a block plane?

Suggestions appreciated

MK

[kiwigeo]

Or is it common practice to approximate and then scribe the sides while the braced back is in the radius dish and fine tune with a block plane?

This is what I do.

[TallDad71]

Side heights are difficult to use as the top is also radiussed(!) hence there is no straight line to measure to.

I scribe, hand plane it rough. My dish has a 60cm diameter round piece of sandpaper in it, so I sand the kerfing and sides using that.

I also use the radius dish on top of the sides and back when gluing the back on. That way it applies even pressure all around the rim.

I also find if I sand the top edge of the sides with a different radius board first, I can sandwich the whole thing between two boards under the go bar press. The sides are still in the mould and I’m not gluing the top on at the same time.

[Dave M]

Yup, fine tuning with the sandpaper covered radius dish. Must admit I haven't worried too much about the exact depth of my guitars. They all come out a bit different. I may be wrong but I don't think it makes a lot of difference - within reason.

[lamanoditrento]

Hi,

Does anyone have a tip on calculating side height contour for various back radiuses?

I have seen a spreadsheet (Dooling guitars) which is pretty tedious.

Or is it common practice to approximate and then scribe the sides while the braced back is in the radius dish and fine tune with a block plane?

Suggestions appreciated

MK

I have a vague memory of a ex-Somogyi's (can't remember who) ig post showing a radiused external mould and simply using a dremel with a disc cutter jig to trim the sides to or very close to radius. I always thought it was a pretty neat way and if I didn't have a ever expanding library of shapes I would have made one.