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I'm working on first solo guitar. OM with engelmann spruce top. I think I may have planed/sanded too much. Top thickness is in the range of 0.90-0.095". I finished the rosette (see photo). I'm about to start putting braces on. Is this too thin? Will it be strong enough? Should I start over? Should I make taller bracing?

Thanks.

I think that without having the top in hand, no one can accurately respond. Wood is way too individual in its characteristics. And everything matters. The size of the guitar matters, the bracing matters, the anticipated string size matters.

.095 is as thin as I would go
if the top feels stiff you should be ok

Ok. Thanks for the input.

I’ve never used a plane before, so I was excited when I was able to sharpen and set up a block plane to consistently shave 0.005”. I did measure as I was going, so I knew where I was. I just went too far.

I bought inexpensive spruce for my first go at it, figuring if I really messed up, it would be better to do so on inexpensive wood, and I could scrap it and start over. Problem is, I’ve put a lot of work into it and I’m starting to care about this piece.

Thanks.

best advice us this
when you find yourself in a hole stop digging but learn from what put you there in the first place

Input from a still-novice - don't fret (that's a luthier term . . . ) about "wasting" a top; you may find if you can't use it on this project, it might do for a future parlour build, or even a ukulele down the road.

I've taken engelmann to .090" and it was fine, but that was My final thickness (the thickness after building). Like you, I was hand planing. It's easy to go beyond your thickness goal when hand planing. You should be okay, as long as you don't have heavy sanding to do.

To prevent this from happening down the road, I suggest you make 2 strips of wood, about .110" thick, which will give you room to sand, that you can attach to a table or large piece of wood. Put the strips along the top and bottom edges of your top. They'll hold your wood in place, and you can plane down to the tops of the strips. When you get close to, or to the level of the strips, stop.

Thanks for all the great input. I guess I’ll go ahead and see what happens. It does seem fairly stiff, but I don’t have the experience to gauge this.

I have visions of, someday, stringing it up and having a catastrophic failure.

I like the 0.110” strip of wood idea.

Now on to making braces….

.095 is about 2.4mm I believe. Englemann has a tendency to have less stiffness than other varieties but you can make up for that with stiffer braces. Check out The Responsive Guitar by Ervin Somogyi, it doesn't tell you dimensions but much like the old anecdote of teaching a man to fish it will give you a better understanding of how the stiffness of the top and bracing work in harmony.

I'm currently building a small bodied guitar with an exceptionally stiff piece of Adirondack that I've thicknesses to 1.9mm, I doubt you'd have to scrap a top that's 2.4mm

Also in regard to hand plane thicknessing, plane cross grain taking measurements as you go and marking the top with pencil. Once all the pencil marks are gone you can assume the thickness is relatively even. Repeat the process until you've reached your desired thickness.