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Does changing the width of the sides by 1-2cm affect the side much? I'm building my first guitar(a 1937 Hauser) from a kit I ordered from LMI. The sides are already bent and thicknessed but the width ranges from about 10.9cm at the top to 11.5cm at the bottom. The Hauser plans I bought ranges in size from 90mm to 97mm. So I guess my question is would it matter much if I left the sides alone or do I need to follow the plans exactly?

Edit: Fixed error in deminsion.

Caleb, in my opinion you need to profile the sides. Remember, the plans give the total side height of the guitar which is equal to side plus top plus back. So with approx 2.5 mm top and 2.5 mm back you are adding an additional 5 mm or so to the already 10 or 20 mm over you have. It will definitely change the air resonance and sound. Who knows, you might like it better, but classical guitars have very similar dimensions because over the years they have given the sound we recognize as a classical guitar sound. It will be easy to profile the sides. Make sure one side is flat, and install that flush on your solera for the top side. You can then use a block plane to plane the back side down to match your plan dimensions. Remember to subtract your top and back thicknesses. It is really easy to plane the thin sides to where you need them.
regards, Mike

I was just submitting the same advise as Mike. Being off by 10 to 20% is huge.

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Thanks for the replies, since both of the sides have already been tapered, would I plane the tapered or flat edge?

For a classical leave the flat side flat, that is for your top. Plane the tapered side. Where are you in the process? I would actually do this final profile of the rims after I have glued the rims to end block and neck. Are you following any book or DVD? There is a bit of trickery how the Spanish style neck top and rims come together.

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I've been roughly following Bogdanovich's Classical Guitar Making, Cumpiano's Guitarmaking, and Robert OBrien's Build a Classical Guitar DVD.

I just started about a week ago, though I haven't had much time to work on it. I started on the scarf joint, but I'm having trouble getting it flat...so I started working on the sides. I was going to profile the sides to the approximate width and then glue on the end block.

I did my first with the same two guides. I would follow Robbie's DVD. The back usually have a radius. Where the waste bends in the sides are a bit taller as they are inside the radius. If you taper the sides to the end measurements in the plan now, the sides will not be tall enough to radius properly. Basically the sides do not end up with an even taper tall to small. Bogdanovich does build his sides off of the guitar, linings and all. He has them properly profiled first, Given that you have prebent sides with some unknown profile I would do the final profile with a 16' radius dish or sanding bar after I had the blocks and neck glued on. I do not think the Hauser 37 plan has a rim profile. If you had profile you could transfer it to your sides and plane them to the correct profile.

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So what you are saying is to attach the neck and end block, then profile the side to the correct width?

On a side note...where could I purchase radius sanding disks or bars, or is there a way I could make them? And how do I determine the radius of the back and soundboard?

I think John Hall at Blues creek guitars has radius dishes. http://www.ebay.com/itm/MARTIN-GUITAR-KIT-LUTHIER-RADIUS-CONTOUR-DISKS-15-ft-/200522323851 get the 80 grit sand paper disk as well. Typically a 15' radius disk is used on the back. What I do is to draw a line with a white pencil parallel to the top a bit lower than height for the neck block. I also mark the final height at the heel and tail. I then as Robbie says drive the bus with the sanding wheel bringing down the rims. I use the parallel line I used to make sure I am sanding evenly side to side. I watch the final heights at the end to make sure I am approaching the finial height evenly. The top is flat with a dome in the lower bout. The Bogdanovich book does have a description on how to make a solera. I really recommend that you make one. I used planes, scrappers and a sander to put a 3 mm dome into my solera. The dish are a pain to make your own, but you can see how on youtube.

You might also consider this mold and work board http://www.ebay.com/itm/1937-Hauser-Classical-Guitar-Mold-/121182667968?pt=Guitar_Accessories&hash=item1c370cc4c0. I would still put a dome in it.

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