slim hollow body with P90

[Graydon Stephens]

Hi, new member here and about to start a new build. Would like to know if anyone here has a build similar to Guild T-50 Slim or Epiphone 1966 Century.. Those are my inspiration for this build, and I have never built an archtop. My builds have been two solid body electrics and an OM acoustic. Thanks!

[Barry Daniels]

Are you going to carve the top or laminate it? What is the back going to be?

[Graydon Stephens]

The plan is to carve the top and back. I haven't firmed up on wood types yet The OM style acoustic I built was sitka spruce top, sides and back were walnut. I had considered building the back the same as the OM (braced dome) and just carve the top.

[Barry Daniels]

Please don't start another discussion on the same topic in the other forum. It really isn't necessary.

[Barry Daniels]

Graydon, Here are photos of a thinline I made back in 2006 that has a carved spruce top and a laminated birdseye maple back and side. It has a 3/4 length spruce block between the top and back to support the bridge and pickups. I couldn't find the original discussion on this guitar. Let me know if you need any more details.

[Graydon Stephens]

Amazing work!! Thanks for the input and inspiration.

[Jim McConkey]

This discussion Barry?

[Barry Daniels]

Sure, that's it. Thanks Jim! Where did you find it?

[Jim McConkey]

New Library, searched "Daniels slimline"

[Graydon Stephens]

I have a question that may offend archtop purists. Could a suitable arch be achieved by the arched bracing of the soundboard? Yes, I am trying to avoid hand carving the top. I built an OM acoustic per the plans in Jonathan Kinkead's book. The arch of the top - created by the bracing - is only 5/64 at the bridge, though under string tension it increases to 5/32. However, the slim body I intend to build will have a trapeze tailpiece so that increased deflection at the bridge won't occur (I assume). Also, because there will be f-holes I believe i can maintain an arch where the traditional soundhole would be. Obviously the traditional bracing pattern in Kinkead's book would have to modified due to f-holes replacing traditional soundhole, and possibly a more severe arch from the braces. Has anyone here done this, is the idea even feasible?? Same question applies to the back, Kinkead's design is for 1/8 arch, could this be increased if necessary? Thanks.

[Brian Evans]

It's been done, over the decades (centuries), mostly an arch in one direction, with the grain. The nuance of a traditional arched top guitar, with the flowing curves and the recurve around the edge, is impossible as far as I can see. If I wanted to make a guitar like that and didn't want to carve the plates I'd just buy laminated plates from one of the various suppliers. I don't see anything wrong with that. All kinds of show wood selections, and I think a laminated plate is better for that kind of guitar anyway. If I was to carve the plates for such a guitar I'd be tempted to leave the inside flat, except for the weight. I sure wouldn't graduate it.

[Graydon Stephens]

Learn something everyday, I didn't know there was laminated plates. Thanks for your input, something I will investigate.

[Freeman Keller]

I have a question that may offend archtop purists. Could a suitable arch be achieved by the arched bracing of the soundboard? Yes, I am trying to avoid hand carving the top. I built an OM acoustic per the plans in Jonathan Kinkead's book. The arch of the top - created by the bracing - is only 5/64 at the bridge, though under string tension it increases to 5/32. However, the slim body I intend to build will have a trapeze tailpiece so that increased deflection at the bridge won't occur (I assume). Also, because there will be f-holes I believe i can maintain an arch where the traditional soundhole would be. Obviously the traditional bracing pattern in Kinkead's book would have to modified due to f-holes replacing traditional soundhole, and possibly a more severe arch from the braces. Has anyone here done this, is the idea even feasible?? Same question applies to the back, Kinkead's design is for 1/8 arch, could this be increased if necessary? Thanks.

Graydon, I have done both sides of this. First, I was asked by a friend to build "an acoustic guitar that looks like an ES-175". The ES175 is has an arched laminated top with a couple of pretty big parallel braces running down the center of the guitar spaced just far enough apart for the pickup routes and to support the bridge. The ES175 is not intended to have good acoustic sound, it is an electric guitar.

I built mine with a lutz spruce top and put in a simple X brace with a small bridge patch. The guitar was built in a 15 foot radius dish and the braces were arched at 15 foot. It has f-holes with the X crossing above them. The result is a guitar with more dome than a standard "flat top" but far less than a true archtop. It does, however have at least somewhat that "archtop sound" - quick attack and short sustain.

I have also built three guitars with laminated pressed plates from one of the suppliers (who I believe is no longer in business). Two of these were semi hollow bodied 335 style guitars with the large kerfed center block, one was similar to a 175 with the two parallel braces as described above. All of these guitars were intended to be plugged in.

I have pictures of all of these but really don't want to high jack this thread. If you want to see anything specific we could start another discussion.

[Graydon Stephens]

Thanks, Freeman. Your build with the lutz spruce top and more dome than a flat top but less than a jazz archtop is very relevant to my design idea. Here's the background, I am a garage player and jam once a week with friends (in my garage). As a retiree I decided to build a cigar box guitar, gave it to one of the grandkids. Built a dulcimer based on a mandolin body, for one of the grandkids. Built myself an electric lap steel, then a Frankenstrat, then a Tele, then the OM acoustic based on Kinkead's book/plans. I am looking for the next project guitar for a a build this winter. The guitar will be mine, played on jam night as a rhythm and for me to noodle on practising blues fills. I am really taken with the Epiphone Century, Guild T-50 Slim, Godin 5th Ave look - they all have that same aesthetic/vibe. And the P90 with a touch of gain/grit will suit our music. So, I am not seeking a jazz sound and in my mind do not want a deep body nor typical jazz arch. I also intend to use the OM body mold I built for bending the sides and assembly of back and top. I did not build nor purchase a radius dish, I carved radiused braces and clamping cauls to achieve the back and soundboard arching. I intend to do this again. Long winded response, but in short I would appreciate and benefit from your input. As a newbie I'm not sure of protocol, but I think you could attach a couple of pics of the X braced lutz spruce top in this thread. Thank you!

[Freeman Keller]

OK, I guess I didn't realize that you were the original poster so its not like I was high jacking the thread. Before I go into the details of my guitar a bit of irony. I was reading the Big Red Book of American Lutherie vol 5 last night (yes, I'm bore silly and reading a stack of old lutherie books). The article I happened to read was by Graham McDonald on building an Irish bousouki. He faced this exact same problem with a moderately thick spruce plate that he wanted to put a 18 mm dome into. He describes how he went about forming the top. The article is out of print, I may be able to help you with it.

Anyhow, here is mine. The top is 0.125 thick and not carved. The back and sides are mahogany, bent and joined in the usual fashion. An ES-175 has a florentine (pointed) cutaway, that was bent and added to the side. It is not a slim body, you need the air volume for its acoustic sound.

Even tho my friend said he would never plug this in I thought I would hedge my bets and install a piezo pickup while I had the chance. Once the box was closed it would be too late. I simply masked the jack hole and put the jack inside the box with a pull string so I could pull it into place after the finish was on. I also like to reinforce the f-holes when the top isn't laminated - just some surgical gauze with CA wicked on to it

I like to do bolted neck joints when possible but because there is no access to the insides this has a dovetail. The other thing about this geometry is that it required a little shim under the f/b extension to provide the correct angle for the floating bridge

Finished guitar

[Freeman Keller]

The other thing I mentioned was laminated top (and sides and back) in the style of Gibson's ES guitars. These are not intended to be played acoustically, the pickups are mounted directly to the top. A true ES-175 is an example. I was able to get ahold of some pressed laminated plates and build two ES335 and one 175 style guitars (mine has a rounded cutaway instead of the pointed one. Here is one picture of the insides and bracing, you can see that it is just two beams running down the center of the guitar to support the pickups and bridge

This guitar also has a dovetail and a wedge under the f/b extension for the same reasons as the red guitar. The sides and back are laminated maple, top is laminated spruce. Here it is finished

Last, just for reference, here is a 335 style "semi hollow" bodied guitar. It is a true slim body with the large kerfed center block. It has a Gibson style set M&T neck and the top, back and sides are laminated maple

Finished guitar

It would be very easy to modify the last one to take P90's and not too difficult to do to the yellow one. As I said before, the first one is designed to not have pickups.

Hope this helps, I also build acoustics in the usual fashion, these are all very different.

[Freeman Keller]

One more idea before I move on, if you want to carve the top a whole world of possibilities open up. I have done several instruments with carved tops and hollowed out bodies - chambering removes a lot of excess wood and weight, yet you can make any kind of support for pickups and bridges that your design needs. This is a les paul inspired guitar with a chambered mahogany body and carved Spanish cedar top. It will get humbuckers and a ToM style bridge. Angled M&T neck joint, no over stand

Finished

Obviously with this kind of construction you can make it any shape you like, any thickness of body. You could, if you wanted, make a thin body like an acoustic with bent sides and glue the carved top on. Work out the neck angle and overstand based on the bridge you plan to use.

So, lots of options.....

[Graydon Stephens]

I agree, lots of options. I very much appreciate your input and sharing your designs. Seeing the X bracing pics, I'm already glad I joined this forum. Hopefully I can pay it forward some day and give a neophyte some helpful advice. I am a fan of the florentine cutaway and realize I can modify my existing mold with an insert, and I may do this. I might also, some day, modify the Tele I built into a semi-hollow. I would remove 1/4'' off the face of the alder body, rout out two body chambers, add on a flame maple top with upper F hole. But, back to this project and a couple more questions. Your spruce top was 0.125, my OM build was 0.100 Sitka spruce top. Do you think 0.100 is structurally unsound if I'm pursuing a higher dome than traditional acoustic? Did you cut your F holes after gluing braces to the top, or prior? One of the pics shows the pots, pickups, wiring installed before back is glued on - or are they just temporarily laid out and then installed later as a final step? I'm glad you pointed out the importance of shimming under the f/b extension to maintain proper neck angle to bridge - I didn't get this correct with OM build and had to correct by reducing saddle hight and shimming neck angle. It worked out well and I was glad I went with a T&M bolt on neck. Without a standard soundhole in the planned build providing access for bolt on, I am nervous about a glued set neck. And, great input on reinforcement of the F holes! I had concerns about those areas being weak if the top was not carved. Thanks again for your help.

[Graydon Stephens]

Quick edit to my last reply: the thickness of the top on my OM build was 0.112, not 0.100 The guidance in Kinkead's book was 0.125 with edges feathered down to 0.095 - 0.110 range. I suppose going to 0.100 across the board could impact tonality/resonance in a bad way, so more to consider than just having it structurally too thin at 0.100"

[Graydon Stephens]

Freeman, BTW, your guitars look amazing, beautiful finishes!!