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Hello All-

I've picked up Benedetto's book and I have to say I'm very suprised the chapter on carving the plates is only a few pages. I've looked at the templates in the back both the overall template and the full size template and it seems like it would take an extremmly long time to lay everything out to create a topography as in Fig 14. Seems it would have been easier to make a template like fig 14 with some depth info. Anyway, can someone please explain how they would go about using these templates or perhaps an alternate source?

Thanks!

Hi Turbo,
I have only made 1 Archtop so far so I'm hardly an expert, but the "topograph" in the book isn't too helpful. I would really only use the
"topo" to hog away some of the material, not to define the curve. Also, I would suggest picking up his video series it has a lot of detail that is either left out of the book or skipped altogether.
   Anyway here is how I did it. I made templates from the book out of 1/8" particle board. I trimmed the top/back to the outside shape of the guitar, and I defined the perimeter thickness ~1/4" using a wagner safety plane. Next I took the lengthwise template and carved along that line until I was in the ball park, then I switched to the lower and upper bout templates. From there it is really just a mater of smoothing it out the diffrences between the various sections.
I hope that makes sense and didn't confuse you more

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Matt Jacobs

"Don't tase me bro"

I posted a tutorial on how I use the templates to layout out a topographical map that should be in the archives. If I can find it I'll edit and post the link. Otherwise if you can wait I think I can recreate it.

Hey, Matt, is an arch top spherical like an acoustic?

Ron

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OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

The Benedetto plans would be a worthwhile investment if you don't already have them. There are full-size cross-sections and lots of detail. Saves considerable hassle in scaling up.
I consider the Benedetto stuff to be in 3 parts- each of which fills in some missing details:book, DVDs, and plans.

Lotsa $$, I know.
John

Ron, no it isn't. If you haven't handled an archtop -- think of the F Type Mandolins or violins you've seen. Archtop guitars are similar.

Starting with the Benedetto templates (or your own thoughts on appropriate arch) I draw on graph paper a set of arch profiles for each the upper and lower bouts, waist, centre of the waist to heel end edge and length of the body. Illustration below is for the Lower Bout of the back plate....

Next I take each of the above described arching templates and plot in one inch increments along the vectors shown in yellow....

By eye I join each of the marks made plotted on the top from the above picture, creating a "contour map". On each of the lines I mark the height of the arch.
Using your drill press and depth stop, drill 1/4" holes to the prescribed depth on each of the contour maps (sorry I don't have a photo) but the Benedetto book has an illustration to that effect.
Once done drilling -- I get out the angle grinder fitted with a Lancelot and start hogging away stock till I only see dimples from the drill holes. Finishing up (on maple plates with Angle grinder fitted with 60 drit paper) using finger planes, scraper, orbital sander...etc. Picture below shows a top and back plate after I've put away the Angle grinder/Lancelot. Then smooth the top to the desired near final plate arching (convex side). Next, carve the inside. Take a scrap piece of plywood with a 1/4" or size diameter dowel drilled and set into the ply (cap with cork/leather or rubber). Clamp the fixture to your drill press table and set the depth stop so the bottom of your drill bit is 5/16" from the top of the dowel. Start drilling holes. The convex or top of the plate rides on the dowel and ensures you have a consistent depth drilled into the bottom. Then hog off the drilled stock down till you see dimples.


ARGGHHHH!!!! -- PICTURE UPLOAD NOT WORKINGAnthony Z39090.9823263889

Anthony!

That post is probably exactly what I need! Do you have the pictures saved somewhere?

Thanks for digging that up

I took a look at the plans and those certainly seem like they would help the overall process. Probably should get the videos too while im at it. Great posts so far.turbo41139090.981875

My ability to post pictures on the OLF is really hit and miss -- I wish I knew why.

Yes I do have the pictures to match the text above and will email them to you.

Anthony Z39091.0079050926

Turbo,
   Since Anthony is having technical difficulties. RM Mottola wrote an article in the GAL mag about defining arches. It is geared more for CAD puposes but it will give you a good idea about the contours and depth.

Arching PDF

Ron,
Like Tony said, the arch isn't shperical. Since you're an Arkansan I'll put it in terms you would understand; the curve is like a recurve bow

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Matt Jacobs

"Don't tase me bro"

Matt the Mottola article illustrates very well how I layout my archtop contour map.

Heck I'm from Kansas and I understand that

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Say what you do, Do what you say.

The Benedetto videos can be rented for $10 from smartflix.com.

CrowDuck

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Chris Nielsen
Soquel, CA.

Dave, Kansans or Arkansasans it's all hillbilly to me! just kidding

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Matt Jacobs

"Don't tase me bro"

I used Matt's method of using the templates as he mentions above prior to going to CNC for rough carving. Cutting the outline of the plate first and then establishing 7/32"/1/4" thickness all the way around the outside is a good start. As Matt said, getting the longitudinal arch established down the the centerline of the plate and then the transverse arches on the bouts works pretty good.
Actually, I cheated on my first couple of archtops by using CNC to cut the "templates" right into the plate and then hand carving to these landmarks. Later found it was just as easy to start carving with the lancelot using the templates.
Nelson

Nelson,
   I used the ibex planes for about 20 seconds before I switch to a cutz-all on an angle grinder, saved me many blisters on my hands. Of course I went back to the planes once I got close to the final shape

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Matt Jacobs

"Don't tase me bro"

Mattyeod, I don't mind being called a Hillbilly. If you want to have some fun ask me how I Pronounce Arkansas.

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Say what you do, Do what you say.

Dave, you can call me plain old Matt. Not to hijack this thread, you should come to the OLF Ar"kansas" meeting in March. Check out the thread for details.

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Matt Jacobs

"Don't tase me bro"