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erikbojerik

Building An F5 Mandolin

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OK, here we go. This tutorial is to build a mandolin in the Gibson F5 style, from scratch. I'll be posting photos and instructions all along the way, but please have patience...you have to build more molds, jigs & templates than actual mando parts. Not to mention I have a day job. :D

I want a mandolin mainly because I like the sound, even though I'm not into country or bluegrass. They add a nice touch for acoustic "unplugged" scenarios. But mostly, this is a good and inexpensive way to get experience with all the skills needed to build an archtop guitar. In many ways, a F5 mando is just a mini-archtop.

The construction methods will closely follow two sources: The Ultimate Bluegrass Mandolin Construction Manual by Roger Siminoff, and Making an Archtop Guitar by Robert Benedetto. You can find copies of these in some libraries, on eBay, or through on-line bookstores.

Here are the base materials for the mandolin: flame maple sides (2-1/2" x 24" x 0.2" thick, five slabs), flame maple neck blank (3-1/4" x 15" x 2-1/4" thick), flame maple back billet (6" x 17" x 2-1/4" thick) and Sitka spruce top billet (6" x 17" x 2-1/4" thick) 20 grain lines per inch, nice stuff. All quartersawn. These were all rought-cut dimensions from larger boards, so about $50 worth of lumber here.

Woods.jpg

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The first thing to build is the body mold. This will be your guide to hold the body piece while you work on everything. It really helps to make this as perfect as can be, this one is my 2nd attempt.

You need a 15” x 18” piece of 3/4” plywood or similar stock. There’s a temptation to use thicker stock for the mold, resist this as you’ll need the room to work on the top & back. Make certain the plywood is perfectly square. Rip this down the exact center (along the 18” direction). I used pattern #4 from Siminoff to trace the body outline, then cut out the body shape on a band saw. Make a good clean smooth cut, you'll need to keep the center pieces for use.

I then took about 2" off the inside pieces using a table saw; you're making room for a turnbuckle, this will become a clamp to hold the sides flush against the inside of the mold. The little squares of plywood are cut from the strips ripped out from the center.

The upper ends of the inside pieces are cut out to make room for the heel block, which will have a scroll cut into it. You can see the shape of the heel block, it is the little piece of paper cut off the pattern.

F5mold1.jpg

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Then mark off lines 2-1/2” in from the edges, and 1” deep from the ends. These will be cut-outs to make room for threaded rods which will hold the mold together. I made the long cuts with a radial-arm saw, and finished the cutting on the band saw.

F5mold3.jpg

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This is what you should have when you’re finished with the cut-outs. Now you need to drill through the tabs and the little squares with a 3/8” bit, so that you can thread the rod though. Measure in from the ends 1/2” and drill in the center. Drill all your holes at this point, before you glue in the squares.

F5mold5.jpg

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Cool Devon! If you have anything to add to this as we go along, please do!

Two 24" long 5/16" #18 threaded rods, 4 washers & 4 wing nuts (about $5 total at the Depot); I had to cut the rod down to 17" with a dremel; that's how the whole thing fits together. The little blocks are glued only to the left half of the mold. With it screwed down, I made one more pass on the spindle sander to even out where the mold halves join at the heel block and tail block.

F5mold10.jpg

A bit of a problem with the turnbuckles (~ $12 for both @ Home Depot), the gap between the inner pieces is not wide enough. After making more room with the spindle sander, I cut recesses for the eyes with a 1" forstner bit 3/8" deep, then drilled all the way through the hole centers with a 1/4" bit, then chiseled out the channels for the eye screws. The eyes are held down with 1/4" carriage bolts. When you install the turnbuckles, make sure they both operate in the same direction.

F5mold12.jpg

The ends of the carriage bolts were cut off with the dremel, so that they don't protrude beyond the nut. This way the whole works will sit flat on the work surface nearly flush with the outer mold.

F5mold13.jpg

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The last step is to glue 1/4" feet onto the back of the mold; not having any 1/4" stock handy, I used fancier laminated feet (cut from a 1/8" paint stirrer). Don't make the feet any taller than 1/4" or else there won't be enough rim sitting up above the mold when it comes time to glue the kerfed linings. The 1/4" is enough so that you can turn the wing nuts and turnbuckles while the mold sits flat on the table.

F5mold14.jpg

And there you have it...finished mold & turnbuckle clamp. About $25 worth of material & hardware, and 2 hours work (not counting the first botched attempt...).

F5mold15.jpg

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Rad! I cant wait to see the rest of this! Thanks a ton for doing this erik! By the way, Siminoffs book is great isnt it!

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Actually, I've been advised by the good folks at the mimf, and at mandolin cafe to go with StewMac's F5 plans. Supposedly there are innaccuracies in the Siminoff plans. And that load of stuff about tap tuning :D. I definitely don't regret getting that book, though. Very informative.

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Interesting about the inaccuracies...could make for an adventurous build.

Siminoff & Benedetto take different approaches to tap tuning; Benedetto taps until he feels things sound "right", while Siminoff actually goes to the trouble of getting a strobe tuner and tapping away on plates and finished bodies to avoid potential resonances & wolf notes, aiming to tune the body to Db or something like that, a note that doesn't much appear in country/bluegrass music.

Not having a strobe tuner, I went & tried tapping my Ovation acoustic plugged into my Boss stomp box tuner. It didn't work all that well until I added a little compression/sustain to the input. Now it gives a consistent note a bit sharper than Bb.

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Its hard to argue with Benedetto's method.

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Today was template day. I used 1/4" plexiglas available from (you guessed it) Home Depot, about $22 worth. I photocopied the patterns & cut them out, staying outside the line so that I would have a clear target to saw up to. I stuck the paper patterns to the plexiglas with spray adhesive. Then on to the band saw, sawing right up to (but never into) the outline.

Templates1.jpg

The scroll on the body plates was tough, but I went slowly with a 3/8" bandsaw blade. On the body and neck templates, I removed the blue sheet from the back side and scribed the center lines; by holding it up to the light, I can confirm that it matches the centerline on the paper pattern. Then I cleaned up the burrs with a spindle sander and files, and removed the blue sheet containing the pattern. I also scribed the name and number of each pattern on each template.

Conserving plexiglas here.

Templates2.jpg

These are the back contours for the neck, at the 1st-3rd-5th-7th-9th frets.

Templates3.jpg

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Any news? How's it coming Erik?

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<sigh> Remember that fully-stocked carpenter shop I once had the run of? Well, the tools are going into storage to get the building ready for demolishing and renovation. For, like, a year. Or so.

Luckily I have my back-up mini-shop at home in the garage, but this means a drastic re-org of the garage situation. Should be back in business in a week or so.

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Well, I sure hope so! I've been waiting for more on this project! Oh, er, and, cause it would be good for you to get your shop together, too, yeah! :D

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Any updates? Looking foreward to seeing this as it gets built. :D

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I'm getting ready to go to Alaska for a month....more stomping around volcanoes...I've managed to do a little bit more on the templates, but that's all. I'll see if I can post a few pics before leave for the great white north.

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Just about done with the templates now. Here's the neck profile, fretboard, scribe template for the volute that is carved on the scroll top, and neck back contours (minus the blue film).

MandoTemps2.jpg

Here's the top plate template (getting ready to cut the F-holes) and the headstock template. I love the F5 headstock.

MandoTemps1.jpg

These cardboard templates are for the profiles of the inner and outer surface carves of the soundboard and back plate. I made these out of cardboard so that I could see where I was "off" by how much light shows underneath. There are 5 sets for different positions between the tail and the heel.

MandoTemps3.jpg

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OK, perhaps the first dimensional issue. The tuner hole spacing on Siminoff's drawing did not match the post spacing on my Grover tuners (good thing I've got most of my hardware, and checked before drilling). You can see how much its off by looking at the holes nearest the nut. So I just drilled the template to the Grover spacing.

MandoTunerHoles.jpg

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Time to cut some wood! The neck profile template is used to trace the profile on the squared-up neck blank.

MandoNeckProfile.jpg

This blank is actually just wide enough to yield two necks; I scribed the location of the neck-body joint onto the fretboard template, then traced out the outline on the planed and sanded fretboard-surface of the neck blank.

Mando2Necks.jpg

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Oops! The neck blank is slightly shorter than the neck profile template, by about 1/2". I'll either add a little bit to the tip of the headstock, or make the headstock 1/2" shorter at the nut. As a result, I won't yet (if ever) cut out the truss rod access hole in the headstock template.

NeckOops.jpg

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How's it going?

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I'll be getting this geared up again soon...had to finish a bass proj first. Going from 36" scale bass to 13" scale mando...it will be a refreshing change.

Silver lining...I KNOW my wood is dry & seasoned now! :D

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