Custom A-4 Style Mandolin #42 177

Completed August, 2017

(click any of the thumbnails for a higher-resolution photo)


At the request of a couple of good customers, I've decide to venture into yet another model: an oval-hole A-style mandolin in the footsteps of the old Gibson snakehead models. This instrument features a Lutz spruce top, maple back and sides, and a 12-fret neck. Vintage looks, with big, tubby vintage oval-hole sound.

Here's a sound clip, composed and played by master mandolinist Ron Webb:

 

Construction Photos

Before I can make the first shaving, I have to create a plan. The Lutz spruce top is joined with hot hide glue. An external form is created. Maple sides are cut to width, sanded to finished thickness, then bent over a hot pipe to the proper shape. The sides are placed in the form, and a mahogany neck and tail block are glued in place.

A neck blank is glued up from curly maple. The clamps are removed, and the inside of the head block is shaped. Strips of mahogany are beveled on the drum sander, then kerfed on the bandsaw to create lining. The lining is

glued to the ribs with hot hide glue. The top and back are cut to shape, and the bevel for the fretboard is cut on the table saw. Edge thickness is established on the router table. Shaping of the plates begins with a finger plane.


Thicknessing holes are drilled to establish the minimum area of the plates. All through the carving process, the plates are examined in raking light to ensure that symmetry and graceful lines are established. When I'm as close as I can get with planes. scrapers take over the work, and finally sandpaper. The graduation is mapped out onto the inside, and thicknessing holes are drilled.

As with the outside, wood is first removed with a plane, then with scrapers and sandpaper. The sound hole is cut and trued on the spindle sander. The plate is constantly checked for thickness, tap tone, and weight. The tap tone is so clear and bell-like that I don't even need to fire up my laptop: the note reads clearly on a guitar tuner.

The cross-grain brace is fitted to the top and glued in place. Hot hide glue is applied to the mating surfaces of top and sides, allowed to dry, and then the parts are clamped together and the glue is reactivated with a burst of steam. Although I don't have any historic numbers to work with, I evaluate the stiffness of the top with my deflection tester. It seems a bit stiff in relation to other models I've built, so I gradually work down the exterior to bring it within an acceptable range. Backlighting the top shows through the translucent spruce how a thin edge gradually thickens toward the center. The head block is extended with a maple addition. Carving of the back begins with removing at least half of the excess wood with a power plane.


Work proceeds with planes, scrapers, and ultimately sandpaper. Raking light checks for graceful curves. The cheeks of the dovetail neck joint are cut on the table saw, and then the balance of the joint is fitted by hand for a perfect mechanical connection. The neck is cut to shape, a slot is cut for reinforcing, and the ears are glued to the peghead.

The carbon-fiber reinforcing bar is glued into the slot. The ebony overlay is glued to the peghead. A pattern is affixed to the peghead with double-sided tape, and the peghead shape is routed through the overlay. The head is roughly cut to shape, and the binding is fitted and glued in place. The "Skipper" logo is cut from mother of pearl, then recessed into the ebony headplate and set in epoxy.

Shaping of the inside of the back begins with a plane, then progresses to a scraper. As I approach final dimensions, the back is evaluated as to thickness, weight, and tap tone, just as was the top. The recess for the rosette is routed, and the outer edges of purfling are glued in; then the center ivoroid filler is inserted.

The rosette is scraped flush with the top. The sound hole binding is glued in place. The maker's label is glued in place, then temporarily protected with a piece of low-tack tape. Hot hide glue is applied to back and sides, then allowed to dry. The parts are clamped together, and the glue is reactivated with a jet of steam. An ebony blank is slotted for frets.

The fretboard is cut to shape, and position markers are installed. Binding is applied to the fretboard. The neck is shaped, and the pegholes are drilled. The plane of neck and body are roughly trued. The binding recess is routed.

Binding is glued in place. The 12th-fret crosspiece is glued in place. The neck is glued to the body, and an ebony heel cap is fitted and installed. The "tongue" of the fretboard is scooped, and false frets are installed. This allows for a traditional appearance, but allows for modern playing style without pick rattle. Frets are cut to length, notched for bindings, set in a thin line of hide glue, and pressed into the slots

The fretboard is glued to the neck and to the body. After the bindings are fully cured, they are scraped level with the surrounding wood. The bridge is fitted to the top. The instrument is sanded to 320-grit. Areas of the binding that can be easily masked are done so, and stain is applied, followed by a light coat of vinyl sealer.

The bindings are scraped clean, and another light coat of sealer is applied. The first of two series of three coats of nitrocellulose lacquer is applied. The following day, the instrument is lightly sanded and given a second series. After a 24-hour drying period, the instrument is sanded perfectly level. This is a tedious job that requires close attention to prevent sanding through the very thin finish. The instrument is given two thinned coats of lacquer, then allowed to cure for 10-14 days before the finish is rubbed out and the instrument is set up. When the lacquer has fully cured, the instrument is wet-sanded with Micro Mesh paper.

Then it's buffed on a flannel wheel. The frets are leveled and dressed, and the tuning machines and tailpiece are installed. A pickguard is fabricated and installed, and with a nut, bridge, and a bit of setup, this one is ready to make music.


Thanks for watching this project

All content and graphics © Skipper Custom Instruments