Official Luthiers Forum!

Iʻm working on my first guitar - a steel string OM cutaway - so Iʻm a total plucked string newbie. Iʻve been a bowed string builder for over 30 years, with about 120 viola da gamba builds and a few cellos. So I have lots of experience and a good collection of hand and tools. Iʻm finding that many things about guitar making are completely familier, but certain things are totally different - primarily binding/purfling/inlay and action setup.

At this point I have my assembled body and Iʻm about to start with edge binding. The body is spruce/rosewood. I have some plain koa/BWB for the binding. I have some BWB/Zipflex/BWB for the trim. The big question: what setup am I going to use for routing, since I may or may not make more guitars and I therefore donʻt want to invest in a big expensive routing setup. Not totally opposed, but Iʻd like to be frugal if I can. Also, part of this build is my wish to get into abalone trim work, as Iʻve always loved abalone, esp blue, and I have a variety of projects for which I want to have some abalone experience.

Hereʻs what I have available...
I have a Dremel, the StewMac tiltable router router base and the edge guide. Iʻm hesitant to use this with the guitar in a clamp base, because itʻs hard to keep the router vertical, from what little I can see in a few test runs.

I have a big Bosch router but not a smaller laminate trimmer.

I have a nearby makerspace with a nice router table - probably a few lam trimmers as well, tho I havenʻt looked yet.

I have the usual violinmakers purfling groove tools, though I mostly used a Dremel setup to cut purfling grooves on the bowed string instruments.

I donʻt have the set of 1" router bit and all the bearings, though I can get a set if need be.

So - Iʻm up for hearing any advice and suggestions. If youʻve used the Dremel/StewMac base and you think it can be done nicely with practice, Iʻd like to hear about it. Likewise, if you think that path is hopeless for accuracy, Iʻd like to know. If you have a suggestion for a DIY router jig that wonʻt totally break the bank and will work well enough for a guitar or three, Iʻm interested.



Thanks for any helpful thoughts - Iʻve wanted to try a guitar for a long time, and itʻs quite a lot of fun so far...

Peter, welcome to the OLF. That is beautiful ornamentation on that instrument.

My first binding job, I spent an inordinate amount of time creating guides, holders, followers and the like for my newly purchased Colt Trim router to cut a binding channel. Practicing with smooth bit stock, router off, I had a 0% success rate of not tipping the router at some point around the perimeter. I never found a way to cut the channel with complete confidence and accuracy without a router mounted in a fixture. The domed top had a lot to do with it.

I finally bought the router fixture and the bits. I never had a mishap (not counting launching a body off the bench and across the room- with a believe it or not, smooth landing on an upholstered bar chair.

Others here will likely have better suggestions for a one-off binding channel solution; I've seen videos of it being done. I just did not have the chops to do it by hand.

_________________
Measure Twice,

Karl Borum

Karl - youʻve hit my main concern. My top is slightly arched, my back more so. In addition, itʻs a Florentine cutaway, and my edge sanding to get the arched back got a bit irregular at the cutaway - so itʻs not the most simple shape to follow.

Personally I find it unthinkable to allow a vicious high speed router near a mostly-finished soundbox made of expensive wood. Especially after seeing the many disasters posted to this forum over the years. Gramil and chisel for me. Unfortunately the gramil was sold by LMI so may no longer be available anywhere, but your violin purfling tools are probably about the same thing. I also use a rectangular needle file with safe edge for refinement, and riffler file for the waist.



I've only done one with shell purfling, but it was surprisingly easy. I used abalam, some straight and some curved strips to minimize chance of visible gaps at the breaks. The only tricky part is getting the channel depth just right so there are no low spots, but you don't sand through the top laminate layer either. But you can scrape at the bottom of the channel if there are high spots, and add paper underneath the shell to raise up low spots. An x-acto blade sharpened to a chisel point is very handy for getting shell pieces back out of the slot and scraping the channel.


P.S. I'd love to see a viola da gamba build process. I've considered making one, or some similar fretted bowed instrument. I'm amazed at how thin that fingerboard is at the end... is the thickness tapered, or the whole cantilevered portion that thin?

If you don't want to invest in a router setup, you can use your transferable skills and just do it by hand, as Dennis does. A purfling cutter should be capable of doing the marking; then you chisel out the waste by hand. I've done it once all by hand. I prefer using routers, but I do have a fancy schmancy tower setup to make it work out well, and it wasn't cheap.

A great tip: When fitting, slightly round over the edge of the binding that fits into the inside corner of the binding ledge. A pointy edge on that edge of the binding is counterproductive, and can make it not fit right, whereas rounding that edge over gets the fit of the inside corner out of the equation, leaving the fit to the mating of the faces, not that corner. I hope that makes sense.

Peter, you asked about the dremel and stewmac precision guide. My first guitars were done with the same. It is doable but frankly, I found the dremel to be under powered for the task. Each guitar I used it on had chip outs on the sides. Some quite ugly and required a lot of fixing (and the fixes weren’t great).
I would recommend the above mentioned approach- dremel and chisels the files. I use these when binding headstocks to this day. Slow but actually kindle of relaxing. With your skills in the images I’m sure you’ll ace it.

Unless you have really good hand and eye coordination and have a lot of experience with intricate chisel work, do not do this by chisel. Invest in a laminate trimmer and used one can be had for about $50 on FB marketplace or CL. You also don't need the entire set of luthier bearings. Figure out which ones and only order about 5 pieces.

_________________
https://www.instagram.com/fostinoguitars/
https://www.facebook.com/PuraVidaUkuleles/

A decent laminate trimmer can be had for way less than a hundred bucks, a Bosch Colt is slightly above. Buy the SM bit and bearings. Tape a couple of wedges to the router base and carefully orient the router to keep if vertical as you go around the body.



I did a half dozen or so "flat top" guitars before I finally broke down and bought a floating router setup to do tops with more arch.

Since Peter has a Dremel and would like to avoid a big investment at this point, does anyone here have experience with the StewMac Binding Router Guide?

https://www.stewmac.com/luthier-tools-and-supplies/tools-by-job/tools-for-binding/binding-router-guide?queryid=0f9ecf3af9471301bfa841967677747e

It fits a Dremel, needs only one bit, and if keeping the cost as low as possible is a priority, there are router guides of the same design available for less than half the price.

_________________
Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Dennis - gamba tops are graduated like violin tops are. They tend to be thin along the edges and thicker towards the center, with a more or less oval thick area centering where the bridge sits - though Iʻve measured lots of exceptions to this!! Back in the day, we measured many museum instrument tops using a homebuilt thickness gauge that used a small magnet and a Hall effect transducer. It was nothing fancy but it worked well.

The bass bar is sprung much like guitar back braces - the bar should push the top up around the bridge area - then the down pressure of strings on the bridge pushes it back down again - these should more or less balance out. The forces involved are relatively small, nothing like on a violin or cello - thin gut strings.

The viol family of instruments were usually played by amateurs in small settings - wealthy merchant families, courtiers - so they varied a lot in shapes and they tended to have a lot of decoration. The violin family of instruments tended to be played by professional musicians - the guys those wealthy families hired to play for evening entertainments, dances and so on. So they tended to be less fancy and less highly decorated. This is a serious generalization, but it stayed fairly true for 3 centuries across many European countries. When tastes changed to larger-scale performances - operas, orchestras, oratorios - the viols fell out of favor as they were quiet chamber music instruments, and the violin family took over.

I bought one when I built my F5 mandolin. It worked with a lot of care and clean up, and might be the best way to do the scrolls (altho I would consider making a gramil if I ever did another mando)



I have never used it after that, I went back to the wedges on the bottom of my laminate trimmer and then built a floater to do archtops.

I did my first four archtops with one and it worked pretty well with a lot of care and concentration and many small bites and adjustments. Probably six or eight trips around both the top and back. Bought the Stewmac jig and bearings after that which made the process a lot easier and less nerve wracking.