Routing the edges of the top/back

[Russ Glazer]

I am building my first steel string and am concerned about using a router to trim the edges of the top and the back, fearing a big tear out. Are there any tricks to it, or should I use handtools, just to be safe? I have the same concern about cutting the steps for the binding and purfling. Any advice is appreciated.

[Howard Williamson]

I'm a newb, in much the same position as you.
I trimmed the overhang on my top and back last week. I had the same concerns as you------- too much time invested to have a disaster now ! --- but I've never done this before !
I had some spare wood and did a "mock up" of a section of a bent side W/kerfing and a piece of top wood glued on.
I did a trial run with the router on the mock-up just to get the feel of it ----- was glad I did.
First lesson was: Think about the rotation of the cutter, don't feed it so the bit is lifting the wood, it chipped a piece out, coming out of the waist, thankfully on the mock-up. Feed it so the cutter is pulling wood towards the body. (feed clockwise)
I used a new, sharp, flush trim bit (1\2") with a bearing.
I didn't shim or adjust the shoe of the router on any way, I let it ride the camber of the top and that tipped it just enough that the bearing touched the sides first and left just a few thou of the top and back overhanging which was easily sanded down flush to the sides in a few minutes.
Some of the pro's on here may find fault with this or have more to add but this worked for me.
Next, I'll use the same mock-up piece for my first binding cuts, just to "get the feel of it".
Good luck

[Bob Gramann]

Generally, you rout from the wide part of the body to the narrow, section by section, to avoid chipout. That means you have a climb cut for some sections. You have to keep a tight and controlled grip on the router. A lot of scrap practice is good.

[Charlie Schultz]

Hi Russ,
I appreciate your dilemma- I often think "to err is human, to really screw up takes a power tool". I did my first one by hand and, yes, it works but keeping the tools sharp is required. The earlier suggestions to practice on scrap are really good. If you've got a dremel tool, you might want to start there as you might find it a little easier to handle (although I think they're a bit underpowered for the task).

[Alan Carruth]

Sometimes you'll get a blowout on the top, most commonly on the upper right and lower left parts, where the router bit rotates into the wood as you feed it. It helps a lot to dampen the top in these quadrants with a light spritz of water just before you rout them. It make the wood a bit less brittle and thus less prone to chip.

Alan Carruth / Luthier

[John Hamlett]

Scoring the wood first helps too. A violin purfling cutter does a great job, and in fact can do the whole job of cutting the binding channels (but it takes a while).

[Darrel Friesen]

I believe Mario has a video out there showing him trimming the overhang with a roto-zip bit in about a minute or less. I haven't been brave enough to try it yet.

[David Malicky]

Great advice above. If you want some insurance, a down-cut spiral bit keeps the fibers planted as they are cut. I use a Whiteside RFTD2100, which seems immune to chipout, going in any direction. Or a down-shear bit (e.g., Whiteside 2602) has some of the same effect, at lower cost as it's not solid carbide.

[Russ Glazer]

Thanks to all who responded - all great tips, much appreciated.

[Gerry Gruber]

I like to make my binding channels in four steps. First I set my router (laminate trimmer) for half the thickness and half the height as the final channel will be. My bindings are just less than 1/16" by 1/4". So, in the first run, I am taking off less than 1/32" thick and 1/8" deep. I then set the router for the full height and do the second run. Then, full depth and half height, and finally full depth and full height. It takes longer this way, but you aren't stressing the tool or yourself as much. (And, it takes much less time than repairing after an errant route. Check the forum archive to see my painful experience in this regard.) And, the first routes are almost like practice, in that, you can see where you might have thought that you had set the router to cut 1/32" deep, and yet it cut a bit deeper or a bit shallower. You can then fine-tune for the subsequent cuts when you get to the full dimensions of your binding channel. Another point is that it doesn't have to be power tool vs by-hand. You could route the channel to be close, and then finish off with chisels and files by hand.

[Len McIntosh]

Russ - after 10 guitars this operation still causes some anxiety, but two tips and a silver lining, 1) always let your router get up to full speed, and 2) Start at the fat part of each of the four bouts, never rout from a valley up to the peak,
Silver lining - if you screw up and chip out a piece ( in my case it was the spruce top) you can always increase the top binding depth to hide the chip out. I considered abalone but ended up with what i refer to as "piano key inlay" (1/4 inch pieces of ebony and maple) which i really think loosens up the top. In retrospect the chipout was a good thing!
good luck

[Louie Atienza]

I guess I've been lucky as I haven't had a rtearout from trimming the top, yet. I will say that my top and back are cu pretty close to begin with. I actually clumb cut all around, then finish conventionally. I even have a zero-clearance plate for the router which I believe helps a little. For binding I also start climb cutting the entire way, and clean up conventional.