Official Luthiers Forum!

So first time using the laminate trimmer and StewMac cutter with bearings.
Apparently I did not tighten the "tilt base" that I had set for the arch of the back and it slipped during the route.
Now I have a "tapered" channel that is okay at the base but tapers INWARD at the top of the route. Of course it couldn't have been the opposite which would have been an easy second pass with the base tightened properly.

IDEAS to fix???

Channel is at .085 at the base but "slants" in to almost .12 at the top.

Don't think I can do much more routing without compromising the back/side joint.

Mike

One of the reasons why I don't use a Router, I just can't trust myself with one.
You could try gluing in a sacrificial Binding. Then create a half edge in which you glue some purfling strips, the half edge would be (ideally) half the thickness of your Back. Finally Rout for your Binding.

Michael N., That's about the direction I was going. Thinking of turning it into a "herringbone".
As you suggested sacreficial wood filler binding / reroute/ and a herringbone purfling "shallow" routed into the back to "clean things up".

So do you cut your binding channels by hand?? I may be going back to that practice OR just learn to be more patient and careful setting up the power tools.

Bummer of a Sunday morning.

Mike J

this is the one area of building that takes a good jig or one heck of a lot of skill. Routers may work on the top but you don't need a tilt base there. On the back you need the jig to keep thing parallel and of the same depth. Fit and finish is the hardest part of building and binding is part of that.
If you don't get a binding jig only use the tilt base on the upper bout of the back. that is the area of most trouble

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Whether you go Herringbone or purfling stripes matters not. Both will look intentional when done - that's the important bit
I'm not very good with power tools, in fact I'm hopeless. The only time I've tried to use a Router on a Binding channel was on figured Maple. When it reached the upper bout/end grain I got serious tear-out. Ended up scrapping it. Not long after that I was routing out a small, oval hole in the middle of a piece of 3/4 plywood (not Guitar related). Of course when I routed through the full thickness of the board I was left with an internal piece of plywood that had nowhere to go except continually crash between the side walls and a cutter revolving at 25,000 RPM. No fun. It's then that I realised that I just wasn't safety conscious enough and that I didn't have a clue what I was doing.

Thanks John and Michael N..

John, I don't have space for one of the "overhead" router jigs but I hear what you are saying I think?? Do you suggest that I leave the laminate trimmer base flat/square except at the upper bout when routing the channels for the back? The routing for the top went fine, set flat. made sure the guide bearing was square to the sides, AND TIGHTENED EVERYTHING TWICE!

Live and learn. I have some .025 maple strips that I will use as sacrificials glued into the channel and reroute with much more care. The add the herringbone. This 000 12fret is going to be just a bit more fancy than it was first intended. Certainly more tooth grinding than originally intended.

Mike

yes the area of the upper bouts on the backs is the area of most concern. Remember the mistakes are time of design opportunity

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Got It! Thanks John. MJ