Built a fretboard radius jig and router sled

[xardoz]

Things are pretty slow in my luthier journey. With the Missus still out of work, we're getting by but there's no money for extras, like luthier tools, or fancy wood. So Home Depot for wood and Harbor Freight for tools are the best I can do right now.

I also am cruising the alleys of South City STL for tossed furniture, junk and wood scraps to make my own damn tools - like this. Thanks to Scatter Lee and all the others who have built similar rigs for the inspiration!

Pretty simple in concept - the router is bolted into the sled, which rides on two curved runners that slide on PVC rails. The runners have a 12.25i radius, and the router bit extends .25i below them, resulting in a 12i radius cut on the fretboard. Secure the fretboard blank to the jig with carpet tape, then run the router sled up and down the length.

Router in the sled.
image removed

What's that box? Riunite on ice - so nice!
image removed

Red oak test blank before:
image removed

And after:
image removed

I need a round nose bit for a smoother cut, so this one still needs finish sanding with a radius block, but not bad for the first run.
image removed
image removed

Not my video, but here's a similar one in action:
[video=youtube]http://www.youtube.com/watch?v=M3JzZN0Moww[/video]

 

[bbmyers]

Simple is good! Looks like a keeper..

Bb

 

[xardoz]

Thanks! I like a 12i radius, but I can easily make new runners for other radii.

 

[TelePenguin]

Pretty cool.

I guess with money being tight I won't be seeing you up at Rockler on the Rock rd, huh?

 

[czook]

Thanks. Easy to understand, simple and inexpensive. I have been having issues with carpet tape to template and routing. Do you rout only lengthways or both?

 

[xardoz]

I've done it both lengthwise and across the grain. Thinking about it, the sled does tend to wander on the lengthwise strokes, so maybe across the grain will be more controllable.

As far as carpet tape goes, I've found that it works best on this rig if I cover almost the entire surface of the blank, then press down HARD. I tried it with just a couple of piece on an earlier test blank, but it popped loose and the blank got screwed up. There's a section on either end of the jig that the bit doesn't hit (due to the size of the sled), so I could anchor either end there with screws, but I'm not sure I like that idea.

 

[Joe Sailor]

Edit: my question was answered.

 

[oldteleguy]

Hi,
I don't think cross-grain routing is such a good idea.Not sure of what wood you will use for
necks,but tear-out is a distinct possibilty.On body blanks,I believe the same holds true. I've
been a woodworker for almost fifty years,and have found that cross grain routing is iffy.On
body blanks,I would rout with the grain,and clean up any problems with a smooth plane or
scraper. You are right about the round nose bit-it should give a cleaner cut.
Oldteleguy

 

[xardoz]

Hi OTG,
Thanks - you're absolutely right about the possibility of tear-out. That being said, it was a new bit and I wasn't intentionally aggressive (deep or fast cuts), and downhill with the grain seemed to give me the cleanest cuts. I'd like to move on to rosewood and other woods for fretboards, but my budget is close to nonexistent right now, so good old red oak will have to do for now.

For the necks, I'm working with HD maple and poplar - poplar for my first builds because it's cheaper. Most of that is going to be hand-shaping with a rasp, though.

 

[MrAstro]

I"ve been looking at the various jigs for this job. I'd like to build this one because of its simplicity but there are two things that worry me.

The first one is electrical conduit isn't very straight/rigid although I guess I could use aluminium tubing. I know conduit would be good from a friction perspective.

The second concern I have is there doesn't seem to be anything restraining twist in the sled ie. anything keeping it at 90 degrees to the rails other than gravity.

Having said all that the results look reasonable in you pics - so maybe I'm worrying for nothing...,

 

[xardoz]

I used PVC plumbing pipe for my rails, mounted to aluminum L-irons that run the full length of the jig. The PVC is smooth so the sled slides easy, and the jig is base is thick and heavy to keep the whole thing straight.

You're right about the potential for sled twist, but if you're thoughtful and deliberate in moving the sled, twist is minimized. It's going to take practice, though.

 

[Shepherd]

I built something similar but if I flip the end pieces I can also make radiused sanding blocks.

 

[guitarbuilder]

and here is my contribution....with PDF files and Thread by Todd Stock. It's all wood and costs very little to build. It rides between rails...no twisting.
http://www.luthiersforum.com/forum/viewtopic.php?f=10117&t=21565&p=298519&hilit=mcclary+jig#p298519

 

[xardoz]

SWEET! I think I can alter my jig and sled to make it similar to that no-twist design. Very cool, Guitarbuilder!

 

[macaroonie]

Regarding stick down issues , an adaptation of my vacuum box would do that job well. Just build in a box below the jig and drill holes through from the base where you would stick on the fretboard.

If you search for vacuum box in the forum you will see plenty of info.

No release problems when done either , just switch off the vacuum.



Here we go ,, drill a pile of holes through under where the workpiece is going to sit ( through the base shown with the arrow ). Underneath the whole caboodle you need to create a box so 1" square all round and then a 1/2 ply bottom will do. You then meed to fix up a connection that you shop vac can hook on to. After that you are good to go.
Prob 1/4" holes and chamfer the top exit so the fretboard sits flat. You will most likely need some bleed air to let the vac run without overheating so a bit of trial and error will get that dialed in.. My vac has a bleed thingy on the hose which is normally used to reduce the vac if you were doing curtains and suchlike.

 

[xardoz]

Brilliant! My Mark II jig will be so much better - once I can scavenge some more wood.

Thanks, gang!