How Would You Improve This Jig?

[Julie Moriarty]

http://i867.photobucket.com/albums/ab233/jules42651/Woodworking/Tools/FretboardRouterJig_zps5230e093.jpg
This is a jig designed to create a 12" radius on the width of the fretboard, all along the length.
The router base needs to run the length of the fretboard and across the width to create the radius.


Potential problems:
1. The aluminum angles could eventually wear the radius on the router jig.
2. The router base may rotate on the rails changing the depth of cut.
3. No dust collection.

Possible solutions:
1a. Replace the aluminum rails with steel tubing. Insert 1/4" threaded rod through them and the end caps and nut them in to stiffen it up. The tubing would not roll.
1b. Use MDF or UHMW stock for the radius guides on the router base.
2. If you can follow the 12" radius, add a second and possibly a third set of steel tubing for the radius of the router base to rest more firmly on. This could be a little tricky.
3. Other than bringing in a hose from the dust collector, just try to figure out how to best collect the dust and maybe close off some of the top.

How would you improve this?

[Myk Rian]

2. The router base may rotate on the rails changing the depth of cut.
Use round stock instead of angle.


3. No dust collection.
I made a 3' router sled to do a table top.
Just make a 2 1/4" hole in the top plate, and plug a hose into it. That's probably the best you'll get.
Side curtains would also help.

277559

[Metod Alif]

Julie,
I would relieve the edges of the rails - say, with 1/4" roun-dover. For each 'session', cover the rails with some masking tape topped with wax for easy sliding. Clamp a cleat/fence under the sled and re-position it for each pass. A pass should be made with a cleat sliding against the rail.
I think that the jig is a neat idea, handy for other curved surface treatments.
Best wishes,
Metod

[pat warner]

The spontaneous x-grain tearout looks like the bigger problem.
Have you got your arms around that?
Rails whose radii are 12" will aid in keeping the platform crossing straight, L to R. Take it a step at a time. You have a good start.

[Julie Moriarty]

I found this on a guitar maker's website. He makes acoustic guitars from scratch. I thought the router sled/jig was a clever idea and thought of making something similar. But before I did, I figured I'd be nuts not to tap the collective knowledge that exists here in coming up with a better mousetrap. :)

[Floyd Mah]

I made a concave sanding block to solve this same problem. There's isn't that much wood to remove, so I just worked through a few grades of sandpaper to get to the final result. No need to sand cross-grain. Also, I did not do this on a neck, but carpet-taped down the fingerboard blank so that it stayed flat. I started with the fingerboard a few inches long so that I could screw it down, both for roughing in the side taper as well as for cutting the fret grooves later. Using a router sled for this task is probably an overkill solution, as well as not as well controlled as a more gradual hand sanding process. The sanding block was controlled on the side by some long wooden guides so that it didn't wander.

[Adam Diethrich]

Make the "rails" as wide as practically possible and radius them to match the sled.
This will minimize wear, and help keep the sled square to the jig.

A.W.D.

[John McClanahan]

+1 on Adam's comments. I wouldn't even use aluminum. Just wood to wood. Seal it and keep it waxed. I think that jig would make a lot of fretboards before any sign of wear.

When the router base is properly seated, the bit is at its closest point. If the base tries to rotate, the bit will be raised off of the work, correct?

John

[Eric DeSilva]

Use round stock instead of angle.

If I'm understanding right, I'm not sure round stock helps. If I'm reading Julie's question correctly--and I may not be--the question is whether there is a way to prevent the arc on the bottom of the router guide from rotating so that it doesn't have four points of contact with the aluminum angle. That seems to me to be something that could happen with round stock too.

I would think the way to address that would be to have a jig with two carriages that are constrained to move along different axes. Imagine a box inside a channel that runs up and down the length of the fretboard. It goes up and down the long side of the fret board but can't rotate.

Now imagine that the inside of that carriage has two moon shaped pieces of plywood with the 12" arc glued inside it on opposite sides--the arc on both sides now provides a "rail" for the other axis of travel. Now make a router base with a corresponding arc cut in it that rides on those rails but is prevented from turning by the sides of the first carriage.

Hopefully you get the idea.

[Mel Fulks]

I think its fine for the number of guitars you are likely to make. Maybe overkill, but that's what comes from watching Norm. You might want to make a curved scraper , or a thin template for checking clean up. Or both.

[Mark Woodmark]

By purchasing knives for my molder and running it through that.....Oh, I guess Im no help at all.....HA!

[Larry Edgerton]

I like Myks round conduit idea and to combat the inclination to rotate I would drill 1/2 holes in the 12" radius arch, then cut the arch through the center of the holes on the bandsaw so that it rode the round conduit in 1/2" increments.

I would use MDF for the sled and treat it with West System on the running surfaces and spray it with top coat ocassionally. Actually copper pipe would be a better choice, which would mean you want to use a 5/8" drill bit to match the OD of the pipe. This would give you a cut every 1/2", and the rest you can fair out by hand.

If I knew how to post drawings I would, but if you do not follow what I am saying I will post again.

Larry

[Eric DeSilva]

to combat the inclination to rotate I would drill 1/2 holes in the 12" radius arch, then cut the arch through the center of the holes on the bandsaw so that it rode the round conduit in 1/2" increments.

That's smart. You end up with a few long cuts instead of a whole bunch of short cuts. I don't know if I'll ever make a fret board, but I'll remember that.

[Julie Moriarty]

I made a concave sanding block to solve this same problem. There's isn't that much wood to remove, so I just worked through a few grades of sandpaper to get to the final result. No need to sand cross-grain. Also, I did not do this on a neck, but carpet-taped down the fingerboard blank so that it stayed flat. I started with the fingerboard a few inches long so that I could screw it down, both for roughing in the side taper as well as for cutting the fret grooves later. Using a router sled for this task is probably an overkill solution, as well as not as well controlled as a more gradual hand sanding process. The sanding block was controlled on the side by some long wooden guides so that it didn't wander.

I did that on a test piece (a one-piece neck). What I found is trying to cut the radius evenly required a lot of stopping, measuring the four corners, applying pressure where it was too high, then repeat. I was thinking if the router could cut the radius evenly throughout, you could just follow up with the radius sanding block for the final finish.

This jig could be used for anything requiring a certain radius. And if you lock the router base to a given point along the radius, you can cut in flutes, v's or whatever you want along the length. So if it's made right, it can be very flexible. The wheels are still turning...:)

[Adam Diethrich]

...If the base tries to rotate, the bit will be raised off of the work, correct?

John

Yes.
Cannot do anything but raise from the workpiece.

A.W.D.

[Michael Peet]

If I'm understanding right, I'm not sure round stock helps. If I'm reading Julie's question correctly--and I may not be--the question is whether there is a way to prevent the arc on the bottom of the router guide from rotating so that it doesn't have four points of contact with the aluminum angle. That seems to me to be something that could happen with round stock too.

I would think the way to address that would be to have a jig with two carriages that are constrained to move along different axes. Imagine a box inside a channel that runs up and down the length of the fretboard. It goes up and down the long side of the fret board but can't rotate.

Now imagine that the inside of that carriage has two moon shaped pieces of plywood with the 12" arc glued inside it on opposite sides--the arc on both sides now provides a "rail" for the other axis of travel. Now make a router base with a corresponding arc cut in it that rides on those rails but is prevented from turning by the sides of the first carriage

I agree with both your assessment of the problem and the solution. Constraining the movement will make it foolproof, which is exactly the kind of jig I need anyway.

Mike

[John Coloccia]

Keep in mind that just before you fret....after all of the other woodworking is done....you should take a long sanding block of some sort, the same one you intend to level the frets with, and true the surface of the fingerboard. That will make your fret leveling job much easier and will conserve the most fret material.

If you really want to use a jig to do this, the best modification I could suggest is to modify it to that it operates on a neck that's already been shaped, not on the neck in block form. The neck will move around significantly as you shape the back of the neck. Building a neck should be thought of as a constant series of steps with the ultimate goal to end up with perfectly level frets, and the way you get there is truing the front surface of the neck as you go along. Do too much too soon and you'll find that to get the playing surface straight may require removing more wood from the fingerboard than you had intended. Let me tell you, it's much much easier to keep something straight, with little tweaks as you go along, than to make something straight.

I don't radius my fingerboard until the neck is practically completely shaped. It's shaped very close with a little bit of extra thickness to account for the fact that I will have to remove a bit of wood from the fingerboard to true it. After I've shaped and trued the fingerboard, then I'll take the last little bit of extra off the back of the neck (so I can accurately measure to the actual trued playing surface, not the rough fingerboard). Then, when the neck is just about ready for finish, I true the fingerboard one last time. Then I fret, and if it's a maple fingerboard I take care of the fret ends now so I won't ding the finish later since the fingerboard will receive finish.. Finally I finish, and very last thing I do is the fret leveling. It's a process of constantly refining that playing surface in smaller and smaller increments, and when you get it right the final fret level will only remove a couple of thousandths from the tops of the frets....practically nothing. Anyhow, that's something to shoot for.

[Michael Kellough]

Anodized aluminum is better way more durable than that mill finish stuff.
Delrin and teflon are harder and more durable than UHMW polyethylene.

That said, for the low speed this jig would travel and small number of times it would be used I agree with the guys who suggest waxed wood.

The possible lateral rotation of the sled could be reduced by making the sled and jig longer.

[Loren Woirhaye]

Unless you're doing production, I wouldn't bother making such a thing. Some people love making jigs however and I'll grant one does learn about wood machining concepts from designing and making accurate jigs. Fingerboards can be profiled in a few minutes by eye using hand planes, then smoothed with curved sanding blocks. Doing it this way also allows conical or other types of compound fingerboard profiling, such as adding relief for low bass strings in extended range guitars.

I believe this job is often done with a belt sander and a rig which holds the fingerboard and swings in an arc over the belt sander. Grizzly sells a fixture to do it.

[Sam Murdoch]

I need to read more closely what others have written and to think about how to keep the sled tracking perpendicularly but for whart it's worth otherwise - you can buy some 1-1/2" wide X 1/8" strips of UHMW from McMaster-Carr. Applied to both the sled curves and the track surfaces you would have one slick and non wearing surface. I attach this stuff to wood using the deep thread 5mm Euro screws. With the right size screw hole and just a slight countersink they flush nicely with the material and hold very well.

[John Coloccia]

It's really not that critical that the sled be perfectly perpendicular. Eyeballing it is sufficient. Again, this will, at best, give a rough radius that will then need to be trued and fixed later. Even the radius itself isn't all that critical. What is critical is that before the guitar is fretted, at some point that fingerboard needs to be trued, and that will remove whatever minor little variations you get because you're not perfectly perpendicular. You'll see when you try it that it's much easier than it looks to eyeball it perpendicular enough.

:::sigh::: But if you really really really want to jig it somehow to keep it straight, and I don't think you need to, but if you want to, simply lay a square across one side, get it straight, and then take two small blocks of wood and clamp them on the other side snugged up to the jig. I don't know if that's clear. If you're in position to make a pass, get the jig square with a square on, say, the left side, and on the right side take two small blocks of wood and snug them up to the body of the jig....one in front of the carriage, and one in back. Clamp them to the carriage, and voila...instant fence. The blocks of wood don't even need to be straight....you could even use random cutoffs because wherever they contact the jig, they'll contact the same place the entire length :)

But it's just really not necessary.

[Jeff Duncan]

I had to do some similar radius's for a project several years ago. I found it much easier to take a card scraper and grind it to the shape needed. It took minutes per piece and they required no further sanding or other attention. I know your looking for advice for the jig, and I also know people generally think power tools are always faster, but unless your making hundreds of these, I think you'd be surprised at how much faster using a card scraper would be than setting up that jig and running the router:o Not trying to be a pushy hand tools guy either, take it from someone whose shop is fairly well equipped with power tools to handle most projects;)

good luck,
JeffD

[Larry Fox]

http://www.stewmac.com/shop/Tools/Special_tools_for_Neck,_fingerboard/Aluminum_Radius-sanding_Beam.html

[Keith Weber]

I would improve that jig by scrapping any idea of building it altogether. Too many issues and a potential for twisting the router mount on the rails. A very simple design that can be used for many different radii without building new router sleds can be seen on the following youtube video:

http://www.youtube.com/watch?v=BNm5G84ht5A

He also has links to plans in the description. This design seems more accurate to me, and will give you a true radius. In your original jig, any flaws in cutting the radius in the router sled will show up in the neck. It's similar in design to commercial, metal ones that I've seen.

I'd just do my fretboards on the jointer, but I'm a classical guitarist, so unlike my girlfriends, I like my fretboards flat!

Keith

[Greg Peterson]

I would attach an acrylic sheet to each side of the jig. The lengths of which would be ensure the case is covered when the jig is all the way at one end of its travel. This leaves some of the sheet hanging over the end of the jig, but I can't think of a less clumsy way to close the jig up. Not yet at least.

[Julie Moriarty]

Just ran across this:
http://sphotos-d.ak.fbcdn.net/hphotos-ak-snc7/384782_10201106829658840_1631521109_n.jpg