Fender curved join fretboard jig....?

[Chris Richards]

Hi,

I was just wondering whether anyone had any ideas regarding cutting the concave surface on the underside of a Fender "veneer" type fretboard (post slab board)... I had originally thought that these fretboards were bent to shape but having tried to do that and found it virtually impossible I'm guessing that they have to be carved to shape.

I have a few ideas in my head of how to do this, most probably using a router mounted in some kind of jig but to be honest none of these ideas are particularly cleaver, on the face of it it's a pretty simple operation cutting a 7-1/4 inch radius trough in a piece of wood but every idea I can think of seems awfully complicated...Any ideas?

Thanks
Chris

[Barry Daniels]

I wonder if you could bend the thick veneer with a combination of heat, moisture, a press with forms, and Supersoft? Carving it out sounds like too much work and I will bet that Fender did not do that.

[Chris Richards]

Thanks Barry....

I've tried bending, you can do it with maple but not rosewood, even after soaking it for days it would still crack when bending and the few that I was successful with, one pulled away from the neck a few days after being glued and the other split a few months later.

The general consensus from my internet searching is that Fender did actually cut them curved but there's no conclusive evidence. I'm pretty sure they did this technique to avoid the necks developing a back bow, I've seen this sooo many times on slab-board necks even the reissues of the early '80's, JV Squire and originals...But never on a curved (Veneer) board.

What's Supersoft I've never heard of it?

[Barry Daniels]

It is a veneer/wood softener. A lot of us acoustic guys use it prior to bending our sides and bindings. It works quite well on difficult to bend and figured woods. You can get it here:

http://www.veneersupplies.com/products/ ... ioner.html

[David King]

Fender started with a thicker slab fingerboard and scooped out the back side on a shaper before gluing it on the radius shaped neck. The playing surface was radius cut on a shaper. The fret slots were cut using a swing arm on a gangsaw so that the slots had a constant depth that followed the curvature of the playing surface. Frets were famously (and inexplicably) inserted from the side of the fingerboard, presumably to lock the tangs in and prevent the frets from lifting.

One could cut the scoop out of the bottom of the board with a 14" diameter tablesaw blade by pushing the stock cross the top of the blade in small depth increments. Safer would be to get a custom shaper cutter or set of shaper blades if you have a shaper hub. For a one-off I'd have the scoop cut on a CNC mill or router.

[Jason Rodgers]

How thick are these fingerboards? Could you stack two or three veneers, maybe with a contrasting layer, to avoid the hassle of shaping that mating surface?

EDIT: Question answered here. http://www.mimf.com/phpbb/viewtopic.php ... ead#unread

[Barry Daniels]

Ha! Second time I've been wrong today. Somebody ask me a question quick so I can go for three.

[Chris Richards]

Thanks David...Nice to know how Fender did it! Is the consensus of opinion regarding why it was done is to prevent the necks from developing a back bow?

Unfortunately I don't have a large enough workshop for a table saw or shaper..Well that's not exactly true it's just filled up with other tools that are more useful to me.I was thinking along the lines of making a kind of swinging gantry for my router with the pivot 7-1/4 inches from the tip of the cutter and either lock the pivot at slight angled increments and pass the fretboard blank underneath or clamp the fretboard and pivot the router across it..If you see what I mean. ut I'm guessing that there has got to be a better way.

[David King]

I like Jason's multiple veneer layer idea. I'd either press-glue all the layers together at once with epoxy and then glue that onto the neck or I'd vacuum bag one layer onto the neck at a time.
The last 1962 neck I had in my hands had the board about 3/32" thick, just a wee bit deeper than the fret tang which was something like .078" or 2 mm.
The story goes that Fender was having issues with the slab fingerboards having a different moisture expansion rate as the necks leading to warping or excessive bowing. They figured the less rosewood there was in the mix the better. Of course the Fender nuts will tell you how different these guitars and basses sounded from the earlier and later slab necks. Eventually Fender decided the extra steps weren't worth the bother and went back to the slabs in 1980. Others have thought that the changes came into being when Fender decided to move the heel truss rod adjuster nut higher in the neck to get more curvature into the rod and help it work better.

[Bob Francis]

I can measure my Precision if it would be helpful to anyone here.

[Peter Wilcox]

Chris - This may be too crude for a fret board, but it worked to make radiused sanding beams. I think it's sort of along the idea you had in mind.

The router is attached to a pivoting beam, which is attached to the bench with a screw (yellow arrow.) The work piece is held vertically clamped between two boards attached to the edge of the bench. When the clamp is loosened, the piece can be raised to a new position and re-clamped, and a new cut taken. It's a PITA and it takes a while, and the resulting surface has to be sanded.

[JC Whitney]

What about your/Peter's method followed by cleanup with a scraper shaped to the right radius (or the right shape when held at the right angle for scraping)? Disclaimer - haven't tried this, just an idea.

[Keith Howell]

What about making a sanding drum with the correct convex curve on it?

I did this with a concave curve to rough in fretboards before final sanding. I first took a piece of board with the curvature I wanted and glued some 80 grit sand paper on it. Then put the sanding drum I made up of pieces of MDF in my drill press and fed the board through against a fence until the drum had the correct profile. Glued strips of sandpaper (cloth backed) onto the drum and then feed the fretboards through to get the roughed in curvature. Make sure you keep a vacuum hose present at all stages it is a plenty dusty job!

[Mark Swanson]

I once used Peters' method to trim a banjo neck heel to fit the radius of the rim. It worked fine.

[Chris Richards]

Hi Peter...

This is exactly the sort of idea I was looking for! Simple and effective, I guess you could either swing the router or increment the angle of the router and pull/push the fretboard blank over the cutter.

I've thought about sanding drums and the like but making something with a 14-1/2 inch diameter wheel would be quite an undertaking and be a big bit of kit for my small shed.

Keep the ideas coming and thanks
Chris

[Keith Howell]

I've thought about sanding drums and the like but making something with a 14-1/2 inch diameter wheel would be quite an undertaking and be a big bit of kit for my small shed.

The sanding drum I made does not have a 12 Inch radius It has a 3 inch radius. The curve is in the Vertical axis. Like a wooden barrel.

[Peter Wilcox]

That's a great idea, Keith. Maybe I'll try it on my next radiused fret boards.

[David King]

To refine the shapes, I would simply sand the curved gluing surfaces alternating the sandpaper from one to the other until they match. They don't have to be perfect geometric shapes they just have to match.

[Chris Richards]

Hi Keith....

Apologies for my dumb response to your sanding drum solution! Yes I see what you mean and it's something I shall try.

Thanks

[Gerry Beckles]

Chris -

One way to create that concave surface on the fingerboard is to take a radiused sanding block and sand a convex curve onto a piece of hardwood, just like you would sand a fingerboard blank. Glue some coarse (40, 60 or 80 grit) sandpaper on the curved side of the wood and use this to sand the underside of your fingerboard. This will, however, take a LOT of hard work and effort the keep the jig straight at all times. After making one of these and trying to sand a curve on some pau ferro, the effort was not worth the result (in my opinion).

Of course, you already know about soaking and bending a fingerboard, but cracking is a very real possibility (as we both know!) - a vacuum bag looks like a great alternative, but they are very expensive (again, in my opinion).

For my next bass, I plan to use a fingerboard blank that I radiused using my router fixed this this jig: