Router Planing Fixtures

[Chris_Toot]

Thanks bruce. The rails are made from 3/4" poplar stood on end and laminated together for extra stiffness. In the end i put the base on my table saw top and sanded it flat until there was no rocking. Although, the base might be a couple thousandths out of square with the cutter because i end up with slight raised lines on one side of the cutter path. Not a huge issue though as it easily sands down.
I want to get some stainless steel dowel rods and locking pillow blocks to make a precise rail-type setup. The locking carriers would allow me to rout straight pockets in either direction or set them both loose and use it as a planing setup.

 

[manupulated]

Love this tread ! I make a lot of router jigs but more at work (cabinet maker) yours are well done sir ! With great explanations with it , love your work and patience your give to the LC !

 

[Bruce Johnson]

Okay, here's a router planing fixture that gets a little more complicated. Continuing on with making up that neck blank, I made this fixture specifically for routing the front and back surfaces of a tilt-back headstock. It's now about 16 years old, and I've used it on at least 800 necks. It's a planer fixture, similar in general design and use to the others, but with a few special tricks.

The whole fixture is tilted, and laid out to handle guitar and bass necks over the whole range. The odd shape of the back end is to allow the neck blank to be clamped in either face up or face down. Most of the tilt-back necks that I make up for my customers are 7 degrees tilt plus 1/4" offset down, so this fixture is optimized for that. But it will handle up to about 12 degrees and 0 to 3/8" offset. I have a different fixture that I use just for flat headstock necks.

The router (same one as the previous steps) slides up on the rails from the lower end, and is stopped by the dowel pins. You can see the extra holes for several different lengths of headstocks. I've standardized my neck building process to mostly use two widths of neck blanks; 3 1/2" and 4 1/4". On this fixture, the two jaws (rails; sides) are both screwed down to the base. The clamping is the flexing of the jaws over a small range. The removable spacer plate pops in on one dowel pin for 3 1/2" wide necks, and is lifted out for 4 1/4" wide necks. When I want to cut neck blanks other than those two widths, I have some other wood shims that slip in.

The stop block at the end also serves as the depth setting gauge. I used the router to shave it to the same height as the two inner rails. That's the height that I cut the surfaces to. The two removable height blocks are cut to be parallel to the inner rails, but 9/16" lower.

Here's the neck blank positioned in the fixture, face up, to cut the headstock top surface. The height blocks are removed, and I adjust the blank in the fixture so that the rough bandsawn surface is just a little bit above the two inner rails. The tip is against the stop block, and the dowel pin stops are in the right position for the length. The router bit depth is set to just touch the stop block.

...And I rout the top surface, up and back, moving left to right, sliding it on the stop pins. Keep the router moving to minimize burn circles.

Now the neck blank comes out and is flipped over. The two height blocks are set in place.

The neck is set in, face down, with the freshly-cut top surface resting solidly on the height blocks.

Then the back surface is routed the same way. Because of the height blocks, the headstock is a uniform 9/16" thickness, with no guesswork. If I want to make a 5/8" thick bass headstock, I raise the router head up 1/16" from the zero position before making the cut.

Fixtures and processes like this are all about saving time and getting consistent results. This pair of operations actually takes me about 2 minutes per neck.

Note: I was making up two necks for Mike Lipe as I was shooting these pictures yesterday. One neck was roasted curly (flame) maple, and the other was roasted bird's eye maple. The curly one is in the pictures where I'm cutting the front face. The bird's eye one is in the pictures where I'm cutting the back face. Sorry for the confusion. It's not a really a magic piece of wood that's curly on the front and bird's eye on the back.

 

[Gilmourisgod]

That is ingenious. I made a fumbling mess of it cutting my headstock flat, took me two attempts after everything slipped a little. The concept of floating or sliding pieces that adjust to width is obvious in retrospect. Thanks for all these post, lots of good ideas here.

 

[franksidebottom]

Bruce, thank you for an interesting insight into the way you create these wonderful basses and pieces for other builders. It inspires me as a novice builder to think more about the work flow I have and different ways to utilise the equipment I have, rather then letting GAS take over!

 

[Bruce Johnson]

By the way, you may be wondering what these little notches are for. They are for sighting pencil lines when aligning the neck blank in the fixture. I draw layout lines on the sides of the blank, usually using a big template, to show where I want the headstock top and bottom surfaces to be. Then I bandsaw away the bulk excess wood, staying outside of the lines. When I align the blank in the fixture, I make sure that the line is right even with the edge of the inner rail. The little notches help me to see that.

 

[Bruce Johnson]

On the first page, Gilmourisgod asked about using aluminum for the guide rails. Here's an example of a fixture where I've done that. This fixture is made specifically for cutting the 1/8" nut slot on Fender-style necks. The router base is a plain rectangle with smooth sides. I mounted two pieces of 3/4" x 1/16" wall aluminum angle as the guide rails. The router base slides neatly between them with very little side-to-side play. So the rails control the depth, and keep the router in a straight path across the neck, perpendicular to the centerline.

To set it up, I've made a mark on the neck's fingerboard. Note the two rectangular aluminum plates in the background. They are cut from 0.100" thick aluminum plate, which happens to be the depth that I want to cut the slot. So, I set those plates on the aluminum angle rails, with the router on top of them. Looking down through the router base (with a flashlight), I position the neck to line the mark up with edge of the router bit, then clamp the neck down. I adjust the depth of the router so that the bit just touches the fingerboard surface in the center. Then, I lift up the router and pull out the two aluminum plates, and I'm ready to cut. Towards me and back, one pass, exactly 0.100" deep.

As I've mentioned before, fixtures like this are all about quick efficient operation and consistent results. It takes me maybe two minutes per neck to cut these nut slots.

The router is an old 1950's Porter-Cable 3/4 hp model, all scratched and battered, that I found at a flea market for something like $10. It makes some funny groaning and squealing noises, but it works fine. I keep it set up with this base and a 1/8" bit, specifically for use with this fixture and a few other slotting operations. A shelf full of little old routers are always useful.

That's the same roasted flame maple neck blank that you saw in the previous pictures. Here, it's sawn out and the fingerboard is glued on and has been radiused. After the nut slot, it got slotted and the final trim, then delivered to Mike. It was s/n 647.

 

[Bruce Johnson]

Here's about the most basic example of a router planing fixture. It's made for one job: Cutting the flat top surface of the headstock of a Fender-style flat-headstock neck. I pulled it off the shelf and used it last night on this bass neck for Keith Horne. And again later on a guitar neck for Touch Singleton.

Not much to it. An MDF base, two MDF strips for side rails, two dowel pin stops. I shaped it so it clamps down nicely to the front edge of the routing bench. This is another one of those fixtures which must be close to 20 years old. It took maybe 20 minutes to make. I keep it right on the shelf with my other general neck building fixtures. I don't make that many flat headstock necks for my clients; maybe 20%. But, it's always there when I need to do this operation.

The small block screwed down inside is trimmed to 9/16" high, the standard thickness for most guitar headstocks. In this case, I wanted a 5/8" thick headstock, so I adjusted the router depth to just touch the top surface of the block, then backed it up 1/16" and set the "0" on the router's depth ring. Then I backed it up another 1/8" on the ring to set up for the 1st pass. I needed to take off about 3/16", so I cut the surface in three passes of +1/8", +1/16", and 0. FOr most of these router planing operation, I take a maximum of 1/16" per pass.

It took maybe three minutes to setup, make the cuts, and tear down. That's what fixtures are for. Efficiency and consistency.

 

[Bruce Johnson]

Here's yet another router planing fixture off of my shelves. Same general design as the others, this one is made specifically for cutting the straight sides of my Scroll Bass necks. Note how the inner blocks are made to allow clearance for the headstock. The fixture is the same at both ends. I cut one side of the neck with the headstock on the right end, then flip it over and cut the other side with the headstock on the left end.

In this case, I'm setting the depth of the router bit so that it just skims those inner blocks. I use gauges to make little pencil marks on the back of the neck, at the heel and around the 1st fret area. Then I adjust the height of the neck in the fixture, putting those pencil marks right at the edge of those inner blocks. Very precise and repeatable, and a good straight edge.

This is the kind of fixture that saves a lot of time. It took me maybe an hour to build it (about 18 years ago!), and it has saved me a half hour to an hour of labor on every Scroll Bass I've built since then. About 60 hours? That's a good investment. I only use it once or twice a month, but it's worth it.

 

[HaMMerHeD]

I confess that every time I see this thread topic, I think of something like this:

 

[T_Bone_TL]

...which are very handy to have in the tool-rack. Just try routing square (inside) corners with the spinny kind.

 

[Bruce Johnson]

Yeah, for square cornered pockets, I rout them first with templates and fixtures, then whip out a nice sharp chisel and mallet. A couple light taps makes the corners sharp. There are many operations that I do in my shop with muscle-powered tools.

I have a lot of nice old hand woodworking tools, but I don't have one of those Routers (which is what that tool HaMMerHed is showing is called). I call them Hand Routers, to avoid confusion with these new-fangled motorized things we use. It would be fun to play around with one.

 

[HaMMerHeD]

Router planes are fun, but they aren't good at the same kinds of things routers are good for. A router plane would do a great (though inefficient) job with truss rod slots, but I'd hate to try to cut a pickup cavity with one.

For square pocket corners, I use a regular router and a very sharp 1.5" chisel.

 

[Bruce Johnson]

Here's a quick example of the flexible use of this type of fixture on a job I did this morning. Keith brought over this 3-piece maple laminate neck blank, for a guitar neck with a steep 14 degree headstock angle. I installed one of my truss rods in it, and used this fixture to level off the top surface of the blank. Then I clamped the blank in the fixture like this, with it hanging off of the right side, to accurately cut the top face of the headstock. It took me maybe 5 minutes to do both operations.

Fixtures like this one, I use almost every day of the week. Sometimes 5 or 6 times in a day.

 

[chinjazz]

Subbed! This is a great thread!

Thanks Bruce!

 

[HaMMerHeD]

Here are a couple that I use.

This one is for cutting the 15-degree scarf angle.

This one is for thinning the backside of the headstock.

 

[Bruce Johnson]

Yeah, that's cool, HaMMerHeD. I like that idea of attaching the riser blocks right to the router base, and having them slide around on the flat surface. That gives you a lot of flexibility in clamping down workpieces underneath it.

 

[HaMMerHeD]

Thanks, Bruce. It works pretty well. I've also been using that router riser to cut the 1/8" taper in the back of my necks between the 1st and 18th frets. For that, though, I clamp the router down and move the neck beneath it, on a sled, with wedges to hold the nut-end up by 1/8" inch.

 

[reverendrally]

Some router horror.. I couldn't look away.

 

[Bruce Johnson]

Some years back, I made up a similar kind of rig, except the workpiece was turned by hand, rather than spun by a motor. Like that one, the router followed a flat linear pattern. I used it to make some ornate table legs, including some spiral ones. Back in the early 2000's, a local movie sets & props company would often come to me for special wood machining. I made a pair of wheels for a chariot that is still on display up in Vegas. And I remember making up some balsa wood break-away tables. And many other things.

Back to the present, here's my current setup for making precision turned wood parts. I use it to make cross-grain plugs for plugging holes, long dowel pegs, and whatever comes up. That's an old 1947 LeBlond Regal 13 metal lathe that was going to be scrapped and was given to me for free. It's worn and a little rusty, but it still runs and can turn precision parts. It's my backup large metal lathe. But these days, it's found a regular job making wood parts. I made up an adapter to mount a Rotozip motor to the tool post. I've got it fitted with a little 1/4" diameter carbide router bit. This setup makes a mess, but it does a nice job. I can turn round wood parts to within a few thousandths. I've been using it a lot in the last few months.