Router Planing Fixtures

[Bruce Johnson]

Something basic about all of these fixtures that I forgot to mention:

For them to work right, the two vertical side rails need to be straight (flat) along their top edges, and they need to be parallel to each other. That should be obvious. These days, I cut all these MDF strips on my tablesaw. It does a good job cutting them all straight and parallel, although I always check the top edges with a straightedge.

But, not everyone has a good tablesaw. Back in my early days, I didn't have one. I did almost everything with my trusty bandsaw. So, the way to make these side rails without a tablesaw was to saw the MDF strips with the bandsaw, to pencil lines, a little oversize. Then screw the pair of side rails together, to each other. Put the pair in the vise, and flatten the top surfaces of both at the same time with a good hand plane. Check to keep them square. Flatten the bottom edges too, and check that the two ends are the same height. What matters most is that the two rails are the same. Straightening both of them while they are screwed together makes that easier.

A good sharp hand plane cuts MDF very nicely. I sometimes use a hand plane to true up rails on fixtures that are starting to show wear.

 

[wagdog]

Hard learned woodworking lesson #1: Always check for square.
Hard learned woodworking lesson #2: Sharp tools are sharp.

 

[Gilmourisgod]

Hard Learned woodworking lesson #3: If you see blood on the wood, it's probably yours. Investigate Further.

 

[T_Bone_TL]

Then #5 (= 2+3) would be my old standby - "Anything that will cut wood will cut flesh"

#4 might be (=1+3) - a perfectly square corner can cut you

 

[mapleglo]

Hard Learned woodworking lesson #3: If you see blood on the wood, it's probably yours. Investigate Further.

Ha! I can't count the number of times this has happened to me. Truer words were never spoken!

What's weird is how is it possible there's all of my blood on the wood, and I didn't feel a thing?

 

[BassHappy]

Ha! I can't count the number of times this has happened to me. Truer words were never spoken!

What's weird is how is it possible there's all of my blood on the wood, and I didn't feel a thing?

So it's not just sweat and tears after all?



It's all that excitement and adrenaline coursing though your veins 'glo~ of course, maybe mixed in with a heroic dose of coffee-related caffeine.

 

[rwkeating]

I found that the lighter the color of the wood, the higher the chance of me bleeding all over it.

I am also starting to suspect there is a correlation between bleeding and wood absorption. Something like; you are more likely to bleed on raw wood that on wood that has a finish on it.

 

[Gilmourisgod]

I call it Carpenters Anesthesia, though it applies to a lot of things I want to do, rather than have to do. I just don't feel minor cuts when I'm concentrating on something else so intensely. The worst cuts I've ever gotten, involving "Old Faithful" type bleeding, were nearly painless, as the cuts were invariably done with razor sharp blades.

 

[Jon Clegg]

I consider a modest blood sacrifice to be be an essential part of all of my projects.

 

[Beej]

Reading over this thread I've decided to update and improve a couple of mine, so I'll add them to this thread. I picked up an old router that I'll dedicate to this and built a new sled and a bed a few evenings ago. I've got a 5/8" wide bit in there because it's a 1/4 collet, but this is a little less complicated than what I was using previously.

I can stack up 3/4" mdf blocks inside the bed to raise it, or add rails to the sides to increase height. I built it to fit the majority of billets I've got waiting for tops and backs. It's 16x24 which gives me just enough room for all of the stuff I have waiting. So far it works great - I've got a douglas fir billet being planed flat in the shot below.

Thanks Bruce for the inspiration and sharing.

Router sled

• Beej
• Apr 13, 2017

Router sled

 

[Beej]

I should mention the construction a bit more I think. I built this fixture using pre-cut off the shelf MDF from a local hardware - they have these at home depot locally here as well. I bought a 2'x4' sheet and a 2'x2' sheet. I used the larger sheet to build the sled and the smaller sheet to build the bed. Because I used pre-dimensioned sheets, I didn't need to bother digging out my table saw; here's how I did that.

router planing fixture

• Beej
• Apr 14, 2017

router planing fixture

As Bruce mentioned earlier, you really need to have the rails perfectly smooth and even for this fixture to work. In my design, only the two rails with blue arrows, and the two edges with the green arrow need to be perfectly true. To make the bed, I used the 24"x24" sheet, and cut one 3.25" wide rail off of each side of the sheet. This gave me two rails with one perfect edge each. I cut the side rails at 3.25" to give me a total of 2.5" of inside bed height (fits my most needed billet size). The remaining "centre" piece of the sheet was trimmed off on one edge to become the 16" wide base of my bed. (Mine is not adjustable like Bruce's as mine has a less flexibly-needed purpose). So, in the picture above, the blue arrows show the true rails and the grey arrow points to the other side of the rail that does not need to be perfectly true.

The sled was made by taking the 24"x48" sheet and cutting one 4" wide strip off either long side. This gave me two 4" tall sides for the sled with one true edge on each, shown in the pic with the green arrow. The other edge of each of those sides does not need to be perfectly true, and you can see where my circular saw wavered a little over length. This is shown by the red arrow. I then cut the remaining piece from the board into a 7.5" wide strip, so that I'd have exactly 6" in the middle to fit my router, once I assembled the sled. The bottom board of the sled does not need to be true on it's edges (purple arrow), so no need for a precise cut. I then used a couple of sapele scraps to make the handles.

All of it is glued and screwed in place. Just thought I'd share...

 

[Geoff St. Germaine]

Just wanted to bump this up and thank Bruce for sharing his ideas. I'm building up a couple of fixtures based on Bruce's and I've finished and Tested the first, which is the neck jig. I used it to bring the back of a neck to final thickness (tapering 17 mm to 15 mm).

It worked well, but I have a couple of things to address.

I haven't put in the collar for the bit to keep the bit from contacting the sides of the jig. I didn't have any appropriate tube stock on hand, so I have to pick it up. Clearly it will make the jig faster to use without the risk of damaging it.

Not getting enough vacuum action. I believe this is likely a case of a dirty filter and reduced suction.

I'll probably get a larger diameter bit to speed things up. I used a 1/2" straight but for the test. Even 3/4" would be good.

Pics:

Note that the clamp is just limiting the travel of the sled at the heel.

I'm also working on a modified version of the body planing jig to use for bodies of flat and carved to guitars. I'll need some swappable inserts at different heights and angles for the carved tops along with a locating system for the bodies.

Thanks again, Bruce!

 

[JoeWPgh]

Bruce
Is there any advantage to making router bases from clear polycarbonate, so you can see what's going on, or do they just get scratched up enough eventually to be opaque? I made a simple plywood sled for my Crapsman, but not being able to see through it worries me sometimes.

Basically, yes and yes. Clear bases are very nice, but they do not last very long. You can squeeze a little more life from them by buffing them out with headlight restorer

 

[Bruce Johnson]

And here's still yet another custom router planer fixture to add to the pile.

My buddy Jon Wilson, whose shop is right across the hall, builds these GuitarViols. It's a crazy instrument, strung and tuned like a guitar, but you hold it horizontally and play it with a bow. They are real popular with movie sound track composers. Many of the "string sections" that you hear in a movie are actually played on one of Jon's instruments. He makes electric, semi-acoustic, and full acoustic versions. Look him up if you are curious.

This is one of his early acoustic models, which has been in heavy service for some years. It's in for an overhaul, including a new fingerboard. On his current models, Jon uses a cast epoxy fingerboard, which is a story in itself. But this one is from back in the days when he used to carve the fingerboards from wood. As you may be able to see, it's a wacky geometry fingerboard. Reverse compound radius, asymmetrical, and scalloped. I used to help him machine them about ten years ago.

Anyway, he needed a way to neatly get the fingerboard off of there. Not interested in saving it. And, in general, coming up with a good method of removing the fingerboards from any of his other instruments that may come in for service later.

This calls for.....you guessed it...a custom router planer fixture! The obvious solution to most of our problems.

Here it is. A real simple design that took me barely a half hour to make up from 3/4" MDF scraps. The basic idea is to get two parallel flat rails above and on either side of the fingerboard, overhanging far enough over the body and headstock for the router to be stable reaching the whole length of the fingerboard.

The two side plates were cut from one board on the tablesaw to make the top surfaces straight and equal in height. Clearance notches for the tuners and body. Those tuners are a little fussy to get seated, so he didn't want take them out.

The two side plates are screwed down to the base, but they can flex a bit side to side. The "jaws" are simple rectangles of MDF that slide down between the side plates. I measured and laid out cross sections of the headstock pegbox and the heel area, and bandsawed them out. Note the 1/2" hole near the bottom and the bandsawn V-slot down to the hole. This lets the jaws flex a little bit when I put a clamp across the side plates. The jaws squeeze the instrument lightly like a vise, holding it solidly.

To use it, I lightly clamp the instrument in there and set the height with this simple depth gauge. I want the fingerboard glue line parallel to the rails. I added a couple of cardboard shims under the rear jaw block, raising it up to match the gauge. I also check side to side to make sure it isn't tilted. Then clamp it and grab the router.

And here's the finished job. The fingerboard is reduced to sawdust, leaving a nice flat surface to glue the new one on to. I worked gently with the router, going down about 1/16" per pass to get the bulk of the wood off. When the remaining wood was getting down thin, I stopped and slightly readjusted the shims. The last pass cleaned off the surface of the maple.

The fixture took me about 30 minutes to make. Setting up and routing off the fingerboard was 20 minutes. Jon will store the fixture, ready for the next time we need it. I made it so it should fit all of his models, although I may need to make new jaw blocks for some of them.

You can see how a fixture like this could be made to repair the fingerboard on a neck-through bass. Same idea, different proportions. Use a flat base on the router to rout off an old fingerboard and leave a flat surface. Then you could make up a router base with radiused side bars to cut the radiused surface of the new fingerboard.

Yes, custom router fixtures are often the answer!

 

[chinjazz]

Very nice Bruce! I really like how it could double up to remove or radius. Thanks

Jon Wilson's GuitarViols are amazing and inspirational instruments. One song I wrote a while back could use a track of a GuitarViol.

 

[rudy4444]

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

View attachment 2584713

Here's a home brew version of a router plane I wrote up for Highland Woodworking:

Dogbone Router Plane | Mark Miller

 

[Bruce Johnson]

Here's a home brew version of a router plane I wrote up for Highland Woodworking:

Dogbone Router Plane | Mark Miller

Very cool! I like your idea of using a cup-type carbide insert as the cutter. I can see that it would be handy for quickly cleaning up rough spots in the bottom of a routed cavity. I may just have to make one of those.

 

[xaxxat]

 

[83_Silberpfeil]

QUESTION: Can these square tubes (pic below) serve as side rails for a router sled? Can I safely assume they are flat/evel? I figure I can just bolt them on to a piece of stock MDF, then create a bridge to ride over the these square tubes.

Looking to improvise a quick & dirty (but precise/accurate) router sled. The application here is to plane the center block for my EB-2 / ES335 build. You can see a pic of the first attempt at the center block here on post #66: ES-335 bass build. That was done at the woodshop, when I had a membership.

I've since revised my bass layout/design --- with the pickups and bridge moved farther down/away from the neck. So, need to cut a new center block. The "wings" of the first center block above are now too close to neck. The center block thickness is only 1.25"

 

[Bruce Johnson]

Sure, those will work for side rails. Kind of overkill in size and strength, but they are ready to go with holes. They are probably straight enough, but check them with a straightedge. If they aren't quite flat or have some raised burrs, dress them with a big flat file.

One note: You said that your block that you need to rout is 1.25" thick, right? The rails need to be at least 1/4" taller than that, so the bit hangs down under the base to make the cut. Do you have any scraps of 8/4 (1 3/4" nom) lumber from making the body? Two strips of that will make nice rails.