Router Planing Fixtures

[Bruce Johnson]

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.

Gilmourisgod;
Well, most of my routers are set up to do collar routing. I'm not going to be able to see through the metal collar anyway. Collar routing through a template is mostly by feel. But there are some things you can do to help . On my setup above, note the Sharpie lines and arrows on the template. Those show me where to line up the front edge of the base, as I tilt the router down into the opening in the template. It helps prevent gouging the template (which I've done) if the bit is extending out much from the collar.

For operations where I'm not using a collar, and I need to see the cut line, I cut out the center of the base as large as possible. For example, here's a PC 691 router that I keep set up for trimming the perimeter of necks in a fixture. It has a long 1/2" bit with a bearing at the bottom. The base is a simple rectangle of 1/2" MDF with a large cutout in the center and small maple block side handle. The visibility is good down through this.

But of course, there's no dust collection hookup. A few of my routers have had those little clear plastic windows that you are supposed to be able to see through. Yeah, right. If you stop every minute to wipe the sawdust off the plastic. I haven't yet found a way to surround the router for dust collection and be able to see down through it. It's one or the other.

So, to answer your question, I haven't found any reason to make a router base from Lexan so far. But, you can if you want to. I use MDF or plywood, and occasionally aluminum plate.

 

[Bruce Johnson]

Here's the next operation, more routing of internal chambers using a template and a collar router. This is another PC7518, with a neater dust collecting base, with a 1" dia collar and a long 1/2" bit coming down through it. I use this router and base for a lot of operations on different instruments. I design my instruments and templates to use it.

Notice how the base is made. It looks solid, but it's actually a 3 piece laminate, hollow inside. The center plate is 1/2" MDF with a large cutout. The top and bottom plates are 1/4" MDF, all glued together. The collar is a piece of 1" x 1/16" wall aluminum tubing, epoxied into 1" holes in the top and bottom plates. I also drilled a couple of 1/4" holes crosswise through the aluminum tube before gluing it in, so the vacuum can draw sawdust out of the inside of the collar, from around the bit. The holes in the bottom plate line up with pattern of screw holes in the router base (for two different orientations), plus four extra holes in towards the center. The hose connection fitting is a standard part you can get from woodworking stores.

This base design works very well, and isn't hard to build. It's only an inch thick, but it picks up almost all the dust. Nice clean benchtop template routing. I've also built a twin to it with a 1 1/2" collar, for use with larger diameter bits.

 

[Remyd]

Fascinating! Sub'd

 

[Gilmourisgod]

Ha! That dust collection base is brilliant! Might have to er.... "borrow" that idea!

 

[Bruce Johnson]

You are all welcome to use these ideas, and to modify them and improve them to fit your own needs.

 

[rwkeating]

It seems like you use a router for just about everything. Do you ever use a jointer or a plainer? If those 2 aren't used there is hope for me getting into powered tools by just going the router + jigs setup. -thanks for sharing this info.

 

[Gilmourisgod]

I have a Delta "lunchbox" planer that works pretty well, but it does snipe the board ends a little, so I run a sacrificial board longer than my good wood through simultaneously to catch the snipe. I use my Jet 6" jointer to square board edges, it does a great job when set up properly. I could build a jig to joint boards, but don't need to. Bruce is right about warped boards though, a planer like mine is nearly useless unless you can shim the whole board on a platen that runs through the planer. I thickness planed my body blanks in the Delta because they were already flat, but used a router for almost everything else. The Porter Cable 690 series gets a lot of good reviews, been looking for a good deal on one new or lightly used. What's the best HP rating for general Luthiery, us 1.75hp enough?

 

[Bruce Johnson]

Sure, I have several jointers and several planers in my shop. My hobby is being a hopeless antique machinery junkie. I have a beautiful 1950's Davis & Wells 6" long bed jointer, arguably one of the finest jointers of that size made. Likewise, last spring I picked up a sweet 1938 Boice-Crane 1000 planer. A monster of a 12" planer, direct drive, all cast iron. Plus, I have a smaller old Delta jointer and one of the fairly modern portable Delta 12" planers. All good machines, kept well tuned, and I use them for many things. But they have their limitations.

For example, a properly tuned jointer can quickly put a nice straight edge on a fairly long and wide board. But, the jointer depends on the board itself staying rigid, because you are only supporting it with your hands. If the board flexes 0.010" in the middle because of your hand pressure while feeding it through, then it's out of straight by 0.010". And the shorter in length the board is, the more difficult it is to feed it through smoothly without getting a lump in the middle.

So, I use the jointer to quickly make the edge of the board square (perpendicular to the surface). It does that very well. And it makes the edge close to straight along the length. Close, but not quite good enough for our work. We want boards that fit together with only 0.001" gap. The last step is to put them in the jointing fixture that I showed above. That clamps and holds the boards solidly, and the router follows the path of the fixture rails. A straight, true edge every time.

It's a similar thing with the planers. The planer grabs the board over a narrow line across the width, and drives the board through by pressure from the drive rollers. A thick, rigid board works great. But a more flexible board that is cupped or twisted will go through and come out the other side equal in thickness, but still cupped and twisted. Not good enough. So again, I use the planer to quickly get the boards down pretty close to thickness and flatness. Then the router planing fixture to hold the glued top stationary and get it really flat.

So, the overall answer to your question is yes, you can do almost all of the planing and jointing operations needed to build basses with just a router and some clever fixtures. You don't need a jointer and planer. But, they make things faster.

 

[Bruce Johnson]

Here's yet another router planing fixture that I pulled off the shelf today, and dusted off to loan to Keith. This is a medium size one, made to hold blocks up to 2" thick x 12" wide. It's a real simple basic design. I've made at least four like this, of different proportions. You may have seen the long narrow ones that I use to surface strips for neck laminations. Same basic design.

It's made from strips of MDF. The crosswise "feet" underneath fit inside each other to keep the basic alignment as the halves are adjusted to fit the width of the workpiece. The height of the feet is set so that standard bar clamps slip underneath and stand up on edge to do the clamping. Whatever number and position of clamps are needed. This keeps the clamps down low, so the router base has clearance to slide around on top of the rails.

 

[rwkeating]

Do you seal or treat the MDF used for the jigs or just leave it raw?

 

[Bruce Johnson]

Do you seal or treat the MDF used for the jigs or just leave it raw?

I usually just leave it raw. But then, I'm in southern California, where it doesn't get very soggy. If I were in a more humid environment, I might slap some quick clear finish on them.

I usually rub some Johnson's Paste Wax into the top edges of the side rails, where the router base slides.

 

[Bruce Johnson]

Here's the other dust collecting router base for my 7518 routers. This one has the larger 1 1/2" collar. In this picture you can get a better view of the holes I drilled in the aluminum tube before epoxying it in. There are four 3/8" holes lined up with the internal chamber. They pull out the dust from inside the collar. An important little detail in making one of these bases.

 

[Rodent]

Here's another similar type fixture, but different proportions. This one is made specifically for precisely edge-jointing body boards. It handles boards up to 7 1/2" wide (vertically in the fixture) x 22" long. When I'm making up a top or back of one of my Scroll Bass bodies, I'll slip the two halves side-by-side in this fixture to joint the gluing edges. It's very fast and precise. In this picture, I'm jointing the edges of a bookmatched pair of buckeye burl boards that will become a thin top on one of Mike's guitars.

The construction is about the same as the others; MDF strips. The right side jaw is screwed to the base, and the left side jaw slides freely. In this case, there are just two clamping screws out at either end of the workpiece board. I used this fixture at least five times yesterday afternoon.

View attachment 1051779

absolutely brilliant!

are you utilizing a similar 'climb pass all around the perimeter before overall leveling' workflow like you noted doing when leveling the top surface of a board or bookmatched top set face?

 

[Rodent]

You may have seen the long narrow ones that I use to surface strips for neck laminations. Same basic design.

Hey Bruce - I must have missed your post on jigs you've built for neck laminations. Care to post an image here in this thread? (found it!)

Question: have you found any reasonable workflows for surfacing a tapered center lamination for a neck-thru neck? I'm guessing a similar approach could also be utilized for surfacing a tapered center block on a body (ala like is common on the old Smith CR basses)

Question: How about a jig for gluing the tapered neck laminate to the other planar laminates? Gluing a tapered center laminate for a neck-thru length blank seems a bit daunting at the moment (being a bolt-on builder, having not done one of these style neck-thru designs before)

 

[Bruce Johnson]

absolutely brilliant!

are you utilizing a similar 'climb pass all around the perimeter before overall leveling' workflow like you noted doing when leveling the top surface of a board or bookmatched top set face?

Rodent;

Yes, when jointing the edges of one or two boards in this fixture, I climb cut it. That is, I come down the right side pulling towards me, go around the end, then go back away from me on the left side. Then back towards me, right down the center. That minimizes any splintering out along the sides. Another thing that helps is to position the boards down in the fixture low enough that the cut is being taken just barely above those two MDF strips that are attached to the inner sides of the jaws.

By the way, on this type of fixture, you can also use those inner jaw edges as guidelines for the location of the cut. Put pencil marks at the two ends of the board, indicating where you the final cut to end up. Then line up the board in the fixture with the pencil marks right at the inner jaw edges. Then rout right to the top of the inner jaws, in several depth passes if needed. This is especially handy when trying to accurately match up the figure on bookmatched pairs.

 

[Bruce Johnson]

Hey Bruce - I must have missed your post on jigs you've built for neck laminations. Care to post an image here in this thread? (found it!)

Question: have you found any reasonable workflows for surfacing a tapered center lamination for a neck-thru neck? I'm guessing a similar approach could also be utilized for surfacing a tapered center block on a body (ala like is common on the old Smith CR basses)

Question: How about a jig for gluing the tapered neck laminate to the other planar laminates? Gluing a tapered center laminate for a neck-thru length blank seems a bit daunting at the moment (being a bolt-on builder, having not done one of these style neck-thru designs before)

Well, sure, you can use a fixture like this for surfacing tapered strips, both horizontally and vertically. I've done it many times. First, the two halves of the fixture are loose and able to be positioned out of parallel, to clamp a strip that's tapered in width.

Or, you can cut the sides of a tapered strip by clamping the strip in the fixture with one end higher than the other. I've made tapered strips using a shim block under one end of the strip to raise it up some specific amount. Then flip it over and raise it up on 2X the shim block to cut the other side. That keeps the grain straight down the center of the strip. Right to the amount of taper you want, both sides dead flat. Try doing that with a jointer.

 

[Chris_Toot]

Awesome thread. I just got my first "good" router (was using my grandfathers plastic b&d from the 80s prior) so i decided to make a quick thicknessing jig. Works great. But now seeing this thread i feel the need to upgrade and build a better one!
Essentially its just a different base with longer rails to accommodate a wider workpiece between the rails.

 

[Bruce Johnson]

Looks cool, Chris! That's another way to build up a medium-size bridge-type router base. Hardwood strips surrounding a thinner center plate.

Remember that as you go wider, like to the 32" one I made, the vertical stiffness of the bridge base becomes critical. If that bridge flexes even 0.005" while you are pushing and pulling it back and forth, you get gouges in the surface that you are trying to rout to flat. The bridge base needs to be stiff, without making it uncomfortably heavy. That's why the front and back walls of mine are 6" tall strips of 3/4" MDF. I've even thought about building a better one from aluminum plates.

Also, that's one of the reasons why I placed the two wood handles out near the ends. Besides making it easier to "steer" the whole contraption, holding it there makes sure that I'm not pressing down on the middle, and possibly causing some deflection. I recommend those outboard handles when you make a wider bridge.

 

[Bruce Johnson]

Okay, here's still yet more about these router planing fixtures, in actual use.

This is the fixture I showed on the first page, routing a fingerboard. Here, I'm using for its main purpose; flattening the top surface of a neck blank. I've made hundreds of partially completed guitar and bass necks for Luthier Mike Lipe, typically two or three per week. This is a guitar neck in roasted flame maple. I've fitted and glued in the truss rod, and now it goes into this fixture, where I use a router to trim off the excess filler strip and accurately flatten the top surface.

In this case, I want to lightly skim the surface, taking off the least amount necessary to true it up. Typically about 0.010". Look at how I adjust the height of the neck in the fixture using this simple two-point gauge. The gauge is just a strip of MDF with two screws in the bottom. I've set the height of the heads of the two screws accurately using digital calipers, to be equal to each other, and about 1/16" above the height of the inner rails of the fixture.

I put the neck blank in the fixture, only gently snugging the knobs, so it can slide up and down. At each end, I lift it up a bit, then push it back down using the screw heads on the gauge, until the gauge contacts both fixture rails. I double check and adjust, making sure that the neck surface is touching both screw heads and the gauge is touching both rails, at both ends. This sets the four points on the neck surface at equal height below the fixture rails. That allows me to flatten it with the least wood removal.

When it all checks with the gauge, I tighten the knobs and set the router on the rails. Adjust the bit so that it just touches the surface, then down 0.010" more (about 2/3 of a 1/64" mark on the router's depth ring, if you were wondering). Down and back, down and back, flattening out the surface.

Here's an adjustable single point gauge that I also can use for setting the height of workpieces in these fixtures. Same basic technique; setting it and using it to check the height at various spots, in relation to the fixture rails. This is also a very simple gauge to make up. A piece of aluminum bar stock, a piece of 3/16" stainless truss rod stock, one drilled hole, one 10-32 tapped hole.

 

[Bruce Johnson]

After the neck blank's top surface is cut flat, I flip it over and pop it into this fixture. Yep, another of the same style router planing fixture, but this one is made long and shallow for a specific job. I use it to cut the whole back surface and heel surface of the neck blank flat and to 0.800" thick, from the top surface.

I set the neck blank in there, making sure it is seated against the bottom, and clamp it from the sides with two bar clamps.

Note the two dowel stop pins. This is a simple way to create moveable stops. Use a square to draw lines across both rails, drill 1/8" holes into the tops of the rails, about 1/2" deep, and insert 1/8" x 1" steel dowel pins. The router base contacts against them, and you can slide it side-to-side against them to make a square end to the cut. The pins can easily be pulled out when you don't need the stop. Some of my fixtures have multiple pin holes for different stop positions.

I've "calibrated" this fixture so that the two inner rails are trimmed to right on 0.800" above the cross bars. I set the depth of the router so the bit just touches a spot on the inner rail at the right front. I rout the whole surface, and it comes out to 0.800" to within +/- 0.005" every time. With a little care, you can get that kind of accuracy from these fixtures.