Making router templates

[Andrew Armstrong]

Has anyone got any clever ideas/tips to make matching internal and external templates? For example: If I want to cut a control cavity for an electric guitar and also make a perfectly matched cover to fit the cavity I need to an "internal" template for the cavity and an "external" template exactly the same to cut the cover. I have been doing this by using 4mm or 6mm MDF, a scroll saw and then sanding carefully to the line and fitting by trial and error. It works but is painstaking and time consuming and achieves a satisfactory but not perfect result. I don't have a CNC machine which is how a hi-tech shop would achieve the same result I presume.

Andrew

[Barry Daniels]

Use one of these.

http://www.woodcraft.com/product/200139 ... t-set.aspx

[Pete Halliday]

One idea that I've kicked around for a while but not tried yet is to make the outer template and a loosely fitting inner template and then fill the gap with a epoxy mix or similar to match the outer contour perfectly. I think that this new inner template would then need to be replicated as I do not know how well epoxy would hold up as a template like that. I'm interested to hear what other ideas get suggested here...

[Paul E Buerk]

The brass inlay set works pretty well as long as you can actually center the bit. My PC 690 never quite wants to stay perfectly centered when the base screws are tightened.

[Pete Halliday]

For those of you that have used the Whiteside set or something similar, do you have any issues with keeping the router firmly against the outer form when routing the inlay piece? I'd be afraid of the router wandering in to the center.

[Bob Hammond]

Paul, are you having a problem in centering the baseplate from the beginning, or does it go off center while routing?

I think that it would be possible to make a dial indicator fixture for centering. I imagine it would be a 10-12" beam with a pin (an old bit) at one end, and a horizontal holder for dial indicator at the other end. The pin would fit in the collet, and then the indicator would be placed horizontally so that its tip is against the edge of the baseplate (and then zero'd). Then the beam would be rotated around the edge of the plate while observing deviations on the indicator. The baseplate would be adjusted until the indicator's deviations are minimized. If you don't own an indicator, then just use a nut and bolt that can be set in a slot in the beam and then tested for clearance, maybe with a feeler gauge or stick.

Oh, and don't forget to unplug the routher!

[Bob Francis]

For those of you that have used the Whiteside set or something similar, do you have any issues with keeping the router firmly against the outer form when routing the inlay piece? I'd be afraid of the router wandering in to the center.

I haven't used mine all that much but it worked withour a hitch.
Your pattern will seem far larger than expected so a couple test runs are in order.

[Gordon Bellerose]

I'm not sure we're answering the question posed in the OP.
It sounds like he wants to cut a control cavity, and then a cover plate.
Usually the cover plate is a separate larger template, as the cover needs a shelf to sit on and screw into. Unless you are simply going Fender style in which the cover sits on top of the body. Regrdless of this the cover will be larger.

It's been my experience that I will spend as much time making templates as I will building guitars. At least until I have to repeat the process.

[Steven Wilson]

I use the kit from Harbor freight. Works well

http://www.harborfreight.com/solid-bras ... 99552.html

[Andy Birko]

I've used the little brass kits and they work pretty well. For larger pieces, I've made my own acrylic offset disks to use with larger collars for use with larger bits and they also work very well, you've just got to make sure that you keep the numbers straight in your head and do a very good job of making the collars. I did mine on a lathe.

Or, if you're going to make a lot of guitars, you could draw it up in CAD and have someone CNC a pair of matching templates to use with either collars or bearing guided bits.

[Paul Rhoney]

If possible a good way to go is to draw it in CAD, or in a graphics program such Adobe Illustrator (what I use) or Corel Draw and have your templates laser cut. There a wealth of independent laser cutter companies, but the one that I used for a long time that proved to be invaluable was Ponoko.com.

[Andy Birko]

Paul,

Have you actually had router templates made on a laser before? I ask because I've not but, I've seen some inlays that were cut with a laser and although they're o.k., I don't see how they'd be able to be accurate enough to create mating parts like that specifically because of the "dirty edge" that the parts had.

Although lasers are good for a lot of things, I still think that a CNC router would be the better choice in this case.

[David King]

Andy, I think that would depend greatly on the laser, the material and operator.

[Michael Lewis]

You can cut acrylic (plexiglas) with a laser but not polycarbonate (Lexan).

[Louie Atienza]

Hello folks... Been a while since I've been around but finally life seems to be coming back on track so....

In answer to to Andrew A.'s question, the router inlay kits do work well, though it is important to keep the collets centered on the bit. It's also preferable to use a plunge router, to avoid damaging the templates.

As to the laser question, a laser with air assist will cut very clean edges at least in acrylic, at least clean enough to use as a template. Of course a lot has to do with the operator as well. I operated a CNC laser for a sign company, and typically it would leave a .005" kerf, which the software would compensate for and was adjustable. You would have to rough your parts to size before using the templates, as the heat from the bearings can melt and distort your new acrylic templates.

It's also not a totally trivial thing to make exact fitting parts on a CNC router, since the driverain and linewar bearings are made to a tolerance, the spindle will have some runout, and even the bits or endmills used are made to a tolerance as well.

You could relatively easily make templates for cavity and cover WITHOUT the inlay collets, by simply using pattern bits and rabbeting bits. You'd need a rabbeting bit that will cut a rabbet the same width as your pattern bit.

[Andy Birko]

I happened to see a piece today that had some laser engraving done on it today with a high dollar laser and was quite impressed with what I saw - totally different league from the inlay I received from a customer. I change my mind.