Template thickness and router bit questions

[Resolve]

Hello!

I'm beginning to make my master templates for a few electric solid body shapes I've designed. Do people recommend MDF or Ply? and how thick do people generally go with?

I'm purchasing a few router cutters. Now presumably, for trimming the body profile to the template, is it better to have a cutter with enough length to trim to entire body thickness in one pass? or to lower the depth of the cutter with a shorter bit?

From this list of cutters here:

Wealden Tool Company Limited Template Trim

What diameters and lengths do people view as a must-have for routing body profiles and neck pockets/pickup cavities?

Thanks

 

[pshupe]

As far as templates I use 5/8" MDF in a box jig. I have a body outline cut out of the MDF which I mark a line around the body, after matching centrelines. Then I cut out on a bandsaw trying to get as close as I can to the line. Then I use a spindle sander to get it right up to the line. I guess you could use a pattern bit as the last step but I wouldn't suggest doing the whole depth in one pass.

As far as bits I use long bits with a collar on the router that way I can just do a short pass and lower it again a short distance for another pass. I think a smart thing is to only take off as little as you can with the router. It will minimize tear out. A lot of people use forstner bits in a drill press to take the majority of the wood out and then use the router bit to clean up the edges along their templates.

Cheers Peter.

 

[bruce bennett]

I live in the south where its very humid and so because of that, I don't use MDF as its will change shape on me from the humidity..

I prefer Baltic Birch plywood either in 1/2 or 5/8 thick. but even using plywood, right after shaping, I will still give it a coat of Watco danish oil or Seal-a-cell oil to keep it fro absorbing moisture.

as for bits I use a wide variety of bits with bearings on either top or bottom.. and/or router collars and standard bits. it really depends on what job I'm doing as to what bit set up I'll use.
getting started the best thing to get is a stew mac 1/2" X 1/2" cutter with a 1/2" bearing. also the 3/8" version is darn handy as well.

 

[Resolve]

Thanks gys. So basically it's better to have a shorter cutter with a template bearing and route as little of the body depth as possible in one pass then lower and proceed that way?

I had thought about buying one of these bits with bearing on both ends with replaceable blades:

Wealden Tool Company Limited Multi Trim

But I guess that'd be a bad solution for routing body profiles as I'd have to route the whole body width in one?

 

[pshupe]

I like a really long bit with a collar. You can use it for almost everything. Router bits are not cheap so anytime you can use a bit for more than one thing it really helps out. The collars have a slight thickness so you would have to take your template in that thickness. If you buy a 1/2" x 2 1/2" bit that will do most of your routing. A long 3/8" bit would be good as well. I think the longest 3/8" bit I could find was 1 5/8" though which if you add the thickness of the template isn't really long enough. The pickup cavities have 3/8" diameter corners, for a vintage correct LP anyway, but again you could use a 3/8" diameter forstner to the right depth and clean up with the long 1/2".

Cheers Peter.

 

[bruce bennett]

Thanks gys. So basically it's better to have a shorter cutter with a template bearing and route as little of the body depth as possible in one pass then lower and proceed that way?

I had thought about buying one of these bits with bearing on both ends with replaceable blades:

Wealden Tool Company Limited Multi Trim

But I guess that'd be a bad solution for routing body profiles as I'd have to route the whole body width in one?

With guitars, your mostly routing blind pockets or outer surfaces
or "trimming" so you'll end up with about 4-5 bits with single bearings that you use the heck out of and replace fairly often.. ( and you'll want to learn about bearing stacking too)

as for cutting a large surface in one pass..

the basic rule with "standard" router bits is never take more than 1/2 the diameter of the bit in one pass. so if you bit is 1/2" in diameter.. then a 1/4" "pass depth" is your safe max for a full "bottom/side" cut.. now that last part is important as you can take a full 1/2" "deep" cut on that same bit, IF the amount your taking is only 1/8" or less and it only on the "sides" of the bit
.
such as in the case of just widening up an existing pocket... but not if your trying to cut on both the bottom AND the side of the bit at the same time.
Better to reach your depth slowly. that way your cutting on the sides AND bottom at the slower " 1/2" diameter" rate. it kind of hard to explain in writing. hopefully I made it clear as mud for you

So the rule is based on how much materiel your removing in one pass.

the Rule changes when you get to spiral bits and other "specially designed Cutters"

My 2" long double bearing spiral cutter can take a full 1/16" material removal pass at full depth with no issues because the cutter has a "shearing action" to it instead of an "impact action" like standard straight bits.

spiral cutters will even take a 1/8" thick pass as long as its not for very far. So this bit I use for cutting outer perimeters in 1 pass.

 

[bghk6581]

For templates, I range from 1/4" (headstocks, cavities), to 1/2"(body, carvetop, neck pocket). As for my bits, I have a range of top and bottom bearing straight bits that I use. I use short ones and eventually move to longer ones. I like to first cut out the body shape using my bandsaw as close to the template as possible. I may even use my spindle sander to get to cutaways and sharper corners and horns as close as I possibly can to the line. I then use my shortest bit(about 3/8") to do the initial cut, and then progress through my other straight bits until I get to my last bit I have to cut. I then flip over the body, and use a top bearing straight bit to get the last bit of wood. I use a finer grit of sandpaper to finish off the router marks. All of my routing I do is on a router table instead of freehand with the router. I feel this way is better because you get a flatter surface with the mdf on the table when cutting, and there is less of a chance you snipe the template/wood if you hands slip. Be wise of the direction of the grain and at sharp corners/horns because of tearout. I'm no expert, I'm just sharing my experiences.

 

[bruce bennett]

For templates, I range from 1/4" (headstocks, cavities), to 1/2"(body, carvetop, neck pocket). As for my bits, I have a range of top and bottom bearing straight bits that I use. I use short ones and eventually move to longer ones. I like to first cut out the body shape using my bandsaw as close to the template as possible. I may even use my spindle sander to get to cutaways and sharper corners and horns as close as I possibly can to the line. I then use my shortest bit(about 3/8") to do the initial cut, and then progress through my other straight bits until I get to my last bit I have to cut. I then flip over the body, and use a top bearing straight bit to get the last bit of wood. I use a finer grit of sandpaper to finish off the router marks. All of my routing I do is on a router table instead of freehand with the router. I feel this way is better because you get a flatter surface with the mdf on the table when cutting, and there is less of a chance you snipe the template/wood if you hands slip. Be wise of the direction of the grain and at sharp corners/horns because of tearout. I'm no expert, I'm just sharing my experiences.

I can tell.. your gonna LOVE this bit..

Eagle America bit #120-0835

We call it "the Death Stick" around here.

the name tends to keeps you alert around it.

 

[bhmcintosh]

I can tell.. your gonna LOVE this bit..

Eagle America bit #120-0835

We call it "the Death Stick" around here.

the name tends to keeps you alert around it.

Terrific bits, these monster spiral cutters, but by all that's holy or profane, be CAREFUL to keep cutting against the rotation of the bit, no matter WHICH direction the woodgrain is going. You don't have to worry about changing grain orientation causing problems because the bit's cutting action is diagonally down the face of the cut, not straight into it. Soon as you forget this and try to go with the rotation, you'll wind up wondering why your hands hurt and how'd (what's left of) your guitar body end up clear on the other side of the shop!

 

[LtDave32]

Terrific bits, these monster spiral cutters, but by all that's holy or profane, be CAREFUL to keep cutting against the rotation of the bit, no matter WHICH direction the woodgrain is going. You don't have to worry about changing grain orientation causing problems because the bit's cutting action is diagonally down the face of the cut, not straight into it. Soon as you forget this and try to go with the rotation, you'll wind up wondering why your hands hurt and how'd (what's left of) your guitar body end up clear on the other side of the shop!

Excellent advice, that.

I've got to get me one of those long spiral bits. I've got several builds coming up, and I'm not relishing the idea of bandsaw/ spindle-sander body shaping, as I've done in the past. I want a cleaner, more positive (and quick) method of body shaping.

 

[cmjohnson]

Templates: Plexiglas or don't bother. Aluminum for master templates. (Working plexi templates are made from the aluminum master, or CNC'ed directly.)

I don't and won't use a wood template. Not MDF, not plywood, not particle board, not hardwood. No wood templates.

I love helical cutters, to the point that I will NOT even bother to try to use a straight flute cutter in a router anymore. They suck. End of story.

The trick to avoiding tearouts with ANY side trimming cutter is to give the cutter as little work to do as possible. If your trimmer bit is a 1/2" bit, give it no more than 1/8" to trim away to get to the template. Less would be better.

It's when the cutter is taking a lot of wood away that it's applying heavy torque to the workpiece. This is when things get out of hand..literally. So bandsaw as close to the template as you dare before trying to use the pattern bit to get to the template.

You'd also be better off to use a shorter bit and make multiple passes. The marks left on the sides from multiple passes sand out easily anyway so why not do it?

 

[tmbrennand]

I recently re-did all of my templates in Corian. Very stable and cheaper than plexi of the same thickness, especially if you can find a countertop fabricator that will give you some scrap (sink cutouts, etc..)