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"I have a buddy with this problem..." "He" wants to build some fixtures and templates, but "he" gets kind of freaked out, worries about stability, etc. I've noticed a lot of you using plywood for jigs and fixtures; do you ever worry about stability? Is MDF stable enough for templates? Baltic birch? Would it be better to get fancy by using lexan?

In order, for jig-making materials, I'd use:

Cast iron - steel -aluminum (properly stress relieved) - phenolic - A/L - plywood - laminated wood - mdf - A/L - solid wood

If it's thin cross-section, then I'd put Acrylic and Lexan right at the end. If it's thick cross-section then I'd put them a bit above ply.

Phenolic is a great material, and ideal for these things, and it's easy enough to work with.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

The short and sweet answer the most stable wood to build fixtures from is high grade baltic birch plywood. The alternating grain direction of the laminations make it very stable in regards to movement and strength.

To answer the direct question... I mostly end up using whatever is laying around at the time -- Plywood and 2x4's and MDF and Particleboard seems to be a significant portion... though I am not immune to using whatever happens to be at hand... Scraps of this and that...

I guess in my mind, you gotta ask what sort of accuracy you are really after? What does the actual job demand? Are we deluding ourselves that our jigs give better accuracy/precision than we think they really do... or do they just keep things from getting too far out of whack?

Take for example, bending sides... My side bending jig is pretty crude.. but so long as the guitar will fit into the case properly... what is the problem?

Anyway, many times, I see wonderful and complicated jigs and tooling... Works of Art and Craftsmanship in their own rite... They take longer to build than the entire Guitar... and then they are used to build 1-guitar!

Over on the Mini-lathe board... one fellow pointed out that the purpose of many Mini-lathes is to make Jigs and Fixtures for the Mini-lathe itself... and that many were never actually used to turn an Actual Part useful for something else.... I realized it was true... so I finally made myself 1 actual part.. a punch for one of my reloading dies! The disappointing part was that it didn't take ANY jigs or fixtures to make it!

Thanks

John

Thanks everyone! I appreciate the responses. I'm thinking specifically about routing templates.

router templates? try delrin. look for it at mcmaster-carr. cuts clean, wears well, kinda slippery like teflon, no dust, and a "pleasant" fish like aroma when cut.

I think that it is important to say again (I said it before in a recent radius dish thread) that "stability" should not be a big issue. If it is, then you have other problems! You are making guitars and therefore should have either a relatively stable shop environment or a relatively stable storage environment with which to return your guitars and jigs after a session of working on/with them. I like mdf for it's milling properties. I would use something else if a screw was invovled in the process. So I have a number of items used in my jigs including mdf, baltic birch, aluminum, lexam, plexiglass, phenolic, steel and solid wood (lots of quartersawn spruce!). So I always start with what my expectation is for the jig, what it's purpose is, what forces will be placed on it and what is the best materials I have for the least cost. On some jigs the "least cost" can be expensive for an accurate jig that has moving parts, a heavy duty cycle and expected longevity. A simple router template used with a guide bushing is well served by mdf.

Shane

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I have a big pile of 12/4 mahogany scraps that I use for jigs and I also use birch ply.

Trev

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