Making jigs

[OpaDC]

I read a lot of good info on jigs and plan on making some. I notice the material of choice appears to be MDF and plywood. Are these, by the nature of their manufacturing process, straight edged already and fairly warp proof? Just wondering, since starting with a straight edge would make the process easier, and I tend to be a "microadjuster" (as my wife likes to say) when it comes to precision. (I don't think I'm that bad. I don't keep adjusting once I get it measured to within .001")

[smorris]

I tend to use what I have in the scrap bin to make jigs. Lot of poplar and plywood scraps get used when I need a jig.

[Wood_workur]

yea, processed wood is generally more stable because the lack of a (unidirectional) grain.

[poolhound]

MDF is very stable and great for most jigs. its also cheap so in a sense its disposbale if you wear it out after a while. where jigs need a lot of assembly and greater strength is rquired e.g. mortising jig then ply would be a better bet.

If you are using ply for jigs then you really need to use the better quality baltic birch. the cheaper (BORG) stuff is pretty much a waste of space as it warps and has lots of voids. Avoid this stuff unless all you are making is a CS guide for rough cuts. The last thing you want is your jig to suddenly be out of true. A few years ago I made a router fence from BORG ply and it was a big mistake.

[Pappy]

I think Jon covered it best. A piece of Baltic Birch has to be really small to make it to my burn barrel!

[iceman61]

Ditto on baltic birch.

[OpaDC]

Thanks guys! Off to buy some baltic birch.