We're all free to disagree.dextermcneil wrote:Stan,
With all due respect, I have to disagree. The poly strips are reasonably cheap and come in the right size to fit most saws out of the box. They're dimensionally stable.
It's all true - about the UHMW - tho, the definition of "reasonably" might vary from person to person. UHMW is dimensionally stable. UHMW will fit most miter slots out of the box.
However, there is more to my advice than getting a perfect fit. There is a great value in working to get the runners to fit and move properly for a beginning woodworker. There is a lot of value in the time spent building that jig from stick parts. Is the "trouble" spent getting the runners to fit the slots any less than you might need for installing h-nuts? or getting the second side to line up? or building the curves for the butt cheeks on a DR? (and so on). If this is the first you have heard of a crosscut sled, then spending another hour or two getting runners to fit is probably a good investment before making cabinets.
It is also possible to spend a LOT of time/$$$ over engineering jigs. Most jigs do not need UHMW, or T-slots, or micrometer adjustments, etc. Hardwood runners are fine. They worked for centuries before UHMW was invented...and continue to get the job done on hundreds of millions of shop made jigs all over the world.
Oh, and for the record, with a coat of poly my jigs are dimensionally stable with humidity from 20% to 100%. I'd be remiss if I were to blame any mis-cuts on the jigs...instead of on the carpenter.
--Stan Graves