al ladd
03-20-2023, 12:47 PM
I've been working on designs for cross cut sleds and then miter gauges for some time, and it's become somewhat of an obsession.
I think I have come up with a design for a miter gauge bar that has advantages over commercially available options, while being economical for a cottage industry scaled business like mine to make.
The commercial versions all work with an undersized bar with adjustable thingies, some spring loaded, some not. So between the nubs the bar is a bad fit. The nylon bits wear out and have to be readjusted and replaced. If spring loaded they introduce unwanted friction, and/or can be overcome for a wavy travel down the slot. The accuracy required for the best performance is intense. Even a .002 undersize is notably imperfect. All sorts of compromises in the woodworking industries solutions. (A large part of why sliders have become popular!)
I start with 3/8 x 5/8 steel bar. Then I adhere a strip of UHMW plastic that has had .03 thick VHB tape adhered to it after the plastic is flame treated for better adhesion. The resulting bar is oversized in width (about .8") and user trimmable, even by hand plane for a super slick finish to perfect width. Because the foam core of the tape has a little give there's some room for oversizing a tiny amount, at least for part of the bar, and it makes sense to slightly oversize the first 4-6" for wide cuts when only that much of the bar is engaged. The whole bar is very slightly springy in width. I could have purchasers measure their slots and I would provide them with a bar maybe .002" oversized for them to custom fit. I can even add a couple set screws at the first few inches that bear against the plastic (don't penetrate it) that remove the springiness there, and can be adjusted to very slightly bulge out the plastic for absolute perfect dimension at the bar's start.
The foam also helps with possible displacement from the occasional knock the plastic might receive, serving as an impact absorber. This tape is used architecturally for adhering non-structural components, lasting many years in hostile environments.
I'm interested in knowledgeable woodworkers response to this. Would you be distrustful of this?
On a related note, how wide is your saw's miter gauge groove?
I think I have come up with a design for a miter gauge bar that has advantages over commercially available options, while being economical for a cottage industry scaled business like mine to make.
The commercial versions all work with an undersized bar with adjustable thingies, some spring loaded, some not. So between the nubs the bar is a bad fit. The nylon bits wear out and have to be readjusted and replaced. If spring loaded they introduce unwanted friction, and/or can be overcome for a wavy travel down the slot. The accuracy required for the best performance is intense. Even a .002 undersize is notably imperfect. All sorts of compromises in the woodworking industries solutions. (A large part of why sliders have become popular!)
I start with 3/8 x 5/8 steel bar. Then I adhere a strip of UHMW plastic that has had .03 thick VHB tape adhered to it after the plastic is flame treated for better adhesion. The resulting bar is oversized in width (about .8") and user trimmable, even by hand plane for a super slick finish to perfect width. Because the foam core of the tape has a little give there's some room for oversizing a tiny amount, at least for part of the bar, and it makes sense to slightly oversize the first 4-6" for wide cuts when only that much of the bar is engaged. The whole bar is very slightly springy in width. I could have purchasers measure their slots and I would provide them with a bar maybe .002" oversized for them to custom fit. I can even add a couple set screws at the first few inches that bear against the plastic (don't penetrate it) that remove the springiness there, and can be adjusted to very slightly bulge out the plastic for absolute perfect dimension at the bar's start.
The foam also helps with possible displacement from the occasional knock the plastic might receive, serving as an impact absorber. This tape is used architecturally for adhering non-structural components, lasting many years in hostile environments.
I'm interested in knowledgeable woodworkers response to this. Would you be distrustful of this?
On a related note, how wide is your saw's miter gauge groove?