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Re: Jigs and Fixtures

Posted: Thu Mar 07, 2024 10:29 pm
by larryhrockisland
A couple more fixes for my crosscut sled. I made some plywood spacers to use with my stop collars so I can easily adjust my main and auxiliary tables for depth of cut for 1/2”, 3/4” or 1-1/2” stock. In this picture I’m set up for 1/2”. The piece of foam is to cover the blade while not in use
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Re: Jigs and Fixtures

Posted: Fri Mar 08, 2024 9:13 am
by BuckeyeDennis
Those spacers are a neat idea, Larry -- I'm going to remember that one.

I can't tell from the pix, but are you using WoodAnchor sliding nuts along with those clamp knobs to mount the fence to the aluminum angle? Be gentle with them if so -- the brass threaded inserts aren't designed to be pulled from the bottom side, and it doesn't take a tremendous amount of force to pull them out of the nut body from that direction.

Re: Jigs and Fixtures

Posted: Fri Mar 08, 2024 10:42 am
by larryhrockisland
BuckeyeDennis wrote: Fri Mar 08, 2024 9:13 am Those spacers are a neat idea, Larry -- I'm going to remember that one.

I can't tell from the pix, but are you using WoodAnchor sliding nuts along with those clamp knobs to mount the fence to the aluminum angle? Be gentle with them if so -- the brass threaded inserts aren't designed to be pulled from the bottom side, and it doesn't take a tremendous amount of force to pull them out of the nut body from that direction.
No, I routed 1/4” slots about 2” long to be able to adjust the fence sideways and used button head screws with idea of having the fixture slot turned to the front for a stop block setup. Of course the screw head is in the way of sliding the woodanchor nut back and forth so I don’t have that worked out yet. Maybe some T-bolts routed to set flush would work. If I figure it out I will do the same for my Mitersaw and maybe my miter gauge fences. I’m not sure there will be enough meat left after flushing the T-bolts.

Re: Jigs and Fixtures

Posted: Fri Mar 08, 2024 1:21 pm
by BuckeyeDennis
For a sacrificial miter gauge fence, I once laminated two pieces of 12 mm BB plywood, and vertically offset the fixturing slots on each side. An alternative, If you don't have the vertical space to offset them sufficiently, is to just laminate up a thicker piece.

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That said, the top of a 3/4" thick fence is one location where ordinary extruded aluminum T-track can be a good solution. The mounting screws can be pretty much as long as you wish in that application, so pull-out isn't a concern. And off-the-shelf flip-stops are usually designed to work with top-mounted track.

Re: Jigs and Fixtures

Posted: Fri Mar 08, 2024 8:01 pm
by larryhrockisland
BuckeyeDennis wrote: Fri Mar 08, 2024 1:21 pm For a sacrificial miter gauge fence, I once laminated two pieces of 12 mm BB plywood, and vertically offset the fixturing slots on each side. An alternative, If you don't have the vertical space to offset them sufficiently, is to just laminate up a thicker piece.
Thanks for the info. How much separation do yo recommend between fixture slots on each side and is 18mm too thin for that application?


That said, the top of a 3/4" thick fence is one location where ordinary extruded aluminum T-track can be a good solution. The mounting screws can be pretty much as long as you wish in that application, so pull-out isn't a concern. And off-the-shelf flip-stops are usually designed to work with top-mounted track. I do have some of the T-track but it is slightly wider than the Baltic birch so I haven’t tried to use it. It worked out that the 1/4” t-nuts will mortise in flush and still leave a 1/4” of plywood to fasten through so I am happy with how that worked out.
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Re: Jigs and Fixtures

Posted: Sat Mar 09, 2024 10:06 am
by BuckeyeDennis
Larry, whenever I need to place two WoodAnchor slots close together, I simply try to keep the closest distance between them (i.e. the weakest section) appropriate for the application. For example, if the closest distance between slots is 3/4”, that “weak” section will have roughly the same strength as a 3/4” board or sheet of the same material and grain direction.

Two slots won’t fit back-to back in 18 mm (0.708”) plywood. The minimum slot depth is 7/16”, so the two slots alone would consume 7/8” (22.2 mm) of material thickness, So I’d say that a 1” material thickness would be the absolute minimum, leaving a 1/8” thick section between the slots. And even though the shape of the fence now resembles an I-beam, without some external stiffeners that thin section may act like a flex hinge.

But if you can offset the slots vertically, and keep about 3/4” of “meat” between them, 18 mm ply should be fine, and the second slot shouldn’t significantly reduce either the strength or the stiffness of the fence.

Re: Jigs and Fixtures

Posted: Sat Mar 09, 2024 11:20 am
by larryhrockisland
Thanks.