|Forum topic by Loren||posted 09-19-2012 12:13 AM||7244 views||0 times favorited||1 reply|
09-19-2012 12:13 AM
I made a bunch of these flip stops for my panel saw. I used 1/4” x 1/2” aluminum bar stock offcuts I bought on ebay from a surplus dealer for very cheap. The brass 1/4-20 thumb nuts were bought from an ebay seller as well. I bought some t-bolts from Woodline USA (like toilet bolts) but these brass thumb nuts don’t fit them (regular 1/4-20 nuts do), so I used regular 1/4-20 hex head bolts and they work well, though perhaps sliding in the t-track a little less smoothly.
The t-track was a cool find from Woodline USA because it has 2 tracks in one extrusion and it’s not expensive. This setup allows me to have “set-and-forget” flip stops set for common cuts on the upper track and 1 or 2 stops for regular movement on the lower track.
I had to design the stop system to be out of the way in less than 1.5” of depth with the stops flipping to stand proud of the plane the panel to be cut rests on. That plane is delineated by the white melamine support bars.
While such a stop system would not be as useful for crosscut fences on miter saws and table saws, it could be recessed into a working table for drilling applications and things like that…. and of course for a vertical panel saw it solves the problem of a stop system neatly.
Making the stops is not difficult but does require some precision in drilling the parts due to their small size. If I started over I might get 5/16” or 3/8” by 1/2” aluminum bar because it would allow the drilling of parts to be a less precise and fussy process. As I did it you can see that the flip-stop is drilled very close to its corner (centered 1/10th inch in from the edge and end) and the profiled sliding part is drilled on its end 1/10” down from its top surface. I misdrilled a few parts as I was figuring the process out. Also the washers are the smallest I have on hand but ones with a smaller OD would be better and make the drilling a little more forgiving.
The end drilled part is tapped for a 6/32 machine screw. I used Loctite, and twist the screw in as hard as I can by hand. The aluminum quickly develops some slop in the fit so making it tight to start prevents floppy flip stops.
Profiling the bar sections to fit in the channel was done on my linotype saw-trimmer in sections about 5” long. The linotype saw has a clamp for holding small pieces of metal so it does this with precision and safety. Lacking such a saw, I would recommend cutting the profiled pieces with a straight bit buried in a straight wood fence on a router table and a work-holding jig with a couple of De-sta-co style clamps to hold the aluminum securely.
After the lengths are profiled I do a little filing and test the length in the track for a good fit. If the “tongue” doesn’t engage in the track, then the stop will twist when bumped and right-angle accuracy isn’t available.
The profiled section could be made in Delrin or maybe even wood. Wood doesn’t hold small tapped threads very well and is prone to splitting so I would recommend the plastic or metal. I didn’t look but you can probably find something plastic already made for t-track that would work if you don’t want to mess the router jig for profiling the part.
After the parts are profiled and fit it the track, I cut them to length (1-1/8” long), drill a center hole and then work the part some more with a file to get it smooth enough on all edges to slide well in the track.
This aluminum can be cross-cut on a table saw or miter saw, but you should make a jig to hold the parts since they are so short. It is important the ends be square for the flip stop to be accurate.