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Originally Posted by Team2374
apalrd:
I have actually not looked at other widths of sheet metal, with or without lightening. As for the speed, I'm not sure where I would get gears to replace the final stage to get comfortable 6:1 and 15:1 ratios (Up from the current 9.4:1 and 24:1). McMaster's options seem to require more machining than I'd really like, so I'd appreciate suggestions.
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Buy AndyMark gears a la carte, and deal with getting the correct ratio via the third stage. Most common two-speed gearboxes in FIRST are geared for about 5/13 or 6/16 ft/sec. We were almost able to completely eliminate the third stage reduction this year, but ended up using a 40:28 reduction mostly to space off the shifter shaft from the output shaft (to avoid alignment issues from having three bearings).
Quote:
Originally Posted by Team2374
Hawiian Cadder:
I think that this frame is already quite versatile, as the wide-open space in the bottom can accommodate either a manipulator or an electronics board. In addition, the pre-punched rivet holes provide ample opportunity to mount manipulators above the drivetrain entirely.
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We always leave 1"x1" square holes in the corner of our frame (see photo below), to allow 1"x1" box tubing superstructure to be added to the robot, even if we don't need it. This year having these mounting points was very useful for our redesigned Minibot deployment mechanism.
Quote:
Originally Posted by Team2374
James:
The gearbox shaft is actually already supported in two locations, and from what I've heard, adding a third bearing is a bad idea. In addition, my team has cantilevered wheels off of toughbox and supershifter shafts every year now and never had any problems with it.
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Stick with the single flanged gearbox plate if you can. This is the third year we've been using this style gearbox, and they work great:
Quote:
Originally Posted by Team2374
Finally, I'd like to re-ask my question about hemming: do other teams that use sheet metal hem their exposed edges in the interest of safety? Is cutting your hand open once the pieces are on the robot even a concern, especially with sheet metal of this thickness and chamfers on corners?
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If you're working with 3/32" or thicker, you don't need it if they deburred the parts. Many sheet metal parts are automatically deburred at the machine shop by running the flat sheets through a brushing machine; this adds a cool brushed look and eliminates most burs. The more important thing through is to eliminate all of the sharp corners on your sheet metal parts. I usually specify an 1/8" chamfer to knock them off.
If you're working with thinner sheet metal (up to 0.062"), particularly varieties of steel, you should hem the edges if the entire part/assembly is heavy. I did some work a few years ago with large stainless steel outdoor weather covers for industrial electronics and controls, and the edges on those parts had to be hemmed or you'd slice your hand open lifting the covers.