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Good thing because this draft assembly is going to so wildly off in so many ways, I’m going to have to do a significant redesign anyway. But this will be good enough to test a bunch of things
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6 parts printed, 2 more printing now, 4 left. Already aware of a dozen design errors (all fixable in post with a hacksaw and sandpaper so not showstoppers for the prototype). But damn mech design is harder than they let on in school. Dunno how my professors let me pass courses
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The basic mechanical frame for NIM has 26 3d printed parts, 8 bits of aluminum tubing 4 off-the-shelf complex fasteners (ball joints and turnbuckles) and probably a couple dozen ordinary fasteners. It’s about 10x more complex than anything I designed or built in mechE school
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This is going to be a bitch to put together. But milestone coming up… metal-work. Need to cut that aluminum tubing into pieces with either a hacksaw or a dremel.
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Soft test assembly of the draft build. With construction paper tubes where the aluminum will go. Don’t want to cut metal and then discover a major error. This looks ok I think.
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First metal… cut 100mm strut.is there any use for aluminum filings? Saving it anyway. 9 more to go. Aluminum is much softer than mild steel, but hacksawing it is still a bit of a workout. Needs some filing
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Ok that was really quick. 5 minutes for 3 cuts. Takes some control though. The cutting disc wanders easily. And aluminum stock does get hot.
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25,000 rpm, strobing with whatever fps iPhone is at. Bad idea to try take a video of dremel cutting. Probably dangerous too, though I had eye protection and mask and it was on balcony. One hand not steady enough to guide. Will need assistant or phone holder to document metalwork.
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Wow this cutting wheel really got ground down after just 3 cuts in 1/2” hollow square section tubes, 1/8” wall. Am I doing something wrong? I thought I was using pretty light pressure. It’s lost like 4mm off the radius. Or is this just quickly consumed?
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Ok this wheel is done. Wore down too much to use for this task, so last couple of cuts were back to hacksaw. I think my last ahacksaw cuts are cleaner.
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Always use a heavier cutoff wheel than you need. I'd recommend putting a thin CO wheel on an el cheapo Harborfreight grinder. I use Klingspor CW00240. they cut steel like butter
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Cutting wheels are consumable (the substrate is meant to wear down and expose fresh abrasive), and Dremel is really light duty for cutting. You're going to need something bigger if you don't want the wheels to wear out fast. Or just buy a lot of them.
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For 1/8 wall 1" tubular 20/20 aluminum you want to use a simple hacksaw with a fine TPI blade and a bit of mineral oil. A dremel wheel is light duty and it's normal for them to get eaten away quickly. Alternatively you could use a true 4.5 inch cutoff wheel with a cubitron disc.
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