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Interesting. Irwin/Lennox makes super-durable cutoff wheels with diamond-impregnated rims for cutting steel. They do seem to work and last - I use them for rough-carving HSS. I wonder why that works? https://www.grainger.com/product/48RW98

What an exquisitely ugly table! The real trick with printing ABS isn't just the enclosure, it's keeping the environment of the printer at a uniform and usefully elevated temperature. Enclosing the printer helps. Enclosing the printer in a draft-free, thermal-stratification-free environment at...

Thanks! We're quite GPL-friendly here, and I'm happy to contribute bug fixes or "improvements" should I find them. I'll be curious to see how you're handling your "eased" surfaces. I've approached that challenge using Minkowski addition/subtraction before, but that certainly isn't a cheap...

Yes please! I wish there was a good OpenSCAD sharing resource (a la GitHub/etc), as I find I'm regularly repurposing bits and pieces of other's well-parameterized code, as well as de-special-casing and parameterizing the less-well-generalized one-offs that I come across. I suspect /everybody/...

Unless the chuck wanders with the drill bit, I cannot see why "the center of rotation wanders with the bit" is true. I think I understand Ian's logic as it applies to the initial "catching the center" process of landing a bit at the center of a rotation of a spinning workpiece. After that, I...

This would appear to only be true if the drill is "rigid", such that the tip doesn't simply follow the offcenter-center around in a circle? (If the tip follows the offcenter-center around in a circle, both cutting edges of the drill take off identical chips, so the load on each must be the...

Having nothing much better to do at the moment, I'd appreciate it if you could argue this point sufficiently well to convince me that it's true. I've certainly seen the claim before, but the physicist in me says that the cutting edges of the drill have no clue whether it's the drill, or...

Oh for crying out loud, someone take pity on the poor guy... Look. Based on the information you've shared with the forum, it's clear that your system has some problem(s), but not exactly what they are. It's not even clear whether your problems are hardware or software. Chasing silliness like...

Thanks - that's kind of what I was imagining, but wasn't sure. With "blue on the reference", and especially with a contrasting background color, as I learned to read it you get a sense of "how far out" a region is, and this is really helpful when you've got a surface where you need to scrub off...

I'm curious how this is read. I assume you need to move the workpiece around on the reference surface to "wipe off" blue from the high spots. Without having tried it, I'm imagining this leaves you with "dark rings" from where the wiped-off blue accumulates around the bare high spots, and...

Being part of the Richard King scraping tradition, Keith is almost certainly using Canode blue and yellow die spotting ink, or possibly Charbonnel Aqua Wash Prussian Blue etching ink with yellow Canode. Canode washes up much more easily than Dykem. (Artco tools, which is frequently the only...

You could either use, as others have said, an escapement mechanism so that the wheel is trapped into only "one band" rotations, or, you need a mechanism to definitively move the trigger2 bar off the sear, so that only the hammer/wheel is supporting the sear and preventing it from rolling back...

Ah, I used a low-ohm dummy load, not a no-ohm dummy load... I'm not that much of a dummy :-) This power supply isn't capable of enough current to do much damage regardless, but in this case it was definitely not helping. And yes, I expected that the timeouts with different caps would end up...

Ok, I'm back with some data. Been working pretty much non-stop on the framing for our new shop, so I haven't torn into any of the engines to get real-live points-dwell times, but I did scare up a batch of caps and test the circuit timeout with a handful of the likely suspects: C2 value ...

Excellent. I wasn't sure the timeout was likely to roughly scale with the capacitance, and didn't want to poke around blindly. I'll just grab some film caps in roughly the right range, and we'll see what we see. You mean there's someone else out there who's obsessive-compulsive enough to...

So, can anyone give me rough numbers on how much the timeout changes, going to, say 4.7, 6.8, or 10uF? Alternatively, roughly how much capacitance would you estimate would be needed, to push the timeout up into the 100+ms range? Thanks, Will

Yup - that's doable with the slot photo-sensor. Hooked up properly they're much like a hall sensor, with an output that sinks current to ground when "on", and that floats when "off". Give it a pull-up resistor, and it should be good to go. With a Dark-on output, the trigger can be just a...

Thank you sir. These are exactly the kind of considerations that I hadn't, umm, considered, when I first started thinking about using your circuit as a way of improving the ignition reliability on my assortment of antique rust. I really do appreciate all the work that you and Jgedde have...

Nope, that's not semantics, and I apologize for pointing it out, but modern ignition or not, you can't beat Ampere's law. The magnetic field is not something that gets "built up" by a big current, and then "kept trapped" in the coil by a small current. The current is why the field is there...

I guess I'm still being contrary, or perhaps it's a matter of semantics, but, the magnetic field is directly proportional to the current. As a result, all of the current is necessary to sustain the field. On the other hand, once the magnetic field has stabilized, very little (theoretically...