Search results

HP 41CX sir. HP calculators have no equal.

Our deaf cat was the sweetest thing. He was deaf due to a horrible ear infection as a very young kitten (I originally found him stuck to the blacktop in the middle of the road during a thunderstorm, at what couldn't have been more than 4 weeks, probably 3 old), and the ear infection left him...

That's ok, he also said "To get a bigger magnetic field we need we need more voltage", and a number of other things that are likely to confuse novice readers who don't understand what he really meant. I generally really enjoy reading what Ray writes, but I'm just going to pretend that one...

Well, even the underlying physics can't tell you what happens when you move the plates apart if your brain is in sideways on a Friday afternoon!

Ok, so I'm not smart enough to stay shut up... I apologize for the digression, but hopefully some precision and accuracy in the use of terms will help some with understanding exactly what's going on in CDI and LDI systems. Yes, I am saying emphatically that a capacitor stores charge, or more...

I'm sorry, I'm sorry, I'm sorry - I should just shut up, I know better, but... No, this is not just semantics. Capacitors store charge. This is physics. Voltage exists because a charge is stored and therefore there is a charge differential across the dielectric. One can say "well, you can...

Are you sure you have a blip in the spark at ~600 RPM, or, are you basing that conclusion on looking at the video? I ask, because sparks are really short, and stuff happens between the frames that are captured in video. It's really easy for a video to miss stuff. It's rather suggestive that...

I'm not confident that the appearance of a continuous arc in his video is actually what's happening. I believe we are hearing the spark frequency in the video, and it sounds like not more than a couple hundred hertz to me.

Regarding a dead center in the tailstock, And generic "oil" is often sub-optimal. The classic solution is white lead paste, but this is not to the liking of those who are concerned that we lick our tooling, so one is stuck with other solutions. You can find assorted high-pressure lubes...

Ah, Dalboy is right. I thought it looked fat, but my brain was not completely engaged when I posted. Not a geometry I use for diameter turning. I suppose it's bi-directional. Anything else to recommend it? I'm less sanguine about this one... Zero back rake does not make for nice diameter...

Ok, now we're getting somewhere. The carbide-insert tool you used is (at best) a threading tool. If you swing your toolpost over, it'll work like a normal turning tool since the inserts are all the same (though the seat angles may not be), but if you presented that point-in to the work, that's...

Heh - I think you have a vastly over-optimistic opinion of the engineering under the hood of commodity Chinese machine tools :-) The machine in question uses a brushed universal motor, and appears to have only a 2-wire connection to the motor. I don't believe there's any way to command zero...

Do be aware that 1018, one of the more common steels you'll find as what I think you'd call "black mild steel" ("hot rolled" over here), can be a bit of a challenge to get a good finish on. It likes sharp tooling and, at least on my lighter lathes, cutting oil makes a big difference. Good...

Ah, never mind - you're absolutely right, I missed that it was a DC drive! Thanks for pointing that out. I think if you look closely at the motor used in the Chester DB10 and similar lathes, you'll see the magic that enables it to be speed controlled when used on either DC or AC... Will

Everyone starts somewhere! This (carbide needs deeper cuts) is partially an old-wives tale. It's closer to the truth to say that the vast majority of carbide tooling, and especially replaceable-insert tooling, is designed for machines that can take a deeper cut, and therefore the geometry is...

Hi John, The (not terribly detailed) schematic does show a whole-system-shutdown switch in the Forward/Reverse/Stop block, so I suspect that what you're seeing is the correct behavior. I would expect it to not shut down if you go Forward - off - Forward, but to shut down completely and require...

A quick look at what I think is your lathe's supposed schematic, and it appears that the Forward/Reverse/0 switch is intended to let you switch the lathe between running (either direction) and stopped, without needing to manipulate the covered/locked Start switch. The instruction manual (if...

With all due respect, no. Unless you are using some kind of servo (or I suppose stepper) drive system, "zero RPM" to the controller means "put out zero power". It does nothing to lock or restrict rotation of the rotor. There undoubtedly are servo-drive lathe spindles, but I suspect very, very...

Umm... I think you've miscounted... The datum dot also returns to its starting point midway between your "Rotate 180 (10T)" and "Rotate 360 (20T)" positions...

Sorry, but no. Take the larger circle, split it in the bottom center and turn the two tails out so that it's shaped like an Omega symbol. Roll your smaller circle along the Omega-shaped path. This will have almost exactly the same "larger circumference that the smaller circle has from its...