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"A typical DC servomotor has a peak stall torque 5-times the continuous torque rating. Peak stall torque is available at zero RPM only. From there it decreases linearly with RPM until it equals the...

McGyver
Increasing the flexural stiffness by putting a high modulus material like steel on the outside of the Filled epoxy core is maximising the performance of your design, nothing wrong with...

"I wonder what is the tensile strength of cast iron or aluminium? The 1000-3000 psi of e/g sounds good to me. I plan to reenforce the castings with threaded rods and rebar."

Cast iron around 30000...

Cheers, I know where you are coming from, I have a hydrostatic spindle project in the background for when the bearings on my 2 grinders fail. No epoxy, conventional turning and grinding from steel...

Take the load off the shaft, if the pinion has a 1/4" bore, turn the mounting spigot down to fit the nearest size bearing and set up this in a housing so that it carries the load, 1/4" is a rather...

An asumption in that analysis is that the magnetic mataterial used in the stepper exhibits constant u vs B at the flux densities in question.

Next is the difficulty getting a clean sinusoidal...

JHudler

I wasn't advocating casting new parts in cast iron, the stuff takes years to become reasonably dimensionally stable unless it can be cooled a lot, I was advocating cruising the scrap...

Mariss your description makes perfect sense, you put a step change in load on your stepper and an error exists until the integral component of the PID loop accumulates enough weight to cancel the...

Ironchips, go with a decent mill, secondhand heavy iron is cheap these days. Though I was answering on the closed loop stuff Fenn and Mariss posted some interesting comparisons between AC servos and...

I like the toriodal transformer and drives packed into an old PC case. Looks like you used 608 bearings as guide rollers. I am curious why the gantry is spaced above the side rails on A frames,...

I don't see any advantages to epoxy granite other than dampening which can be achieved by constrained layer techniques on existing structures anyway. The thing going against epoxy granite is it's...

One of my pet ideas, will get around to it type things. They are 1 axis machines if they are used for making tubes and tanks. Set up a simple lathe with a speed controlled workholder on a spindle....

I actually have enough chain and sprockets to do the job (photo minilabs are great machines to wreck) I was worried about dirt pickup on the chain but That bicycle dry lube may work OK. Slides are no...

Ironchips, interfacing the encoder is the easy part, quadrature encoder reading hardware is readily available and given the overhead of handling interrupts on the PC platform, it would be silly to...

Did it when I was a kid only a small 4KW input furnace, power is what you need and lots of it, at a guess 10Kw for a few Kg melt, If you can get one of the large flux cored or sub arc wire feeders...

What do you mean by closed loop with steppers? reading off a shaft encoder is pointless unless it is to determine a step error and issue a fault (how the fault is handled is another matter) On the...

dakiller what are you running on the serial port, is it an ocean controls or silicon chip type serial command interpreter?

You will have to write a device driver for the HAL, I am looking at the...

Cast Vs machined, fabricated from machined parts and machined after fabrication are my preferences, making short runs of complex parts is faster by machining as the time to make the pattern needs to...

Why build one? when they are fairly common, even in a backwater like Australia, in the last 3 years I have had the chance to aquire 8 of them from 300Kw to 1.5Kw The 300 Kw was a bit big I was outbid...

First post

Does not seem to be much interest in CNC oxy fuel profile cutters, anyway I have been collecting motion control stuff for years and decided it was about time to build a simple X/Y...