Member postings for Robin

The little lawyer in my head says that wear is unlikely. Rusted to buggery OTOH...

I need a 30mm reamer, preferable spiral flutes.

OMG the prices. Long story short, I have bought a vintage 1945 hand reamer by James Webb and Sons of Bloxwich from that auction site.

WD marked, never been unwrapped EN-128 whatever that means. Haven't got it yet. Is it likely to be useable or have I wasted 40 quid?

Can you tell? Whaddya think? I need patting on the head but will settle for ridicule if that is all I deserve

From my chemistry days I seem to remember that nitric passivates iron, so after a brief fizz you get nothing. Alum dissolve iron, caustic soda to dissolve aluminium. Nitric is good for degreasing aluminium and getting that pesky oxide layer off the surface. We used to put old copper coins in brown sauce to clean them back to the shine, I think that contains nitric..

Kinetic energy is 1/2 mv squared.

If you chose the speed of light as your velocity then v squared becomes a constant because the speed of light never varies.

If the velocity is constant then what you are left with is energy = mass times a constant and you have your conversion.

Simples.

Whitworth by Jove! Well done indeed. A 1/4" x 3/16" BSW has been ordered. If it fits I will have to wait for something more Myford looking to turn up, it's a bit on the shiny side.

I also seem to be missing all my old Allen Keys including the truncated key that separates the pulleys from the back gear on the spindle. If it's an unknown size I can probably fetch it out using gas pliers

There are some bolts on my ML10 I do not have a spanner for and I feel it is time to get one.

The change wheel quadrant has one at the bottom.

The clamps that tie the head stock to the bed use them.

It is too big for 13mm but 14mm is a loose fit so it must be one of those whacky British things and I am lost. Somewhere between 1/2" and 7/16".

Is 17/32" (13.5mm) in anyway sensible? If I type 17/32" spanner in to eBay it laughs at me. My search for 13.5mm was equally derided.

Someone must know.

I think these people who cannot take a bit of stick over their dismal failure to spell, punctuate, use good grammar etcetera, should try being an irritable old git for a few days and see where that gets them.

I was educated in Oxford by Victorians so I use an apostrophe to denote possesion. Robins' problem. Pretty bad eh? Split infinitives grate on me.

I spend an inordinate amount of time correcting peoples use of the caps key in their names and address before sending stuff out.

I think it is in my nature. Maybe it is an ape thing, like picking burrs out of the cats tail with my nimble monkey fingers.

A new suds tank. I bought a 16 litre storage tub, some PLA filament the same colour and some fittings.

I printed the 3 pipe return to go through a 4" Koi carp tank filter sock, a fitting to hold the tap and a strain relief for the pump cable because it didn't have one.

It won't be clean for long so this is one for the album

Also ABS can supposedly be fumed over hot acetone to smooth out the surface. I am very nearly tooled up to try that. I have bought gas jars, need to print a support structure in PLA

Forgot to mention... when comparing printers white plastic hides surface imperfections that would stand out like a sore thumb in black.

It is a curious question, is ABS "better" than PLA?

If you don't buy ABS+ then you may be buying regrind.

To get a good stick between layers of ABS I think you need to get it down before the previous layer has chilled, so close the fan shutter and print tall and thin perhaps.

If the ABS cooling contraction lifts a corner from the bed you can never recover.

PLA seems to stay pliable until cold. No real thermal stability but you can print it 99.9% solid without problem, a surefire distortion in ABS.

ABS dissolves in acetone, PLA doesn't seem to dissolve in anything.

I don't know

I have 3 the same so nothing to compare.

ABS is much trickier to print with than PLA.

ABS has a higher melting point and is prone to lifting from the print bed. However it is not biodegradeable. OTOH none of my PLA prints have degraded, yet.

I think printer rigidity is the key, you want something rigid so it doesn't go out of alignment every time the cat sneezes in the same room.

Getting the print head from point A to point B, without the nozzle stringing, requires violent accelerations. Need a printer that won't shake itself apart.

Every printer has several Facebook Groups dedicated to it. Have a sticky beak why not?

I was almost tempted by the notion of a dual extruder to print dissolvable supports, but after only a few years of stabbing my fingers with sharp objects I have become a dab hand at removing it.

Edited By Robin on 20/06/2018 10:15:48

Ricin by Jove, have you annoyed Mr Putin?

Edited By Robin on 05/06/2018 10:03:27

Both lines still need to be inverted

RS232 is a combination of V24 and V28.

IBM did away with V24 and the Chinese have now done away with V28.

Perhaps RS232 only exists as a microprocessor die labelled UART

Latest plan...

I drive TX with an op-amp wired as an inverter, an easy way to get 5V to light the TX LED.

I handle RX with a comparator wired the same way. The processor pins are 5V tolerant but why take a chance?

I hardwire pin 7 to power.

Simples

Pin 7 on a db9 would be the output pin RTS. To make it high you have to set RTS=0 in the UART. The output then drives through what I take to be a 1n4148 glass diode before powering a PC400 isolator.

The TX line back to the inverter looks even less friendly. When they want to light up the opto-isolater on RX they drive through a 470R, when I want to light the other side I have to drive through a 2k43. I can see that coming out

If Teco wanted simple RS232 why didn't they stick in a MAX232 chip requiring no external power supply?

Do we presume 'elf'n'safety?

The Baud rate and stuff is either switches or front panel selection, can't remember.

I want on/off, not reverse and frequency determined by the G code. Those accidental reversals are seriously unfriendly.

For lights out operation I want stall/over torque detection so I can 'pause cut' and 'call for help'.

If the torque is readable then it might be possible to detect a tool break or know if the drive belt is on the wrong pulley pair.

Such fun

I could try, but what about the RTS pin where it expects 5 Volts to drive the RX pin?

If I had a 1488 line driver with access to a +-12V PC PSU then I expect it would work. However I only have 100mA of 5V being squeaked up and down by a USB to serial adapter.

I think I need to lay out the PCB so I can hardwire RTS to a hard 6 Volt rail