Member postings for Robert Atkinson 2

If using a MIG clean the tank well and then fill it with shield gas to displace vapours and oxygen. Close the filler with a bit of plastic film and an elastic band so any thermally induced pressure increase is vented..

Robert G8RPI

Edited By Robert Atkinson 2 on 23/12/2019 07:21:21

Good to see I'm not the only Time nut on here. Why did you phase lock the reference for the GPS rather than the more common method of using the 1 pulse per second output?

Robert G8RPI.

Hmm that takes me to a spill contol product site. Were they taken over?

Robert G8RPI.

Halfords

Robert G8RPI.

Two similar lathes so condition and included accessories are probably the deciding factor. Manuals are available for the Kerry, not sure about the Viceroy and this can be important with lots of users.

Robert G8RPI.

The lamp designation are a bit of a nightmare. MR16 is the reflector size (16x1/8" or 2". The connection is a separate designation The two small diameter straight pins common on "MR16" lamps are GX5.3 (5.3mm spacing). Neither of tese set the voltage, but again the common "MR16" is 12V. Both designtions are quite old and were used on early halogen lamps for projectors and scientific instruments. Voltage can be 6, 12, 14, 48, 120, 240V.
GU10 was originally a halogen lamp with a reflector, mains voltage rated, but no reason why you could not make a low voltage one. Ther was also a GZ10 halogen with a dichroic reflector which allows the infra-red light (=heat) to pass out the back so it does not over heat wht it is illuminating. Of course the back of the fitting needed to cope with the heat so the GZ10 "plug" has a square edge so you cant fit it inplace of a GU which has a 45 degree chamfered edge. Moot point with LEDs as they do not dissipate as much heat.
A conventional "iron" transformer feeding a 12V LED lamp like a 12V MR16 is the most reliable solution. The electronic "transformers" (small light switch mode converters) are not as reliable and cheap ones can cause radio interference and some have safety issues.

Robert G8RPI.

Hi,
Is this for a static restoration? The original parts are almost certainly forgings. Weight and strength are critical on aircraft especially helicoptors. If this is even a ground running restoration you need to be very careful how they are repaired.

Robert G8RPI.

Hi,
It is not good practice to use mains voltage bulbs or LEDs on machine tools. I'd suggest keeping the MR16's but adding a small blob of RTV silicone (bath caulk) between the body of the bulb and the socket. Vibration resistant but easy to remove if you have to change the bulb.

Robert G8RPI.

The support / bearing on the side has at least got a spring in which transfers energy into the rotor when the pin is pulled. You can see effort being applied to pull it up at the end of the "run". It is large enough to have a AAA cell and solenoid hidden inside too if heeded. The small item under the wheel is also un-explained.

Robert G8RPI.

line bore the holes and fit bearings (I'd use Iglidur like this **LINK** and a ground rod shaft with a flat for the grub screw.

You will only have to do it once.

Robert G8RPI.

Be careful, metrology can be addictive. I have caught it for electronics (81/2 and 71/2 digit voltmeters, Kelvin Varley dividers Atomic and GPS frequency standars and high resolution counters, Various precesion standards).
Fortunatly have not caught it for physical measurments but used to work with XYZ "robots" with 1 micron (0.001mm) resolution. Those needed thermal compensation. We (well me mostly) used a Rennishaw ML10 laser interferometer to confirm their performance. I do have a small surface plate and a old set of slips though. Nothing wrong with using them for setting up, marking out etc as long as you don't fool yourself as to the accuracy you are acheiving. Everyone should have at least a couple to verify other devices like micrometers and verniers. They don't have to be perfect, if you look after them they will be effectively constant and will allow comparative checks. If your micrometer said it was 14.98mm for years and now reads 14.80 it's likey your mic is wrong if you have 2 slips and the mic says they are both wrong, its 99.99% sure to be the micrometer (unless you have sat rubbing the slips together or warmed them up).

Robert G8RPI.

People have been maimed and killed by aerosols and gas cylinders in bonfires. Just reminded me of the time someone threw a full box of 303 cartidges into an incenerator (45 gallon drum) with the empty packing on the range at Army Cadet Force annual camp. Bits of brass case flying everywhere but no injuries. The bullets don't go far as they are too heavy. Not so much Health and Safety in the seventies.

Robert G8RPI.

I had a scare and lucky escape as a teenager. Short verson, I was using a 1.5" torch with regulator on the LPG tank in a closed workshop. After a while of using it at bench level, I lowered the torch and there was gentle "woof" ans a sea of flame spread across the workshop a about knee hight. I stood there watching it burn down and waited for a bang that never came. The hose was damaged at the regulator fitting and had leaked. I did not even loose an eyebrow, very very lucky. If there had been a draft to mix the gas and air there would have been a big bang. As it was the layer on the floor was so rich it just burnt at the gas air interface.

You don't have to be a smoker, any spark, from a brushed motor like a drill, grinding etc can cause ignition.

Robert G8RPI.

Speedy builder 5 is correct, t's a DC motor.

Robert G8RPI.

It appears to be the kind of drill that would normally be used on a magnetic base fitted to a bench stand. The magnetic base drills are used by steel erectors etc to drill holes in structural steelwork in-situ.

Looks nice.

Robert G8RPI.

A small arbour (arbor?) press is not expensive and a better tool for the job than the lathe or mill. Once you have one you will find it useful for all sorts of jobs. a 1/2 ton one from china starts at about £35 shipped on ebay, with 1 ton "shipped from UK" at under £50.

Robert G8RPI.

Hi,

Saturation voltage is an educated guess from experience.

The circuit shown will work fine up to full current (5A in this case) on one variac. Think of 2/3 of a 3 phase star connection run unbalanced.

I just looked to see if I could find justification ofr my statement and found this  "CONNECTION — SINGLE PHASE SERIES: By jumperingthe common connections, two equal single units (or two equalgroups of paralleled units) driven by the same shaft may beused at double voltage (line-to-line) in single phase serieswith external connection only to the input and output termi-nals. The load must be grounded. If an input neutral is con-nected to the common, an output neutral may be used.Transformer or loads need not be balanced to neutral "

at  https://variac.com/staco/PDFCutSheets/VT%20designengine.pdf

Robert G8RPI.

Edited By Robert Atkinson 2 on 15/12/2019 20:41:59

Hi,

Yes it will saturte at around 180V. To get 0-120 volts connect two sections in series and use the output from one. No connection to the "upper" wiper.

Robert G8RPI.

If you can bring it to Cambridge (UK) I'd happily swap it for a 240V unit

Robert G8RPI.

Hi

This Variac was wired for 208V line to line (Star). Each section sees 1/root 3 (1/1.73 =0.578) of 208V = 120V.

So you have 3 x 120V variacs.

Robert G8RPI

Edited By Robert Atkinson 2 on 15/12/2019 16:27:29