Member postings for Martin Shaw 1

Chris P asked

"I am afraid that it is not quite as simple as that.

What type of earthing do you have please: TN-S, TN-C-S, or TT?"

Like most properties of the age of mine in a town or city the earthing is TNS. Obviously TNCS could cause confusion dependent on where you measure the neutral current but ultimately phase current less neutral current should ideally be but rarely is 0A. If it isn't then there's a leakage to earth which is simple enough. Finding the path of that leakage may well be complex, although I would agree with Chris that you would expect the majority to flow in the CPC and main earthing conductor.

Regards

Martin

Edited By Martin Shaw 1 on 26/09/2023 00:02:08

As a matter of interest since I have a clamp on ammeter I thought to measure the earth leakage current in my house, by no means a scientific and accurate measurement and more of a look and see. The house is nearly 100 years old and of typical interwar construction so not much leakage via extraneous conductive parts, plastic water pipe and bonded gas supply and wiring that is all fairly modern which has all been either replaced or tested satisfactorily for leakage.

I turned as much as possible on, milling machine and lathe both with DC electronic motors, single phase 2.5hp air compressor, several electronic fluorescent and LED lights, hifi, fridge, about the only high current device not on was the washing machine which may well prove to be the worst case.

The ammeter reads to the nearest 10mA and the displayed leakage was exactly 0, both on the main earthing conductor and the phase and neutral conductors, so less than 5mA total. Entirely possible that I have good quality equipment that doesn't leak much to earth but I wonder on this basis how much domestic plant as opposed to poor wiring or miswired plugs actually causes RCDs to trip.

Regards

Martin

Just to finish this off. I made one that would have been fine except it was blocked by excess solder, a second more careful attempt works perfectly and bending was much less scary than I imagined.

Regards

Martin

Dave wrote "I've an account somewhere of the smoke-box of a full-size engine being seen to glow dim red, which must be at least 410°C."

This will almost certainly be caused by char igniting and burning in the smokebox, caused by an ill fitting smokebox door permitting air entering and promoting combustion, rather than the effect of exhaust gases. I suspect that this would be pretty unlikely in a small scale model. The sheer volume of material needed over an extended period of time is never going to be achieved, operator fatigue will set in long before then.

Regards

Martin

I had this very issue last winter, Jason suggested Volkel split dies and a rigorous attention to stock OD. I have had no further difficulty. I get them from Rotagrip or Shop4Fasteners in Sheffield. They are probably one of the most expensive ranges but since moving to exclusive use of their taps and dies my threading has become trouble free.

Regards

Martin

Bruce

Copper, 2 turns, no just a piece of bar.

Harry and Bernard

Thanks, you have confirmed my thoughts.

Regards

Martin

I have to make a siphon from 1/16" pipe bent around a 1/2" former. Should I anneal the pipe before bending, personally I feel so but guidance would be welcome?

Regards

Martin

I think you're right Paul and when I assembled it a niggling thought lurked at the back of my mind. I have decided to make a mk 2 version where everything is threaded together.

Regards

Martin

Thanks very much chaps, it would appear that there is a diverse opinion so, these are the bits,

the small spigot is an interference fit into the brass bush and sealed by soldering, the BSPP bush will jam in the BSPT fitting and with a drop of thread seal probably not leak. For the occasional test of one of my locomotives at 60psi it will probably be adequate. Many thanks for the most interesting discussion.

Best wishes

Martin

Ignore

Edited By Martin Shaw 1 on 23/07/2023 17:30:56

I have an air line fitting with a 1/4" BSPT female thread and I want to make a mating part. BSPT dies are for a one off job are quite expensive and I do have a BSPP die already. It obviously wedges into the female thread. Since I don't need to take it apart will a drop of loctite be adequate or alternatively can I tap out the taper thread with a parallel plug tap for a better fit, overall size and TPI are the same so it doesn't look as though too much material needs to be removed?

Regards

Martin

Well it seems that if you have https level security in Firefox it will prevent you accessing some websites, Rotagrip appears to be one, relaxing the security level to http will allow access to place an order I have established. Chrome works straight off the bat fine but neither browser allows me access to Rotagrip's index page and I still can't find a login other than on the checkout so I suspect there is an issue with their website as Bo'sun suggests. Problem in getting stuff fixed even if there are obviously website issues.

Regards

Martin

Thanks guys, I hadn't thought of browser issues and I am using Firefox, I'll try Chrome tomorrow, I had a look at the ebay store, the prices I was looking at were considerably more than the website,.hmm.

Regards

Martin

Has anyone tried to order through there website and had difficulty? I was trying tonight and I could place items in the basket but when looking at the basket it was empty and told me so. Nor could I find a way to log in. I will ring them tomorrow and find our whats what. It's not a disaster in that the items are gettable elsewhere, just interested really.

Regards

Martin

That’s why we don’t buy Lurpak😁

Other butter like spreads are available, however as in most things in life you get what you pay for. I'm quite old enough to remember margarine and how truly disgusting it was and probably still is. I'll stick with just about affordable Lurpak thanks.

Having commented earlier that I hadn't received any notification a letter came in todays post, dated the 11th March, informing me that my state pension had increased by £15.92 a week. Whilst not overly miserable about this I had just returned from the supermarket having paid £4.60 for a tub of Lurpak and a bunch of bananas, it isn't going to go far.

Edited By Martin Shaw 1 on 27/03/2023 12:42:43

Peter and I share the same surname initial and I too haven't had notification of a state pension increase, I don't suppose I'm going to be jumping with joy when it does arrive.

I can share Vic's sentiment and whilst I am slightly younger than him my pension amount was impacted partly through my opted out employment but also by the increase in contibuting years and date of retirement. A group of people were put in the unhappy position of not being able to complete the full 40 years after it had gone up from 35 and the date when the counting started. I think I understood the ramifications when they were explained to me actually by the governements pension service, the outcome is none the less shabby but unsurprising.

Record are now owned by Irwin and you can get soft jaws for 1/2/3 size vices from RS, at some price increase from the displayed advert above.

I did exactly as the OP proposes before Christmas and I got a piece of CI from M-Machine in Darlington. Excellent service and not exhorbitant for the carriage. They were by far the least expensive and it machined very nicely despite some folk telling me an 80mm face mill would destroy my milling machine, it didn't.

I can't praise enough Machine DRO for customer support although it was related to the lathe rather than the mill. I have 3 axis magnetic scales on the mill and 2 axis on the lathe. I found them easy to fit and far less bulky than the glass ones. I would also agree with Jason 5 microns is more than adequate for most model engineering, in my case often the nearest 0.5mm but they do make hitting it much easier. Wouldn't want to be without them.

Regards

Martin