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Member postings for Geoff Theasby

Here is a list of all the postings Geoff Theasby has made in our forums. Click on a thread name to jump to the thread.

Thread: miniature 3 pin sockets
28/03/2019 06:58:29

Basically, you need Molex connectors. If a panel plug/socket, do not use stereo jacks, as has been said, because the wrong contacts 'make' as they are connected. Microphone connectors, available in many 'ways' can be used, but not if there is danger of harmful, inappropriate connectors being mated, causing hazards.

Thread: Wentworth woodhouse
22/03/2019 15:02:31

How wonderful, Mick. WW is only a few miles from here, and this year we are going on a tour, when it reopens. I've seen some photos, and we have walked through the estate, gardens and garden centre.

Thread: LED lighting
08/03/2019 18:22:36

AdrianR, on a point of information, yes, SCR dimmers did that, if suppression circuitry wasn't designed in. However, using a zero-crossing circuit, which switches the current on or off at the very point at which the mains sine wave (Ha!) goes from +ve to -ve, results in little interference, and it is easily suppressed.

08/03/2019 11:12:52

LED lights are great, and very versatile. For domestic situations straight replacement is good, but the dearer ones £3-ish are better than the 'bargain' types. Philips Hue are expensive but can change colour and intensity. For the workshop, I buy reels of LEDs at £8 for 500, on a self adhesive strip, with suitable resistors, often run on 12 volts from a 'wall wart'. These strips can be stuck up anywhere, or fed through clear plastic tubes to make a strip light.

Thread: Plastic Balls in Bearings?
26/02/2019 09:38:55

Re: Dyson, I originally got one because they are good at picking up dog hair. They filter the air, which helps asthmatics, they do not lose suction, you can see when they are full. I also have a newer VAX. It clogs up regularly, sometimes every time it is used. It is lighter, and it is cordless.

Thread: Trends in Radio Ads
07/02/2019 07:49:58

Nothing wrong with a bit of self-promotion, several times I have heard details of a forthcoming programme that might interest me.

Anyway, I like Radio 4 almost exclusively, or the BBC World Service, mostly at night. However, I work in silence, the better to avoid distractions.

Thread: Free Electricity
17/01/2019 10:05:38

John, Yes, a solar panel would be the modern way. Tracking the LO would not work with a simple, non-superhet radio, trf, direct conversion, or SDR. The last has a crystal oscillator 'clock' to drive the electronics, but it is very low power, and easily shielded.

17/01/2019 06:21:05

Running clandestine radios from a large wire loop laid under a power line doesn't sound very clandestine to me. Also, one could detect the use f a superhet receiver by listening for its local oscillator, TV detector van style.

Thread: Telephone / Internet Scams
11/01/2019 13:15:47

Apart from the two (Two!) calls from 'BT' yesterday threatening to cut me off, as they have been doing for months, I got an English voice asking if I had taken out a plan to protect against spam phone calls. As this provision only came into force on Monday, they are quick off the mark. I asked after the cost, and he said 39p per week. I told him that was £20 a year for something that is allegedly free, ... and he cut me off.

Thread: Simple and accurate home "switch"
03/01/2019 10:36:43

Robert, I hesitate to cross swords with a practical and qualified expert, but in respect of silver contacts, the tarnish (Usually sulphide) is conductive, as is the oxide, which can be used to make batteries. In VHF/UHF circuitry, items are silver plated to aid conductivity through the 'skin effect'. Furthermore we are advised not to polish these surfaces because the conductivity gets worse.

Geoff, G8BMI

Thread: Measurements from the past
31/12/2018 22:11:31

Up to the start of WWII, electrical capacity was expressed in 'jars',after the Leyden variety. That was not long after spark transmitters ceased to be installed in new ships.

Thread: Year of Engineering
16/12/2018 11:40:00

My wife refers to me as her Household Technical Consultant. As a member of IET, IEEE and ETA, I feel qualified to mend anything with materials at hand. Glue, duct tape and WD-40... Yesterday I attached magnetic catches to the kitchen door, and, at her request, stood near the computer to make it work properly. It's true! Five times now, when it wouldn't load her e-mails, I looked over her shoulder as she tried again, and Hosannah! It worked! Even if it's a loose floorboard resting on a cable, it does work. then also, lightbulb replacement service, painter, car dashboard function diviner, setter-up of electrical devices, tv remote operator, (out of six) battery stockist, furniture repairer....

Thread: Mini-Lathe Repair
13/12/2018 14:07:45

Thank you, Hopper. The lathe is back together, but I have to replace the leadscrew gear (stripped teeth). I bought a set of metal gears, but the one needed was bored too small for my leadscrew, and the keyway is too small. I opened up the bore, and am filing out the keyway to suit the key. Otherwise, everything's fine.

I shall align the leadsrew as suggested, the bearings bolt on to the bed.

Geoff

09/12/2018 11:03:39

Success! Bearing freed off with a combination of brute force and persuasion.

After soaking all night in penetrating fluid, (The shaft, not me!) it moved a little, but not much. I then warned up the bearing with a butane torch, and heard a 'crack' noise, which was promising. Then, resting the shaft vertically in the vice, loosely, not gripped, so the bearing rested on the jaws, I whanged it with a lump hammer, protecting the end... A sliver of light showed where the leadscrew was shouldered next to the bearing. Thus encouraged, I applied my 75 mm gear puller to it, and it began to move! Then I just wound it off. The bearing area was black, suggesting lack of lubrication, so I polished it, made sure the oil holes were clear and, feeling & seeing no obvious problems when held up tho the light, reassembled it in the reverse order, as the Haynes manuals say.

Now, before I was so rudely interrupted, what was I doing?

08/12/2018 15:07:45

Update:

It's the LH leadscrew bearing. Seized. Can't imagine why, it's had the same lubrication as the other end bearing. Maybe it was tight to begin with. Anyway, now soaking in penetrating fluid (Brake fluid + 3-in-1)

08/12/2018 10:58:25

What a timely thread! Or the cause of my trouble... A harbinger, in fact (Dic. one who harbingers) My super mini lathe has just stripped the leadscrew gear. Removing it reveals a jammed leadscrew, so I slept on it. My task, should I accept it, is to take down the leadscrew and find out why. The carriage moves freely.

Thread: Interests other than Model Engineering
04/12/2018 10:31:28

Hmmm, electronics, photography, astronomy. Very popular here too. Too many cloudy nights and city glare for skywatching, but I combined two and built a series of radio telescopes. However, all can be done at home, in the winter and alone if required. As you know, I write, Practical Wireless and Radcom, in the main, but many other, mostly science-based, for instance I just made my first microwave radio system, and transmitted my voice across the room, with no prestidigitation, hidden assistants or optical illusions, and at no time did my hands ever leave my arms!

Then there are railways, of all sizes, industrial history, real ale, reading, (NF) listening to music, aviation, that'll do for now...

Thread: Melton Mowbray and District Model Engineers
21/11/2018 01:45:36

Hi Steve,

if you publish a club newsletter, or even if you don't, I would be pleased to include MMDMES in Club News. Tell me what you have been doing, send me newsletters, photos, press releases etc., or just chat when you can. Perhaps appoint a publicity officer? Send your future meetings schedule to Martin Evans, for inclusion in Club Diary.

Geoff

Thread: AF socket sets. Are they extinct
12/11/2018 04:11:55

If I were to nominate a mentor in engineering, I wouldn't start in the USA. With notable exceptions, their liking for big, slow, shiny-chrome motorcycles makes me weep. Their jet engines run roughly, and everything must be cheap. Cars have huge engines, rather than efficient ones, and they don't do 'small'.

Sorry, I'll be better shortly

Thread: A New Golden Age of Model Engineering Exhibitions
23/10/2018 07:37:19

Paul Kemp thinks people make lots of money from exhibitions, and talks of 'honest accounts'.

I find this insulting. I volunteered to help at recent MEXs, paying for my own transport & accommodation. Steve Eaton & Mike Law were also volunteers, I believe. MTM is a business, and if it were so easy to do, lots of chancers would be trying it. Try checking the cost of hiring a venue, insurance, and so on, then taking brickbats from troublemakers claiming there are vast profits to be made!

Geoff

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