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Member postings for Rod Renshaw

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

Thread: Coping with voltage spikes
16/08/2020 11:18:58

I really, really, hesitate to second-guess Andrew but I think SOD's circuit, though flawed, could indicate a simple solution.

The LED symbol in SOD's circuit is the wrong way round, as Andrew says, but it's also a simplified version of reality. The LED that Tim is using has a series resistor or other circutry built in, as supplied, to render it suitable to run off a 12 v supply. The zener circuit (once corrected) supplies 12 v whatever the input voltage, as long as it's > 12v and within reason ,Then the LED should light happily?

Rod

Thread: Watchmaker's lathe
13/08/2020 17:49:43

+1, it's a safety pulley. For clarity, I would like to add that it goes on the headstock end of the lathe and as Michael says it is used when turning work between centres. The work is held between 2 (usually female ) centres and it has a small pulley ( called a ferrule) mounted on it. The drive belt, whether from a bow or a motor, goes around the safety pulley , which rotates freely, and just brushes the ferrule. By adjusting the position of the safety pulley the drive belt wraps around the ferrule to a greater or lesser degree and provides a greater or lesser drive to the work - useful for very delicate work.

Rod

Thread: Left handed lathe?
12/08/2020 12:27:28

Not uncommon to have " left handed lathes" in watchmakers' sizes, especially on the Continent, and these are preferred by somw workers, even if the worker is right handed. Less common in Gb, I think.

Rod

Thread: Paint for mild steel sheet brazing hearth.
11/08/2020 14:19:08

Thanks to all who contributed ideas on this.

I have decided to get some of the high temperature exhaust/ manifold paint as recommended by Brian and Anthony.

Rod

09/08/2020 17:54:50

I noticed a recent thread about painting older galvanised garage doors, and the multiple suggestions for paint schemes. Also that Hammerite,which I have used successfully in the past, no longer seems to be the same product.

What would the team use to get a degree of corrosion resistance on a newly made brazing hearth made of bright mild steel sheet with welded corners which will be stored in a notionally dry, but unheated, garage in the UK? There will be firebricks inside the hearth so the paint will not be exposed directly to the propane torch flame. I don't need a showroom finish but it would be good to think the thing would not look like a rusty mess for at least the first few years.

Rod

Thread: Small Tap Holder
04/08/2020 12:50:12

E141 is the smallest "standard" size. Old ones, found on eBay etc, tend to be better made than new ones.

The pin chuck, as recommended by Paul, grips best for very small taps (12-16BA sort of size.)

Rod

Thread: Coping with deafness
03/08/2020 13:11:57

Thanks again for the further suggestions.

I am sure that something can be arranged technically, it's just a matter of gently persuasion, and backing off if it's really not wanted.

Rod

01/08/2020 21:11:01

Lots of useful ideas here.

I fear I may have given a rather false impression of my neighbour. She is elderly and very deaf but otherwise is very active. She lives alone and has no carers etc., she gardens, she lip reads very well, she drives, she uses a tablet more, and more expertly, than I do, she gambles when playing bridge and ( in normal times) she sings in a choir and has a very active social life. I think it is perhaps because of this social life that she is so reluctant to have anything that might make her appear to be disabled.

She does though seem to want a solution to the doorbell issue, though she does not seem so focused on the smoke alarm.

I will list all the ideas that you have all suggested and let her and her 2 adult children ( who live elsewhere) decide what she will do to enable her to answer her "doorbell."

Many thanks to all who contributed.

Rod

01/08/2020 15:50:57

Hi all

My next door neighbour is aged 88 and she is very deaf and getting deafer as time goes on. She can no longer hear her doorbell easily and wonders what she can do about this.

My neighbour is very mentally alert and she recently called in the Fire Brigade to fit her up with a smoke alarm. She could not hear the alarm sounder so the brigade installed a vibrating thing on the end of a flex which she was to put under her pillow. She has now rejected this, apparently on moral grounds, and had it removed. She says she is too old to be running outside if there was a fire.

I have suggested she has a flashing light doorbell but she is not keen on this idea because she thinks it will make her seem like a disabled person!

Anyone any ideas about a "doorbell" she could hear/ see/ become aware of?

Thanks

Rod

Thread: Jobs
31/07/2020 11:38:52

Anyone remember where the quote "What if they gave a war and nobody came" comes from?

Rod

Thread: Time for new collets?
31/07/2020 11:29:34

Add : could use a flat oilstone instead of a diamond file.

Rod

Edited By Rod Renshaw on 31/07/2020 11:30:35

31/07/2020 11:26:47

I have found it best to harden and temper while the blank is still symmetrical, and quench vertically as suggested by Dave, then check it is hard and straight.

Then rough grind the flat on the off-hand grinder if nothing better is available

Then finish the flat with a diamond file while supporting the blank in a rough vee groove in a piece of hardwood held in the vice. The blank rotates slightly in the groove under the pressure of the file and the flat comes out better than one might think. Check progress with a mic.

Rod

Thread: Higher trolley for surface plate?
29/07/2020 19:27:40

Thank you to all who contributed ideas and photos on this topic.

I had been concerned about a trolley being top heavy but the plate weighs about 120 pounds and if I put it on a trolley the combination will weigh perhaps 180 pounds, plus weight of items stored beneath the plate, which is quite a lot more than me, so if I bump into it I think I will just bounce off rather than knock the trolley over! Still best to be safe so perhaps a stand, ie with feet rather than castors, would be best. Having said that, John Pace reports no stability problems with his trolley and ingenius side table, and I am not sure mine would be much different, just a little bigger in all dimensions.

I like the idea of drawer slides but was trying to get the plate higher rather than lower.

I like the idea of standing the plate up at the back of the bench but it's more than I can lift!

The different ideas and solutions have given me a lot to think about.

I will mull it over but at present I am thinking of trying to make space for a "high bench" somehow, and standing the surface plate on one end and using the rest of the surface for marking out/ tiny work /desk work. I have a high stool left over from a kitchen refit and it would be good to be able to sit down for fiddly things.

Thanks to all who contributed.

Rod

27/07/2020 19:00:48

Hi all

In order to free up some workbench space I am thinking of making a trolley to hold my surface plate which is about 20" X 16" and always seems to be in the way.

I was thinking I might make the trolley rather higher than the workbench to reduce the amount of bending down involved when trying to read the height gauge and similar tasks.

Has anyone done this and is the increased height helpful?

Rod

Thread: Bulbs Electric Life of
24/07/2020 20:05:22

It's old technology but it might be worth trying a neon lamp, which may not give exactly the colour you need, but it should last a long, long time and consume very little power. ( mains voltage so may not be safe, depending on location.)

Rod

Thread: Making sense of big numbers
24/07/2020 18:47:58

I heard a snatch of someone on the radio the other day explaining a method of understanding big numbers which I thought might be of interest in these days of huge sums of money being used or promised for recovery from coronavirus or huge National Debts etc.

The model is based on the idea of using one second of time as a basic unit.

So, 1 second lasts one second.

A thousand seconds lasts 16.6 minutes.

A million seconds lasts 12 days.

A billion seconds lasts 32 years.

And a trillion seconds lasts 31,709 years.!

So when the politicians talk glibly of millions for this and billions for that and debts of trillions, it makes me think how big these sums really are

(All figures rounded and subject to correction by the usual suspects.)

Rod

Thread: How to stop scam phone calls for good?
21/07/2020 13:01:27

I don't have a solution, but just for information, our home landline has "always" been ex-directory and we still get scam calls, so going ex-directory may not help much.

Rod

Thread: Engineers' Level adjustment - why 4 holes?
20/07/2020 20:39:04

Yes, and quite a lot of repeats in my experience!

Rod

Thread: Science Museum needs help identifying mystery objects
20/07/2020 20:32:38

I was given a "Hobbies" treadle fret saw for Christmas in about 1970. Money was short and mine was a "Gem" model which cost about £7.00 IIRC. The "A1" model, which is the one in the museum collection was about £11.00. The Gem was mostly made from pressed steel sheet, but the A1 had a cast iron construction.

They were listed in the Hobbies catalogue as " fret saws" I don't recall "scroll saw" being a term in those days. I used it to make lots of small practical things but never got into the elaborate decorative fretwork which had been very popular a few years earlier.

The saw really came into its own when, with together 3 friends, I built 2 two-seater canoes to a published design. The design called for frames cut from plywood held together with longitudinal strips of parana pine and covered with "canvas", which was really a kind of plastic covered fabric. The fabric had to be ordered from "CB Cross " at the bottom of Deansgate in Manchester. The frames gave the canoe its shape and were cut to paper patterns from an 8 foot by 4 foot sheet of marine ply, which was much bigger than the work the saw was designed for.

To cut this sheet into frames, we had one child ( we were all aged about 10) on his knees under the saw, working the treadle with his hands, while the other 3 balanced the ply on the saw table all trying to keep the saw on the cutting line. It was hard work and we broke a lot of blades!, but the canoes were finished and we had lots of fun with them.

Rod

Thread: What's this for?
13/07/2020 21:13:34

Martin Cleeve's articles are in ME Vol 116 of 1957. I don't know if Martin invented this design but he was very enthusiastic about it and wrote about the advantages and methods of working.

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