Member postings for Neil Wyatt

Well, I finally got to view the pages on Lathes.co.uk - actually I have seen one of these in an old advert.

I remember endlessly adjusting those Sturmey Archer links to get reliable gear changing on many a bicycle!

I like the two arrangements of the single speed gear - gear up with a motor, down for hand cranking but use the same two gears! The hand cranked version must have been deathly slow to use!

Neil

> Neil..my guess would be three at 120degree but if not would like to know reason for 135..

Probably that I'm stupid. I added 45 to 90, instead of dividing 360 by 3.

I think Michael has slightly crossed lines. I can guess who he's complaining about, but that person appears to have made no contribution to this thread?

Neil

I'm hearing all these comments; I'm also receiving private emails with other comments. John is right when he observes that although this forum has a surprisingly large membership, the actual readership is way bigger. there really is a silent majority.

Life isn't made easier as there are no right answers here, just balance of opinion one way or the other and there are always at least a few people who disagree with what may appear a unanimous view to the casual reader.

The vice article was long if seen as a description of how to make the vice. On the other hand, the reason it was long was that the series was packed with a lot of very useful advice for the beginner by a very experienced model engineer. Perhaps it should have been packaged as a beginners series that just happened to feature the vice - but then would that have been disingenuous?

Another series is aimed at the beginner. The criticism voiced here is from experience model engineers. Is there a beginner reading this thread who can offer a perspective?

On the subject of tips, I'm in discussion with one of our advertisers to sponsor a 'tips' page with a modest prize each month. I'm hoping this will unleash a small tide of short snappy 'a few hundred words plus a picture or drawing' responses.

Neil

Hi Jason,

I deliberately didn't mention that the pipework could act as a receiver..

In theory three pistons at 135 degrees to each other will produce a steady pressure, if the valves are arranged right. In practice not really constant, but good enough I would guess.

I can't possibly comment on off label use of such products in my new role.

Neil

For clarity, the pressure systems regulations don't apply to pipework (i.e. pipes that don't leave a premises) that hasn't got a receiver OR systems with a working pressure of less than 0.5 bar (excluding steam).

Any system for other than personal use, e.g. at a show, would probably have to use a properly inspected compressor or be restricted to 0.5 bar/7 psi or the alternative is a pump that has smooth delivery of air and doesn't need a receiver.

**LINK**

I think there are two possible routes this could take:

1 a large rotary or three-throw pump to give smooth delivery of bulk air at modest pressure for use in public demonstrations. (i.e. an alternative to a bulky, noisy, commercial unit designed for high pressures).

2 a smaller pump designed for home building to power one large or several small engines in a domestic setting. (i.e. an alternative to small, noisy pumps that tend to provide low volumes at high pressure, rather than the reverse).

Neil

One idea I have is a piece of 110mm soil pipe with a bung in one end and a diaphragm or piston at the other. the swept area is separated from the bulk of the pipe with a simple flap or reed valve. The bung has an a air outlet and a simple pressure regulator/safety valve. If rated at 10psi and the pipe is vertical the valve could be a loose weight, as used for pressure cookers - with a simple shroud to reduce noise.

It should be possible to make a lightly loaded piston, if the stroke is long enough a port in the side of the pipe would do instead of a valve.

10psi is easily within the capacity of soil pipe (think potato cannons).

Any thoughts on making a piston to run in soil pipe?

Neil

Hi Jason,

The first job of this thread is to define things like 'few' and get a proper spec.

So some thoughts...

I'm guessing the Victoria would be near the top end for demand. A 10V is less than a cubic inch, and I'd guess most stationary engines would be smaller than the Victoria.

Speed is the main issue, most engines look best at a 'realistic' speed of 60-90 rpm, although many small engines won't run smoothly at less than 120rpm. It's the little 'wobblers' that need to run fast, but they only need a breath of air. How fast do you run the grasshopper, I'm surprised it uses so much air?

1 cubic foot per minute should easily run a dozen 10Vs. My little diaphragm compressor (I'd guess 1cuf/m?) runs a 10V at very scary rpm without difficulty...

The Victoria at 200 rpm should need less than a cubic foot a minute, and to my mind would be running too fast.

But another issue is the benefit of having lots of air in a receiver and keeping a steady pressure so when one engine is added or taken away the others aren't affected. Also, may people like to control speed with bleed valve, rather than restrictors, so air is wasted.

Finally, I do think that, at low pressures of a few psi, slide valves probably don't seal very well and I guess a lot of air gets wasted.

Neil

Arc do useful large diameter blanks. Below are pics of an MT3/ER25 collet holder I made from one. The steel turned and threaded very nicely.

Neil

By 'eck Bazyle, 250lbs is a pair of nine-stone weaklings where I come from!

Neil

(196lbs on his own...)

I bought (for a pound) a cheap laser pointer, several years ago. It came with some very cheaply made plastic end caps, each of which contained a cartoon hologram that made the laser project a simple picture. At least one of those is a fine cross hair, if only I can find where I put it..

Neil

Hello Dennis,

As you have the ME photos already, I can't help further, but I'd be keen to see pictures of the tank as it is today.

Diane might be interested in publishing an 'update' on the tank in ME.

Neil

Just for the record, the last few months of MEW saw a complete series on making a machine for injection moulding plastic.

Keep up at the back!

Neil

Edited By Neil Wyatt on 09/03/2014 18:52:43

It looks like the contributor who advised me to don a rhino-hide suit was on the right track...

Neil

Michael's suggestion should work fine. A filed dome on the end of a silver steel bar, then file half away should create a tool that works well.

Neil

For teh curious, Screwfix and B&Q both state that their copper tube is to EN1057.

"7.1 Composition
The composition shall conform to the following requirements:
Cu + Ag: min. 99,90 %;
0,015 % ≤ P ≤ 0,040 %.
This copper grade is designated either Cu-DHP or CW024A."

There is an array of tests applied ona sample basis including a pressure test. 35 bar for tube up to 54mm diameter (nearly 500 psi).

Neil

Thanks Doug,

I've just looked and, yes, the Velleman kit is now just £499.

Neil

Issue one of a magazine called 'Model Engineers' Workshop' had an article on making an optical centre punch and an optical centre finder. Apparently it went on to be quite successful.

Will Doggett covered making an optical centre punch in issue 191 as well.

Sounds like a good magazine, consider taking out a subscription

Neil

Hello Greville,

Welcome to the forum. I can't help with your query as I have no experience of clockmaking. Hopefully someone who can help will be along soon?

Neil

It was suggested we should move a discussion here to avoid cluttering Allan's Stuart Victoria Thread.

The issue under debate is a design for a low pressure but reasonably high volume compressor for demonstrating (unloaded) steam engines.

The basic specification would be a maximum pressure of 10-30 PSI (personally I think 10psi would be ample), a volume sufficient to run a few engines at once, and low noise. Low noise would include ensuring any safety valve or regulator doesn't make loud or sudden hissing noises!

This would suit it to use at exhibitions or even in a domestic setting.

I may be being optimistic, but if a very simple design can be generated through this forum, I'd be happy to publish it in MEW.

Neil

Edited By JasonB on 09/03/2014 19:19:47

Finally saw some 3D printed bits. Finish was almost like wood with a fine pronounced grain, but more regular. It could clearly produce usable light duty gears, for example.

These were from a mid-range printer. Would anyone with a reprap type printer be willing to send me a small sample to compare?

Thanks

Neil