Member postings for Geoff Sheppard

I happened to be standing behind Malcolm when the mis-fire occurred and the prop wound its way off. Luckily the plastic safety fence was far enough away so that gravity caused the prop to hit the fence at about knee height. I had a perfect view of the face of the man standing directly in line with its trajectory - talk about a paleface! I've made a mental note to check that all crankshafts have a flat on them and a matching washer to discourage rotation.

We miss Malcolm.

Geoff

Stuart

I believe that the techniqe of wrapping steel bar with brass shim is known as 'close plating'. Used on car steering columns to give an air of 'luxury'. Never known to miss a trick in the parsimonious stakes, were they?!!!!

Geoff

I would hazard a guess that, before the advent of the Dore-Westbury milling machine, most small i.c. engines were built without the use of a mill. Westbury's little book "Milling in the Lathe" contains a wealth of valuable information. I'm sure that a copy could be found somewhere (mine cost the princely sum of 7s 6d (37 1/2p))!

Regards

Geoff

Michael

I'm racking my brains to remember any operation of this sort carried out during the production process. Do you mean the wrist pins attaching the slave connecting rods to the master rod? I remember that there was a complex routine of honing these in which there was a complex routine of turning them end for end. This was entrusted (during my time in the shop, at least), to one experienced fitter, who had a little ritual to ensure that, if interrupted, he didn't start again in the wrong place. I think that he may have been nicknamed 'Sailor' and was easily distinguished because he didn't have a hair on his head and he always wore a blue boiler suit whereas most of the other fitters wore brown warehouse coats or jackets.

It's all a long time ago now (mid 1950s), so the details are vague.

Geoff

Sorry Bob,

Not quite sure which show you are writing about. There were thirty to thirty-five people on the Bristol Society coach on Sunday and we enjoyed a sociable day out despite the snow. No hold-ups anywhere.

Geoff

In M. E.s 4391 (Nov. 2010) and 4424 (Feb 2012), Bob Lilley described progress with the Bristol Society's new petrol-electric 7 1/4 inch gauge locomotive. He is aware that a number of people are either building or are interested in building something similar and he has received many queries about technical and construction details. To provide a focus for these queries he has created a website dedicated to this project. It can be found at http://thomastelford.wordpress.com.

Bob hopes that the experiences of other builders can be shared.

Regards

Geoff

Edited By Geoff Sheppard on 15/01/2013 12:28:48

Rod

Steam pipe? It sounds as though it's going to be a formidable model!

Regards

Geoff

Ian

Being much involved with our local Industrial Archaeological Society, I sometimes get the opportunity to express an opinion - not popular on occasions. One of the worst offenders is, perhaps, the biggest of them all (no names, no pack drill). Elegant ladies with double-barrelled names seem to spend all their time and lots of money changing the shape of the organisation, then re-organise themselves and start all over again. Hence, no money for the important things and a lot of frustrated volunteers.

Yours (slightly incandescent)

Geoff

Rod

By coincidence, the speaker at last evening's local model engineering society meeting was Mike Horler, the wheelwright who restored the Conestoga wagon which is now at the American Museum at Claverton. As you may imagine, he is none too pleased that it is now kept in the open.

He mentioned an excellent model built to the drawings produced by the late John Thompson. Now that you have joined the Guild of Model Wheelwrights, you have probably been pointed to a source of these drawings. The Guild web site illustrates a nice example built by John Castle. This may have been the one you saw.

We look forward to seeing your version at exhibition.

Regards

Geoff

A few years back, I was offered a single-speed Hegner at a sensible price. The original owner just couldn't get the hang of it. After using it a few times, I found out why - it was just too fast for metal cutting. The blades would overheat and break, then all hell was let loose before I could switch it off. I didn't fancy the end of a broken blade through my hand.

The solution was to remove the motor and substitute a simple jackshaft running in a bearing block. The original 'crankshaft' was fitted to one end and a pulley to the other. A second-hand small three-phase motor under the bench which could be plugged into the Eurotherm drive which powers my milling machine completed the ensemble. Now, a wide-range variable speed. Perfection!

Regards, Geoff

Deltic

If you can get a sight of MEW 29, you will find a reference to cotters (and proportions) in Alan Jeeves' article on Keys & Keyways (page 17). hope this helps.

Geoff

Bob D

It's interesting that you mention the "diutees". I seem to recall that there was much discussion in 'M.E.' in the early years of the war about how people with some knowledge of machining could prepare themselves to be recruited for munitions work. However, it was a bit of a sensitive subject due to the reception that they were likely to get from time-served workers and the unions. My father was one of these, being right on the upper age limit for military service, he was never 'called up'. Being a painter and decorator, he was directed into the aircraft industry and spent the whole of the war fabricating engine exhaust systems. I think that once all the able bodied men had drafted into the services, the severe shortage of labour meant that the opposition somewhat faded away. When I went into the industry, there were still people there who had been recruited as dilutees and had just been absorbed.

The other thing that I remember from those war-time M.E.s was Edgar Westbury's design for a de luxe stirrup pump (far better than the issue standard) for fighting incendiary fires.

Geoff

Sorry to disagree, but the term 'machinist' has always been a familiar one to me. When I started my apprenticeship in the aircraft industry back in the early 1950's, one of the apprentice grades was 'Machinist and Fitter' , these being expected to become proficient on a wide variety of machines. As it happened, many of these became draughtsmen or jig and tool designers after a few years. Most of the long-serving machine operators came from the 'Trade' grade. The terms we used for the engineer grades were 'Aeronautical' or 'Student' depending upon the type of academic training one was to receive. A skilled machinist was always held in high regard, capable of producing precision components from exotic materials, using (for the time) quite sophisticated equipment.

Additive Layer Manufacturing (ALM) is already being used to make precision components out of high-strength heat resisting alloys. The days of experiments with plastics are well behind us.

That said, the Roll-Royce Heritage Trust stand at the recent Bristol Model Engineering and Hobbies Exhibition featured a fascinating exibit. It was a cut-away model of a small radial piston engine which showed all the main moving parts - crankshaft, connecting rods, pistons etc. A small handle on the back allowed the crankshaft to be rotated and the movement of the parts to be studied. The astonishing thing was that this was made, from plastic by ALM, not as a series of parts for subsequent assembly, but as a finished, assembled unit! How the piston/cylinder and crankpin/connecting rod clearances were achieved defies belief.

The company that made it were exhibiting their ALM machines at Farnborough and used this little engine as a demonstration model. When they heard that RRHT were coming to Thornbury, they made an example available for display on the stand.

Engineering manufacturing processes are not just changing, they have already changed. I don't think that I would put money into a foundry now. The company that made these ALM 'printers' as they call them, is apparently of the opinion that, soon, "every home will have one". Imagine producing a set of GWR cylinder/smokebox saddle assemblies with all the ports and passageways in situ (and perhaps the pistons, valves and rods already in place). The mind boggles.

Geoff

As you suspect, this can only be a bodge. However, the clearance between the mandrel and the pulley bush is quite small. After a long back-gear operation on my Super 7 (facing with a fly-cutter), I sensed that the pulley was picking up on the mandrel. Perhaps I had the V belt a tad tight, so it was putting a lateral load on the pulley. Stripping out the mandrel revealed the slightest sign of pick-up in the bush, which was soon corrected with a bearing scraper. I resolved after that, always to make sure that it is all well lubricated when back gear is engaged. Perhaps a previous owner of your lathe experienced something similar and decided to make sure that all was locked up solid!

My worry is that the superfluous grub screw has raised a burr on the mandrel which will drag its way through the pulley bush as it is removed. It's probably too difficult to see down to the bottom of the hole. I was going to suggest the gentle application of heat but, of course you cannot remove the mandrel from the lathe with the pulley seized on. Mine wasn't that tight, but it still took a bit of more than gentle persuasion to drive the mandrel out through the pulley. I think that you will have to bite the bullet and drive it through, accepting that the bush may well be scored. It's either a new bush or plenty of work with the bearing scraper. Sorry about that.

Geoff

Cars that can park themselves are already available, Tony.

Regards

Geoff

If you can take time out for a 'diversionary' project, try making the elegant little device described by Peter Rawlinson in MEW 118. Held in the spindle collet, a probe rotates around a pin or a bore, but a dial gauge stays facing you. I've just completed one and its smashing!

Geoff

I now see that Maxitrack "Through Maidstone Engineering" supply drawings from the Greenly archive. They list the four drawings of the 1 inch engine.

John

If you are looking for back numbers of 'M.E.', try The Toolbox at Colyton in Devon.

With regard to prototype designs of small traction engines, one starting point would be Henry Greenly's 1 inch 'Model Engineer' model. This had a boiler of 2 3/4 inch diameter, front wheels 4 inch and hind wheels about 6 inch. It was re-drawn by Greenly & Steel in 1956 and I have a feeling that someone has current rights to the Greenly & Steel designs. A search of the web may help.

Geoff

On my first day in the Apprentices Basic Training Workshop, I was allocated to the team on the one shaper in the shop. In those days of plentiful apprentice positions, we had to share machines and, as the new boy, I was put with a couple of right rascals. A favourite trick was to keep increasing the depth of cut until the ram appeared to be capable of only just dragging itself back. That was when the machine really did appear to start heading for the nearby exit door! Things had to be hastily restored to 'sensible' before the ears of the nearest instructor picked up the familiar sounds of the machine in distress.

Happy days

Geoff