Member postings for Nigel Bennett

One of the main problems with using a vee-ended slot drill or end mill is that the cutting speed of the centre tends to zero, giving very high cutting forces and the tendency to break the cutter at the sharp point. A vee-shaped side and face cutter (as on horizontal milling machines) would be a far better bet.

Suggestions to using standard end mill/slot drills are the way to go if you can position the job and/or the cutter rotation to do what you need to do.

Inspector Meticulous was, IIRC, a reference to one of the ME contributors of the time. It's certainly entered Model Engineering vocabulary!

As he was a Freemason, he often referred to people as Bro. - as in Bro Wholesale (Was that Noel van Raallte of Bursledon?) and Bro. Coopie, who kept chickens. I seem to recall "Tubal Caine" being picked up by LBSC in a letter by Tom Walshaw; whether it was his or an ME typo I don't know, but LBSC referred to him thereafter as "Bro Tail-lamp" - referring to the extra "e" at the end of Tubal Cain's name.

What a character, though. What can you say about a chap who would pull his own teeth out after his dentist retired?

I have always been a little concerned about LBSC's boiler design for Lion. Using a cast gunmetal firebox top is not the best way to do it, and neither is it prototypical. Metal defects in castings often occur, and using them as a pressure vessel invites problems. Yes, I know there have been many built, but I can't imaging the Australians, for example, passing the design as sound.

The real Lion has a round-topped affair of fairly conventional construction, with the "haystack" effect merely cosmetic. I am sure it would be much easier to build like that, using copper sheet.

Comments, anybody?

A story I heard was about a chap in the Army during the war. He used to write to all manner of companies, back home, saying how wonderful their products were. The flattery produced results - he got loads of stuff sent to him by companies. He met his match with Wilkinson Sword, however. He wrote to them, saying that their blades were excellent; he had only got one razor blade, and it had lasted for six months.

Wilkinson sword wrote back, thanking him for his kind words. Enclosed with the letter was a single razor blade, with words to the effect of "Please find enclosed a further six months supply..."

Edited By Nigel Bennett on 25/03/2015 13:01:58

We do lots of square hole broaching at work, both pull (through) and blind (push). We always drill a larger pilot hole than the square AF to reduce the load on the broach. With push broaching - which is what you look like doing - you can essentially just take out the corners if your male square is anything like - I,e, it doesn't have rounded corners. We did a test on an aluminium handle broached 8mm square, with a 10mm pilot hole. The handle spindle failed first in torsion.

No. If you do, you'll end up with Pringle-shaped brass sheet. It will really soften it and it'll be much more difficult to get the flat bits flat again. There'll be no strength to it!

3/8" rad should bend well in the "half hard" state that brass sheet is normally supplied. Try it out on a bit of scrap first (assuming you've got some!)

Good luck - and remember to measure twice before cutting once....

I was very disappointed with my Rishton VM60. The feedscrews wore very quickly - I think they were made in leaded mild steel. I did manage to make a new one for the Y axis - just to sell the thing!

+1 about the comments about the poor fine feed on the Z axis.

2MT tooling was also a pain in the botty to change.

I bought a Chester Lux mill in its place. Much better machine.

BS 1400 of fond memory shows that you can have 1.5% lead in G1 gunmetal; the leaded LG1 & LG2 have 4% - 6% lead. It is quite likely that the casting supplier will only do LG2 in any case. You may get LG4, which has has less lead - 2.5% to 3.5%.

LG2 is a "useful all-round alloy, used in pressure-tight castings"
LG4 is "used widely in the valve industry" for sand & chill castings.

Strength: LG1/LG2: 180MN/mm^2
G1: 270MN/mm^2
LG4: 250MN/mm^2.

I have often silver-soldered leaded gunmetal with very good results. The lead will promote machining (as well as improving its bearing performance, as Jason has already said).

Hope that either helps or clouds the issue further!

Yes, I have, and I am perfectly happy with them; it seems that A&R were the original suppliers to Myford of Beeston anyway, so they ought to know what they're doing.

I've had some dodgy ones from other sources too, but I have managed to bodge them to fit by attacking them with carbide tools.

A lot of people slag off Tich as being unsuitable as a beginner's loco. It's what I started with. I didn't finish it, but I did learn a lot from what I did.

I also own a venerable 3.1/2"G 0-4-0 ST locomotive mid-way in size between Tich & Juliet.

I can say that if you can build a Tich and than have the driving skills to drive and fire it continuously, you can probably build and drive anything. Tiny locos are very unforgiving of errors in construction and inattention in driving. Unlike say a 5"G Britannia, you can't leave it in steam for ten minutes whilst you have a bite of lunch!

Good luck in your project. I seldom build anything nowadays without building it as a 3D model first - I find it helps enormously to visualise methods of construction, assembly pitfalls, and you can also add a whole plethora of your own mistakes as well as finding original ones...

A couple of the "Standard No.4" jobs should deliver enough - or fit a No.3 and a No.4. You can probably leave the smaller one on a lot of the time that the loco is working fairly hard.

Your failures on the Marie E may be nothing to do with the injector itself; a number of possibilities can be as daft as fitting it the wrong way round, or inadvertently missing out or mixing up the delivery/steam cones! Other possibilities are inadequate steam supply, contorted delivery pipes, insufficient throughput of the boiler check valve, leaking check valve, too hot a water supply, restricted water supply....I would eliminate all those possibilities first before condemning your injectors.

If it still fails, you need to try it out on somebody else's loco with a working injector - or at least borrow a known-to-work one first.

Well done, Russ B, for studying Mechanical Engineering. Stick with it - we need some Mechanical Engineers! ( I speak as one myself, but like Muzzer, I was lucky enough to do it for free, back in the 1970s.) I also did it via a Student Apprenticeship, so I went through the Apprentice School and followed an excellent course of training in all aspects of the Company.

I hope your course is better than the MSc course at Huddersfield seemed to be a couple of years ago. We took on a chap from there with an MSc. He claimed to be proficient in SolidWorks (hadn't a clue) and he didn't even know what a countersunk screw was, for crying out loud.

It has always seemed to me that if you want to make money, go into the parasitic professions. If you're not too fussed about money, but want to have an interesting time working for a living, become an Engineer. I've never regretted my decision to become one!

Employers are always whining about lack of qualified and experienced staff, but they seem to be doing sod all about it themselves - where are the Apprentice training schools today?

Julia Olds wrote a series of articles about boiler building recently.

I had one - a Rawlplug model. I made up a big aluminium shroud and handle for it so that I could get a decent grip on it when in use. It got used for drilling a lot of holes in the floors of Class 442 EMUs down at Bournemouth railway depot and it eventually wore out, having had a very hard life indeed. It was an excellent piece of kit.

I use a scriber as a centre punch to very gently mark the point - using a 12x loupe to ensure I've hit the right spot - and then bop it with an automatic centre punch prior to drilling. Use a small drill to start and open it up.

Obviously the scriber isn't one of those bent-end ones - or Tungsten Carbide tipped! - but a Priory PR127

They're on Fleabay (usual disclaimer)

**LINK** (I forget where I got mine now, but for under a fiver it's not expensive!)

Gary's suggestion is valid if you can swing the bar in your lathe! The longer it is, the more accurate it is. Per contra, the more pain it is to get the head set level with a large distance between clocks when you use it...

Apart from the relatively huge surface area of swarf, it's also likely that there will be no oxide coating on freshly-removed swarf, so that the surface is more likely to be reactive. Oxides on the surfaces of bits being welded together would therefore be unlikely to ignite easily - as has been discussed.

John Durrant's comment about the Adour in the Harrier is puzzling - I thought it was a Pegasus in there. Mr Wiki says the Adour was used in the Hawk and Jaguar.

It's usual to have some fairly small pipes leading from the bottom of each gauge glass to "blow through" the glass to clear scum or debris, and to check that the water level restores to its original position. There's usually a blowdown valve mounted low down on the firebox for the purpose of draining the boiler. Having it low down enables all the accumulated pooh to be blown away with the water/steam when the boiler is drained at the end of a run.

That's a pretty impressive loco to build - and in 5"G it will be a similar size to a 7.1/4"G Standard gauge loco! My current project is a wee bit smaller - I can actually just pick it up - and I've used 3D CAD to design it all.

I wish I'd actually finished the CAD model properly before making some of the bits, because I've found I need to do semi-impossible things to fit the metal bits I hadn't done on the "virtual" loco...

Has anybody ever done a model of David Wardale's Class 26NC "Red Devil" with all the gizmos? That would be something to occupy a few idle hours.

Enjoy the project; I look forward to seeing it develop.

Just looking at the pictures, it seems to me that the tube diameters are either very small or there aren't enough of them.

I would suggest that you look at a comparable 2" scale published design and simply blag that; John Haining's ploughing engines or his Durham & North Yorkshire would be a good starting point.

The D & NY has a 5" dia boiler, with 13 off 1/2" tubes, plus three 1/4" bronze longitudinal stays.

See ME 3596 (3-16 Nov 1978) p 1297-1299 for drawings.

(edditid foar spelin)

Edited By Nigel Bennett on 11/09/2014 11:14:24