Member postings for Nigel Bennett

Erm.. yes, that what it does, ejects the tailstock chuck. I agree that until you get used to it, it can be a little frustrating, but how else can you eject tools? When I had an ML7, I kept a suitable aluminium-headed steel rod in the tailstock to knock out tools, but I soon learned to love the Super 7.

Perhaps you could mark on the barrel where it starts to eject so that you don't go past it.(This position may vary with other taper-shank tooling, though.)

I think I'd be a little nervous about swapping tailstocks between lathes; although they're supposed to be the same centre height, I imagine there could be a bit of variation, which might upset your ability to turn parallel when using a.tailstock centre

I think the prices of machine tools of any persuasion have risen sharply over the past couple of years. Finding a bargain on eBay now is a rare occurrence.

Mark

If you order a metric machine, it will be more difficult to do Imperial screwcutting, and vice versa.

A DRO on either metric or Imperial will give you complete peace of mind as you will be able to switch freely from one to the other by just pressing one button.

Personally I was brought up with Imperial but I now use metric pretty well all the time. I simply can't understand now why 3.37/64" should make more sense to anybody than 90.88mm, but there you go. To use the Imperial measurement on a DRO you'd need to convert fractional to decimal anyway.

If you don't have access to rolls, try this:

Soft solder the two angles together (to form a T section) and bend them to suit with your fingers. Match up to a radius drawn full-size on a piece of paper or to match the curve of the front/rear cab sheets. Melt them apart and fit. Might be best to make them slightly over-long and cut the ends off, because getting the beginning/end sections to curve isn't easy.

I still like Neville Shute's introduction to "Trustee from the Toolroom" -

"An engineer is someone who can make for five bob what any bloody fool can make for a quid."

To quote Tim Vine, I'm going to have to get rid of my vacuum cleaner. It's just collecting dust.

I have often machined holes with a boring tool in my lathe, setting the tip height well above centre height. Yes, the tool geometry is probably wrong, but it means that it is possible to have a little more meat on the tool to support it without it rubbing on the bore. Meatier tools are always an advantage in deep bores.

If the boring tool height is way out, remember that the amount of metal you take off will be a bit less than the cross-slide dial (or DRO) would have you believe.

The tip was given to me by my apprentice school turning instructor, rather more years ago than I care to remember.

It would help if we knew how big the boiler is! What's it off - a Gauge 1 Mamod or a 15" gauge 4-6-2?

Assuming a standard model-engineering-type 3.1/2" or 5" gauge loco (or 1.1/2" or 2" scale traction engine) , 1/4" x 40 or 5/16" x 32 are likely sizes.

1/4" x 40 should easily open up too 9/32" x 40, which is a relatively common size.

5/16" x 32 (if there's enough material in the bush) could be re-tapped 3/8" x 32.. An expensive option would be 11/32" x 32 tap and die, which would be the least invasive option for a 5/16" thread, but it may take some searching to find them. (Amazon in the US has them, but neither Avon nor Tracy have them off the shelf.

Hope that helps.

Mark

John's suggestion to re-tap the bushes is probably your best bet. Don't forget that there are 9/32" x 40 taps available, and you can probably source others 1/32" larger than you have now; I don't know what size yours are.

I bought a 12" square off eBay a while ago, knowing that at that price new it was going to be a joke one. So I set to with my milling machine, then files and scrapers, and gradually got myself a perfectly acceptable tool.

Yer pays yer money...

I thought Roger Thornber had described a Gauge 1 14XX in EIM not long ago. Certainly there are several G1 designs which would be a good starting point without spending too much. If you make a decent job of it, at least it can sit on the mantelpiece when you're not running it! You'd certainly learn about the more "fiddly" aspects of modelling.

Good luck whatever you decide to build.

I did one by planing it in the lathe, using a square tool wide enough to create the flats, and gradually moving the cross-slide out until I'd got a full flat. Indexing the job round 60 degrees isn't hard if it's in a 3-jaw chuck. Yes, it was tedious but it ended up OK. Bopping a suitably-sharpened hexagon down a slightly undersized planed hexagon hole might be a better way of ensuring consistency. Don't take too much out, or if you do or it'll look bad when it bursts out. Countersinking the hole beforehand would help.

I fitted a Transwave inverter drive to my Myford Super 7. A birthday present from my wife! I had to make a new pulley for the motor as I got the much cheaper Metric one. (Boring out the original Myford one for a 19mm shaft would have been a bit dodgy). I upped the size of the pulleys by about 3mm or so. I finished that earlier in the week, and I hacked it out of a 6" x 6" x 1.1/2" chunk of aluminium. Lots of swarf!

It all went very smoothly; just had to chew a lump out of some nearby shelving to accommodate the motor terminal box.

"Terminal Box", said my wife. "Isn't that a coffin?" Which I thought was a pretty clever remark!

So now I have to get used to the new control arrangements and make something on it.

According to the lathes.co.uk site,

"The spindle was bored through to clear 26 mm, fitted with a 4 Morse nose and came with a choice of a B.S.4442-A3 or (at extra cost) a D1-3" camlock nose as commonly used on small industrial lathes. Both fittings allowed accessories to be mounted close to the front bearing with the minimum of overhand and, while the B.S. nose required chucks and backplates with 3 inconvenient studs and nuts to fasten them in place, at least it uses the same tapered spigot as the more convenient D1 fitting and so allows accessories to be made or adapted with comparative ease should factory parts ever dry up. "

Clive

I'm doing exactly this but with a 9F. LBSC's design for the 9F is pretty lacking both in detail and in adherence to prototype (e.g. his horns are inside the frames as per his usual arrangement - but the real 9Fs had the horns outside). I started building it to the LBSC design (a long time ago!) but when Les Warnett's 5"G version came out I scrapped the frames I had cut out and made new ones. I then started to scale everything down from Les' design, but using the LBSC design castings.

The LBSC Britannia design is better than his 9F for fidelity to prototype, but still lacking.

So if it's accuracy to prototype you want, use the 5"G drawings and scale it down.

You will need to take great care when laying out your valve gear and motion. Clearances are tight, and plate thicknesses, wheel standards and everything else all conspire to make everything hit everything else! If you have access to 3D CAD, I'd use that before cutting metal to check clearances and alignments.

Yes, just use it. As folk have said, it'll go in time and with use.

(But if it really bothers you, simply get a really big chisel and a lump hammer and cut them out. Smooth off with an angle grinder.)

Yes, excellent bit of "bodgy engineering", John!

Good to point out the advantages of brazed tooling over inserted-carbide when doing heavy or interrupted work.

Back in the 1950's, Michael Oxley, writing in ME in one of his brilliant pieces of Christmas Fun, wrote that one of the beauties of tipped tools was that would completely remove two or three sets of chuck jaws before they even needed touching up...

We have a lot of bits done at work by Wallwork in Bolton. We use the Tufftride AB1 process, which come out a lovely black colour - rather like the firehole door and other bits on my Edward Thomas... It is possible to have silver-soldered assemblies done, but the process is rather close to the melting point of Easyflo 2; however I've had no problems other than having to paint the silver solder black to match the rest of it!

It adds little or no size to the part. You need to have bits you want as running surfaces smooth before processing, otherwise smoothing it off later is a) difficult and b) wears away the very thin surface hardening.

Much of our stuff is just plain mild steel - 220M07 (En1A) or 070M20 (En3B).

A very useful aspect of the process is its excellent corrosion resistance - better than zinc plating.

It's not terrible expensive, but it's usually done by weight with a minimum order charge, so if you're doing watch bits they'll work out expensive.

(edittid foar spelin)

Edited By Nigel Bennett on 14/05/2014 13:10:20

It is a strong spring, but it's perfectly feasible to compress it again to re-assemble it. It's important that (as you say) you screw the pushrod IN and not out to dismantle it. I have dismantled mine a couple of times when I've changed the bearings in the clutch - it made a racket when disengaged.

You need to have the push-rod and ball bearing assembled in place on the clutch operating shaft, press hard down on the driving plate and whilst it's pushed in, insert a smallish screwdriver (biggest you can get into the hole!), and rotate the push rod anti-clockwise to screw it into the drive plate. Make sure you engage at least a couple of threads before you stop pushing. A smear of grease on the threads beforehand may help.

If you aren't strongish in the hands or suffer from arthritis or something, you may need to scheme out some kind of tool to compress the spring to re-assemble. I believe Myford of Nottingham had such a device, but I've no idea what it looks like. I guess it may have been some sort of device which fitted to the right hand end of the clutch assembly, presumably with the clutch operating arm removed.

Get a 5/32" ball before you start, and then when the original one pings off and disappears, you can fit the spare.

Thanks, chaps, for the very valuable and thoughtful advice. It is much appreciated. I think I'll probably stick with the VFD-driven 4 pole motor, then.

Your wizzo motor mods look very impressive, John!

Nigel

I am thinking seriously about upgrading my Super 7 to inverter drive. It would be rather useful to increase the top speed of the lathe, and speaking to the nice man on the Transwave stand at Harrogate yesterday, he said that the only sensible way to do that was to fit a 2800rpm 3-phase motor and control the speed of that. He explained that although you see inverters showing 200Hz, it is usually physically impossible to run a motor at much more than 120% of its rated speed.

A 2800rpm motor would mean a lathe top speed of 4000rpm or so - useful for drilling weeny holes and turning weeny diameters. Running the motor at 25Hz would give me the same lowest speed as now.

I suppose one worrying thing is running large diameter chucks at 4000rpm - bursting one would be -erm- interesting. Hence I'd only use it for collet work at that speed.

So has anybody out there tried this? If so, are there any drawbacks like increased noise? Will a 2-pole 3-phase inverter-driven motor run "lumpier" than a 4-pole 1400rpm one and thereby negate some of the advantages over 1-phase?