Member postings for SillyOldDuffer

I stripped the headstock gears in my mini-lathe. This is not a good way to start the bank holiday.

Lesson learned: use a steady when the work needs one. And don't assume that a border-line case will be OK just because the steady is awkwardly stored behind an inconvenient heap of plywood.

The 38mm diameter rod I was turning wasn't securely held in the chuck. It twisted out during a cut and jammed itself neatly between the jaws and the toolpost. The lathe stopped dead with a horrid crunch from inside the headstock. Dismantling revealed ten loose teeth and two mangled gear wheels. Also the drive belt has a small tear in it.

The good news is that:

• replacements are cheap and available.
• this is the first serious problem I've had with the lathe in 6 years.
• there was no sand or other nastiness inside the headstock casting, just grease.
• I now know how to get inside the headstock.

Taking the headstock apart was fairly brutal. I hope I can reassemble it without damaging anything!

Thanks guys - more useful info.

I have had the engine running today using air from a car foot pump plus a 2L lemonade bottle as a reservoir. I hope the exercise is doing me good because it was hard work!

Neil was right about 'mindlessly spinning' the engine to loosen it up and also about checking the valve timing.

I'm pretty certain the bad joint was caused by poor technique. I was holding the blowlamp in my left hand and applying solder with my right. This meant that rear-right corner of the joint were the solder didn't take was "in the shade" and - as suggested - it's likely that it wasn't hot enough. Lesson learned: make sure all the parts and all parts of the parts are hot enough. Now I need more practice using all the advice offered!

Cheers,

Dave

Hoorah, it's fixed!

I used electrical solder to fill the gap and then ran a fillet over the existing brazing so that the whole joint is colour coordinated. Now my guilty secret is hidden forever.

The hardest part was cleaning up the cylinder afterwards.

The engine very nearly runs. I think it would go if the valve piston was a slightly better fit and/or my electric tyre inflator had more puff. Guess what I'll be doing tomorrow.

Thanks again,

Dave

Very many thanks to everyone! Excellent responses.

As a picture is worth a 1000 words here is a snap of the best side of the engine. It is 100mm long and needs more tidying up apart from the duff joint.

Next a close-up of the bad joint which is on the other side of the cylinder. The scale is given away by the out-of-focus M2 screwheads.

As it came from the hearth the fillet ended in an unsightly blob that I ground off with a Dremel. That's what skidded over the brass leaving the odd circular marks.

pgk spotted that my original post is ambiguous about the size of the gap; it's about 5mm long not 5mm wide. The overall joint seems to be mechanically sound but I'm suspicious about what lies beneath especially under the cylinder flange.

As it's unlikely that the engine will ever taste live steam I'm going to try soft soldering as per Neil and IDP. Michael's Locktite suggestion is very tempting but I don't have any 290 to hand and can't go shopping until Tuesday. Wensleydale will on my list.

Having read all your advice I'm much more confident about what to do next!

Special thanks to IanT who for answering the questions I should have asked for before melting expensive metal! My next go at silver-soldering will pay close attention to his words.

I tried to get EasyFlo but it seems to be Unobtainium because of the Cadmium content.

Julian's kind offer is very much appreciated. I'm trying to build skills but will be in touch if all else fails.

I shall report progress later.

Now I have a really big problem. Foolishly expecting adulation I made the mistake of showing the engine to my family today. Someone should have warned me of the need for slick, convincing answers to: "what's it for?" "does it work?" "how long did that take?" and worst of all "how much did it cost?" It seems that not everyone appreciates model engineering...

Best regards,

Dave

Hi all,

I've nearly finished Mogen Kilde's Miniature Side Lever Steam Engine (ME 11 Jan 2011). It is my first model engine and I've got a problem. The work also included my first attempt at silver soldering because I used Silverflow 55 to attach the brass steam chest to the mild steel cylinder.

The joint is OK except for a 5mm gap at top right where the solder failed to flow into that part of the joint. Trying to run the engine on air reveals that the piston operates only on the downtroke and that my dodgy joint leaks on what should be the upstroke.

What's the best way of fixing a mildly botched silver solder joint please? I can't find anything on fixing brazing mistakes in my books. Should I simply reheat the cylinder and apply more silver solder to the gap or am I in big trouble? (I've done electronics where remelting old solder isn't a good idea - it's often better to remake with fresh solder.)

Despite the setback I have to say that this is a fantastic hobby!

Thanks,

Dave

Neil's Vibroplex post is scary-spooky because I only decided this afternoon to make a bug key as my next project! I shall have to scale the dimensions from a photo because I don't have plans or a real bug to copy. Now Neil has provided just the picture I need. That's what I call service! The man must be a mind reader...

I'm looking forward to reading Askild's article because I now think he's on to something! This is because there looks to be strong evidence that at both Shepard and Turpin thought that EN=England. And these guys were far from being ignorant bystanders: Turpin worked for RSAF Enfield and Major Shepard was recalled to the colours after retiring from Woolwich Arsenal to work for BSA.

I initially preferred the idea that EN=Enfield because this is consistent with BREN, ADEN and TADEN. But this may be a red-herring because of these acronyms only BREN predates STEN. Is it possible that on first introduction in 1937 that the EN in BREN also stood for England? I'm beginning to think officialdom started their nomenclature with EN meaning England and then changed to EN=Enfield a few years later.

None of the early references to the BREN gun I've found explain how the BREN was named: they just call it the Bren Gun. Askild has made a strong case using Model Engineering Magazine that EN probably meant England when the STEN was first introduced. Can anyone undermine his case by proving that the EN in BREN definitely meant Enfield before 1941?

Perhaps we will never know because the origin of the acronym seems to have been thoroughly muddled by the mists of time.

**LINK** quotes evidence given to the Board of the Royal Commission Awards to Inventors. Lord Cohen: "Why was it called the Sten?" Colonel Shepard: "It was called the Sten by the then Director General of Artillery. The S was from my name, the T from Mr. Turpin who was my draughtsman and who did a very large amount of the design and the EN was for England. That is the origin of the name, for which I accept no responsibility."

But In the official history of the Royal Ordnance Factories, ST is for Shepard and Turpin and EN is for Enfield.

Note that the acronym was coined by the Director General of Artillery, not by Shepard or Turpin. The DG might well have said "England" by mistake. It won't have been the last time a senior bod was later corrected by his officials! My money is on EN=Enfield because this is consistent with British naming policy at the time. May I have a Nerd badge please?