Member postings for stephen goodbody

Hi there, and glad that you enjoyed the Elephants series.

Two things to consider if you're looking for a second hand lathe are: (a) what items does it come with? and (b) can I still obtain suitable extras from other sources if I might need them?

In my view, as a bare minimum you'll need a three jaw chuck with both inside and outside jaws (for round things) and ideally a four jaw chuck for turning non-round items. You'll also need a tool holder and a few basic tools (high speed steel (HSS) would be my preference for starting out), and ideally a drill chuck for the tailstock too. Others may disagree, but to me that would be the absolute bare minimum; everything included beyond that is a bonus.

Beyond the lathe itself, don't forget you'll also need a bench grinder to keep your tools sharp, and its grinding wheels must be appropriate for the type of tools you have. Notably, tungsten carbide tools are harder than HSS tools and can't be sharpened on the type of wheel that likely comes with an off-the-shelf bench grinder, so you'll likely need to buy an additional grinding wheel to fit to one end of the grinder if you have carbide tools.

As you know, I was fortunate to acquire a great deal of tooling with the lathe itself, which has enabled me to do everything covered in the articles and more besides. Much of that tooling would have been likely impossible to obtain after-the-fact, given the age of the lathe, and were the lathe younger and the tooling still available then those tools and attachments would likely have cost many hundreds of pounds more and would not have been immediately to hand when I needed them.

Best of luck with your search, and I'm immensely pleased that the article has inspired you to have a go!

Cheers

Steve

Welcome aboard, Jack

For those unaware, Mr. Bodenmann is, without doubt, the premier model engineer in the USA. His models are, frankly, jaw-dropping in their quality and detail, and we are all in awe of his skills and grateful for his willingness to record and share his methods with us mere mortals over the web.

Be prepared to be impressed!

Hi all,

Here are a couple of pictures of the first of the three L&B-based wagons taken last weekend. While not yet fully complete or painted, I wanted to get the loco to the track for its first run before the season ended and this wagon was sufficiently ready for the job.

The wagons are not exact replicas of any particular L&B wagon, and I'm making compromises to allow them to be practical for my purposes, but hopefully I'm capturing the spirit of the L&B at least. The couplings work as the prototypes and interchangeably connect, at least on the workbench!

The book by Messrs. Phillips and Bishop has been very helpful, and Mr. Phillips confirmed that the handbrakes were of the ratchet type. You'll see my attempt to recreate the working handbrake in the first picture.

Best regards

Steve

After a year in the making, the first of the three Lynton and Barnstaple-based bogie wagons is finally complete to the point where I could take the loco to the track last Saturday to try everything out.

This was not an unqualified success, the loco foamed and primed badly when under load, so the boiler needs a few more steamings and blowdowns before I will take it to the track again.

In retrospect however the day had more successes than failures and so I'm looking forward to next spring to have another go.

The rolling chassis' for the remaining two wagons are also complete, so I'm aiming to build their bodies this winter and then get everything painted and ready for next year's season.

Wish me luck!

Steve

Edited By stephen goodbody on 01/10/2021 23:02:12

Many thanks Bill, that's much appreciated.

Nigel - a definite mea culpa on my part. My brain knows it's Barnstaple, my mouth calls it Barnstable, and my typing finger flip-flops randomly between the two!

Best regards

Steve

Many thank Bill, I was unaware that such a book existed and have now ordered a copy as it sounds like an excellent resource. A shame I didn't know about it earlier as it would probably have saved me some research time and puzzlement.

The book will probably highlight the things I've already deduced and built wrongly as the three chassis', their running-gear and the couplings are already built and I've nearly finished the first body in addition. Fortunately I'm not building exact-scale replicas and so will simply call my errors "artistic license" and move on from there!

Best regards
Steve

Hi there,

I am building some open bogie goods wagons in 3-inch scale (7 ¼” narrow gauge) based on the 1897 Bristol Carriage and Wagon Works prototypes delivered to the Lynton and Barnstable Railway. My reference source is predominantly the period-photographs and historical information available on the internet.

Unfortunately, despite much searching and peering with a magnifying glass, I have been unable to determine the following two details. Is there someone out there who can help me fill in the gaps please?

1. How were the bottom of the doors (gates) secured in the closed position? I can see the catch which closes across the top of the doors and ties them together, but have been unable to find any information as to how the bottoms were secured from opening.
2. Were the handbrake handles of the ratchet type (whereby the handle slots into a toothed rack) or of the pin-and- holes style?

Many thanks in advance,

Steve

Hi Bob,

I applaud your willingness to attempt injector construction which is certainly an interesting exercise. That said, I would hate you to become disillusioned if/when that injector doesn't work.

Unfortunately, as Stewart suggests, I'm not sure that you will achieve success with LBSC's injector designs no matter how careful you are in their manufacture. While LBSC was undoubtedly a gifted author and prolific and talented builder, I believe his level of knowledge and understanding of injector design wasn't quite up to the job.

While I am sure that there is someone out there who has succeeded in getting an LBSC injector to work reliably, I have never yet met one of those people. Perhaps one of them will respond to this thread! Conversely, I know of many, many folks that gave up in frustration, including one of my early mentors - another Bob - who was an excellent machinist. I still have a small drawer full of Bob's discarded LBSC injector bodies and cones.

As a practical alternative, I can heartily recommend DAG Brown's book "Miniature Injectors Inside and Out". I've made three injectors to Mr. Brown's designs and they all worked first time - much to my own surprise. If you're interested and willing to put in the effort to make your own injector then I think you will stand a far better chance of success if you follow this route.

Best regards,

Steve

Andy,

The 47xx was another GWR 2-8-0, although intended for fast-freight working rather than the hard slog of the 28xx (Swindon). Upon review, the prototype 47xx had significantly larger diameter wheels than the 28xx but I believe a similar cylinder stroke. Hence the crankpin throw will presumably be similar, but I suspect the wheel diameter will present a problem.

I must say that I'm on the same page as many of the other respondents - if your friend's problem is worn treads and/or worn or damaged flanges, and the rest of the wheels and the overall axle assemblies are in good shape, then I would go for the shrink-fit steel tyre solution. In addition to being the most straightforward option from a machining perspective, it would also prevent the need to remove the wheels from the axles, and get the new wheels accurately quartered, and then re-set the eccentrics to suit the new quartering position. It would also presumably be cheaper than buying new wheel castings!

Best regards
Steve

Edited By stephen goodbody on 07/05/2021 14:45:46

Hi Andy

I’m not sure whether the wheel dimensions are the same for the two designs, but I believe that GLR Kennions sells wheel castings for the 5” gauge Keith Wilson 4700 loco. It might be worth contacting them with the question.

Best regards

Steve

Hi Nigel,

Sorry to hear about your fall, and hope that you're soon back on your feet in the workshop.

If it helps, here's a sketch of how I made the sectional liner:

It seems to me that, if your choke section is short and opens immediately into a much larger diameter chimney, you run the risk that, when the engine is working harder and the exhaust jet sharpens (ie, the jet's cone angle decreases), the exhaust jet may not fill the chimney. In that case the choke probably won't provide much benefit.

While it would be an interesting experiment, if I were you I'd plan things so that you can readily extend the liner at a later date.

Best regards
Steve

Hi Nigel,

You've got a really interesting project there! If it were me, and given your willingness for adaptations(!), I think I'd approach this as follows:

1. Keep the regulator at the boiler end, but take precautions to prevent water ingress. The safest bet is to have the steam takeoff as high above the water level as you possibly can. Estimate the effect of hills, camber, and water-sloshing on the headspace between the water level and the steam takeoff point. Perhaps add a steam dome if there appears to be a risk of water carry-over and if that's possible in your design.

2. Add at least one low-point drain to the superheater circuit to allow condensed water to be removed after a run. This could be a simple screwed plug, or a manual valve, or an automatic snifting valve held shut under steam pressure but open to atmosphere otherwise. If using a snifting valve, make sure it's accessible for removal and maintenance.

3. Thoroughly lag the steam pipes wherever they're outside of the boiler to prevent condensation before the superheater and loss of all that superheat after. Even if the pipes are under the boiler cleading, if the superheater did its job then the surrounding temperature will still be much less than the temperature of the steam within.

4. If possible, configure the setup to allow the superheater to be bypassed in the future. Assuming there is a shorter and more direct route from the regulator to the cylinders, it would be interesting to determine if the superheater provides any real benefit given the amount of external piping and complexity it involves. If the benefit is marginal, then you can choose to eliminate the superheater circuit and save some maintenance hassle in the future!

I hope the above is somewhat helpful Nigel, but won't be in any way offended should you disagree with or ignore some or all of it! I would certainly like to hear how things go however, so please keep us posted.

Best regards

Steve

Edited By stephen goodbody on 01/04/2021 15:04:39

Hi Nigel,

Thanks for providing the background information on your wagon, that sounds like a fascinating project.

I'm not at all familiar with E.S Hindley and Son, but a quick search on the internet has given me some information on the company and a picture of the Light Steam Delivery Van. I certainly like the look of those patent wheels!

As an aside, and although you've probably already thought of this, there's an argument to say that, when a long superheater circuit is used, the regulator may be better placed at the hot-header end rather than the boiler end. The reasoning is that, should a slug of water get past the regulator, it will flash to steam in the superheater which may over-speed the engine. Shutting the regulator won't help as the engine will continue to run until the flashed-steam has been expended.

Conversely, the arguments against having the regulator on the hot-header side are: (a) the superheater is always at boiler pressure, decreasing its life and increasing the chances of a leak, and, (b) the regulator has to be designed to withstand a higher operating temperature than otherwise, and (c) if water was carried over, and the regulator shut, and steam prevented from escaping through the cylinders perhaps by putting the engine in mid-gear, then the unrelieved pressure trapped in the superheaters will potentially become great and may cause them to rupture. The latter concern could be resolved by installing a safety valve for the superheaters, however.

I'm not sure which side of the argument I would come down on and, as you know, most superheated railway locomotives have the regulator at the boiler-end of the superheater. Additionally, the consequences of water carryover for a model are likely less than for the full-size, and so I'm not sure that arguments based on the full-size risks would necessarily be relevant for our models in this regard. It would however be possible to do some rough calculations to estimate the volume of steam generated by a given volume of water carry-over and see if this presented a potential risk.

That said, provided the water level is properly maintained in the boiler, the risk of priming (water carry-over) is perhaps generally less for a railway locomotive than for a traction engine or wagon because the locomotive isn't subject to the bumps and jolts and quick grade-changes that is the case for a traction engine travelling along a field or road. However, when priming happens and water gets carried into the superheater the results can be extremely dramatic, as I believe was unfortunately witnessed with LNER A2 "Blue Peter" a decade or so ago.

None of the above is intended to imply a problem with your arrangement or be otherwise melodramatic, however it may be worth a look if you're still at the stage where adaptations are feasible.

Best regards

Steve

Edited By stephen goodbody on 30/03/2021 17:12:17

Glad to hear Nigel, and please keep us posted on how things work out.

I suspect that you may need to extend the liner further up the chimney from the choke, but it would also be an interesting experiment to firstly try it without and see what happens. That's an experiment I may do with the Allchin one day, when time allows, having made the liner as a stack of interlocking sections, each approximately 4 inches long, which, together with the choke, are held in place by gravity, some centering rings, and the chimney's taper. By removing the chimney from the engine and turning it upside down, out come the liner sections one-by-one followed eventually by the choke. Hence, I can reduce the length of the liner in increments of about 4 inches at a time – it would be interesting to see what effect that has on the smokebox vacuum and draught when the engine’s working hard.

As a further thought, one other feature you may want to consider is regarding the blower. My Allchin's original blower was little more than a single 3/32" diameter nozzle centered within the blast pipe and therefore jetting centrally up the chimney. This made a lot of noise but produced very little draught and would not draw sufficient air through the fire to keep our local coal burning.

During the redraughting exercise I made up a four-jet blower using removable jets, each having a much smaller hole than before, probably around 1mm if memory serves, and mounted in a circle surrounding and centered on the blast nozzle. I based the jet dimensions and the mounting PCD on the principals advocated by Laurie Lawrence in the ME magazine, probably in the early1980's. The results, coupled with the overall redraughting exercise, were dramatic – the engine now has an almost-silent blower that draws the fire superbly.

I was so pleased with the Allchin’s blower that I recreated the same arrangement on my 3” scale Hunslet loco which has very similar draughting dimensions to the Allchin. Should you be interested, there’s a video on YouTube of the Hunslet’s first steaming and you can gauge the performance of the blower, and its effectiveness on our hard-to-burn coal, from around the 12’:20’’ mark onwards.

The video and some pictures of the smokebox arrangement are under the thread "Elidir – 3 inch scale Hunslet", should you be interested, or you can get to the video directly at: https://www.youtube.com/watch?v=5FbTqFqHD-M

Finally, it would also be good to know more about what you're building - a large-scale model of a compound overtype wagon sounds intriguing!

Best regards
Steve

Hi Nigel,

Hopefully you’ve now received the spreadsheet and find it of help.

In response to some of the foregoing, the advice given was based on personal experience of the results, in this case successfully re-draughting a single-cylinder 3” scale Allchin that steamed okay on Welsh Steam coal but simply would not burn our local coal.

Testing the unmodified engine’s as-designed draughting using an inclined U-tube manometer, there was little discernable vacuum in the well-sealed smokebox suggesting improved draughting would help. Doing some research, the engine’s front-end proportions were indeed significantly different to the rule-of-thumb ratios mentioned in my prior post.

Knowing that the firebox, boiler and tube dimensions were fundamentally capable of generating sufficient steam to meet cylinder demand, there were still two questions in my mind regarding the rule-of-thumb ratios:

1. Would they work for a single-cylinder traction engine? All the sources were for multi-cylindered locomotives.
2. Although clearly rule-of-thumb, were the ratios actually reasonable or was this a case of an oft-repeated fallacy becoming a falsely-perceived rule?

Repeating the manometer tests after modification, there was a significant increase in smokebox vacuum. Steaming the engine verified the result – the fire was now bright and the engine steamed happily on our more challenging coal. In summary the rule-of-thumb ratios solved the problem for me, and Nigel’s boiler and chimney dimensions sound similar to mine, hence I believe they will be of help for him.

In conclusion, while there is no doubt that Messrs Ell and Koopmans provide the gold-standard authority on the subject, Nigel was looking for a simpler answer and I believe the provided information will be of help. While perhaps not perfect, “good enough” is sometimes sufficient.

Best regards

Steve

Edited By stephen goodbody on 24/03/2021 13:49:07

Edited By stephen goodbody on 24/03/2021 13:50:19

Hi Nigel,

No problem, I’ll send you the spreadsheet when I’m at my computer tomorrow.

Regarding your post above, yes you should multiply the grate area by 0.005. A starting point of 3/8” diameter for the blast nozzle sounds about right to me, I apologize if my post wasn’t clear. Hopefully the spreadsheet will make the 1:3 and 1:6 blast exit cone distances and diameters clearer as well.

As an aside, I installed a liner inside the chimney of my Allchin in order to reduce the chimney’s internal diameter. That way the chimney looks externally correct but the drafting is much improved because, in addition to the other modifications, the blast always fills the chimney, even when the engine is working hard.

Best regards,

Steve

Hi Nigel,

In case this is of help, I've found the following guidelines to be reliable to get you in the right ballpark for a single-chimney design for burning coal. The ratios were distilled from proportions published in ME (and other sources) for railway locomotive designs over the years and where the credibility of the author was high and/or the results were plausibly verified. 

I modified the drafting on my 3" Allchin based on these ratios with good success, it will now make steam on local coal that wouldn't burn with the original front-end arrangement. it might be worth a pencil-and-paper exercise to see if you can get these proportions to work within your constraints.

- Blast nozzle diameter (in inches) = 0.005 x grate area (in square inches)
- Choke diameter (in inches) = 0.06 x grate area (in square inches)
- Height of petticoat choke = 1:3 cone (with the tip of the cone below the blast nozzle, such that the cone touches the inside diameter of the nozzle)
- Top of chimney = 1:6 cone (with the tip of the cone below the blast nozzle top as above)

I can send you a simple Excel spreadsheet that calculates the above based on your grate area, if that's of help. PM me if so.

Best regards

Steve

Edited By stephen goodbody on 22/03/2021 19:26:49

Many thanks for the research and additional info Dave.

Best regards

Steve

Many thanks Simon. I'm not sure about your first statement, but I definitely agree with the masochist part! However that's the challenge I set myself when I was 17 and I'm glad i saw it through.

As an update to those that may have watched the video, the niggles have been taken care of and everything's hopefully ready to run at a track next year. As suspected, a bit of boiler muck had somehow worked its way into the regulator during the pre-steaming washout and then become trapped between the disc and port-face when the regulator was first opened under steam, causing it to leak. Fortunately the seat hadn't been scored and the offending muck could be seen and removed without major disassembly. I took the opportunity to install a more powerful spring to hold the disc to the port-face when there's no boiler pressure and the regulator's now leak-free once again. Hopefully this will prevent any future recurrence of the problem.

Next step is to build a few wagons to go behind it. I'm aiming for one bogie wagon as a driving truck and two bogie vans for passenger transport, all being based on Lynton and Barnstable Railway prototypes which seem to scale nicely for the tasks in hand. Wish me luck!

Best regards

Steve

Thanks Paul,

I suspected that very few have been built - a couple of part-built examples have shown up at Station Road Steam over the years and there's a 3 1/2" Hall on Youtube in the guise of the Harry Potter loco which may or may not be to the LBSC design.

Now that the big Hunslet is finished I have been thinking about what to built next. 3 1/2 inch gauge has the appeaI of portability and is a size more suited to my workshop equipment. It has the added appeal that it's the only gauge common throughout the USA and the UK, making it a portable choice in all respects.

A chap in the US has a full set of Lifford Hall drawings and castings for sale that have lain under a bench since the late 60's. The apparent rarity of models built to this design is also appealing, so I am keen to understand if there's a specific reason for the lack of popularity other than the design wasn't serialized through Model Engineer magazine and hence may not have been well known.

Best regards

Steve