Member postings for Lawrie Bradly

Hi Brian, While I was messing about taking photos of the drawings, Jason has much more elegantly provided the same message the photos were meant to convey. Like you, I couldn't work out the travel of the valve until a bloke at the local steam railway club suggested I photocopy the drawing of the valve and make a cardboard copy of it, to superimpose on the drawing of the steam chest. I thought it was a very clever Idea. It cleared up the mystery for me.

Model making certainly can be a pain in the backside, can't it.

JasonB's advice that the cover face against the steam chest may not be at right angles to the hole seems to me to be worth pursuing. To add though to the possibilities, the valve gear that I'm making works more smoothly in one position (180 degrees) opposed to another. I haven't got to the point yet of trying to make anything work, but I think to fix my problem I might have to allow a little more clearance (maybe a thou or two more) between the valve and the hole it runs in. Maybe your valve needs a smidgen more clearance too?

Unrelated, I actually can't agree with Jason that it would be a good idea to retain the flywheel's 82mm diameter. The piece of 5mm aluminium packing is never going to look elegant. The specs say 80mm, so why not go with them? The YouTube video of the prototype shows it running very smoothly indeed.

Yeah Brian, Before reading the edit to your post just now I checked the dimensions of my engine. The small wood block is 17.7mm thick. I had machined the flywheel to exactly 80mm and the clearance between it and the wood base, measured with a feeler gauge is 20 thou (0.5mm). Pretty tight.

I can't wait to hear how it works!

But, from my experience in making and restoring various machines, can I say that if it doesn't work first up, a bit of perseverance won't go astray.

Best of luck.

Hi Brian, I am very impressed with your soldering of the crankshaft and cylinder. I am yet to build up the courage to tackle mine. I do intend to link the twin cylinders with a common inlet steam pipe. I've also bought some displacement lubricators on eBay and will use one on the single and one on the twin engine. The lot I bought (buy it now) had 3 for about $140 (So I've got a spare for the next project.) Two types of lubricator were advertised by the same seller in China with different prices for lots of 2 and 3. I bought the more elaborate type and buying the 3 was better value. I got a similar one locally years ago and fitted it to a rotary valve engine that I had also got the plans for on eBay. The lubricator works okay, not brilliantly, but I think it's better than nothing.

Hi Brian, I bought a second-hand, big copper 'vintage' soldering iron on eBay a while ago. I had look just now again on eBay and there are a few for sale. If you search for EVRO SOLDERING IRON you should turn up one like the one I got. I think it's about $35 plus $8.50 postage. I didn't have a proper look and there may be better ones.

Roy, A single crankshaft would mean incorporating it with the flywheel. I thought about it, but then decided, in the interest of being able for maintenance etc., to pull it all apart, I didn't want to do it. Regards, Lawrie.

I'm beginning to doubt whether I'm going to get these bloody crankshafts to line up! I'm just going to have forge ahead and see how it goes. I'm not all that confident.

Hi Brian, The crankshafts aren't finished yet. I plan to screw them together with M2 x 5mm stainless steel grub screws. i drilled the holes 5.8mm and reamed them 6mm, holding them in alignment as I did it with short bits of silver street. It remains to be seen if I can retain the alignment in the process of drilling and tapping the holes for the grub screws (that I intend continuing a short distance into the silver steel rods) I'll let you know how I go. I may have to revert to solder, as specified in the Bends plans, but that looks like a fraught process to me.

I thought people might be interested in photos of the bits for the single and twin cylinder versions of the engine, I have made so far. I had a bit of trouble getting the photos up, so I hope it works.

Jason, Thank you. Sounds like good advice. I have been thinking that timing the engine within its inaccuracies will be what it will be all about in the process of getting it spinning. I think I'll just forge ahead. Regards, Lawrie.

A question to anyone. The other thing I'm worried about is that initially drilling the steam chests I just used a ruler to mark the holes. That was before I figured out that using the graduated wheels on my Optimum mill/drill gave greater accuracy. As it stands then, some of the holes I initially drilled (now measured with a digital vernier caliper) are around 0.2mm to 0.3mm out of position - in relation to the valve slide or piston. My question to everyone is, how critical are these measurements - what tolerances should I allow. Should I remake the steam chests before I go anywhere near soldering anything to the cylinder? Regards, Lawrie.

Hi Brian, I'm yet to mill the three cylinders I'm working on (one for the single cylinder Bengs kit and two for the twin cylinder scratch-built version), but I too have been thinking about the posssibility of the inlet holes being blocked by solder and the need to adequately line up the holes. I too was thinking about using stainless steel pins to locate the steam chest against the inlets, but it might be a big ask to get the holes on the steam chest and the cylinder to line up absolutely exactly to fit metal pins. I am thinking that using matches might give a bit of leeway, even if it does start a nice wood fire when soldering, it might be possible to just blow out the ashes. I am still weighing up the options. Regards, Lawrie.

I think the expression I might be looking for is "pulling it into a taper"!

Hi Brian, I reckon I would try to grip the ends of the cylinder with not quite parallel brass jaws - so the outside of the jaw grips (with a bit of clearance) towards the slide. Sort of clamping the work piece against the slide. It would involve making a shallow angle (a couple of degrees) chamfer on the brass jaws. But then, what would I know. My only qualifications are in economics!

Brian, Success at last. How anyone at Bengs could suggest that 'the flat' could be achieved with a file is beyond me. (Though apparently apprentices at Rolls Royce in the early 20th century had to be able to file a one inch square on a round shaft, to earn their papers.) Anyway, with the vertical slide, for you and the Danni engine hopefully it'll be all plain sailing from here on in!

In the meantime I've been trying to post a photo of my progress making a scratch-built twin cylinder version of the Danni, alongside the single cylinder kit - which still has a long way to go - but I can't access my photo album when I try to post it to the forum. I might have to ask my son how to do it.

Hi Brian, Yeah I reckon a 12mm cutter is what I'll use. My approach is to take cuts of only about 0.5mm to 1.0mm deep at a time - nice and slow. That way you don't get a lot of stress and vibration - and for me 'time isn't of the essence.' Regards, Lawrie

Hi Brian, I stumbled across this stream of consciousness a couple of months ago. I was then and still am in the process of building a Danni engine and was very interested to hear about your progress and problems. It all sounded very familiar. I'm lucky to have a (small) Optimum OPTI BF16V mill, which is brilliant. Having bought the mill after I bought the pre-milled Danni kit, I thought I might have a go making a twin cylinder version, milling my own frame, etc. So that's what I'm doing, making the single and twin alongside each other. In the next week or two I plan to mill the flats on the cylinders and expect to use either a 12mm or 20mm cuttter. I also am untrained in milling, but I figure a larger diameter cutter will give a smoother finish than (say) a 6mm one. By the way, I had thought, from the absence of your posts for many months, that you might have given up on the project. I'm so glad to see you're still at it - such is the resilience of the human spirit. Regards, Lawrie