Casting defect in cylinder wall

If you reduce the bore by fitting a sleeve then yes the rings will need replacing, if you make the liner to a standard size eg 1.375" bore then you would have the choice of either making your own which is not hard or buying them off the shelf from the likes of Reeves or Stuarts

If you were to skim a bit more out of the existing bore and take it upto 1.675" then you could make your liner bore to the original 1.5". However like I said on another forum this will depend on how close you can get without drastically cutting into the steam passages or getting close to the cylinder cover stud holes.

J

Machinery's Handbook is great, but it's a refernce manual, not a how to guide.

I recommend Peter Wrights Model Engineering a Foundation Course.

Neil

What success have people had with machining these expoxy resins?

Dave

I've not actually machined the JB Weld but have machined parts that are bonded together with it. For example the valve chest on this engine is bonded to the cylinder with the stuff and I was able to use a 40mm indexable endmill to machine the valve face with a fair depth of cut and it held up.

I mostly use it to create fillets when fabricating "cast" parts and from whats required to blend it out I should think what they say about being able to machine it is true.

J

Hello Sarah,

Yes, my compound engine will have cast iron piston rings, I will make them myself to fit the new bore sizes,

Piston rings are not too difficult to make, and are a very satisfying little project .

Stub, I did state in my previous reply that "Machinerys Handbook" is a reference book,

Sarah was asking about interference fits, "Machinerys Handbook" has got all the information on shrink fits, press fits, running fits and every other kind of "fit" that she will ever need.

Richard.

Hi Richard and Neil,

Thank you both for the book recommendations, I'll have a look out for both of those. I have a couple of projects where I need to make some plugs with interference fits and I do need to do some research before I do this. I also want to find out dimensionally what is a good fit for crankshafts into brass bearing blocks. The No.4 engine does have too much play between round the bearing blocks and it would be nice to make the new bearing blocks to a specific size rather than just machine a bit then check, machine a bit then check etc.

I am learning a lot with the steam engines, but still a lot more go

Many thanks for your help again,

Sarah

Sarah

You say you don't know if the engine has ever run. If it has then the imperfection in the bore is probably contaminated by oil, if this is the case it will be almost impossible to clean the hole of oil in order to get the JB weld to adhere, as I suspect the cylinder is cast iron. In which case I would opt for the sleeve route.

Edited By Dusty on 20/10/2012 21:49:41

Not all Stuart has 2 rings in one ring groove. I has Stuart compound steam engine, it has 1 ring in each ring groove, also 2 ring for each piston. And other to example no rings in piston in Stuart D10, it has bronze piston in cast iron cylinder. Some time can it be O-ring in bronze piston for reduced leakage (improved by model-engineer/hobby mechanic in case the piston is sloppy in cylinder).

Sarah, the compound steam engine has cast iron rings, 2 rings for each pistons. Height of ring groove is 1/16".

Hi Jens,

Sorry if I misled you and others by saying 'common Stuart practice'. That was a sloppy description, I should have said that Stuart designs often use two rings in one groove and it is common practice across several of their designs. I made both my 10H and 10V without rings. Just goes to show how easy it is to confuse by poor use of language and how difficult it is to clarify precisely what is intended. That is why we use drawings rather than text to describe components.

best regards

Terry

Terry, Iwas going to use PTFE tape instead of rings, but as I had the cast iron, I though I would at least try Iron rings, I'll use the PTFE for the glands. Ian S C