Author Topic: Twin Cylinder Steam Engine (Read 80546 times)

Darren · « **Reply #25 on:** April 09, 2009, 03:45:08 AM »

Eh?

How do either of those links indicate what you prefer to use

But you have answered it now. I've never found a use for metric fine, I just wondered if this may be it with such tiny & thin parts. Seems not.

bogstandard · « **Reply #26 on:** April 09, 2009, 04:45:37 AM »

Darren,

The links were to do with your comment

Quote

Bogs, I bin readin your book and you linked this place

http://www.jjjtrain.com/vms/library.html

Now that will keep me out of trouble for days, I'm trying to read your build but now I'm distracted....

Bogs

Darren · « **Reply #27 on:** April 09, 2009, 05:05:04 AM »

oops, too early for me, I don't come alive till the afternoon

Not sure why I hadn't spotted those links before, too distracted at the time I guess

Darren · « **Reply #28 on:** April 09, 2009, 05:52:19 PM »

And with that I did wake up somewhat later and moved on a little with the engine build.

I have decided to go with Johns plans so everything from now on is to those dimensions unless otherwise stated.
I won't repeat the how to's etc, just snippets here and there.

For no other reason than I simply wanted to try a bit of micro boring I decided to make a very small boring bar. I could have just drilled this part.
I picked up a good handful of different routing bits from the market recently for 20p each, all tungsten tipped. For the boring bar I had a choice of two designs.

I chose the one on the left, they were both 1/4" and I needed about 4mm or so. So off to the grinder we go..
A little while later

Now for a holder, the shank was 1/4" and my holder was 10mm. A small alloy tube was drilled out to 6mm as I wanted a tight fit.

Tube was cut down its length with a slitting saw

Pressed together in a vice

Job done and ready for action

Darren · « **Reply #29 on:** April 09, 2009, 06:01:53 PM »

Now to see if it works

Yep, worked a treat and I did all four pieces to an exact fitting to a length of 5mm Silver Steel.
Oh yes, forgot to mention the Silver steel rods turned up this morning...

Next I made a jig as John suggested in his write up. This worked really well. Thanks John, that really did save some headache...

I did mark out the piece where it needed to be drilled. Then I figured out the miller could have dine this a lot easier...

I've never used the graduations on the miller before, yes I know tell me about it....

But this job gave me a chance to work out the grads and if they were accurate. I'm pleased to say they are spot on and no doubt more accurate than my marking out

Next the 2mm hole, well I made it 3mm and countersunk both sides...just for fun...

Wahey, they fit

Darren · « **Reply #30 on:** April 09, 2009, 06:06:13 PM »

Now for the bit that was getting me nervous......

The milling......

One side

Then the other, ok I know they look the same but they arn't....

And this is the result

A little flattening back, I'll leave the final cleaning up till they ae finished

I have to say I feel quite please with myself

Twinsquirrel · « **Reply #31 on:** April 09, 2009, 06:08:55 PM »

Quote

I have to say I feel quite please with myself

So you should be, great piece of work, love the idea of using router bits!

David H

bogstandard · « **Reply #32 on:** April 09, 2009, 07:47:14 PM »

So my little tips work then Darren?

If you can finish that engine, you should find that small parts (engineering bits that is) hold no terror any more, and you will be able to look at a lot of other jobs, and transfer the info you learn across to them.

I made two of these engines in parallel, in just over two months, designing and making as I went along.

Can you make one in less by following the book?

Bogs

Bernd · « **Reply #33 on:** April 09, 2009, 07:54:08 PM »

Darren,

You look at you go, nice bit of work there

I really like that idea of using a router bit.

Bernd

Darren · « **Reply #34 on:** April 09, 2009, 08:01:41 PM »

John that little fixture was so simple to make it's almost unbelievable how important it is.....

One of the reasons for tackling such a complicated build, (to me) is to learn. I find I do that every time I switch the machines on

I've no idea how long it will take to finish, I'm still not sure what I've let myself in for here

I thought the crank webs looked complicated and ultra accuracy needed, that's why I did them first. If I couldn't make them then I would know I wasn't ready for such a project.
As it turns out, they were not difficult at all by following your logs.

What would I do differently next time....erm....don't use SS, it's just a pig to part, drill and tap. Lathing and milling it is great and leaves a superb finish from the off. But the rest is not much fun.

I'm not looking forward to drilling and tapping the clamp, I might no tap it at all yet. We shall see. If I have any foul-ups I will buy some brass and start again.

I was pleased with the milling this time around, that came out quite nicely.....

sbwhart · « **Reply #35 on:** April 10, 2009, 01:12:44 AM »

Well done Darren Nice Job and right up

Stew

Stilldrillin · « **Reply #36 on:** April 10, 2009, 01:59:31 AM »

Very nicely done Darren!

I`m enjoying this project.

David D

Darren · « **Reply #37 on:** April 10, 2009, 04:17:49 AM »

Thanks both Davids, Bernd and Stew,

Just like to say the feedback is very encouraging

I'm enjoying this project so far, it's amaizing how much you learn just making such a small part

ozzie46 · « **Reply #38 on:** April 10, 2009, 06:59:10 AM »

I'm in the process of gathering material for this engine as well. I will be trying to make it on my 7 x 12 lathe and drill/mill. So I will be following your thread with great interest and anticipation.

Great start by the way.

Ron

bogstandard · « **Reply #39 on:** April 10, 2009, 08:00:18 AM »

Ron,

Your lathe and mill will be able to do all the jobs no problem.

If you are only ever going to run it as a display model on air, you can use almost any materials to make it. I designed it to be run on steam, so cast iron was used for the cylinders and stainless for the rods. You could just as easily use ali for the cylinder and valve blocks, even the bits Darren has just made out of stainless, brass for the pistons and silver steel (drill rod) for the rods. Plus normal steel fasteners. You will need to use the right materials for where pieces are silver soldered together. So just use your imagination and enjoy yourself. It is not a bible, to be followed religiously, use whatever you think will work.

It is really an exercise in making complicated looking bits in an easy to understand way, using no super expensive workshop tooling, rather than the manufacture of a working model engine. That is just a big bonus at the end.

The crankshaft is a perfect example. If you make bearing blocks to support between each crank, you could easily make a 12 cylinder in line crank, with any angle offset you require. Try doing that on a little lathe, out of the solid.

As I said, I designed and made two, and when I show them at steam rallies, people just won't believe that they could be made by a novice to machining, with most bits coming from the junk pile. So I hand out freebie CD's with the 'book' on to those that are interested (plus of course a plug for the website).

Bogs

Darren · « **Reply #40 on:** April 10, 2009, 02:40:43 PM »

John, you mention using Cast Iron for the block if running on steam.
Can I ask why wouldn't brass be appropriate, or other metals for that matter

Darren · « **Reply #41 on:** April 10, 2009, 02:46:52 PM »

Hi Ron,

I would say go for it, but then I've no idea what I've got into here

Deep end comes to mind

bogstandard · « **Reply #42 on:** April 10, 2009, 04:06:31 PM »

Darren,

The standard materials for steam cylinders on models are cast iron, bronze and brass in that order.
They all have good wear resistance and are stable when subjected to heating.

In small engines, if you use standard steels, including silver steel, they will go rusty and jam up in no time under the hot humid atmosphere when running on steam, hence stainless should be used for shafts if possible. Model locos usually get away with it because most bits are easy to get to and can be kept well oiled.

Hot steam will cut through ali under certain conditions plus also it has large expansion rates. So that really must be avoided.

That is why I asked Ron if he was running on air.

If you are running on air, almost anything goes as long as you keep it well lubricated.

Hope that explains it OK.

John

sbwhart · « **Reply #43 on:** April 10, 2009, 04:16:13 PM »

Quote from: ozzie46 on April 10, 2009, 06:59:10 AM

I'm in the process of gathering material for this engine as well. I will be trying to make it on my 7 x 12 lathe and drill/mill. So I will be following your thread with great interest and anticipation.

Great start by the way.

Ron

Hi Ron I'm shure you'll enjoy this engine build I've seen Johns engines and they do make a very nice project, and when you break it down into easy step as John has done its well within the scope of a newcommer: if you get stuck ther's plenty of chaps on her who will give good advice, but the most important thing is for you to have fun with the build.

Cheers

Stew

Darren · « **Reply #44 on:** April 10, 2009, 04:42:56 PM »

Thanks John, that was well explained.

One more question, I understand than Stainless steel galls in a sliding motion. Do I take it that it's not suitable for cranskshafts in these models or can we get away with it?

Sorry, a second one...
If used for a piston rod do you put say a bronze bush in or again can we get away with it.

Darren · « **Reply #45 on:** April 10, 2009, 04:51:19 PM »

Look what I found under the hedge in the garden today

I wonder what I could do with these

bogstandard · « **Reply #46 on:** April 10, 2009, 06:44:20 PM »

Darren,

I have never had any problems at all using stainless rods in any of my engines, either in a rotary or sliding motion.

I would suspect stainless running in stainless might cause a problem.

I think you might be getting confused with stainless steels ability to have a grab factor. That only happens when stainless is tightened onto another metal.

With regards to your sash weights, don't go diving in like you usually do. There is a technique to cutting that type of casting. Using say an angle grinder, grind a groove all the way around the bar. Either drop it onto concrete or tap wiv a big 'ammer, it should break around the grind line. This will allow you to mount it in the lathe and start your cutter off under the hard outside skin, say a 0.025" (0.5mm) deep. This should then cut along the good material under the skin, taking the rock hard outer casing with it. You might find that the last 3 or 4" at the end opposite the loop is full of dross and can usually be discarded. I have never worked with square ones, so you will have to work how to get under the skin on those yourself. I can normally get at least 12" of very good material out of them, about 1.25" diameter.
I know Steve bought a load and they turned out to contain nothing but dross. You win some, you lose some. Up to now, after many dozens, I haven't had a single loss.

John

Darren · « **Reply #47 on:** April 10, 2009, 06:54:47 PM »

Quote from: bogstandard on April 10, 2009, 06:44:20 PM

I think you might be getting confused with stainless steels ability to have a grab factor. That only happens when stainless is tightened onto another metal.

Thanks John, I have no doubts about getting the wrong end of the stick. I used to have parts made at a machine shop and they would give me all sorts of excuses not to use SS.

I'm beginning to think they just didn't like machining the stuff and I was fed a load of drivel. They always wanted me to have the parts made in brass. It was a fully fledged modern CNC shop too.
Mind you, I'm beginning to understand their reasoning, but I find it hard to believe they would have the same problems as I do.....

Darren · « **Reply #48 on:** April 10, 2009, 06:59:07 PM »

Quote from: bogstandard on April 10, 2009, 06:44:20 PM

With regards to your sash weights, don't go diving in like you usually do.

OK....

Quote from: bogstandard on April 10, 2009, 06:44:20 PM

I have never worked with square ones, so you will have to work how to get under the skin on those yourself.

I'm thinking, abrasive chop saw or angle grinder, cut the length for an engine block in the manner you describe and then slice the side crust off with the bandsaw??
Maybe that might work

bogstandard · « **Reply #49 on:** April 10, 2009, 08:29:02 PM »

Darren,

That just might work. Just make sure you are cutting in virgin good metal and not the skin except for the two outside edges.

If you are after making it square from square, you could try milling it first, starting off from a previously cut edge, put a deep enough cut on to get it under the skin.

If you have any spare tips you want to get rid of, just try turning the skin off the surface without going deep enough. Just to see what I am on about. There is most probably 100 years of crustiness on there, but also 100 years of lovely matured cast iron underneath.

Bogs

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Author Topic: Twin Cylinder Steam Engine (Read 80546 times)

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