First Engine Build - Elmer Wobbler Number 25

[Propforward]

Hello!

I am a bit hesitant to post this, thinking I ought to progress the project some more before talking about it, but on the other hand, it's cold out, and I'm in front of the computer and I have a nice cup of tea, so here goes.

Yesterday, I finally made a start on my first steam engine. I selected a very simple wobbler to begin with - this seems like a sensible approach, to build a bit of confidence on some more straightforward parts, and learn the necessary techniques and so on.

So, here is the first part. It is the brass bearing for the crankshaft.

I chose this component to start with, because it's the only one on the design that I had a suitable piece of material for.

On the one hand, I am pleased because I machined it to the correct dimensions without screwing it up. On the other hand, I am not at all happy with the finish - it's quite rough really.

So I anticipate making another one of these (or as many as it takes), and figure out what I am doing wrong.

This is actually the first time I have machined a brass component, so I am not too disheartened by any means.

So that's it - not a hugely exciting thread, but I'll keep adding to it, and maybe a steam engine will pop out the end of it.

Today I'll put together my material list for this little beastie, and tomorrow I'll spend a little bit of time rummaging around the scrap bin at work. Thm:

 

[Inky Engines]

This was also my first build, and I would expect that of several other members of this forum. I'll follow your progress with interest.

In terms of the brass - a good finish is usually obtained with a sharp tool with zero top rake. Although I've had to retrieve some badly finished components with the 'careful' use of emery cloth - rather than scrap and remake. A 'google' search also returns lots of advice re turning brass.

Good luck with the build

Geoff at Inky Engines

 

[Propforward]

Thanks Geoff, your comments are greatly appreciated. I have been doing a bit of reading on machining brass, on this forum as well as other sources, so I hope to go and make a few more test cuts this afternoon.

 

[Propforward]

I think this is going to be a slow thread.

So I looked in the scrap metal bin at work - nothing of any use at all!

So I have put in an order to McMaster Carr, I should have material in the next day or so.

In other news, I attempted to turn some steel on sunday afternoon - just for practice. Oh dear. Very disheartening - I could not achieve any kind of reasonable finish. I am absolutely NOT going to post a picture of that.

So I have spent the last day or so reading up on the matter again, both on this forum and in my text books, and it is quite clear that I need to get familiar with grinding HSS bits to shape. I am quite certain that the bulk of my problem was there. So I have resolved to spend time doing that this week. It suddenly occurred to me yesterday that although I do have some experience of machining from school and college - I have never had to grind my own tooling. So that's the next item on the agenda. I am more of a novice than I had realised.

Luckily I am really enjoying all this. So - it may be a while before the next component gets posted. But I have next week off work, and will spend some quality time in the workshop and make some chips!

 

[Propforward]

Well, I am back. I have not been idle since my last post - though arguably I haven't achieved a lot either.

It became very apparent very quickly that I really had a heck of a lot to learn. My first few attempts at turning steel were awful. I quickly decided to pause on the manufacture of engine parts and go back to basics. I looked back at my notes, did some searching on the forum and the net, and went back over basic machine set up, grinding and setting up HSS tool bits, and after spending some time doing that I began to make some headway.

I had another go at machining a piece of steel to make a drill jig locating pin, and after more carefully refreshing my memory on tool set up, this was successful.

I then turned my attention to machining brass. The con rod for this engine gave me a bit of trouble at first, and I was worried that I had actually chosen too big a lathe for the job. I consulted someone with a lot more experience though, and he gave me some really good pointers on holding small diameter work, and again I made some progress.

So, although parts are slow coming out, they are starting to come out. Finish isn't always what I want, but I am now into 2 steps forward and 1 back, rather than 1 forward and 2 back like I was a couple of weeks ago.

The really important thing is that now I have got started, I am really enjoying it.

Here are a couple of pics - nothing very spectacular yet.

Assortment of parts - including a home made "collet" which allowed me to turn the con rod to length without destroying it (unlike the first two attemptes)

Close up of conrod - next it needs a flat on the big end, and a hole for the crank pin.

I added a shelf behind my lathe today, which is really nice for holding calipers and micrometer.

 

[Propforward]

I'm continuing to make VERY slow progress.

First of all, I realised that the steel I was attempting to machine was 1018.

:wall:

It must be possible to machine this material, but I decided after much searching and many scrapped parts that I can progress to that material again at a later date. For now I'll take the easy route and stick to 12L14.

So I obtained a few bits of material and started afresh.

First though, new tool addition:

Yes - a baked bean tin with coolant / cutting fluid in it. I recommend beanie weenie cans, as they have a pull off lid and don't leave a sharp edge. They are just the right size, too. See here in use:

So here is the first part of the crankshaft.

Not very dramatic, but I want to photodocument this first build in detail The crankdisc will be a little more demanding, but as I am starting to have more success with the machining, I am gaining confidence too.


Also, started sizing up some aluminum for the frame. Tomorrow I'll actually get the frame machined and cut and assembled. I think I want to complete that before I turn any more parts, so that I can start fitting parts together as they get completed. Most parts are only semi finished, which is fine, but it's time to start bringing it together somewhat, then I can move on to the more demanding parts, such as the cylinder.

Aluminum foot - first time I have used layout blue since......1985 I think. It's been too long.

It may not look like I have been doing much - to an extent that is true - but there is a lot of background reading and research, as well as practice and in some cases machine set up and checking going on between posts.

All this background work will pay dividends as I keep going with the hobby, I think.

Cheers!

 

[thayer]

Elmer's #25 was my first as well. You might also want to consider the primary thing I changed though, which was the foot. I drilled the two holes to take the frame, then put another in between that I tapped to accept a mounting screw that comes up through the wooden base. I thought it would give a cleaner look than having the two extra fasteners Elmer marks out. And for those who claim it isn't done until the video is posted, here is a link of it in action.
[ame]http://www.youtube.com/watch?v=AcOpUwI-v70[/ame]

Thayer

 

[Inky Engines]

You seem to be making good progress with the engine. As Thayer suggests other designs for the base are possible - many do seem to opt for the concealed screw between the frame screws rather than sticking to Elmer's two visible screw holes - it's entirely a matter of personal preference. What is important IMHO is that you fix the engine to a solid block of wood, tile, slate, etc - that way it should run without walking around the workbench, and both hands are free to take the photographs!

Kind regards

Geoff at Inky Engines

 

[Propforward]

Oh yes, I see what you mean. Thayers engine there looks very clean without those two screw holes, I think that's a great idea.

 

[maverick]

A little tip, put a magnet in the bottom of your coolant can to keep it
from falling off the cross slide. your engine is coming along nicey,
keep up the good work.

Regards,
Maverick

 

[Propforward]

What a great idea! I knew there was a reason that a bean tin was superior to a small plastic cup (which I had been using). I just happen to have some nice neodymium magnets too. Cheers!

 

[Propforward]

I have been making some progress, although I haven't posted about it in a while.

I finally got to the crux of the matter, and did some work on the cylinder:

I know it's not great, but on the other hand - first piece of work in a 4 jaw, which I think counts for something. I need to make a pump center finder though.

I also made the piston

The piston fits into the cylinder OK, not perfect, but I was able to feel compression before I drilled the port into the bore. I am fairly confident that it will work.

And tonight, I got around to cleaning up the frame and making a base for it.

I'm actually quite close to finishing. Tomorrow I hope to make the flywheel and crank disc, then I need to make the pivot pin and solder it in to the cylinder, and it will be ready for assembly.

 

[Propforward]

Well I've put a bit more time into it. I had a go at cutting the crankshaft disc to shape, but that turned into a hideous failure, so for this engine I'm just going to leave the crankdisc as a plain circular disc. I don't think it will matter. The replacement crank and disc are made, and ready for use. I made little jigs to keep everythig square when pressing the crankshaft and pin into the disc. (I didn't want to use loctite as in Elmers instructions).

I also made the steam connector, and began work on the third flywheel.
Originally I was using aluminum, and making it a simple plain disc, with a hole through from the perimeter of the flywheel, but I don't think aluminum is massive enough for a flywheel really, and I don't like the lock screw right through the flywheel.

So my third attempt is in steel, and I have changed the design to a flywheel with a boss, and the boss will have a set screw in it.
I was also bound and determined to make it look like a flywheel - ie machine a groove both sides. I am giving up on aesthetics on the cylinder and crank disc, in that the cylinder will not have chamfers on the outside edges, and the crank disc will not be cut to look "balanced", so I need to add some interest somewhere, and this seems like the best place.
This is the flywheel part way into machining.

In this picture the groove has been machined both sides. Not to any specific dimensions, but even both sides. You can see some burrs and marks on the flywheel - that's OK, it isn't complete. The next stage is to drill and tap the boss for a set screw, then I will mount it back in the lathe on a shaft, and take the last finish cuts to true it up and clean it up.

It's not the best finish, although the magnification of the camera makes it look worse than in real life (honest). I am actually pretty satisfied. At least it looks like a flywheel, with rim, web and boss. I used a form tool to make the groove, and that is a tricky piece of machining. The bit wants to chatter like mad. Note to self - read your reference works on using the lathe BEFORE starting new to you operations. Turns out that having a rake angle on the form tool was a mistake. It worked much better with no rake, but this time I saved the part and didn't need to trash it.

So progress continues in a two steps backwards, three forwards kind of way. Yesterday, by lunchtime, I had fewer available parts than when I started in the morning.

However, since then things are well back on track.

 

[robcas631]

Wow that is small. How many jaws do you have on your chuck? Also, how much material do you remove per pass?

 

[Propforward]

I have both 3 and 4 jaw chucks. I used the 3 jaw for most of this engine, including the flywheel. The only thing machined on the 4 jaw was the cylinder.

I was moving the form tool into the flywheel about 25 thou at a time, then cutting across the face, then moving in another 25 thou. The whole process was very slow.