Question regarding Tiny

[Alex]

Hello all,

I'm new to the world of model engineering, but got some experience using a lathe.

I've decided to have a try at the little oscillating engine named Tiny. Everything is clear except for one thing. What's the technique for machining the port face on the column? I would be very glad if you wanted to tell me a little closer.

Best regards

Alexander, Sweden

 

[Ralph]

Welcome Alex !!!
I'm sure you'll enjoy yourself here and there's a wealth of knowledge here also. As for your port-face on the "Tiny" engine, I'm no expert but I just hand-lapped it on a flat surface with fine grit sandpaper. It runs like a top. They are pretty forgiving as far as tollerances go. Have fun with it.
Ralph

 

[Alex]

Hello Ralph, and thanks for your welcoming!

Did you start rough with a file or did you hand-lapp it with sandpaper all the way? Did you make any kind of jig to hold it in the some position while lapping?

 

[Ralph]

Hi Alex,
I started with a piece of half inch square stock and cut it to length. After drilling the ports just hold it in your fingers and make circular motions on fine grit sandpaper turning the part ninety degrees to avoid getting out of square. No jig required, just a steady hand. Good luck
Ralph

 

[rake60]

Hi Alex
I milled the flat in a mini-milling machine.
The part is small enough that it can be milled in a lathe without a milling
attachment. It can be clamped tightly in the tool post holder and milled
with an end mill chucked up is a 3 jaw.

 

[Alex]

Hello rake60

Your idea sounds interesting. What size of end mill do you recommend?

 

[Alex]

Ralph,

If I got your message right. You started to cut it to correct length, drill the ports, lap the square piece rectangular and then turning to final shape?

 

[Ralph]

Alex, Sorry I misunderstood your dilemma. After seeing Ricks pic I realized I didn't know what I was talking about. The "Tiny" I thought you were refering to, like mine has all square parts. (standard and cylinder) It too is a simple oscillating engine, just not as cute as Ricks (round base and cylinder. Sorry if I tried to lead you down the wrong path.
Ralph

 

[Alex]

No worries Ralph! Do you have a plan of that engine you want to share?

 

[Ralph]

Hi Rick,
I've got the plan just dont know how to post it. It wont copy and paste

 

[Ralph]

Help me out here and I'll be happy to share it.
Ralph

 

[rake60]

I'd use an end mill larger that the width of the flat.
A 7/16" or 12MM would work. Snug up the gibbs on the cross slide
and lock the saddle so it won't suck into the end mill.

Before I had the mini-mill I built Elmers Horizonal Mill Engine, doing all the
mill work on the lathes.

The piece was shimmed to center in the tool post and the 1/8" pockets in
the top face were milled with a 1/8" end mill chucked in the 3 jaw. To drill
the 25 degree holes I set the compound to 25 degrees and chucked the
drill bit in the 3 jaw.
A machine is limited only by the ways we can't think of using it.
But use them SAFELY!

You can download the plans at this site:
Elmer's Engines 2 Yahoo Group

Ralph you'd need to post your plan to a server then place a link to it here.
If it is in .jpeg form Photobucket will work. If it's .pdf and you'd like to
share it e-mail me.

 

[Alex]

Rake60,

Would this also work for the cylinder of Tiny? Milling on side of a round bar. Maybe it's hard to get the piece parallel with the tool post holder.

 

[rake60]

The cylinder is brass so it would mill easily.
To get a good clamping you'd need to place a piece of thin flat stock
across the top and try to keep even pressure on all the screws.
If your tool holder is indicated perpendicular to the chuck, all you need to
do to keep it parallel is put a piece of too steel behind it tight against
the back of the holder.

There is an OLD set of plans for building a lathe milling attachment at
this link:
http://www.vintageprojects.com/machine-shop/lathe-milling-attach.pdf
They would give you an idea of what it should be anyway.

 

[Alex]

Thanks, seems as a good device.

What do you think about building it totally in brass with exception for axles, pins and axle bearing which I intend to make out of some bronze I have laying around. I've never turned brass but from what I've understood it's a lot easier than steel. I also like the idea not having to paint it to prevent from corroding.

 

[rake60]

You can make it out of any material you like.
I would make the chankshaft and flywheel steel as you said.
When it's running it can spin pretty fast.

[ame]http://www.youtube.com/watch?v=YBX0HQEA3zg[/ame]

 

[Ralph]

Hi Alex,
I posted the plans you asked about, in the plans section. Its the "David" and its easy to build. Have fun.
Ralph

 

[1Kenny]

Some questions about little crank and rod pins.

When the term drill rod is used does that mean useing the shank portion of a small drill bit by just cutting it off to the length needed?

Is the rist pin full floating......or pressed in the piston, floating in the rod......or pressed in the rod floating in the piston?

Is the pin for the flywheel just pressed in and is something like 680 Loctite used to hold it?
:?

The Tiny engine looks real cool.

 

[Alex]

Hi there Kenny,

Not sure about the drill rod. But I do know that there's no wrist pin at all. The piston and piston rod can actually be made in a single piece. Take a look at this link and you'll understand how the piston and rod act.
www.keveney.com/oscillatingSteam.html

 

[rake60]

When I build steam models with 1/6 or 3/32 shafts in them, I use welding
rods. If you chip the flux off the steel rod it's self is usually mics real
close to size.