I bought two stuart steam engine castings kits at NAMES a couple years
ago. Every so often I get them out and do a little work on them.

I was wondering how much piston/cylinder clearance is required.
The bore is 1 inch and the stroke is 1 inch. The cylinder and piston
are both cast iron and the piston is suppose to have 1 ring.

Should I stick with the CI ring or change to a teflon ring like
PM research uses?

I hope to build a PM Research kit and run them on live steam but
I suspect they will run on compressed air most of the time.

chuck

Chuck Sherwood wrote:

I bought two stuart steam engine castings kits at NAMES a couple years
ago. Every so often I get them out and do a little work on them.

I was wondering how much piston/cylinder clearance is required.
The bore is 1 inch and the stroke is 1 inch. The cylinder and piston
are both cast iron and the piston is suppose to have 1 ring.

Should I stick with the CI ring or change to a teflon ring like
PM research uses?

I hope to build a PM Research kit and run them on live steam but
I suspect they will run on compressed air most of the time.

chuck

And for that matter, where do you get cast iron for piston rings? I've
seen centrifugally cast recommended, but how do you get your hands on
it? Regular cast is $$$ from McMaster -- can I just visit my local
engine rebuilder and saw the snouts off of a bunch of trashed crankshafts?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Chuck Sherwood wrote:

I'm not that much a steamer ...

I was wondering how much piston/cylinder clearance is required.

The less the better. 2..3/100 mm is good enough (with a ring). Get a
good surface!


The bore is 1 inch and the stroke is 1 inch. The cylinder and piston
are both cast iron and the piston is suppose to have 1 ring.

The CI-ring will wear in and forgive your extra clearance.
In a first attempt, I would use the CI-ring. It will smoothen the
cylinder by time. Later, if you are not content, you can always fit a
teflon ring.


Should I stick with the CI ring or change to a teflon ring like
PM research uses?

It would be better, if your surface is very smooth. I've heard that the
"Vitron"-brand is best. I guess it's some kind of PTFE.


HTH,
Nick

--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

Chuck,

I build lots of 1/8 scale live steam, and have built a Stuart 10H.

Clerance should be a nice 'sliding fit'... that translates to about .001
undersize, IIRC there is a number for both cylinder bore and piston diameter
on the ST prints.

When doing small bores like these (1 inch or under) I cheat and use a spiral
flute chucking reamer, that way the bore is EXACT. Always bore the cylinder
first and make your pistons to match, and don't worry, we ALL screw up
pistons now and then and they aren't that hard to make from scratch.

As for rings, I use CI on the 1/8 scale stuff, but usually go 'old school'
on the small stuff and use graphite impregnated string...Teflon will work
but.... FWIW I pack my piston and valve rod glands with graphite string,
even on the 1/8 scalers... NEVER under any circunstances use Teflon to pack
the glands, it will actually 'extrude' out around the rods in paper (skin?)
thin sheets...

One other advantage of the graphite string is that you will do less damage
to the cylinder when you run on air. It's tough to get any lubrication to
the valve and piston on air. Of course you will have a displacement
lubricator when you run on steam won't you :-)

FWIW, a lot of live steamers use brass for the pistons... If you use brass
and graphite string as the ring you will never have a piston rust to the
cylinder... as counter intuitive as it sounds, you have a greater chance of
that when you run them on air, mostiure does condense from the air and
without the heat from the steam has no way to evaporate... If you do run
them on air, give em a good squirt of "kerosene in a can" (WD40) up the
cylinger cocks when you are done running to displace any trapped mostiure..

If there is a live steam club near you, go join it, most people in this
hobby are pretty good about helping 'newbies'

--.- Dave




"Chuck Sherwood" wrote in message
...

I bought two stuart steam engine castings kits at NAMES a couple years
ago. Every so often I get them out and do a little work on them.

I was wondering how much piston/cylinder clearance is required.
The bore is 1 inch and the stroke is 1 inch. The cylinder and piston
are both cast iron and the piston is suppose to have 1 ring.

Should I stick with the CI ring or change to a teflon ring like
PM research uses?

I hope to build a PM Research kit and run them on live steam but
I suspect they will run on compressed air most of the time.

chuck

Chuck,

I am plowing the same ground. I'm working now on a PM Research boiler for
an old Tiny Power engine. Tiny Power includes a groove for 2 rings. They
imply you can either make CI rings or use teflon tape packed in the groove
for a piston ring. Teflon tape and saturated steam probably will make a
pretty good ring for use on saturated steam. Another approach I have used
on small cylinders, is to make the piston a very close moving fit and cut
some shallow grooves in it to act as "rings" with retained moisture.

Bob Swinney
"Chuck Sherwood" wrote in message
...

I bought two stuart steam engine castings kits at NAMES a couple years
ago. Every so often I get them out and do a little work on them.

I was wondering how much piston/cylinder clearance is required.
The bore is 1 inch and the stroke is 1 inch. The cylinder and piston
are both cast iron and the piston is suppose to have 1 ring.

Should I stick with the CI ring or change to a teflon ring like
PM research uses?

I hope to build a PM Research kit and run them on live steam but
I suspect they will run on compressed air most of the time.

chuck

Tim Wescott wrote:

And for that matter, where do you get cast iron for piston rings?

You can use the same CI that you use for the piston.
Even better, you can make the ring and the piston in one pass.


I've seen centrifugally cast recommended, but how do you get your hands on
it?

That would be hard. You could ask manufacturers of cylinders (just the
sleves). But I doubt they do have the sizes you want.
Centrifugal CI is mostly used for cylinders in cars.


Regular cast is $$$ from McMaster -- can I just visit my local
engine rebuilder and saw the snouts off of a bunch of trashed crankshafts?

A crancshaft? It will be hardened. CI from continuous castings *) isn't
that expensive. But, you get a lot of swarf ... err coal making a piston
ring out of round stock. :-)


*)
Don't know how you call it. It is a continuous process using a water
cooled, tube shaped copper mold.


Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

Clerance should be a nice 'sliding fit'... that translates to about .001

OK. Glad I asked because I was going to shoot for 2 thou.


flute chucking reamer, that way the bore is EXACT. Always bore the cylinder
first and make your pistons to match, and don't worry, we ALL screw up
pistons now and then and they aren't that hard to make from scratch.


I will bore the cylinder on the mill with a boring head. It is a bit
tedious but I get a better finish that way. I will probably make a
lap to polish it afterwards. I did that with a hit-and-mill engine
and the bore came out wonderful.


lubricator when you run on steam won't you :-)

I bought the PM Research lubricator when I bought the horizontal boiler.
I also got the nice minature gauge. Pretty expensive package today.


FWIW, a lot of live steamers use brass for the pistons... If you use brass
and graphite string as the ring you will never have a piston rust to the
cylinder...

I like this. Simple but effective. Where do I get graphite string and
what size do I need? Multiple turns in a groove? FYI the piston is
1 inch diamter and 5/16 long.


Someone asked about buying CI for pistons and rings. CI bar stock
is widely available. I have bought it from MSC, enco and metal express.
Not too expensive and turns really nice! Almost like cutting butter.

FYI, I am building the 7A and #8. They share a lot of parts so I
figured it would be easier to build them in parallel, but my focus
is to get the horizontal running on the PM research boiler. I got the
reversing gears for the 7a too. These kits are from the 1960s.
The castings look real nice and machine well. The plans are one
piece of paper. Included hardware is BA sized. I will change to
american taps sizes. I don't remember what I paid, but it was in
the neighborhood of 130 for each kit (including cylinder drain cocks
and the reversing gears). A bargain by todays prices of 157 pounds.

chuck

an old Tiny Power engine. Tiny Power includes a groove for 2 rings. They
imply you can either make CI rings or use teflon tape packed in the groove
for a piston ring.

I looked at a tiny power kit a long time ago. At that time he was
recommending and including graphite string in the kit. Don't know
what he does today.

I build the coke bottle PM research engine. The plans called for a tiny
teflon ring but the teflon supplied was cut from a sheet and was not
made from string.

chuck

Nick Müller wrote:
Tim Wescott wrote:


And for that matter, where do you get cast iron for piston rings?


You can use the same CI that you use for the piston.
Even better, you can make the ring and the piston in one pass.



I've seen centrifugally cast recommended, but how do you get your hands on
it?


That would be hard. You could ask manufacturers of cylinders (just the
sleves). But I doubt they do have the sizes you want.
Centrifugal CI is mostly used for cylinders in cars.



Regular cast is $$$ from McMaster -- can I just visit my local
engine rebuilder and saw the snouts off of a bunch of trashed crankshafts?


A crancshaft? It will be hardened. CI from continuous castings *) isn't
that expensive. But, you get a lot of swarf ... err coal making a piston
ring out of round stock. :-)


*)
Don't know how you call it. It is a continuous process using a water
cooled, tube shaped copper mold.


I just checked -- it's way less expensive than I remember; much more in
line with what I thought it should be. Now where did I get the idea
they wanted 10x more for it than it is?

So if you don't make rings from round stock what do you use and where do
you get it? The "cast iron pipe" you get around here is just cruddy
mild steel.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Tim Wescott wrote:

So if you don't make rings from round stock what do you use and where do
you get it?

No, I make it from round stock. What I wanted to say is:
If you make the piston, make the shirt a bit longer for the ring.
Make the same outer diameter as the piston, inner diamerter per specs, a
bit deeper then the thickness of the ring. Then you part the ring off.
Voila!

Take the finest blade you can find for your jig saw and split the ring.
Now, put some iron crap laying around (your shop isn't messy?) and put
it into the gap you just sawed. Put the ring between to steel plates
that you screw tight (one screw in the center). Heat the "burger" up to
a dull red and keep the heat for 5 minutes. Let cool down, open the
sandwich and remove scale on the ring with an oilstone.
Next, you continue with the ring groove in the piston and use the ring
as a reference.

You didn't want to hear that?
OK, maybe someone else. :-)


The "cast iron pipe" you get around here is just cruddy
mild steel.

That kind of CI-tubes was in use for ****-pipeing.


Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

Nick Müller wrote:

Tim Wescott wrote:


So if you don't make rings from round stock what do you use and where do
you get it?


No, I make it from round stock. What I wanted to say is:
If you make the piston, make the shirt a bit longer for the ring.
Make the same outer diameter as the piston, inner diamerter per specs, a
bit deeper then the thickness of the ring. Then you part the ring off.
Voila!

Oh, I get it. Clever. Perhaps make two, one for the piston and one for
the breakage?

What about aluminum pistons?

Dykes rings?

Take the finest blade you can find for your jig saw and split the ring.
Now, put some iron crap laying around (your shop isn't messy?) and put
it into the gap you just sawed. Put the ring between to steel plates
that you screw tight (one screw in the center). Heat the "burger" up to
a dull red and keep the heat for 5 minutes. Let cool down, open the
sandwich and remove scale on the ring with an oilstone.
Next, you continue with the ring groove in the piston and use the ring
as a reference.

Yes, my shop is very messy.

I've seen a good website on this that goes into more detail -- but
you've actually built engines that work, so I'll bow to your superior
knowledge.

You didn't want to hear that?
OK, maybe someone else. :-)



The "cast iron pipe" you get around here is just cruddy
mild steel.


That kind of CI-tubes was in use for ****-pipeing.

True, and code around here says cast iron or plastic -- high-end houses
use CI for 2nd-story facilities because it doesn't make as much noise
when you flush, other than that it's pretty much all PVC.

But the 1/2 inch water pipe is also called "cast", just to confuse the
amateur machinist.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Tim Wescott wrote:

[making rings]
What about aluminum pistons?

Grrrr
Proceed as described, just leave out the CI-piston. ;-)


Dykes rings?

What's that?


Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

Nick Müller wrote:

Tim Wescott wrote:
--snip--

Dykes rings?


What's that?


Nick

It's either a small piece of jewelery used in 1/2 of all same-sex
marriages, or it's a L-shaped ring with low tension that lets the
combustion gases press it against the cylinder wall when it's really
necessary:

//--------------------..-.
|| |
.--'| |
|.--' |
piston || | - ring
|'----'
'-----.
|
|
|
|

Because they reduce friction on the down stroke they were a Big Thing in
model airplane engines before the advent of ABC, AAC and AAO engines
(lapped aluminum pistons into a chromed aluminum, chromed brass, or
hard-anodized aluminum sleeve).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Tim Wescott wrote:


or it's a L-shaped ring with low tension

Now I know! We call it by the name: "L-Ring".
Thanks.


Haven't made one. Turning it wouldn't be that diffcult, but baking in
the tension would distort him. I guess.


Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

My dad and I made a steam engine a long time ago. We cut open shock
absorbers and used the cylinders and pistons inside for parts. Worked good.

Jeez I get a MUCH better finish with a reamer on these small bores, most of
mine come out like glass, require no lapping/honing, and as I said are
EXACT on diameter... I have a friend who likes to build steam pumps, I do
all his boring, he works mostly in brass and I find the reamers do a MUCH
better job, are faster, and are more accurate on this small stuff... Most of
his pumps use SS rams that are cut from precision SS stock, so doing the
reamer deal makes it all a 'no-brainer'.... but what ever works for you.

FWIW I have a Criterion boring head knock off that I bore all my big stuff
with... here's another good practice, if you build a 2 cylinder engine (like
a locomotive) rough bore both cylinders, and then set your head and final
bore both cylinders with the same setting... as Joe Nelson ("So you want to
build a live steamer") says, better to be the same, than have one correct
and one off... this goes for everything, especially anything in the valve
gear, eccentrics, straps, links blocks.... I even tend to do this for
drivers...

I will bore the cylinder on the mill with a boring head. It is a bit
tedious but I get a better finish that way. I will probably make a
lap to polish it afterwards. I did that with a hit-and-mill engine
and the bore came out wonderful.


Most of the suppliers to the hobby sell it. I haven't dealt with Coles Power
Models since they sold the company several years ago but I bought a bunch
from them way back when. Go google it, I'm sure you'll find it... lots of
people still use it for packing glands... Grrove size etc will be determined
by what you buy, but at least 2 turns and groove depth should be like for an
O-ring... and again, if ya screw up, it's only a piston, easy enough to
make a new one...

I like this. Simple but effective. Where do I get graphite string and
what size do I need? Multiple turns in a groove? FYI the piston is
1 inch diamter and 5/16 long.

A friend gave me his 10H kit that he bought as a kid back in the 60's and
was un-built, and still inthe original box.
I'm so compulsive I bought bought a BA tap and die to build it.... LOL....

FYI, I am building the 7A and #8. They share a lot of parts so I
figured it would be easier to build them in parallel, but my focus
is to get the horizontal running on the PM research boiler. I got the
reversing gears for the 7a too. These kits are from the 1960s.
The castings look real nice and machine well. The plans are one
piece of paper. Included hardware is BA sized. I will change to
american taps sizes. I don't remember what I paid, but it was in
the neighborhood of 130 for each kit (including cylinder drain cocks
and the reversing gears). A bargain by todays prices of 157 pounds.



--.- Dave

The hardware store has graphite packing in the plumbing section. Usually
only one size though.
Karl

"Chuck Sherwood" wrote in message
...
Clerance should be a nice 'sliding fit'... that translates to about .001

OK. Glad I asked because I was going to shoot for 2 thou.


flute chucking reamer, that way the bore is EXACT. Always bore the
cylinder
first and make your pistons to match, and don't worry, we ALL screw up
pistons now and then and they aren't that hard to make from scratch.


I will bore the cylinder on the mill with a boring head. It is a bit
tedious but I get a better finish that way. I will probably make a
lap to polish it afterwards. I did that with a hit-and-mill engine
and the bore came out wonderful.


lubricator when you run on steam won't you :-)

I bought the PM Research lubricator when I bought the horizontal boiler.
I also got the nice minature gauge. Pretty expensive package today.


FWIW, a lot of live steamers use brass for the pistons... If you use brass
and graphite string as the ring you will never have a piston rust to the
cylinder...

I like this. Simple but effective. Where do I get graphite string and
what size do I need? Multiple turns in a groove? FYI the piston is
1 inch diamter and 5/16 long.


Someone asked about buying CI for pistons and rings. CI bar stock
is widely available. I have bought it from MSC, enco and metal express.
Not too expensive and turns really nice! Almost like cutting butter.

FYI, I am building the 7A and #8. They share a lot of parts so I
figured it would be easier to build them in parallel, but my focus
is to get the horizontal running on the PM research boiler. I got the
reversing gears for the 7a too. These kits are from the 1960s.
The castings look real nice and machine well. The plans are one
piece of paper. Included hardware is BA sized. I will change to
american taps sizes. I don't remember what I paid, but it was in
the neighborhood of 130 for each kit (including cylinder drain cocks
and the reversing gears). A bargain by todays prices of 157 pounds.

chuck

Recommended procedure is to unravel graphite packing to obtain smaller
strands when needed. Good hardware stores also stock Teflon packing cord.

Bob Swinney
"Karl Vorwerk" wrote in message
...
The hardware store has graphite packing in the plumbing section. Usually
only one size though.
Karl

"Chuck Sherwood" wrote in message
...
Clerance should be a nice 'sliding fit'... that translates to about .001

OK. Glad I asked because I was going to shoot for 2 thou.


flute chucking reamer, that way the bore is EXACT. Always bore the
cylinder
first and make your pistons to match, and don't worry, we ALL screw up
pistons now and then and they aren't that hard to make from scratch.


I will bore the cylinder on the mill with a boring head. It is a bit
tedious but I get a better finish that way. I will probably make a
lap to polish it afterwards. I did that with a hit-and-mill engine
and the bore came out wonderful.


lubricator when you run on steam won't you :-)

I bought the PM Research lubricator when I bought the horizontal boiler.
I also got the nice minature gauge. Pretty expensive package today.


FWIW, a lot of live steamers use brass for the pistons... If you use
brass
and graphite string as the ring you will never have a piston rust to the
cylinder...

I like this. Simple but effective. Where do I get graphite string and
what size do I need? Multiple turns in a groove? FYI the piston is
1 inch diamter and 5/16 long.


Someone asked about buying CI for pistons and rings. CI bar stock
is widely available. I have bought it from MSC, enco and metal express.
Not too expensive and turns really nice! Almost like cutting butter.

FYI, I am building the 7A and #8. They share a lot of parts so I
figured it would be easier to build them in parallel, but my focus
is to get the horizontal running on the PM research boiler. I got the
reversing gears for the 7a too. These kits are from the 1960s.
The castings look real nice and machine well. The plans are one
piece of paper. Included hardware is BA sized. I will change to
american taps sizes. I don't remember what I paid, but it was in
the neighborhood of 130 for each kit (including cylinder drain cocks
and the reversing gears). A bargain by todays prices of 157 pounds.

chuck