Piston and Cylinder stock

[majorm]

I dont have a good way to make a really smooth cylinder or piston surface finish wise. Have any of you found a good premade cylinder or piston? Preferably it would be more in a stock form where I could cut it to length but beggars cant be choosers. I thought about things like drill bushings but is there anything else out there that you have found? How about some kind of pipe that has a pretty good inside finish that I may could just use a cylinder hone on?

I think I could probably make a piston since its a little undersize but thought would throw that out there if anyone found something good to use for one. Do any of you use some type of metal rings, precision fit or is a o-ring the more common seal? you would have to cut a deep groove but maybe even a backup ring could work.

My application would be more in the steam, compressed air and CO2 realm.

 

[lohring]

Piston, ring, and liner combinations are widely available for model engines. OS makes a huge variety of two and four stroke engines with ringed and ringless pistons.

Lohring Miller

 

[GailInNM]

For sizes up to 5/8 inch ID K&S thin wall extruded seamless brass tubing works quite well as a liner. It is available from most hobby shops that have building materials for radio control planes or online from stores like Tower hobbies.
http://www3.towerhobbies.com/cgi-bin/WTI0096p?&N=N&C=&P=7&S=0000000&F=K%2BSR5094&L=K%2BSR8100&S1=KS&S2=TUBING&S3=&S4=

It has a nominal wall thickness of 0.014 inch and is specified by OD. For instance to get a 1/2 ID you would order 17/32 tub which would have a nominal ID of 0.502. Inside finish is suitable for a 1/2 inch diameter piston with an O-ring such as AS568-012 which has a nominal OD of 1/2 inch and ID of 3/8 inch. O-ring AS numbers are standard and available at any seal shop and manoy hardware stores or online.

You can drill or bore a slightly loose hole in your main cylinder block and install the liner with any Loctite 600 series product or even super glue in a pinch. Don't make a press fit or you will distort the brass liner.

Gail in NM

 

[aonemarine]

on the older mercruiser type r outdrives the trim cylinders have a tube inside them (available as a rebuild kit) that is about a 1" bore that could be used....

 

[myrickman]

Some of the compressed air cylinders can be modified for air/steam use and are plentiful from surplus stores. For something larger and thicker, hydraulic cylinders may work . I used some 2.375" ID hydraulic cylinders on my Brayton. The bidirectional air cylinders may have lip seals or o rings. Just a thought...

 

[texta]

there is a clip on you tube some where of an engine a bloke made from a vehicle brake master cylinder .

johno

 

[Chiptosser]

If you find something to make a piston out of, you could possibly us chromemoly tubing.

It comes in so many sizes and wall thickness, that you may find just what you need for clearance and size.

 

[majorm]

Those are some great ideas. I also thought about a moped/ scooter one but haven't seen any cylinder sleeves. The tube could be an answer to thst though if i could find a good id. It must not be an expensive enough part on those to warrant a sleeve.

 

[werowance]

i found some oxygen machines like people with copd or lung problems use at the metal scrap yard (guess one of the home medical supply places had discarded them). they had very nice thick walled long bras piston sleeves with brass pistons with teflon rings in them. the pistons had a nice flange at the top. there were 2 sizes in each machine so i grabbed up as many of those i could (only 3) i have yet to do anything witht those but i feel like they are perfect for steam engine.
those machines are the ones that look about the size of a suit case or vacume cleaner and make a phewww noise about every 15 seconds and feeds the patient oxygen constantly.
google home oxygen concentrator and the first link is about what i bought. i only paid its price in value of scrap per pound so they were cheap. i bet they didnt know they had brass inside them. wish i could remember the exact brand