Sans Brass

[Captain Jerry]

I am thinking about building a steam engine without using brass. I also cannot locate a big enough piece of cast iron for the cylinder but can find smaller pieces for the piston and D-valve if needed. Plenty of SS for rods and shafts and flat CRS of 1/4" or less.

Now my question is if I use Aluminum for the cylinder with no liner, what would be best for piston, CI or CRS or 12L14 steel? And is it possible to use a CI D-valve against an aluminum face. I could make a CRS face plate for the valve but I'm just asking.

For other wear points like con rod ends and crankshaft bearing, I'm thinking CI. I'm not sure which way to go with the eccentric. I could go with a CI eccentric strap, but would CI, 12L14, or aluminum be best for the eccentric?

For the cross head, I'm thinking a combination of CI crosshead on SS or drill rod but other suggestions would be welcome.

Cylinder dimensions of .625" bore x 1.25" stroke.

I have not yet decided on the configuration but probably horizontal mill engine.

Jerry

 

[portlandron]

I chart I have gives the following ratings for materials used with aluminum for moving & wear resistance:
Excellent- Cast Iron, Nickel Iron, Drill Rod/Tool Steel.
Good- Nylon, Teflon, Steel SAE 4140H.T.
Poor- Oilite, Steel SAE 1020 & 1040, Stainless Steel
Bad- Aluminum, Brass (free machining), Cast Brass, Bronze

 

[arnoldb]

Hi Jerry

;D - As always, it all depends. If you don't foresee the engine running too much, and you're not overly concerned about getting absolutely maximum performance out of it, pretty much anything goes - I have built 4 engines with aluminium cylinders and brass or bronze pistons so far, and they all run on breath power. Phil Duclos built his "Little Blazer" engine with aluminium body and piston (one of the worst combinations possible) - and some other HMEM members have done the same.

Cast Iron piston and aluminium cylinder should be fine - the only disadvantage is that the cylinder wears quicker than the piston.
CI bearings with drill rod shafts would be fine, and CI/CI for the for the eccentric and strap would be just dandy; CI is one of the few metals that runs well with itself in such an application. Same with the valve - the valve surface would wear a bit quicker, but should work with CI valve and Ali surface.

Now I'm ready to be told off for not following all the rules of metallurgy and all the rules in the books, but if one just have certain things available, then that's what one use.

Are you thinking Live Steam, or compressed air ?

Kind regards, Arnold

 

[kvom]

Based on what I've learned on my last two builds, I am staying away from aluminum on wear parts. If you need to make th cylinder out of al I'd recommend using a liner.

 

[Brian Rupnow]

Jerry---Unless you're worrying about running this engine 24 hours a day, do like I do.--Aluminum cylinder with brass piston, or brass cylinder with aluminum piston. You probably won't live long enough to wear these engines out. Aluminum and brass are so much easier to machine than steel, that I generally use steel only on extreme wear parts like crankshafts, cams, and slide plates. I'm sure that once I die, all the engines I have so lovingly created will go to a yard sale or be packed into a box and eventually given to the Sally Ann. I have three wonderfull kids, and not one of them has enough interest in the hobby machines I build to make a gnat sweat. Unless you are into creating heirloom engines, go with whats easiest. You can enjoy the build, amaze your friends when you have them over, and if the cylinder bore wears out, its only 20 minutes work to make a slightly larger piston.----Brian

 

[Captain Jerry]

Thanks for the replies. This forum can always be counted on for help and advice. Its not that I don't have brass or can't get it but I just want to see what can be done without it.

Thanks for the chart, Portlandron. From that, it looks like cast iron is the best choice for piston and valve, being in the 'excellent' category. I'm surprised to see that brass and bronze are in the 'bad' category, along with alu/alu.

If you consider 4 or 5 hours per year as hard use, I might be in trouble. It might be run under heavy load for a few minutes per year because I do like to put them on the dyno to see what they can do.

I have always been told that when a hard metal wears against a soft metal, that most of the wear is on the hard metal, so will the hard CI piston wear faster that the soft Ali bore or what?

Kvom, what would you use for a liner? The bore is only 5/8".

Brian, If I were to run an engine for 24 hrs, I would have to have a 500 ft air hose so I could put the compressor in my neighbors garage. I know I won't live long enough to wear one out. I'm just hoping I live long enough to finish a few more projects and prove (or disprove) some of my ideas. Like you, I do this for my own enjoyment. I have learned to enjoy the glass eyed glaze of family members when I talk about my shop and it's output. One particular son-in-law is good for a laugh when I extoll the virtue of carbide tools at high speeds! It will be a very poor museum that would display my engines so I don't think that's going to happen. My plan to design and build an engine without brass is more or less an exercise in alternative thinking. I think that's a big part of the fun. As to materials, brass and bronze are great to work with but you might be surprised how nice it is to work cast iron (except for the clean up). Some grades of steel are not that bad either. I'm anxious to see your 'over crank' side plates that you specify steel for. Every challenge is just an opportunity to learn a new skill.

Thanks for the replies. I'll post something about the results of my effort.

Jerry

 

[Swede]

Now I'm curious, no brass just for fun and/or appearance? Whatever the reason, an engine that is all stainless, or at least silver in color, is really eye-popping, IMO. Harder to execute but very good looking.

I was going to suggest bronze as simply looking (and aging) better than brass, but it sounds like you want to get away from the brassy color.

One final option is nickel plate. Electo nickel is really easy to do and what you get looks wonderful. Plus, the nickel surface, if allowed to build up, simply a matter of longer plating) is exceptionally hard.

 

[Captain Jerry]

Swede

Yes, sort of. I think the monochrome appearance of an engine without brass will look good, as you said. We tend to use brass for its workability but I think that there may be better materials to use in some of the places that brass is used. I am learning to deal with the differences in the various metals and decided that this was a way to expand the range of possibilities. Nickel plating sounds like a good 'look' but my shop space is limited so I'm not likely to try it. It may even end up painted.

Jerry

 

[dalem9]

Try www.micromark.com They have plating kits that are resonable Dale

 

[Hilmar]

Jerry,

go to a pluming store and buy a bronze or cast iron pipe fitting for the cylinder or as a liner. I take it that you can not get the right size material.
Hilmar