Injector

[Fender]

I have one Ohlenkamp and one Superscale economy injector on my mogul. Both are very reliable. My understanding is that Emery Ohlenkamp based his design on a Penberthy. I believe the Superscale economy, in turn, was based on Emery's design, and was offered after these were no longer made. Now we are going into the third (or fourth?) generation of the same basic design from new suppliers. Nothing wrong with this in my opinion. After all, it's a 150 year old concept!
Below is a picture of the internal components that Howard Gorin offers on his website for these injectors.

[AnthonyDuarte]

I've toyed with the idea of making cones out of stainless. If you go for it, I would recommend staying away from 400 series and stick with 303 or 316.

I'd be interested in hearing your reason. 416 is very unlike the balance of the 400 series materials, in that it is free machining. I would agree if you hadn't included 316, or if you were considering 410, 431 or 440C. I'd even include 17-4 PH, which, thus far, has not been included in the discussion.

Harold,

My only thought is that 400 series, being a ferritic grade of stainless, is not completely resistant to corrosion at the introduction of rust. I'm no expert with stainless by any means, so I can't say with confidence that it would actually be a problem, but I personally would choose to avoid it. I've seen enough pitting in wire EDM tables to know its possible.

By the way, I hope my comments weren't taken to be discouraging. I take no issue with people making their own injectors. As someone that dug in from scratch and had a great deal of fun doing it, I can't in good conscience tell someone else not to. I hope to see where the project goes, especially if Greg goes the stainless route since it's something I've been curious about myself.

My 1¢
-Anthony

[Bill Shields]

no axe to grind or discouragement -> just facts and experience and what to expect so that people are 'eyes wide open'.

If you like a challenge, build a working injector...then another....

Personally, I would rather build a half a dozen duplex steam pumps...because I know that I can make all the parts, put them together and it will run.

Note...DUPLEX....

Regarding choice of stainless: would not really be based on corrosion resistance since the failure mechanism of the cones is not one of corrosion (usually)...think more erosion and / or impact resistance -> you want something really tough since several of the old injectors that I have clearly have distorted cones...the thin edges have been beaten out of shape by impact which is probably why they no longer work.

[Greg temp]

Anthony
Your right the whole point of making my own injector is to challenge myself,just to be able to say at the next convention at my local railway, (yes I made it,)I can order one online tomorrow if I wanted but what's the fun in that.
It's better to try and fail than not to try at all,

[Harold_V]

Thanks, Anthony. I understand your concern. Fact is, 416 heat treated is actually quite good at corrosion resistance, so I expect that the fear of rust introduction isn't one of real concern. Fragile components made of that material, properly heat treated, would most likely outlive the locomotive. It would address, far better than non-ferrous components, the erosion/distortion mentioned by Bill.

As is normally the case, stainless is best put in service in a passivated condition. Even the 300 series can rust superficially if they do not undergo that process.

H

[jma1009]

Hi Greg,

I would not advise making the injector cones out of stainless.

In any event it is unnecessary.

Your 'large' size injector required will have much thicker walls to the steam cone nozzle than those for 'small' injectors.

If you are worried about Bill's "wear" comments, simply make a few spare steam cones at the same time, or you can use the Bob Bramson type steam cone nozzle.

I would disagree with Bill regarding "wear". However brass steam cone nozzles of the non-Bramson type do get damaged by dezincification if the wrong cleaning regime is used.

Cheers,
Julian

[Trainman4602]

I have been watching this post for a while. It has become an injector free for all. Do this don't do that and so on.

I have two Super Scale Chicago style injectors on the 1361 and THAT IS IT. No god awful axle pump or your pump your guts out hand pump.

I have never cleaned the injectors now after 10 years of running they work every time.

Take it for what this is worth.

Constant cleaning even in vinegar will were out the cone. It eats them away there is the problem.

[Greg temp]

Just a update,for those who are interested,
Spent some time in my workshop getting a start on the injector,made the 9degree D reamer,from a broken tap,(I new I kept it for a reason)annealed it first then machined the tapper,surprised how easily it machined,,then reharden it. next is the 13 degree D reamer,,

[Trainman4602]

Greg
I though of using engraving bits. They are carbine and can be re ground with a diamond wheel.

[Greg temp]

That's a good idea trainman,I've got some for my dremmel,will have to investigate
I gave my D reamer a test and it worked well on phosphorous bronze,haven't tried it on anything harder yet don't want to distroy it

[Trainman4602]

You can get them on ebay cheap and near the degree you need. I though of doing this but have put the injector on back burner for now. I will work on it when I have time.

[Greg temp]

I've had a look as well,gotta love eBay they got everything you could possibly want