Piping Kits for Locomotives

[cbrew]

ah...that was the trick...get a glass that fits the ball.

glass is 1/2 ID, ball 3/8

wow, that is a big glass,, thanks

[Bill Shields]

size matters here...

[cbrew]

size matters here...

maybe if you are blind

[Bill Shields]

actually...I created this ball in the float for a friend who was totally blind in one eye and had 10% vision in the other (Glaucoma).

this was the only way that he could see the water level in the glass. For him I put a black card behind the glass so he had a white ball on black background.

even with me sitting directly behind him while running to read block signals and help with other things, he REFUSED to sit behind the steamer unless he could see the water at any time with no assistance....very old-school about that.

this was our only solution that worked for him....and I have had a lot of fun with it over the ensuing years...everyone wants to know how I get a ball that will float and withstand steam temps.

[cbrew]

makes since,

[Greg_Lewis]

Something else to think about is what thread system to use. Some folks like taper, some like straight. Personally, I tried both and wish I'd used straight for everything. Model taper tapes and dies are quite expensive. You can get 40 tpi straight thread taps from Victor Machinery at a good price in nearly any size you want. This thread works better on larger sizes such as 5/16 and 3/8 since it leaves more wall thickness on the tube. Fittings supplied with tapered threads can be easily re-cut with straight. And straight taps are easier than taper to run to the bottom of a hole or the turn in an elbow. You can screw them down tight and, as Chris has said, use Loctite to seal them. I'm sure someone else will make the case for tapered threads, but I don't like 'em.

[Bill Shields]

I hate straight threads for small pipe fittings. It is OK for 5/16 and 3/8

Early on in my live steam career, when much was modeled after UK practice of straight threads and crush washers, I fought it like everyone else.

1/4-40 TAPER PIPE requires appreciably no more wall thickness than 1/4-40 straight and are no more real trouble in fittings than straight.

Realistically, if you are worried about the cost of the taps and dies as a reason to use one over the other then I would have to say that perhaps you are in the wrong hobby.

I just recently replaced a 50 year old boiler on a friend's loco that had straight fittings all over the boiler and they were always leaking or not lined up correctly. Every bushing on the boiler is now taper pipe (of one size or another ranging from 1/4 MPT to 1/16 NPT) and was zero trouble to assemble and have leak tight.

[Greg_Lewis]

Bill makes valid points. I know one builder who just standardized on 1/4 MTP for everything, and his engines are top quality and good runners. Regardless, pick one and stick with it. My mixture of the two now means that I have to figure out which is which when I do any disassembly.

[Bill Shields]

and I have an old LBSC Juliet on my bench that has a mix of straight imperial, tapered model pipe, BS straight pipe, BA bolt and Metric threads...so I will trade you sorting problems any day (but then I volunteered for this job)..

Who in the heck ever saw the need for 47-1/2 TPI?

In reality, it is close enough to 3-48 that I am going to just ignore the difference and play dumb (which is really easy)....

Greg:

big problem is not in disassembly...is in ASSEMBLY. Any monkey (like me) can get something apart. Getting it together so that it fits and doesn't leak

[Greg_Lewis]

Bill: I just don't bother to put it back together.....

[Bill Shields]

I have a couple of those also...all the parts are glass jars, pill bottles..Tupperware...to keep them organize.

the problem is that while all the stuff is 'together' I have no idea to which 'project' they belong.

[Harold_V]

Bill (and his camel) has it right. Pipe threads are very different from straight threads, which require clearances for all features in order to be assembled. That, naturally, leads to issues with sealing. Pipe threads, by contrast, at least in theory, are 100% V threads and are capable of being assembled with zero clearance. Assuming the threaded portions are reasonably round, they can be self sealing. Threads generated by thread milling with a CNC are a wonderful choice, as the familiar step left by dies and taps isn't created in milling.

I've not piped an engine, but I can assure you, should I live long enough to do so, tapered threads will be my choice. I clearly don't understand why anyone would choose to fight with straight threads that must be assembled without leaking.

Harold