The Home Machinist!

FKreider wrote: ↑Wed Jan 19, 2022 5:44 pm

RR Ty wrote: ↑Mon Jan 10, 2022 6:19 pm If not, my current plan would be to build from stock unless I can find others interested in making a few sets of castings.

As someone who has spent a decent amount of time making patterns/castings and speaking with foundries I would agree that for a one off making as many parts out of bar stock as possible is the best way to go.

Finding reasonable foundries to deal with has become very difficult and for complex patterns and core boxes you really want to be able to drive there and discuss your designs with them before/during your progress in making the patterns to ensure they will be willing to cast what you have made.

Besides the "critical castings" like driving wheels and maybe cylinders it just realistically it just isn't "worth it" for a one-off engine, if your making a number of them then the economics start to work out a little better.

Just my 2cents. Good luck with your project.

I couldn't agree with you more. I recently reached out to a foundry about having drivers cast for my 3" scale Berkshire project. I had them quote casting the 3 different drivers in both gray ductile iron and also cast steel. I was sticker shocked at the numbers I got back. $650 - $800ea in ductile iron and $800 - $1000ea in cast steel, and this was based on a minimum order of 8 wheels of each. That doesn't include the cost for the patterns. Needless to say I will be making them myself from A36 steel on my mill.
I also contacted a different company about having cylinders cast. To have the patterns made, in this case sand printed, and have one set cast was in the $16-20,000 range. Fabricated they will be, and I will use a set of auto /truck liners for the bores.

Nyle

LIALLEGHENY wrote: ↑Thu Jan 20, 2022 2:32 am
I also contacted a different company about having cylinders cast. To have the patterns made, in this case sand printed, and have one set cast was in the $16-20,000 range. Fabricated they will be, and I will use a set of auto /truck liners for the bores.

Nyle

That's complete lunacy. The directly 3D printed sand molds are really cool but out of the realm of us hobbyists. They can clearly charge that kind of money to large companies and the government and get away with it.

If you really wanted to have the cylinders cast you would need to make the patterns yourself and then send them down to Cattail foundry where I'm sure they could do them for a reasonable price. Cattail makes all kinds of reproduction castings for steam tractors so its right in their wheelhouse.

Again its a lot of work and effort for one-off castings. Not impossible but not easy or fast.

Really just depends how much $ you want to spend. You might be able to hire someone like Dave Sclavi or Richard Ronne to make you cored cylinder patterns. Pretty sure Richard did a lot of pattern work on Roger Goldmann's challenger then of course Dave has worked on various cylinders etc. Probably others in the hobby that have made very high quality cylinder patterns you could hire for certain key components. I wonder if you could adapt something like Godshall heavy mikado cylinders for the 2-6-6-6. Or just use Jim's Berk cylinders.

Making wooden patterns shouldn't be beyond the ability of most of you guys. Metal working machines will suffice, and they provide a higher degree of precision, It's a matter of how much time one wishes to spend.

H

I have built several locomotives using built up cylinders including my cabforward , 3 SP daylights, a WP 2-8-8-2, a SF 4-8-4, 2 SP 4-4-0 s , a 12" shay. I'm presently building a 1.6 SP&S Z8 4-6-6-4. I use thick wall tubing for the cylinders and bronze liners. The pistons are stainless steel and the rings are hydraulic cylinder teflon. The valve rings are automatic transmission hook rings. The teflon rings have been in my cabforward over 40 years.

^^^ are you running superheat and if yes, to what degree?

Mountaineer

No

wonder if superheat would make more of a difference on an articulated than a traditional locomotive since they would have much longer steam supply lines, at least getting somewhat hotter and drier steam to the cylinders.

I was asking due to teflon rings. Was wondering if steam was cool enough by the time it got to cylinders to allow for a little superheat.

Appreciate the info from someone with long term experience like LSGOD.

I don't think you will get true superheat on a 1.5 scale locomotive. Just hotter more dry steam. Really form what I've read, you'd want a radiant superheater that extends to the back of the firefox, and uses hollow stays to transit the boiler length, not open flues ( prevents cinder buildup etc). I think the steam temp would drop quite a bit going through the longer steam delivery pipes on an articulated vs a standard locomotive. Hence a super heater might make a bigger difference.

Having engineered a 110-ton 2-6-6-2 Mallet with super heat for several thousand miles, superheat is a requirement.
The compound forward cylinders required the cylinder cocks to remain open for several minutes of operation before sufficient heat let steam out and not water.

By comparison, the recently rebuilt 2-4-4-2 "Skookum", with saturated steam supply, requires a much longer period of operation before the front cylinders begin to dry out.
This was apparently one of the reasons that Baldwin did not build more of these small compound locomotives.

Compound steam locomotives work better with super heat steam. Likely true in small scale too.
RussN

(crap! Inverted photo.)

Superheat is of vital importance. While it may be "steam drying" in some uses, I tend to believe that under most circumstances if a railway engine is loaded even remotely to scale (thinking of 7.5 gauge locos...smaller ones that's not usually a problem !), then superheat is absolutely happening.

The example I have is Caribou I in 3.5". If you don't keep the water level WAY up in the boiler, or use 1200w oil, then the piston valves will get "tight" due to the superheat & expansion...or at least if I'm driving they do. If you are ginger in how you drive, and don't get much superheat, then the engine is fine with a lower water level and/or using the TK460 that I have a pail of. (600w oil).

Anyone care to disagree that I'm getting fairly substantial superheat in order to have piston valves go "tight" ?

(and yes, they have been polished a tiny little bit, to ease the problem. Of course, there's not much between "too tight" and "too loose" on a 3.5" gauge engine !)

Superheat is the answer to latent heat losses.

James