Small blowdown valve?

[DianneB]

I have a confession. I almost never blow down my 1.5" scale American because it fitted with a small "radiator drain valve" (1/8 pipe thread) located between the drivers and behind the side rod. It is hard to get at, takes multiple turns to open, and sprays steam around your fingers when it is open .... hot HOT HOT! LOL!

I'd like to replace this with something that is quick-acting and not a finger-burner! The Everlasting valves look nice but are a bit large and more modern looking (also expensive) - I am trying to stick to the 1860s time period. In the UK they use a right angle valve with a square head for the operator and they are inexpensive but I can't find any drawings for them.

What other alternatives are out there? Buying is preferable but I don't mind making one to save some $$

Thanks for the help gang!

[Bill Shields]

If you need a design for such that is not a 'radiator' type of valve, you can get on from my Tom Thumb magazine article, or I can send you PDF files if you like.

Instead of the square head, I like to use a socket head set screw, made from either stainless or hardened steel...much easier to operate

If you make a special wrench to grab the existing "T", what you have will work....

[Builder01]

Here's the drawing and photos of the blowdown valve I made for my loco. I made the body from hex so I could make sure it was driven into the bushing on the boiler tightly. The position for the discharge pipe was marked after the body was screwed into the bushing. Then removed, and tapped for the discharge pipe.

You almost never blow down? Is your boiler steel?

David

[DianneB]

Is your boiler steel?

No, copper.

Bill: sent you a PM.

[Builder01]

By the way Dianne, you can see the thread relief on the part that screws into the valve body. This may help to answer your other question about threading up to a shoulder.

David

[mattmason]

I use a ball valve. Quick acting.

[Builder01]

Matt, a ball valve would probably work just fine, but, you need one rated for steam temp. Also, it must be of a short enough profile to fit between the connecting rod and the frame. It also needs to have the same thread as the bushing in the boiler. An adapter would only make it longer. Maybe you could tell Dianne where you got yours, the thread it has, and what the total length of it is.

David

[DianneB]

I found a steam-rated ball valve that I am using as a throttle and it has 1/8 NPT (female) threads but it is almost 2" long and would not fit behind the side rods.

[JBodenmann]

Hello My Friends
I just finished up the blowdown valve for the Disney American. It's an odd valve because it fits between the front of the fire box and the front driver axle. The operating shaft has a small stainless steel U joint (Mc Master) and then angles up through the running board on the fireman's side to a hand wheel above the running board. Its such a tight fit that you have to remove the bonnet and stem so that it will clear the left hand eccentric and strap. If you look at photos of the CP 173 you can see the hand wheel above the running board. The outlet pipe wiggles around and exits in front of the right hand driver. I think I have some scribbles of the valve if you are interested. It wouldn't be difficult to make, just some brass and silver solder with a stainless stem. The little hand wheel would probably be the most difficult part to make.
Happy Model Building
Jack

[JBodenmann]

Hello My Friends
I wasn't too clear about the part about removing the bonnet and stem. It's only removed so you can thread it into the front of the firebox. Probably a 1/8" iron pipe thread. After you thread it in tightly you then replace the bonnet and stem. Its a pretty tight fit.
Jack

[Dick_Morris]

I think I have some scribbles of the valve if you are interested.

Yes, please.

I have a 1/8" NPT ball valve buried under my RRSC CP-173. A street L threads into the throat sheet, the valve is pointed downward, and another L and a nipple direct the steam to the side. To actuate it I use a length of 1/8" rod with an L bent in the outboard end and a slot on the other that I thread between the spokes on a driver. The slot mates with the valve spindle. It works, but it's far from the best arrangement.

[JBodenmann]

Hello My Friends
Here is a photo of the blowdown I made. The 1/8" iron pipe thread fits into the front of the fire box. The valve stem points upwards towards the fire mans side running board. The union faces upward and through a street ell towards the engineers side. The outlet pipe which is 5/16" wiggles around and exits in front of the right hand front driver. The little hand wheel is on top of the running board. I'll post couple more photos in the Disney American thread.
Happy Model Building
Jack