Hi James,

I will upset a few by saying niether. I have built both Stroudley and disc type. Both leak. I have now converted to a simple screw down type. Easy to make and dont leak. Most useful at boiler test time.

Regards

Bruno

Posted by Bruno Taylor on 04/02/2018 17:52:19:Hi James,I will upset a few by saying niether. I have built both Stroudley and disc type. Both leak. I have now converted to a simple screw down type. Easy to make and dont leak. Most useful at boiler test time. Regards Bruno

Posted by David Wasson on 04/02/2018 22:14:20:My vote is for the screw down type, especially for a beginner. It has the fewest parts, easy to make, and seals tight 100%. David

+25 from me!

Attached should be drawings for two screw down regulators. Martin called them pin valve regulators. The larger regulator has it's dry steam feed from the tube that is pointed upward. This tube would go up into the steam dome. This is the type that was used on Evans' Super Simplex. This is the better design of the two.

If you don't have a steam dome, the smaller regulator might work. It gets it's "dry steam" through the pattern of holes drilled into the top of the regulator tube. But, it is easy for boiler water to splash into this pattern of holes. This regulator, along with many other boiler fittings, was described in Vol #3228 of ME.

The crossed drilled pin that connects the valve spindle to the "handle" spindle, is buried in a counter bore inside the threaded center part. This is so if this pin ever worked it's way out, or loose, it would be captured in the counter bore. It would be not good if the regulator was open, and the pin came loose! Take the extra time to make the center part exactly like the drawing.

David

Edited By David Wasson on 06/02/2018 02:05:51

Edited By David Wasson on 06/02/2018 02:07:31

Hi James

just a word of warning, if you do use the Simplex design, do not use brass for the regulator tube, it will dezincify over time inside the boiler.

I have just had to replace 2 simplex regulators with this problem. I have made the replacements using stainless steel tube.

Colin

Yes it can affect boilers or bushes made out of brass.

Neil

Hi Julian,

Yes, there are probably more "correct" regulators than a screw down type. I guess we need someone to post a few more drawings and photos. For ease of construction, the screw down type is pretty simple and effective and does not leak.

I'm not sure what you mean by "prototypical angle" of opening. If you mean, where the handle comes to rest when it is open or closed, if you add a few more tapped holes, like I did, on the threaded part, the angle of the handle can almost be set anywhere you want.

Yes, it is true, you should certainly open this type of valve before everything has cooled down after running. This is actually my normal procedure for all of my valves, not just the regulator. I recommend that every one should do the same.

David

Edited By David Wasson on 07/02/2018 23:02:41

If a screw down regulator had a flat face you would need to open it by 1/4 diameter to get full area opening, allowing for a 90 degree point my sums suggest this increases to nearly half. Taking the above example with a 3/8 bore you need 3/16 lift, which with a 3/8 BSW 16 tpi thread is 3 turns. Fortunately you don't need anything like full opening, but it can be seen that taking off the pointy bit to say 5/16 diameter would reduce the opening you do need substantially.

I would suggest using a high pressure (the type with a gland on the operating spindle), stainless steel ball valve.

it would easily fit into the dome, and give you a leak free silky regulator, and a very controllable loco.

I have decided that I will never use any other type.

Regards

Brian

Hi John,

Your regulator looks great! Yes, you are correct, I run with the regulator open about 1/8 of a turn, anymore than about 1/4 of a turn does nothing.

As for making the tube out of copper, I would be careful. When you close the valve tight, all the tension is on the tube and transferred to the three little flat head screws at each end. Copper is pretty soft and it might actually stretch at the screw holes. Given time, it might eventually break. Just a thought.

David

As promised here is an image captured from Fusion 360 which I have used to develop my next regulator. The body has a PEEK bearing face pressed in and an O-Ring at the Backplate. I have put a 15 degree chamfer on the valve itself.

Aha, If I show the whole thing, perhaps it helps. I am going to put two short inlet pipes in the top like this. The plan being to put the regulator body through the backhead flange and then insert the short pipes in through the safety valve bushes, taking care not to drop them! The idea is to collect steam from the highest and dryest part of the boiler. The boiler is domeless so cannot do the taller style of collector pipe.

I don't think it is too complicated. I will drill through in several diameters to form the step for the PEEK valve face to be pressed in, the valve cavity and finally for an M10 thread. Reverse in the chuck and then drill and tap the other 5/16×32 ME for the steam pipe. The PEEK valve face being a press fit from the M10 threaded hole.