Small globe valve. (How to make)

[gbritnell]

Gentlemen,
When I attend model engine shows some of them supply compressed air for the steam models, or air models as the case may be. For years I have had a little brass manifold with some aquarium valves on it. It works well enough but I decided I needed to class it up with some new valves, so five new ones were in the works. I know it's not a complicated build like making an engine but thought that there might be some who could gain from a photo essay. I started out drawing out what I wanted on AutoCad and then headed for the shop. First up would be the valve body. It would need to be a fabrication because of the shape. I have quite a few high speed steel forming tools that I have made over the years but I didn't have one for the body of the valve so I ground up another. I first roughed it on my bench grinder then with a small mounted stone in my Dremel I cleaned up the radius, matching it to my radius gauge. First I turned the .50 brass stock down to .36. Why not use .375 stock? I find that when using a forming tool everything needs to be as ridgid as possible, stock and tool, so I like to use larger stock to eliminate any chatter.


I then put in my small radius tool to do the blend radius at each end. I have a Trava-dial gauge on my lathe so I touched off to the end of the stock and moved over the required amounts, plunging in to the needed depth

Then came the body forming tool. It is a .18 radius. I find that you want to go to your depth and as soon as you get there back out before it sets up a chatter. You can eliminate the chatter by slowing down the lathe but with my Logan that means shifting the belts so I have good luck this way.

Next came the drilling and tapping for the for the valve spindle tower. Not much explanation is needed here, just a couple of pictures.

 

[gbritnell]

Next it was over to the dividing head. I have a set-true chuck on my head so I indicated the stock to get it trued up. This chuck is very repeatable but the chuck on my lathe is .002-.004 out at times so I always indicate before cutting.

Next some more center drilling and then drilling for the right angle part of the valve.

After this step the piece was parted off leaving .01 for cleanup.

I then made up a 10-32 mandrel to mount the valve body on so that I could clean up the cut-off end and drill and tap the bottom.

Next came a small bushing that would fit in the right angle piece and the valve body to line everything up for silver soldering. The bushing OD. was the tap drill diameter for the outlet piece. It only had a .006 wall.

 

[gbritnell]

Here are several pictures with the outlet pieces pressed onto the sleeve.

Now it's out to the garage to do my silver soldering. I threaded the end of a piece of steel to mount the bodies on. I use steel because it doesn't transfer the heat as much as a piece of brass would. I only fluxed around the mating surface as everything was clean from just being machined. As the flux gets hot and turns liquid it wicks into the seam anyway. I have a full sized torch with a small tip but it's not small enough for some of the parts I make so a number of years ago I invested in a tiny oxycetylene torch by The Little Torch Co. It has 5 tips, the smallest being so small it's made with a ruby. Probably lasered in. I also had to buy the oxygen regulator for this torch because with the largest tip it only uses 5lbs of oxygen. The acetylene regulater works fine.

After soldering I boiled the pieces in water to clean off the hardened flux and then I put them into a glass bowl with a diluted mixture of water and sulfuric acid. I had read about this when building my traction engine boiler many years ago. I left them in the solution for about 2 hours. It doesn't make them shiny but it removes any burnt marks or traces of flux.

Next I made up the spindle tower, the valve stem and seat and the packing nut. The spindle thread is 1-72. It's made from bronze. I had to solder the seat onto the stem because I wanted an area with no threads so that the packing would have a smooth surface to seat against. Working with something this small doesn't allow for a larger screw thread than the spindle so you have to improvise.

 

[gbritnell]

Next came the handle. I wanted it large enough to get my fingers on but not so large as to look odd with the little valve. I layed out a pattern of 5 holes that would fit between the hub and the outside rim and have enough stock between them to still have some strength. I first turned the OD. of the stock, .613 and then relieved the face .01 out to the edge of the rim. The rim was formed with another ground forming tool. The radius is .03. I then put the piece in my dividing head and turned the head vertical. It was indicated true, offset the required amount and then drilled.

I drilled deep enough to get five pieces plus the width of the cutoff tool. No sense having to do this twice. After the first piece was cut off I made a split holder so that I could put it back into the lathe to face, recess and finish the rim on this side.

The final few pictures are of the assembled valve. I screwed the handle onto the spindle and then locked it in place with a .125 hex nut.

I hope this was informative, if not, at least entertaining. As the members of this forum have come to find out, I just enjoy making things on my machines, from the mundane to sometimes the extreme.
gbritnell

 

[Mainer]

Great sequence! Can you post the AutoCAD drawings?

 

[bearcar1]

G, thank you for that outstanding 'how to'. Marvelous! :bow: I have always purchased the cast forms but I may attempt your method the next time.

BC1

 

[steamer]

Wonderfully done Mr. Britnell!

I like that!......

Dave

 

[RonGinger]

Very nice valve, but I do not fully understand the valve seat. Can you post a section drawing that shows how it works.

thanks

 

[rake60]

Beautiful!

Rick

 

[cobra428]

Rake didn't say it quit right

Beeee.....uuuu....tiiii.......full
Tony

 

[gbritnell]

Thank you gentlemen,
Ron, Here's a quick fix of my AutoCad drawing. I had to clean it up to post. My working drawings aren't quite like my finished drawings.
gbritnell

 

[gbritnell]

Ron,
To answer your question about the valve a little better. The spindle tower is threaded 1-72 from the 10-32 side as deep as my tap will go. The tower is then put into a threaded plug and the top side is threaded 4-48 and the spindle hole is relieved .073 diameter about .125 down. The spindle is threaded as you see in the picture. I screw it through the spindle tower and then thread the valve piece onto it and put a drop of solder onto it. There's probably enough room to just use a thin locknut on the top side of it but being as I'm just using it for air control with no heat involved I just used the solder. Once it's assembled it won't come back out of the tower but it really doesn't need to. The sectional view shows the thin sleeve that goes into the outlet neck and the body to locate for silver soldering.
gbritnell

 

[gbritnell]

I see an error on the sectional view. The thread on the spindle tower should go all the way up to the hex shoulder. If anyone would like a finer resolution picture in a different format please let me know. Photobucket only takes jpg's so the scan quality isn't very good.
gbritnell

 

[Maryak]

gbritnell,

Thank you so very much for this thread. :bow: :bow:

You have just brought my thinking about a model boiler one step closer to actually getting something done.

Best Regards
Bob

 

[RonGinger]

Thank you for the drawing, a very clever design, and a very nice series of photos to show how its done.

 

[Paolo]

Great!!! I did one horizontal...Nice idea to use the ex instead the plate!!!
Cheers Paolo

 

[ChooChooMike]

:bow: :bow:

Excellent tutorial and pictures !

 

[itowbig]

VERY nice thank you. this is good for me mr newbie. i had a small clue as how to make them . but now i have a really good clue with pics on how to make them. :bow: and im sure other newbies like me will be very grateful even if they dont post anything. (hint hint newbies) THANK YOU :bow: very informative in deed

 

[4156df]

Great post. Tips like using 1/2" rod instead of 3/16" for rigidity and how to grip the handwheels, etc., etc. are priceless.

Dennis

 

[Metal Mickey]

Excellent post and wonderful sequence of photo's. Well done and an inspiration to us all for high quality work even for small items. :bow: :bow: :bow: