Hi
Well its been slow going of late, not much shop time but I have managed to make this little valve.
While going through my drill drawer looking for something else I came across a taper reamer I have, I don't know why I have it, it's just one of those things you pick up. Anyway it gave me the idea to make the valve you see here. The correct method is to make a tapered D bit (described by John Bogstandard somewhere on the forum but I can't find it at the moment) and while the lathe top slide is set over make the tapered part of the valve at the same setting thus ensuring that the two parts fit together ok. I decided to have a go using the taper reamer I have ( I believe they are used for making the holes that tapered pins are knocked into).
I started with a bit of 7/16 brass held in a collet, drilled through and then the tapered reamer used too make the tapered hole.
Then I held the reamer in a collet and with a dial gauge set the top slide over until I achieved a zero reading along the reamer. his operation turned out to be easier than I thought.
Now with the top slide set over I turned a taper on a bit of brass.
A trial fit of the two parts. They fit together quite well. I carried on turning until I had about 3/8 extra sticking out of the body.
Next job was to turn the end down to 3mm and thread.
I used the tapered part as a mandrel to hold the body which I turned down to 10mm.
Centered in the milling machine and cross drilled 1/16.
Two pieces of 1/4 brass about 7/16 long are threaded 1/4 x 40 and drilled through 1/16. Each piece is held in a mandrel and the ends profiled with a 10mm cutter to match the radius of the body.
Here they are on the body.
Here the parts are assembled and held in a clamp. Note I have used a bit of 1/16 brass rod to keep the parts in line.
After silver soldering.
After a pickle to clean it up and the valve part has a about 1/2 inch turned down and parted off. I had to run a 1/16 drill through the body to clear the bit of 1/16 brass I used to keep the parts in line.
Very carefully heat up and bend over to form the handle.
Make a brass washer, about 1.5mm thick.
Assembled with a short length of stainless steel spring.
After a polish up, the finished valve.
I had one problem with the method I used. When I silver soldered the parts together the pressure of the clamp squashed the body slightly making the tapered hole oval. I had to run the tapered reamer through to clean it out and re cut the hole. Now of course the tapered valve part is too small so I had to make another (the one you see here) to fit. Next time I will do the soldering first then cut the tapered hole.
Anyway I got there in the end and the valve seems to work ok.
[ame]
http://www.youtube.com/watch?v=og2nmhnmKzw[/ame]
I'm not sure yet whether I will use this valve on the engine but its been fun.
Cheers
Rich