High flow valve I made this week
Hey guys, Im going down the regulated route and decided that my modified talon valve wouldnt be able to dump the space of regulated air quickly enough so I decided to make a valve.
I had some stainless steel lying around and decided to give my little chinese lathe a workout. I roughed out the shape and bored out all of the internals. However I cant cut threads on my lathe and am about to order some dies for the threads.
Today I made the valve stem from another piece of stainless i had. The stem where the ports are cut is 10mm and there are 3 5mm ports.
Hopefully this should give me a good velocity with my regulated tank.
Oh and I worked out today that my barrel had just over 10cc volume and have designed in 20cc of regulated volume which should give me less of a pressure drop and would also be suitable if I wanted to get a 24″ barrel. Do you think this is okay?
Anyway, too much talk and not enough pics 🙂
Dave
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It sure is nice when you have access to quality tools and machines.
Today I fully polished the stem and valve body which made it look LOADS better.
Still trying to find a suitable valve return spring, 10mm ID 13mm OD
Dave
I have sure been wanting to get me a small lathe myself guys… I use to work where I had access to a mill and a lathe all the time and sure got use to that…
I have found myself forced to blacksmith any of the stuff I have done… You guys have some good stuff going on here and sharing with the rest of us… Way cool…
Well guys, My gibs are not tight at all, they move nice and smooth. My ways end up prettymuch constantly bathed in oil so I dont think its running dry.
I did notice that the tip towards the tailstick was slightly bent which gave me a tight spot in rotation of the chuck.
I think it needs a strip down and re-lube and I’ll see if that sorts it.
I have a metric leadscrew but when Im cutting imperial threads, I keep the half nut engaged and use the reverse method.
Dave
Eddie, you hit on something there…. I wonder if Dave has tightened the gibs up too tight or it came that way? might be running pretty dry as well.
Dave, check the slide it should slide easy back and forth even by pushing it.
Are you leaving the half nuts in for metric threads? and doing the reverse thing?
Walter….
Dave like Voltar said you should be able to cut threads with your lathe I was a machinist for 35 years worked on all kind of lathes and mills sounds like something somewhere is putting a load on it when in threading mod, your half nut slipping out like that might be a good starting place to look for a problem might be bound up in that area I would talk a look 🙄 take if off make sure everythng is turning easy and not bound up!
built that valve body and all went well:)
A lathe is a great tool but I wished that I had saved up more money and bought a bigger and more powerful one. But my little one has done well for me.
I agree entirely with you Voltar, the threads were lathe cut.
However on one of the passes, the half nut jumped out aqnd dissengaged. This took out a big chunk and ruined that part of the thread. But this can be salvaged because the ruined part was in the first couple of threads and the threaded portion of my valve is over twice the length of a standard AF valve. I will just cut down the first 0.25-0.5″ of the threads and finish the threads with the die that I have coming.
This still leaves me with threads 1.5X the length ov a standard valve.
Dave
EDIT: Voltar, ar you aware that you can cut metric threads with an inperial leadscrew with a very small percentage innacuracy?
Look in the referance of the littlemachineshop website for a calculator for gear combinations.
Good luck with the threading!
I cut the 7/8-14 today and had a go at the M18 x 1.5mm and managed to F**K it up, but I quit while it was still salvagable and I have a die comming that will clean it up nicely.
I move closer each day 🙂
Dave
Don’t compromise safety on that 18mm thread. If it ain’t perfect after the die then IMO you would do well to start over.
Was this lathe cut threading? I’m about to try my first go at metric threads on my old Boxford 9×24 🙂 see how that goes….
Walter…
that’s badass Dave , wish i had a lathe.
You guys would laugh your ass off if you saw what it took for me to make my shroud.
I should have takin pictures and documented it, for viewing pleasure. 🙄
I cut a O-ring groove in the stem and installed a O-ring for super air tightness but kept it nice and smooth riding.
I cut the 7/8-14 today and had a go at the M18 x 1.5mm and managed to F**K it up, but I quit while it was still salvagable and I have a die comming that will clean it up nicely.
I move closer each day 🙂
Dave
Im using a Chester Conquest lathe which is a re-branded version of the 7×14 chinese lathes
http://www.chesteruk.net/store/conquest_lathe.htm
I was originally using the cheap carbide tools (Not indexable inserts) but I seem to be getting a much better finish from Home ground HSS so I might try and grind a threading tool today and have another go at it
Dave
Dave, what kind of lathe are you using? what size?
tooling?
pressure calcs look good 🙂 thank you.
Yeah my bad, I was just saying that as I was working out the general shape and function. I was following blodnobs design. I was/am in no way trying to pass this design or whatever as my own.
Im not sure what’s up with my lathe but I suspect that there is some unwanted tightness in either the gear terrain or the saddle which is making the motor bog down when threading.
Im only spitballing with the wall thicknesses, its 11:15 PM here so all the numbers will be crunched tomorow……. oh what the hell, might as well have a go at it now. I do have some large stainless steel round bar that I have been working on but im not sure if my little lathe will take all of the drilling and boaring.
Using a tensile strength of 49,312.8309 psi
An OD of 1 3/8″ and a wall thickness of 0.31496063″
P = (2t x S) / O
p = (2*0.31496063*49,312.8309)/1.375
This gives me a BURST pressure of 22 591.4186 psi
With a safety factor of 5, this still gives over 4500 psi
I can do the maths when I need to (An I know that I do when working with high pressure etc.) and was going to all along but I was just roughing it out in my head.
Dave
Wow!!
Looking good Dave… 😎
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somtimes hard to find where you are getting bogged down on power for threading all I can tell you from my experience is threading is a really neat thing to do on a lathe it was one of my favorite things to do! Just keep checking any drive components that have to do with your threading I am guessing something is causing you a prolbem why you having trouble threading I know it can be hard to find sometimes we had problems with are lathes and mills at times only problem there to many hands in pot! I always tried to let the guys I worked with know there was a problem and even worked on my own time not to be a know it all just after I figured it out I liked to get it fixed and make notes on what I did so if it occured again at least I could tell someone or fix it again and maybe better the third time!! LOL