SpudFiles

Its been in my head for a little while from now, making a look-alike airforce condor wit a 7 x 12 mini - lathe.

The trickiest part would be no.2 as i will have to thread it to male 1/2 BSPP.

But, there is a little flaw in the design, i cant see where i can get a 1/2 bspp coupling/union (part no.3).
Can i remedy to that by tapping an aluminium piece? If so i could be also making the part no.2 with a 1/2 bspp die instead of threading it on the lathe.

I will need to, with a high pressure hand pump, get 300 psi, so no plastic here.Will aluminium be safe?


The drawings are an hammer valve, wich is connected by a modded co2 tank pin valve to an co2 tank (part no. 6) to the left.

NO.3 would be this, but 1/2 bspp. I cant find one.
http://www.orphanespresso.com/images/Fe ... itting.jpg


Or, maybe there is a metric coupling that could fit well?

To get your threads right up to the hex piece, place your bit on the back side of the work piece, starting at the hex and put the lathe in reverse. It will thread properly (right hand) and you won't have to worry about it running into the wider work piece. BSPP is a 55deg thread, I think, so you'll have to make a thread cutter that will cut at 55deg.

You don't necessarily have to duplicate their parts, exactly. If the finished size is right for your needs, why would you need the same threads, unless it is to replace parts on an original.

EDIT: Aluminum should work OK. T6-6061 or 6063(for outdoor use). If some PVC can handle close to 300psi, then aluminum in the same size will definitely do OK.

To get your threads right up to the hex piece, place your bit on the back side of the work piece, starting at the hex and put the lathe in reverse. It will thread properly (right hand)

I am not shure to get what you mean... I dont have any hex piece(dont even know if it exists in that 1/2 size)so you mean an aluminium tube? and what bit? the tap? If i am right then i understand.else... explanation please... :scratch:

You don't necessarily have to duplicate their parts, exactly. If the finished size is right for your needs, why would you need the same threads, unless it is to replace parts on an original.

Do you mean by the real airforce talon ss? Dimensions and pieces are'nt the same, but look alike the co2 adapter to replace the hpa tank on the real airgun.

http://www.airforceairguns.com/images_n ... %20web.jpg

Ahhh, I was referring to doing the tapping on the lathe with a standard cutting tool, but with the tool post on the opposite side of the lathe from where you stand.

The hex piece was referring to the hex nut part of parts 2 and 6. I've cut many threads right up to a shoulder like that, but you really have to do it in reverse so your cutting tool isn't going to end up crashing into the shoulder part of your work piece.

I thought CO2 tank fittings used 0.825-14NGO-RH-EXT or a CGA-320 fitting.

Part no. 3, well, you might not find exactly what you need, ready made, but if you can get hex (or round) stock (or even pipe the right size) you can drill it out until you can thread it with either the lathe or a tap.

BTW: Which 7x12 did you go with?

Ahhh, I was referring to doing the tapping on the lathe with a standard cutting tool, but with the tool post on the opposite side of the lathe from where you stand.

:scratch:

But if i place the bit on the left side of the tool post, why would it collide?

standard cutting tool

:scratch:

Dont i need a special angle bit? Like 55 or 60 degrees?

I thought CO2 tank fittings used 0.825-14NGO-RH-EXT or a CGA-320 fitting.

Thats the outlet thread, wich is also 1/2 BSP (British Standard Pipe) wich uses o-rings on the shoulders to seal.The inlet thread of an co2 tank is 5/8-18 UNF.

Instead of modding a co2 paintball tank pin valve (removing the pin) and using a 1/2 bspp(CGA-320)union wich is hard to find, i will make the "pin valve" in aluminium and replace the CGA-320 by a metric thread instead and replacing the 1/2 bsp union by a metric one, wich is availible at my local hardware store...

Little schem to show what i am talking about.

Seems to me that I have an adapter around somewhere for those little prefilled co2 bottles that has a CGA-320 thread on one end. When it is screwed in the whole way it has a valve on it that acts like what you are describing. My problem was that it was very leaky while screwing it on tight. It would pierce the bottle a little too soon and I had a heck of a time twisting that thing on without losing half my CO2!

Ahhh, I was referring to doing the tapping on the lathe with a standard cutting tool, but with the tool post on the opposite side of the lathe from where you stand.

But if i place the bit on the left side of the tool post, why would it collide?

standard cutting tool

Dont i need a special angle bit? Like 55 or 60 degrees?

I thought CO2 tank fittings used 0.825-14NGO-RH-EXT or a CGA-320 fitting.

Thats the outlet thread.

Take a look at this ;

http://www.shop4paintball.com/Co2_Pin_V ... pinvlv.htm

The 5/8-18 unf thread is where there is an O-ring.
I would replicate this piece but with a metric thread replacing the CGA-320, all in aluminium.


QUESTION ;

How can i get the closest possible to the neck with a lathe? Or i will have to buy a 5/8-18 unf die?

Buy a long piece of high speed steel and grind the tip as needed. If you only remove a little metal at a time you can get away with it. One of my lathe bits is 8 inch's long.

Ok, thanks.

Now i know at least that it can be done, i just need to practice, get the right tools and thats pretty much it...

Making the hammer and trigger will be easier ( on the prototype at least, il have to make it look like the real one )



According to my schematics, what would be the maximum safe pressure (not the one at wich it blows up, but where i can safely handle it?) ?

Demon wrote:According to my schematics, what would be the maximum safe pressure (not the one at wich it blows up, but where i can safely handle it?) ?

Are you talking about safe operating PSI ?

Yes, or in bar if you know.

Would 600 psi be totally unsafe or ok?

Demon wrote:Yes, or in bar if you know.

Would 600 psi be totally unsafe or ok?

I don't know and wouldn't venture a guess either. Looks like a good situation to do some safe testing...

Normally your tool tip is pointing away from you. Normally you start the process of cutting threads from right to left, toward the chuck, power feed in the forward position. If you do it in power mode with the motor running, you'll have a good chance of running the tip into the work or the chuck. By starting on the chuck side and going right, you can actually catch the index on the right number and use the power feed to turn your work. BUT, you have to move the tool post to the other end of the cross slide and point it back toward yourself. Plus, you run the lathe in reverse so you can cut RH threads and move the cross slide to the right. Turning the lathe by hand is what a lot of folks do, but with a tap or die.

For the threads you mentioned, they are 55 deg threads, not 60. You can cheat and take a preground 60 deg cutter and trim it on both sides. Saves you some time and effort. For a bit that can go to the neck, make your 'V' shape at the edge of the bit instead of in the middle. Works for me. Take your time and cut a few thou at a time and it should turn out pretty smooth.

Edit: If you're concern about aluminum not being strong enough, then use brass. It is way better and machines very well.

Ok... I get it !

Its because i wont have enough time to stop the autofeed cutting and probably damage the lathe with a collision of the shoulder and bit, so reverse the speed and toolpost.

Thats a brilliant idea

I might try brass, but i will make the prototype in aluminium not over 160 psi until i get brass valve and high pressure pump (300 psi)
I might have to tweak the valve cap when i switch of air pressure.

You really hepled me, thanks a lot.

Take a look through this page www.palmers-pursuit.com They have a great selection of pneumatic parts and regulators. How big of a ballast will you have? also, how big of a main valve orifice?