Short question topic

[Goats spudz]

i need the exact thread dimensions as its critical it seals and it will be used at high pressure, i know its a non commercial tap size so ill set the lathe for internal threading,

[Petitlu]

1/2 BSP !

I have already used!

[jackssmirkingrevenge]

[Gun Freak]

First result
But as said above, it fits 1/2" BSP.

[Goats spudz]

First result
But as said above, it fits 1/2" BSP.

I want the reg output, not the tank
threads which are 5/8" UNF and actually its 3/8" BSP that fits, JSR kindly gave me that link which has a 1/2" NPS tap but i found one at work, and will be machining them soon, i didn't want to use "similar" threads because it will be used at 800-1500 psi.

[Gun Freak]

It's 1/4"-14, make sure your tap matches in TPI.

[Goats spudz]

Im getting a Machinist to make it on the Hurco cnc, will post pictures in this thread tomorrow.

[MrCrowley]

Since my piston hybrid requires a dozen hits from a mini-sledge hammer to seat the piston, I was thinking about buying a small (30mm diameter piston) pneumatic cylinder that will push the piston in to place and then be disconnected when the cannon is fired.

Thoughts?

[Crna Legija]

Since my piston hybrid requires a dozen hits from a mini-sledge hammer to seat the piston, I was thinking about buying a small (30mm diameter piston) pneumatic cylinder that will push the piston in to place and then be disconnected when the cannon is fired.

Thoughts?

why is it so tight? i'm guessing its the only way you could make it air tight.

[MrCrowley]

I epoxied the o-rings in to the grooves as I couldn't get washers that were the perfect diameter for the piston housing so it was possible for the o-rings to get ripped out of their grooves. Performance is probably better than before so I don't mind it too much.

[jackssmirkingrevenge]

I epoxied the o-rings in to the grooves as I couldn't get washers that were the perfect diameter for the piston housing so it was possible for the o-rings to get ripped out of their grooves. Performance is probably better than before so I don't mind it too much.

Get someone to machine you a proper piston and get o-rings to fit?

[MrCrowley]

The o-rings fit perfectly, the problem is the washer is probably 1.5mm smaller in diameter than it should be so the o-rings only have a small 'wall' on either side to hold them in place.

Been tempted to get one made but don't want to sink the money and effort and trying to explain to some Kiwi bloke why I need this metal stock to be cut in to a piston with two o-ring groves allowing it to seal and slide within this iron pipe with the seam removed.

[DYI]

Gee, here I am machining pistons to within 0.001" of the bore diameter to prevent extrusion of the o-rings when I could have just used washers and gratuitous amounts of epoxy...

I have no sympathy for you at all

[mark.f]

Been tempted to get one made but don't want to sink the money and effort and trying to explain to some Kiwi bloke why I need this metal stock to be cut in to a piston with two o-ring groves allowing it to seal and slide within this iron pipe with the seam removed.

Just give him a drawing with "Piston" at the top.

[warhead052]

Been tempted to get one made but don't want to sink the money and effort and trying to explain to some Kiwi bloke why I need this metal stock to be cut in to a piston with two o-ring groves allowing it to seal and slide within this iron pipe with the seam removed.

Easy, just say its for a homemade water hammer, you've been having problems with the hammer effect, and that the others you have looked for online cost too much with shipping. And if that doesn't cut it, well go with Mark's plan.