Tech Question

[Ronin]

Thread Pitch question gents.

 

 

I know there is a formula for working this out, but cannot seem to find it....

 

 

Barrel thread pitch is 18tpi, what length does one revolution (360 degrees) move.

 

 

For that matter it would help for 16 Tpi too..

 

 

I am on with a build using a BAT SV action and fluted barrel.

 

 

The SV has an extended "sleeve" forwards of the action shoulder making it arkward to measure how much to remove of the barrel shoulder to get the flutes lined up.

 

I usually use feeler guages, this time, I can't..

 

 

 

Your help, Ian, Dave, Neil, would be most useful :D

[1967spud]

would 1 inch devided by 18 be the awnser making it 1.41 mm or 55 thou

[Ronin]

Then use a division of the angle its "out" by eg

 

5 degrees out

 

55/5 - .011"

 

 

I think...

[1967spud]

Ronin not sure youre right there, as the datum point i.e. the top dead centre of the thread would be the same after 360 deg i cant see how the pitch would make a difference as its still moving 1/18 off an inch

[Guest dasherman]

If you need to turn it 5 deg its 360/5 = 1/72 of a rev. 1 rev @ 18tpi =0.0555" so 0.0555/72 = 0.00077"

 

PM me your address please Andy - I've a stock to send you.

[Ronin]

Mark

 

thanks for the help,

 

 

knackered, full of man flu so unable to compute properly.

 

 

Pretty certain there is a simple formula to work this out.

[Ronin]

Neil

 

 

thanks, that was what I was after - forgot to transpose degrees to the fraction of the angle - doh.

 

 

Incoming PM by the way.

[1967spud]

i was nearly there,

[Vermincinerator]

Looks like a good rap on your action wrench with a piece of 3x2 will align the flutes no problem without affecting headspace.

 

Ian.