brass gun help

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jordzan
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Joined: Thu Jul 23, 2009 10:42 pm

Sat Aug 01, 2009 12:56 pm

i double checked and its definitely .408 ID .... 10.34mm

To find volume.. Take the cross section of the cylinder and multiply by length. To find the cross section, use Pi times the radius squared.


got some measurements of the piston barrel and tried to get the pilot valve volume, definitely messed something up in the maths ... any ideas?

3.1416 times 1.299 (piston barrel radius) squared equals 16.6464

16.6464 (cross section) times 1.417 (piston barrel length) equals 23.587
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Technician1002
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Joined: Sat Apr 04, 2009 11:10 am

Sat Aug 01, 2009 2:09 pm

jordzan wrote:i double checked and its definitely .408 ID .... 10.34mm

To find volume.. Take the cross section of the cylinder and multiply by length. To find the cross section, use Pi times the radius squared.


got some measurements of the piston barrel and tried to get the pilot valve volume, definitely messed something up in the maths ... any ideas?

3.1416 times 1.299 (piston barrel radius) squared equals 16.6464

16.6464 (cross section) times 1.417 (piston barrel length) equals 23.587
??? WTF.. Diameter is 0.408. Radius is 1/2 the diameter.. 0.204. 0.204 squared is 0.041616. Times by pi.. 0.130740826 square inches.

In metric.. 10.24 mm.. radius 5.12 mm. 5.12 squared is 26,2144, Times Pi. 82.355 sq mm.

Just how did you get 16.64??

For a sanity check.. Google shows 1 sq in = 645.16 sq mm.
0,130 sq in is very close to = 82 sq mm.
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jordzan
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Posts: 20
Joined: Thu Jul 23, 2009 10:42 pm

Sat Aug 01, 2009 10:55 pm

??? WTF.. Diameter is 0.408
your seat (marked as vent in your pic Smile ) seems quite large... have you measured its ID or OD ??

the .408 diam is the seat diam inside the piston. i marked it as vent diam on the pic i posted of the piston opened. sorry i should of made that clear.


do i need a measurement of the barrel that holds the piston/spring etc to get a not garbage pilot volume number correct ? if i have the correct idea there it comes in at about 1.299 wide (0.6495 radius)

0.6495 squared is 0.4218 times by pi is 1.325
this is looking more like the correct maths i think? :?

Just how did you get 16.64??

i honestly have no idea but hopefully with the maths above i am on the right track .. had to learn all this stuff from scratch sorry i never knew maths would be useful when i was in school haha. thanks for being so patient with me :D
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