Airsoft rifle bolt dimensions

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flashskate13
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Sun Dec 18, 2022 3:54 am

Hello,

As the the heading states I'm looking for the dimensions of a Airsoft rifle bolt assembly, I've recently brought a lathe and wish to build a Airsoft rifle.

Any help appreciated
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Doc j
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Mon Dec 19, 2022 9:36 am

Hey Dude ,

Not that straight forward .
Have to sit down and nutt out a plan , design .

They are mixed bag really .
Differ from makes and models .
Sizes may or may not line up with material able to get " off shelf".

Starting point and commonality amongst .
Comes down too , I.D. of cylinder , piston stroke/ = cubic cm of volume .

Stock Cylinder range is like :
22mm I.D. up to 24mm.

Bunch of things have to line up , trigger sear , nozzle into BB T / mag feed .

Then I'm guessing availability and costs ,
Or what material sizes available .

Checked out tube online , seems reasonable for min cut , of 12 inches . 36 buks u.s. (with out freight/ shipping costs)
Either stainless 316 ,
Brass , ( depending supplier , min cuts could mean longer lengths ) about 18 buks . 12 inches .

Where it could blow out in costs is , solid round BAR .( At glance about double cost of cylinder material.

Cheapest bar being carbon steel cold finish 1018. , 10 buks for 12 inches / compared to 56 + for brass or stainless .

Considerations off top of head .
Materials , to make . ( From Scratch )
Cylinder (tube ) ,
solid round bar for cylinder nozzle , rear pull bolt attachment .
Piston ( tube thinking aluminium be the go / again is see wat off shelf material available ) , would have to incorporate from main body a bigger od front and rear . Rear consideration / harder material for wear (sear catch )
( front For piston seal/ rear for sear catch )

Smaller bar or rod for spring guide / has a flat disk on back , which is held against a bar / spring guide stopper that comes from trigger mech ,inturn allows the piston and spring to be compressed and sear to be engaged .
All above :
Allowing enough material length and thickness to machine a thread .( Not sure wat thread or pitch used ) metric , NC , NF .BSPP ? Etc, etc .
Also have to slot the cylinder tube ( not all the way ) leave part not slotted for piston compression stroke )
Slot allows for spring compression and piston sear to catch trigger mech ( slightly protrudes into cylinder for it to happen ) + allows for piston to gain momentum untill hits non slot part of cylinder where air compression starts taking place .

Sizes I checked , ( tube )
Where 1 inch O.D . 0.902 I'd = 22.9108mm I.d. ( thicker wall )
Or thinner wall
1 inch OD 0.93 I.D.( 23.62mm I'd )
Not sure if enough meat to put thread into .?

Length of cylinder bolt , allow for the internal , piston length + stroke/ pull , the compression length , spring catch , and spring guide .
Also for the bolt pull if mount on back ,
There are designs with the pull on the cylinder head .( Refer below later replies)

A piston , with a I.d , that doesn't bind the spring .
+ Spring to suite .

Seems majority around the 36/37 cm3.
( Rounded )

On above material of 0.902 I'd .
90 mm piston stroke = 37.14 cm3
Sorta be ball park . ( Repeat ball park)
Allowing for thread depth either end , ( for cylinder head/ nozzle & stem for rear bolt pull )
245 mm tube , / cylinder .
120mm piston .
100mm spring guide .
Maybe looking at 12 to 13mm od spring
At 250 mm ish long .
Guessing start point be 1.4mm/ 1.5 thick wire
( Depends on piston dimensions / I.D.
Fps , ( force required to pull)

Having said all that .
For sake of simplicity and functioning .
Taking system of A pump Action , type cocking and trigger sear / using altering it , use a floating type bolt pull might be a simpler way to get feet wet , on build .
Last edited by Doc j on Tue Dec 20, 2022 4:56 pm, edited 6 times in total.
Doc j
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Mon Dec 19, 2022 8:23 pm

Above wrote ,
Make sense ,
Check out following pic .

https://sniperpedia.com/wp-content/uplo ... 68x432.jpg

*Note: the spring actually goes into piston itself.
Is not drawn in .
Does not sit on back of piston.
As depicted and not seating in piston ( with room for tolerance / loose fit .
It would bind when cocking .

*Also not depicted , the bolt pull handle rear ,
Is connected by which a hole in bolt handle ( loose enough to allow pivoting on a stem so can pivot and guided through external groove guide , when cocking and locking.
The bolt is secured by a screw and washer? into the bolt pull stem .
The stem screws into cylinder .
Attachments
bolt action.png
Last edited by Doc j on Wed Dec 21, 2022 9:45 pm, edited 7 times in total.
Doc j
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Mon Dec 19, 2022 9:15 pm

]" Having said all that .
For sake of simplicity and functioning .
Taking system of A pump Action , type cocking and trigger sear / using altering it , use a floating type bolt pull might be a simpler way to get feet wet , on build ."

Above , idea.

Watch this ,



( vid internals of pump Action a/s)

Combine it with this .
Attached pic ,
Instead of cocking by pump mech , is replaced by the cocking is done via a bolt .
Done by Basically attaching bolt to cylinder head .simplicity .
No slot cylinder , no extra length of material for cylinder , rear spring guide and stop .
(Seperate from trig mech.) +( not Internal like traditional design )
Should be relative easy , make trigger sear mech , align up .

My thoughts anyhow .
Attachments
images (7).jpeg
images (7).jpeg (17.66 KiB) Viewed 2462 times
bigger pic cylinder + nozzle +bolt combo .png
bigger pic cylinder + nozzle +bolt combo .png (47.42 KiB) Viewed 2435 times
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