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carbon fibre pen gun build log
Posted: Thu Jan 31, 2013 2:38 pm
by jackssmirkingrevenge
I've been commissioned to build a pen gun similar to
this and though I would document the build process for those who are interested
First step is rather basic, the CF body is cut to size and the ends are squared up on the lathe using a carbide tool at high rpm:
Posted: Thu Jan 31, 2013 2:54 pm
by mark.f
Sweet. Should be interesting to see your construction methods in use that don't involve epoxy. :p
Posted: Thu Jan 31, 2013 3:03 pm
by jakethebeast
I bet JSR used epoxy somewhere
Posted: Thu Jan 31, 2013 3:18 pm
by jackssmirkingrevenge
mark.f wrote:Sweet. Should be interesting to see your construction methods in use that don't involve epoxy. :p
Don't worry, epoxy will feature here too
Posted: Thu Jan 31, 2013 4:03 pm
by JDP12
this looks awesome! Been absent from the forums for awhile, but this looks interesting, can't wait to see it.
Posted: Thu Jan 31, 2013 4:03 pm
by yodabeast14
How much psi are you planning to operate at?
Posted: Thu Jan 31, 2013 4:36 pm
by jackssmirkingrevenge
yodabeast14 wrote:How much psi are you planning to operate at?
Should be able to take 400 psi safely.
Here's the front endcap, threaded 1/8" BSP to allow a 0.177" barrel adapter to be fitted to the 0.22" barrel. Note the grooves to improve the adhesive grip.
Posted: Thu Jan 31, 2013 4:36 pm
by jrrdw
Arrow shaft?
Message toooooo short!
Posted: Thu Jan 31, 2013 5:34 pm
by jackssmirkingrevenge
jrrdw wrote:Arrow shaft?
10mm ID 12mm OD tube sold as outriggers for quadcopters.
Here's the barrel setup, note the delrin sleeve at the breech end which increases the area on which the piston seal pushes, reducing wear. The OD of this sleeve is 8mm, you would think that it leaves too small a gap between barrel and chamber for air to flow but in fact, the cross sectional area is greater than that of the 5.5mm barrel.
Also illustrated is the schrader valve prepared for attachment, along with a "virgin" example.
Posted: Thu Jan 31, 2013 5:46 pm
by jakethebeast
Hehe nice work, your almost finished, now all you need is... epoxy
Posted: Fri Feb 01, 2013 9:19 am
by Oxy
This looks awesome! Can't wait to get it, great work.
I'll post a video of it in action when it arrives
Posted: Sat Feb 02, 2013 1:34 pm
by jackssmirkingrevenge
Here's the piston and rear endcap, hopefully this thing will be ready for testing tomorrow.
Posted: Sun Feb 03, 2013 2:00 am
by jackssmirkingrevenge
Worky bits all put together and polished, will do some high pressure testing later in the day.
Posted: Sun Feb 03, 2013 5:05 am
by jackssmirkingrevenge
Here's the triggering assembly before being epoxied in place, with the threaded part to fit the schrader cut from an alloy cap.
Posted: Mon Feb 04, 2013 3:24 pm
by jakethebeast
Nice one! How´s the power?