Ok so I kinda got a bit sidetracked these last few weeks with exams and other boring stuff hence the delay.

Taking your advice I tracked down some nylon rod for the piston.

Today I quickly knocked up the barrel support/spacer and the piston.

Sure they may not look fantastic but they're out of ...

Slowly coming together.

Didn't get a lot done today. Tapped the rear plug and blowgun for the schrader valve.

Ordered some M4x6mm bolts for securing in the end cap & barrel cap.

I have a heap of those little self adhesive silicone feet to use as a bumper. 7 of them fit quite nicely on the end cap (each one is about 8mm round).

To attach the caps I will be drilling and tapping for 3 or 4, M5x8mm button head screws.

I'd considered forgetting the o-rings and epoxying it all ...

I plan on plunging a 20mm slot drill into the piston to make the cup shape as JSR advised.

I have the 1/8" BSPT tap to tap the schrader into the bottom of the blow gun, once again following smirking Jack's advice. Not sure if I want to just cut the hook off or cut the whole thing a bit shorter ...

Didn't get a whole lot done today.

My o-rings arrived, woot, I actually got something right! Thankyou Parker O-ring Handbook. http://www.parker.com/literature/ORD%205700%20Parker_O-Ring_Handbook.pdf

Machined up the barrel and chamber. Yeah I know, I scratched the heck out of the barrel with the ...

24) Check that threads are clean and everything fits together
http://i47.tinypic.com/2vhu2y0.jpg

25) Setup up fork arm in vice, square it up ready for bending
http://i45.tinypic.com/jj0g90.jpg

26) Using a rubber mallet bend the fork to shape
http://i50.tinypic.com/fbcg90.jpg

27) Put ...

17) Mark out and punch the centre holes in the main fork arm
http://i49.tinypic.com/2eci42c.jpg

18) Drill holes and tidy up with another lick on the belt sander
http://i50.tinypic.com/ejxuv9.jpg

19) Bolt them together and round out the corners as well as sanding the ends flush
http ...

9) Getting started on the forks. Mark out the blank stock ready for cutting
http://i45.tinypic.com/2rmwb4n.jpg

10) Cut the pieces out using the bandsaw
http://i48.tinypic.com/348lija.jpg

11) Clean and square up the ends on the disc sander
http://i46.tinypic.com/15qtd2q.jpg

12) Mark ...

Here's some slingshot porn for all of you who like build along threads.

This is me making another MBBS with Aluminium Handle.

If anyone has any questions regarding any of the steps you see here, please feel free to ask.

1) Cut stock to length using band saw
http://i47.tinypic.com/2qcjupk.jpg ...

That's awesome, thankyou!

I can do that. Would you recommend filling it with something, hot glue perhaps to keep dead space to a minimum ?

Made up the other end cap today.

Arrrrrgh ! Where did I put my 1/4" BSPT tap ? Cant find it anywhere

Hmmmm, ok.

I'll shorten the piston a bit. Currently it's 21.5mm sitting inside a 28.8 ID tube.

I've been looking at purchasing a length of delrin rod which I can later make the piston from. Just using what I have on hand at the moment.

I have not added the rubber to it yet.

And so it begins.

I've shortened the chamber to 40cm, about 32 effective length when assembled.

Piston and front cap machined.

Thanks for the feedback...

Very nice barrel support / spacer you have there. I need to rework my design a bit I think.

Why the double O-ring ? Well, not being up to speed on what pressures I can expect them to hold, I figured 2 would be better than one, they are pretty cheap after all.