Input request - RPG7 trigger group design

[Kokanee]

Starting some "exploratory fabrication" and I thought I would throw this up if any of the usual suspects have any ideas on improving this design;



I've left the functional bit of the trigger for later, most likely will take the form of an extension protruding out of the top of the mechbox to activate a firing pin.

[MadMax]

Looks like a workable design. I recommend cutting out templates in 1/8" thick cardboard before commiting to more difficult materials. Even better would be a non corrigated material like matting board or thick white styrene available in some craft/art/hobby stores.

You can stick pins into the pivots into a soft pine board to model working pivots and use rubber bands and hot glue to make a functioning spring so you can test the shape of your parts and test your safety function.

In your PM, I think you mentioned making moulded parts. It looks like your parts are pretty 2D. It would probably be less trouble to saw them out of sheet plastic with a jig saw as you can make your direct part instead of having to make a male part and cast a mould around it. If your aims are production (50+pc), then take a look at laser or plasma cutting. You can crank out economical parts in steel with both techniques and you wouldn't have to deal with goopy resin techniques which produce parts with worse properties than steel. Plasma/laser cutting is also often cheaper as it's less labor intensive. If your aims are low/mid volume (say 10pc jobs) then use double sided tape to tape together blanks of plastic sheet and stack cut your profile with a band saw. You could crank out several parts in one cutting run and you wouldn't need a multi cavity mould or run too many moulding cycles.

If your aims are to set off a Moscart type grenade with the trigger, you could make a sear surface which holds back a cocked hammer which comes sliding forward like a Spyder pball valve hammer. You can also take the easier route and include a long arm with a forward pin which just pushes directly onto the trigger plate of your grenade.

aside from the firing mechanism, i often make patterns using plastic. its fast, easy and really solid.

for material I often use http://www.alumilite.com/ plastics. Its wickid fast and really solid. Add metal pouder to make it heavier. just make a pattern for the part out of sheet wax and take a casting and use the aluminite plastic and cast your parts. the aluminite goes off really fast so you can pump out parts quickly.

check http://www.alumilite.com/ for info. I use their stuff everyday and its fantastic. Its a cheap alternative to metal machining.

[Kokanee]

LOL, I think we're all on the same page!

Carl, what you are looking at is indeed a styrene sheet mockup. I was considering casting for the final product with (yup Droc, hit it on the head) Alumilite (avec metal powder) as the end piece will be quite thick , however so far the base of the trigger group is x2 0.118" pieces of styrene thick, and it's rock solid, so I'm also considering just skipping the casting step and doing the piece in styrene.

Nope, I don't have any "Production" ambitions so far, but was hoping to make some moulds to preserve the ability down the road - I suppose I can always take moulds before final assembly and shelve them.

Thanks for the thoughts fellows