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Building (crafting?) your own A-Arms

Posted: Wed Feb 18, 2009 6:13 pm
by fakiee
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Re: Building (crafting?) your own A-Arms

Posted: Wed Feb 18, 2009 7:15 pm
by ROH73
Delrin is the commercial name of acetal. Nylon 6 and Nylon 6/6 are just different formulations of nylon, with the 6/6 being stronger. The original RC10 parts are made of Nylon 6/6. Both nylone and acetal machine well. Acetal is more rigid and slightly more susceptible to fracture, while nylon is more flexible. Acetal is usually available in white or black and the white is more UV stable than natural (off white) nylon, which tends to yellow over time. Natural nylon can be dyed, acetal cannot.

8mm thick should be sufficient, but it's hard to be precise without knowing your exact application.

IMO it's definitely worth doing if you have decent machining skills and access to a mill. Doing most of it by hand with a dremel tool is hard work and it's tough to get things exact, but I'd say try it and see what happens.

I fabricate my own parts all the time, but I have access to a full machine shop at work and a lathe and drill press at home; that makes things easier.

Regards,

Robert

Re: Building (crafting?) your own A-Arms

Posted: Thu Feb 19, 2009 9:14 am
by jwscab
I've made a bunch of parts myself, I'd recommend the nylon 6/6. It's not hard, just time consuming. Mcmaster-carr might have better prices, I didn't investigate your link.

do you have factory arms? if so, use them as a template, and try to mimic the thickness, unless you want to beef up the arms.

rough cut the plastic with a hacksaw blade or jigsaw blade, go slow though, if you create enough heat, the plastic will melt and smear and the finish isn't the greatest. try and get the edges as square as possible, and drill the through holes for the hinge pins/shocks while the part is still rectangular and square, so the holes end up square. drill press and vise make this easier. Once they are drilled, then you can shape the arms as needed. it's soft enough that most rough openings I make with a drill or series of drills, then trim with an x-acto and a fresh blade. Oh, and to help make the arms symmetrical, I'll stack them up on top of each other and do as much drilling, sawing, machining as 'one' thick peice. This way they should be pretty darn close to the same.

Re: Building (crafting?) your own A-Arms

Posted: Wed Feb 25, 2009 10:41 am
by fakiee
Thanks for the help Robert & jwscab,

I have ordered a 8x250x300mm sheet of the Nylon 66. I will use the old A-arms as templates and hopefully be at my dads workshop this weekend to use the bandsaw and get started. I will post the experience here GULP!