Cast bellcranks

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Jason Lynch
Posts: 76
Joined: Thu Apr 03, 2014 12:42 pm

Cast bellcranks

Post by Jason Lynch »

Ok, so I spotted an ad for a local man who casts parts using lost wax and I thought I'd contact him to see if he could cast me some aluminium bell cranks. Apparently cast Ali is not as strong as machined billets.
"What about Brass?" He asks
Hmmmm
Thoughts?
maxi19
Posts: 365
Joined: Mon Oct 22, 2012 12:55 pm
Location: Milton Keynes, England

Re: Cast bellcranks

Post by maxi19 »

Hi Jason, 'billet' or 'extruded' aluminium is stronger than cast aluminium due to having a finer and more uniform grain structure.

Best Regards

Ron Mc
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Bill Ford
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Location: Aiken Co., S.C....U.S.A.

Re: Cast bellcranks

Post by Bill Ford »

Stay away from any cast parts, you will probably need to have them machined so, the end cost is a wash..B
Bill Ford
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Jason Lynch
Posts: 76
Joined: Thu Apr 03, 2014 12:42 pm

Re: Cast bellcranks

Post by Jason Lynch »

Not having access to a milling machine I've started to think of other ways I can make my bellcranks and still end up with something elegant and functional.
I'm thinking folding steel to make something like a schild, which means lots of holes in the cross shafts.
Or how about using delrin or Nylon? Do they need to be aluminium? Opinions?
Ross Shafer
Posts: 189
Joined: Tue Nov 24, 2009 11:52 am

Re: Cast bellcranks

Post by Ross Shafer »

Neither of those plastic materials is strong enough for this application without a lot of extra material that you probably won't have room for.
Jason Lynch
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Joined: Thu Apr 03, 2014 12:42 pm

Re: Cast bellcranks

Post by Jason Lynch »

Thanks Russ. That surprised me a little. I'd have thought Delrin or Acetal would have enough tensile strength. Does anyone have a ballpark figure for how much pull these bellcranks have to withstand roughly?
rtp_burnsville
Posts: 21
Joined: Sat Oct 17, 2015 12:14 pm

Re: Cast bellcranks

Post by rtp_burnsville »

Here is an idea that may work for you..... Get some aluminum bar stock, cut rectangle blocks the size needed, drill one larger hole for the crossrod, drill smaller holes for the pull rods. You will also have to drill and tap a hole to secure the bellcrank to the cross shaft. No milling machine required, but a small drill press and a simple holding fixture would greatly speed the process.


Robert
willkemp
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Joined: Wed Jun 10, 2015 12:33 am

Re: Cast bellcranks

Post by willkemp »

I used 1/4" x 3/4" aluminium bar stock and cut to 2" long with 5/16" ia. hole for cross rod and 3/32" holes for pull rods. Easy and light
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