That was my original plan, water jet cut and ream, but I was told
recently that plasma cutting is ok, I was a bit suspicious about that
comment, hence my asking.
Chris Johnston
North Richmond NSW
AUSTRALIA.
----- Original Message -----
From: "Brian Kraut" <[email protected]>
To: "KRnet" <[email protected]>
Sent: Wednesday, August 23, 2006 12:03 PM
Subject: RE: KR> WAF Plasma cutting
> Absolutely not. Plasma cutting leaves a very hard edge. I have had
> several
> 4130 parts plasma cut including my lower gear attach fittings for the KR
> and
> the seatbelt attach fittings and canopy latch parts for the Stang. I did
> some finish machining on some of the parts and the edges were hard as
> rocks
> and needed carbide tools to cut them. Hard edges mean brittle edges.
> Brittle edges mean the high liklihood of cracks starting. The parts I
> have
> plasma cut are sent to a heat treater to be normalized when done, but if
> you
> are not getting that done don't do it for structural parts. Same applies
> for laser cutting. Water jet is O.K.
>
> Another problem with plasma and water jet depending on the thickness is
> that
> they both cut with a taper and sometimes also a slightly rough edge. If
> you
> do water jet and have the bolt holes cut you want to have them done
> undersized and ream them to finish the holes.
>
> Brian Kraut
> Engineering Alternatives, Inc.
> www.engalt.com
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On
> Behalf Of Chris Johnston
> Sent: Tuesday, August 22, 2006 6:56 AM
> To: KRnet
> Subject: KR> WAF Plasma cutting
>
>
> Can you plasma cut the wafs without affecting the metal??????
> Are the tailplane hinge ply backup plates glued in place or just held
> on
> by the nuts and aluminium backup plates?
> The plans state the inner hinges have two bolts, does this mean the
> outer hinges have only one bolt per hinge half?
> Can you use two bolts on the outer tailplane and elevator hinge without
> weakening the spars too much?
>
>
>
>
> Chris Johnston
>
> North Richmond NSW
>
> Australia
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