Re: Vendors and Toby-TABs

["tmpintnl" <tobyp@xxxx>]

Actually, the TAB's are loaded up in a combination of shear and 
bending ... the bending is what kills them. As far as NAS or AN spec 
bolts (these are government specification bolts - sort of generic 
aerospace standard fasteners), the main challenge is the metric 
diameter. The SAE equivalent is approximately a double oversize 7/16 
inch bolt, which is hard to come by, especially in the lengths we 
need. You can get decent A286 CRES material with these standards, but 
the size represents a real problem IF you want a proper fit in terms 
of diameter. You can put a standard size 7/16 inch bolt in there, but 
it will be very sloppy - and bad IMHO. The inconel 718 is a bit of an 
overkill, with a margin of 50% over the OEM bolts (at least), but 
you'll never have to give it a second thought. The 747 airplane has 
four independent hydraulic systems, plus a spare just in case, but 
only needs two systems for safe flight. Overkill? It depends on who 
you ask. The guy maintaining the systems probably thinks so, but the 
pilot probably thinks that five is just right. But ... I digress. I 
hope that makes sense.

Toby Peterson VIN 2248
Winged1


--- In dmcnews@xxxx, "checksix3" <checksix3@xxxx> wrote:

> Toby's bolts. First off, I will say this is as good as it gets, from 
> a guy who obviously knows his stuff. (Since I drive his company's 
> equipment, I have to trust him.) The properties of Inconel 718 are 
> impressive but I question if they are overkill for this application. 
> Why not cad NAS or even AN? Why go through all this when NAS is off 
> the shelf, much cheaper, and (I would assume) plenty strong enough? 
> 
> Toby, care to offer an opinion? Not on costs (your bolts are worth 
> it), but on why such overkill? Are you saying that NAS can't handle 
> the tensile loads when torquing and not exceed the elastic limit? 
> I find that a bit hard to believe. Once installed, the running loads 
> are mostly in shear, right? Or is it a SAE vrs metric issue? No 
> offense, just curious.