Undersized bolts?

RobW · Post by **RobW** » Sun Jun 26, 2011 7:53 am

I'm having a problem finding the right bolts for my Nipper.
The ones in question relate to control horn/bell-crank pivots etc.
The originals were, I believe 2BA, i.e. with diameter 0.185 inch. Some look to have been replaced with AN3 (0.187 inch). However, on closer inspection many are in fact 0.180 (in similar sized holes), meaning standard bolts won't fit.
It's possible that the bolts have been ground to a smaller diameter, but I'm reluctant to do this. Would it be better simply to ream out the holes to 2BA?
Alternatively, is there a source of 'undersized bolts' that I can use? Is such a thing as a 0.180 inch bolt available??
Thanks

mikehallam · Post by **mikehallam** » Sun Jun 26, 2011 9:19 am

Rob,

FWIW 4 1/2 mm is nominally ~ 3 thou of an inch under 0.180".

Rather a sloppy fit ? I Googled to find this source :

http://www.nutsaboutbolts.org/bolts.html

mike hallam.

RobW · Post by **RobW** » Mon Jun 27, 2011 11:19 am

Thanks Mike - that's a good point, and something that I hadn't considered.
I suppose my Nipper could have been built using metric hardware (built by Avions Fairey in Belgium in 1959) ??. If that's the case it looks like a previous owner has perhaps squeezed in BA/BSF bolts into it, in line with later (Slingsby) Nippers...?

Just guessing really. Rather than use 4.5mm bolts I'll have a word with my inspector to see what he thinks...

I've posted similar questions on the Nipper forum, to see what's known about early Nipper hardware. The joys of older aircraft!

Rob