The 3/8 ths arived today, and they too do not fit........
**#& landroversZen
Defender Rear Step fitting
Jan 24, 2004
24 Replies
On or around Sat, 31 Jan 2004 17:53:07 +0000, Zen enlightened us thusly:
I'm surprised, they definitely *are* M10 on the back of mine, which is an "A" year chassis (the 10th letter of the VIN is the date code, A is
1983-1984)which sort of 3/8" did you get? The most likely options would be UNF or UNC, but a UNC won't of course fit a UNF threaded hole. If you can see the thread in the hole, try a guess at the thread pitch. M10 are typically
1.5mm pitch (10 threads per 15mm) while UNC are 16 TPI (and indeed a 3/8" UNC will fit an M10x1.5 tapped hole, but be a bit loose - 9.525mm dia.) UNF however are 24 TPI, so pitch of a tad over 1mm.
Mine were definitely 3/8" Whitworth - we tried metric, BSF, UNF, and UNC, but none were correct. Perhaps it is Whitworth rather than metric because mine has a military rear cross member. There's a bit of background on threads at
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I wouldsuggest either finding a friendly fastener company (try Yellow pages) whowill have a look for you or failing that drill it out and tap it to a metricsize - the welded pads have got plenty of meat in them. So far I have foundvirtually every thread known to engineering on the Landy so it could beanything!
Be a bit careful of Stainless in contact with the mild steel - it can actually cause more corrosion because of the different positions in the galvanic table (the two different steels form a battery) - there's a picture which shows it quite well at:
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Good Luck
On or around Sat, 31 Jan 2004 23:50:11 -0000, "Bob Miller" enlightened us thusly:
however, according to my list a 3/8" whit is the same diameter and pitch as a 3/8" UNC (16 TPI), so the only difference will be in the thread form:
whitworth threads are 55 degrees and radii top and bottom (in theory) which gives a slightly smaller core diameter (7.493mm instead of 7.577 for UNC).
The Unified thread form is 60 degrees and has a radius at the root and a flat top. I see no reason why ordinary commercial bolts and nuts of these 2 sizes would not be interchangeable.
However, if the tapped holes are UNF, then they won't fit, since UNF has a pitch of 24TPI.
in fact, a whitworth thread is very unusual on anything these days (though for some reason those easy-bolt threaded rods are available in metric or whitworth)
ISTR the last thing I met with whitworth and BSF threads was a reliant
3-wheeler from about 1965. I think the series ones might have whit and BSF, but the series II 1961 that I had was, IIRC, unified.Hi Guys,/Gals
Dug out the box of tools nuts/bolts things etc. from my Grandfather.
Found some bolts in there that fit perfectly.
Not got a clue what size they are, so its still a mystery.
Still we all learnt a llot.
Thanks again
Z
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