[Healeys] hardtop fasteners - the sequel

[Mirek Sharp]

Hey all,

You may recall a few weeks ago I posted a plea for information on 8-36 machine
screws in stainless, Phillips drive, oval head, for attaching the toggle
clamps on the front corners of factory hardtops.  I have no idea if the
specification changed over time, but I have a very original hardtop dated
1960, and the threads are definitely 8-36.

Many thanks to all who sent leads, but it turns out these seem to be
unavailable.  I had one offer from a fastener manufacturer in the UK to make
them, but it was a minimum 250 quid, and I figured it may be a while before I
could recoup this, selling 4 screws at a time to those of you out there with a
hardtop restoration in your future.  Peter Svilans and I checked out a few
examples and it turns out that the toggle clamps are often fastened with
self-tapping screws.  I am sure this is not right - who would use a
self-tapping screw to fasten something to a block of aluminum?  My opinion is
that when the original 8-36 machine screws loosened and fell out, or were
removed and lost, owners also found replacements were unobtainable and used
the self-tappers.  On my top, one side had machine crews and the other had
self-tapping screws.

I had given up on the 8-36 screws and was over at Peter's discussing a
solution.  I figured I would try taking the nearest, larger thread I could
find, and re-thread them with a die.  Peter and I checked through some metric
sizes and lo and behold discovered that an M4 with a 0.7 pitch is, for all
intents, an exact match for an 8-36.  Moreover, it is available in Phillips
drive, oval head and stainless.  So there we have it - I bought 4 and my
toggle clamps are re-installed - the metric screws went in perfectly.  I am
sure the thread form is different, but guess what, once installed you can't
tell - I tried and you really can't see them (and if any concours judge
reading this ever removes one of these screws with a thread gauge in hand, I
will break his Phillips drive).  I have no idea how common this particular
metric machine screw is, but Spaenaur carry them and the part number for a 16
mm length is 425-008.

Cheers,

Mirek
60 BT7