Ford Capri Mirror Screw Size

[Onoff]

Trying to gauge this thread size:

It's not M18 x 1 or 1.5. Core measurement below in metric & imperial.

Consulting Mr Zeus then ¾-16 UNF is my best guess at the moment where the core is 0.6823". Currently printing a test thread. Somewhere around 20tpi maybe...

 

[Bullet2012]

are you sure on the thread count ? looks more UNC, but what do i know

 

[Nomad]

This website often has a parts drawing / diagram next to the piece they are selling - that might give you the info you need

Capri

For oldschooloval Restorers

oldschooloval.com

 

[zzr1200]

20 x 2mm probably, in the Engineers Black Book

20 X 2 METRIC - Taps & Dies, Reamers, Milling Cutters, Tracy Tools

www.tracytools.com

 

[Onoff]

Well ¾-16 UNF goes in a couple of threads nicely then just stops so a higher tpi:

 

[dave h 2]

UNEF is a thing, 3/4 20 tpi 60 deg flank

 

[8ob]

And there is always cycle thread.

Bob

 

[Onoff]

UNEF is a thing, 3/4 20 tpi 60 deg flank

Yep, exactly that. Built in to the Fusion 360 generator which is handy. Also tried ¾-18 UNS but too coarse still.

 

[Kram]

If the calipers are reading 17.82 the the thread will be larger than 18, likely 19 or 20mm depending on pitch.

Lightly oil the thread, wd40 or similar then press a bit of bluetac or anything soft to get an impression that can easily be measured for the TPI

 

[Onoff]

If the calipers are reading 17.82 the the thread will be larger than 18, likely 19 or 20mm depending on pitch.

Lightly oil the thread, wd40 or similar then press a bit of bluetac or anything soft to get an impression that can easily be measured for the TPI

It's ¾-20 UNEF for sure.

 

[dave h 2]

To be fair mixing metric measurements and threads per inch doesn't help.
Anyone know when Ford went from American to metric threads?

 

[bricol]

You could argued the unified threads are not "American", but actually international. Developed between Britain, the US and Canada as a common specification.

Although until relatively recently, you'd find suitable sized tools for it in US stores labelled as "domestic" and metric as "foreign" - not seen that for some time as metric fasteners seem to have taken over in US made vehicles and machinery.