mk1-forum.net

Could anybody confirm the dimensions of the original mk1 rear light lens bolts? I've got the head as being 7.8mm diameter, the shank 4.7mm. Then the lengths of screw from the start of the shank to the end 31.5mm and 45mm? I

I know you can buy them new but I'm planning on making them myself from some metric allen bolts.

Cheers Alex

Sorry, I am not near my car at the moment so I cannot measure them for you.

I made mine also. It has been a long time but if I remember correct, the screws are not threaded full length but are more or less... shoulder screws so you won't overtighten them and over compress the gaskets. At the time I had limited resources and remember cutting the heads off of some old rusty lens screws and silver soldering stainless steel Philips head screws onto the shanks to keep the original length and shoulder screw function. Were I doing this today I would probably find some slightly longer screws, cut them to length, and fit a bit of stainless or brass tube to their shanks to provide the shoulder screw function.

dklawson wrote:Sorry, I am not near my car at the moment so I cannot measure them for you.

I made mine also. It has been a long time but if I remember correct, the screws are not threaded full length but are more or less... shoulder screws so you won't overtighten them and over compress the gaskets. At the time I had limited resources and remember cutting the heads off of some old rusty lens screws and silver soldering stainless steel Philips head screws onto the shanks to keep the original length and shoulder screw function. Were I doing this today I would probably find some slightly longer screws, cut them to length, and fit a bit of stainless or brass tube to their shanks to provide the shoulder screw function.

Thanks Doug, I've got access to a lathe so will be able to make them to original from M5 allen bolts. I've found a short one but can't my other ones.

Alex
I know you want the best screws for the lenses...have you tried 1071bob on this forum...he actually makes these screws. I can highly back Bob's work.

360gts wrote:Alex
I know you want the best screws for the lenses...have you tried 1071bob on this forum...he actually makes these screws. I can highly back Bob's work.

Thanks, I'll send him a message.

The screws are good old english 2 BA threead.

Not sure they are 2BA ? I think the thread is much smaller, maybe 4BA . The repro ones have the wrong size head but Bob Davis ones are stainless and have the right size. Also, don't forget that all 3 are different lengths.
Ps. On a recent visit to Australia I saw some locally made ones with only 2 screws.

Yep the thread is 4ba, checked that with a tap yesterday.

I made some of these few years ago, I had to make them in two pieces. A modified M5x12mm philips dome head machine screw for the head, and the shanks were made from stock A2 grade 3/16" stainless steel bar. I had to make some tooling to hold the machine screws in the lathe, here is a picture guide if you want to make your own :-

Extraordinary craftsmanship. Like a boss....

Thank you very much Bob, Exactly what I'm looking for. Was there any reason why you made them from 2 bits. Was it just to make them more original?

Fantastic information Bob. Thanks for posting that.

nick rogers wrote: On a recent visit to Australia I saw some locally made ones with only 2 screws.

Aussie cars had Australian made lights (Lucas) with two screws. I am not sure when production started but I think maybe '65. They work just fine and just a little simpler than UK versions. OK, this is not a racial comment but could be !!

Regards
Al

All this fantastic technical stuff does detract from the .........grind old turned off stubb, drill out with 1/8th drill and find some wood screws to fit. Ah the simplicity before we got too anoraky, head down!!!!!!!!!