Lotus Elan and Lotus Elan Plus 2 Forums

Hello,
as Alex at present cannot supply more of his much acclaimed clamp screws and he was encouraging me to source them by myself, so I tried to do.
I bought sets of different M6 screw types, different materials, some with even a hole (length wise) in them, and then tried for myself.
Alex advised to have professional equipment, I can now confirm that with "consumer level" tools it is quite difficult. Even buying professional drills and taps, all more or less broke.
I then came up with a different aproach, I think a smooth one.

So, I went to a professional with a lathe, he is willing to do the work.
He is currently working on a steel screw replicating the Alex Black screw and will come back with an cost estimate for doing 50. I will update here as soon as I get feedback.

Now to my approach to the clamp screw:
The original screw catches the cables by the force of the nut "against" the window glass (with some washers in-between).
Alex Black separates that and uses a grub screw to hold the cable and a nut to fix the assembly to the window glass (less force on the glass).

My approach is a mix between the Lotus and Alex' one. Instead of using a nut, I use a shortened version of Alex' screw (about 10mm long), but the grub screw has a wide head and his length is exactly that needed to hold the cable. And the space between the heads is exactly that needed for window glass and spacers.
I was advised to do this in brass, as it is much easier to manipulate then steel.
The prototype does work quite well, so I would like to ask the more experienced people here what the think about this approach, about doing it in brass. Same question applies to the replication of Alex Black's screw, would it be OK doing it in brass ??

Here some pictures:

These are M8 screws made of brass, threads taken off, interior M4 thread, cross drilled hole for the cable


Shortened to correct length and head flattened to half

with washer placed

pressed on glass from below, wit cable and washers

assembly completed but not screwed down.

Is the force on the cable equil between all contact surfaces?
I am midway restoring an old pedal bike, I have used some newer hard plastic directional plates under the crank. Toyed with a few different options. Though, I know not what would work best here.

It looks to me to be too long and will foul on the metal frame or pulley spaces.

Grade of Stainless is everything when it comes to machining, some grades, 201, will work harden making life difficult. Grade 303 is your best chance in taping the central hole, have a clearance diameter hole other than length of grub screw.
Brass is a machinist dream material.
Personally I think the original arrangement with correct soft copper and fibre washers suitable, using a stainless nut & bolt.

billwill wrote:It looks to me to be too long and will foul on the metal frame or pulley spaces.

It does not. And this screw is not yet perfectly grinded, it is crooked.

This is at the lower plate


This is at the top plate, tight, but still passes with no touches.

Has anybody one of Alex Black's screw at hand ?

I would like to know the height of the screw head.

gherlt wrote:Has anybody one of Alex Black's screw at hand ?

I would like to know the height of the screw head.

Is this what you're looking for? About 95 thou. I'm sure 1/10" would be fine.

Nick

Great, thank you very much Nick !

Hi Elan Owners
I bought a set of Alex Blacks Window Clamps possibly 8 or 9 years ago.
Putting back together after re spray and new clamps fitted many months ago.
Tried today with Motor and Cable slipped through Clamp when Window at bottom of travel. Still happened even after tightening grub screw more.
I understand Alex is not well at the moment
otherwise would have asked him.
My question is has anyone else experienced this and any thoughts or do they have a photo of the Clamp Bolt as I am not sure if my Clamp Bolts are the correct version.
Many Thanks

I could imagine that the clamp bolt might be too pointy or the cable too thin,
It might then not being held properly. I filed my clamp bolt to have a flat "bottom" (??),
so that the contact surface with the cable is as wide and flat as possible (special attention to the border, so that would not cut the cable at tightening)

Here are some images of the screws I bought from Alex a few years ago, they are stainless 18.5mm M6 hex cap screws drilled and threaded for flat ended grub screws (2mm hex key). The pan head is 3mm thick as can be seen from my calipers on the images.

I really can't imagine the grub screws not exerting enough pressure on the cables to prevent slipping, in fact Alex cautioned me not to tighten too much as the cables could be cut through by the grub screws.

I have made and fitted quite a number of these and as Alan says they grìp really well.
So well in fact that if your motors are in good condition with good supply volts they will pull off and mangle one of the nylon corner pullies if somebody holds on to the switch when the travel is complete and they hit the stop.

Also, I only fit one for the cable joint position. Not needed on the other position. Original spec is good enough.

My AB clamps slipped as well

My solution was to fray the cable out, and epoxy the frayed end so that it can’t get pulled back through the clamp. I’ll cut the fray off with a cutting wheel dremel when I need to.

go to RDENT .com

I know you guys are in the UK BUT Ray at RD Enterprises have all the parts you need to re-build your windows.
I have t 2 full kits that I bought off them a year ago. ALAS not installed yet.