The Lotus Grand Tourers

Before you do anything Richard let me see how well metal bonds to the plastic with epoxy. I'll try tonight if I've got enough time.

Does anyone know the diameter of the pin itself?

Pete

Thanks Pete. No rush, I plan to do all this at the Resto Show at the NEC end of March. Just want to make sure I have all the bits I'll need before going to the show.

If the pipe/bush can be clamped in place by a penny washer either side of the plastic, no epoxy nor other glue will be required - but there will need to be room for the washer and bolt head between the lever and the housing.

I managed to find the pin rolling around the footwell on one of my infrequent car cleans (and before it was sucked up by the vacuum cleaner!). I make it about 4.5 mm diameter, and the snapped-off bit is 15 mm long.

OK - just tried to drill out the plastic moulded arm - fine up to 6mm then snapped the end off as I went to 8mm. So - when you drill it out go in much smaller increments! I made a triple-diameter bit to bond in - I'll still go ahead and do it to test for bondability!



I'll report back.

Pete

That’s marvellous Pete. There are clearly more options available when you own a lathe…

I follow your plan Richard. Sounds solid. I think you will have a bolt head clash on the inside though. You can see from the later pictures I posted that it is very close. You might get away with cutting the flanges locally back, but not sure. May be a bit terminal if you take too much off.
There looks a lot of room coming out board. Wouldn't be too difficult to move the cable outer clamp spring plate further away. That could give you room to bond a plate with a pin to the outside face of the arm ?
Tony

There is about 4mm between the back of the arm and the body of the assembly

Pete

From Tony's photos it looks like there is enough clearance for a bolt head for most of the arc, except in the rear-most position where there is that straight channel with another bit of white plastic in it. But I could conceivably cut a little bit out of the side of that channel to give clearance for the bolt head and washer. At a push I could try grinding half of the bolt head off to make it a bit skinnier (and add some lightness!).

It won't be a bolt head - it will be a nut. There isn't room to get a bolt in from the back. If I were doing this now - having experienced how brittle the plastic is - I would drill a 4.5mm hole and fit a flanged dowel of the type I turned but 4.5mm on either side of the flange - not try to take it to 8mm. I'm happy to turn one up for you Richard. I'll be bonding it today to see how well it sticks.

I also like Tony's idea of bonding to the whole arm. A flat steel plate with a 4.5mm stud welded to it might work equally well. Even better a brass one with a 4.5mm stud front and rear soldered on.

Pete

Just had a look at mine cos the dash is still out, I think I'm preferring Tony's method as it supports the whole arm. When it comes to glue Ive had alot of success with plastics using superglue and bicarbonate of soda.

Bash

Pete Boole wrote: ↑

Tue Feb 07, 2023 12:02

It won't be a bolt head - it will be a nut. There isn't room to get a bolt in from the back. If I were doing this now - having experienced how brittle the plastic is - I would drill a 4.5mm hole and fit a flanged dowel of the type I turned but 4.5mm on either side of the flange - not try to take it to 8mm. I'm happy to turn one up for you Richard. I'll be bonding it today to see how well it sticks.

I also like Tony's idea of bonding to the whole arm. A flat steel plate with a 4.5mm stud welded to it might work equally well. Even better a brass one with a 4.5mm stud front and rear soldered on.

Pete

That sounds good Pete. Yes, if you could turn something for me that would be brilliant, better to have something purpose-made for the job. I'll be interested to see how you get on. Will you be visiting the NEC Resto show next month?

bash wrote: ↑

Tue Feb 07, 2023 12:23

When it comes to glue Ive had alot of success with plastics using superglue and bicarbonate of soda.

Bash

I've not heard that trick before - what does it involve?

This arm is clearly brittle ( the pin has broken off both your's and Pete's, then when Pete drilled out, the arm cracked again). Drilling even a small hole is taking away what little strength it still has.
If it were mine, I'd certainly be going down the "bond a plate on" line. Or I'd at least have a plate with pin ready in reserve in case the drilling broke the arm further.
There's a lot of webbing on the plastic arm. A flat piece of maybe 3mm thick plate, with a couple of holes drilled in it so the epoxy pushes through and Bob's your uncle. The two parts would be well locked together. Not sure, but you might be able to do it just by removing the clock panel ?
Here's a thought - How about butchering a motor cycle drive chain split link?
Tony

Repaired pin. Used the slow-cure version of JB weld to bond it (the slower the stronger). Very strong repair. I would have no hesitation in using it:



Richard - pm me your address and I'll send you a pin. I'll make it 4.5 mm but I'd recommend drilling the hole at about 4.7/4.8 mm to accommodate the adhesive and allow for any non-perpendicular drilling . File a flat before drilling to ensure you get it centred.

Pete

Ive repaired a few things with superglue and bicarbonate of soda, try it, just put a small amount of bicarb in a small pile and drop some superglue on it. When its set hit it with an hammer, you will be surprised how hard it is.
Bash