The Eerder QR replacement handle is compatible with the original Brompton seatpost QR used on the main frame and the telescopic seatpost. When the Brompton QR is overtightened with the 10 mm nut on the right side (because your seatpost keeps sliding down), the plastic lever might slip 60 degrees on the steel hex if you put a lot of force on the lever to close it. If that happens the timing of the excentric spanner mechanism isn't right anymore and the plastic won't probably hold firm on the hex if you would force it back into position. So I figured let's design a virtual indestructable version made of laser cut stainless steel

Assembly:

See photos for instructions. The QR axle can be hammered out of the plastic handle using a 3mm punch or the 3mm pin provided with the lever. The punch fits the hole at the flared end of the axle. Make sure to support the plastic with a 13/14/15mm hex socket, ring spanner or a piece of wood with an appropriately (13-16mm) sized hole in it. Once the axle is hammered out you can clean the parts. Put them back together again with some bearing grease (or chain oil if that's what you have). Add the three supplied washers to the axle. Now flare the end with a tapered punch so the washers are fixed. Flaring the end too much might cause the axle to not rotate freely, too little and you can loose the washers. Put the steel lever onto the Brompton QR hex part, make sure it's aligned with the tiny bump in to the groove of the hex. Tighten the grub screw carefully, not too tight (it's just a tiny screw) and use a good quality 1.5 mm allen key.

Specs:

• Material: 304 stainless steel
• Laser cut out of 6mm thick plate, edges are rounded off by machine tumbling with ceramic media, final finish by tumbling with steelshot
• 78 mm long, same as original
• A2 stainless steel M3 allen grub screw for locking the lever on the hex end of the original excentric axle
• 3x M5 washer
• a little piece of 3mm rod to act as a punch for removing the axle from the plastic lever
• optional: 7x80 mm mild steel punch with pointed end for flaring the QR pin in case you don't have a pointed punch
• Weight: 20 gram (original plastic handle is 13 gram)