Allen Key Brand - to protect bolt head on Rare EBB

[Pebble]

The OPs eccentric seems to tighten by the semi-lunar "wedges" going up a slope towards the centre of the BB; I would expect the thing to tighten at the sides of the BB to stop rocking, like this Cannondale one from SJSC https://www.sjscycles.co.uk/bottom-brac ... e-rohloff/

this is what I was trying to allude to earlier, silly design having the wedges going towards the centre to create a potential pivot point. The one you link to is the one an engineer would design.

[Brucey]

I took a look at you photo (ta) and the 'shoulder' has just been added to make the bolt captive so it can't fall out and be lost or jam somehow. when it is loose If you can identify the threading I would expect to be able to use an ordinary bolt with just an 'o' ring for the captivation function (if this is really necessary).
The shoulder piece may just be screwed on in which case it can be unscrewed too, eg. using grips of some kind. Normally a 5mm allen key fitting would suggest M6x1 threading so that might be what you have.I don't think you really need it, but if there is room on the outside for a nut, then the bolt could perhaps be replaced with a length of studding, a longish tube spacer, and a nut. If the eccentric itself is anodised aluminum, it will be kind of slippy. If any anodising is removed (eg. using an abrasive) on the OD then the grip will be improved although you may also need a shim if you do this. If you have a 0.1mm clearance then you should think about a shim.
You may find the grip is improved if you just spray paint the insert on one side.

[Jupestar]

I also thought the shoulder was not needed at first. But actually I think it forces the wedges apart in a way that just having a bolt going through both would not guarantee they split.

Pretty sure the bolt can be recreated with a full threaded bolt and suitable placed and sized lock nut.

But the bolt is good and the head is good. And hopefully the Wera t handle will keep it that way.

[531colin]

The bolt draws the wedges together to clamp up
Shirley?

[Pebble]

and have you noticed how the chamfer on the wedge is on the trailing edge when tightening. I'm sure a small chamfer on the leading edge would help when tightening (esp the wedge being pushed (the wedge closest to the allan hex head))

i suspect the purpose of the fixed flange in the middle is to help release the wedge on disassembly

[Jupestar]

The bolt draws the wedges together to clamp up
Shirley?

Yes. At which point I don't think the shoulder is used. When you release the bolt to loosen the wedges I think that shoulder forces them apart from their wedged position. Without it I reckon you could take the bolt out and potentially the wedges would remain 'wedged'.

[531colin]

The bolt draws the wedges together to clamp up
Shirley?

Yes. At which point I don't think the shoulder is used. When you release the bolt to loosen the wedges I think that shoulder forces them apart from their wedged position. Without it I reckon you could take the bolt out and potentially the wedges would remain 'wedged'.

Yes, that makes sense

[drossall]

The OP might usefully rename this topic as something such as "Unusual eccentric BB". It's interesting - it's just not about Allen key brands, so it's not going to get found by people who might want to see it.

[Jupestar]

The OP might usefully rename this topic as something such as "Unusual eccentric BB". It's interesting - it's just not about Allen key brands, so it's not going to get found by people who might want to see it.

It started off about Allen Keys and the advice received was excellent. I would never have brought that brand, as to me it looked like a cheap Amazon allen key...

I'll rename it, although i'm not sure it unusual. Cannondale do one similar (although the bolt it made of cheese on that one. and Bushnell (i've never used one). It just the size which is rare.

[Brucey]

The bolt draws the wedges together to clamp up
Shirley?

Yes. At which point I don't think the shoulder is used. When you release the bolt to loosen the wedges I think that shoulder forces them apart from their wedged position. Without it I reckon you could take the bolt out and potentially the wedges would remain 'wedged'.

Yes, that makes sense

this could easily be overcome. For example if you were prepared to drill a hole parallel to the clamp bolt, through both the EBB insert and the threaded wedge, a flat-ended punch could be used to release the other wedge, working from the far side. Again, no special bolt required. It'd be lighter too.