What are the tiny holes in the axle ends for?

[bjamesw]

At some point this must have been covered here, but I have no idea how i would search it.  

On front and back axles, at one end is a hole through the diameter near the end that is evidently used to insert a rod in order to 'wrench' the nut off of the other side of the axle.   That's pretty straightforward.

Between that hole and the axle shaft face near it is a tiny hole drilled through the axis with a slight countersink on the shaft face.  

One day, for some odd reason, it occurred to me that I might hang the wheels/tires at eye level above the workbench by a wire through one of these holes and then slowly rotate the wheel and, voila,  use weights to static balance.    I tried it and it worked perfectly.  

Is this what the hole is for?

[Justin B.]

I THINK what you are describing was probably made by a "center drill" to allow precise location/support in a lathe tailstock (or between centers) when turning the axle.  Without a pic I can't be 100% sure that this is what you are referring to.

[bjamesw]

I'll try to get a pic up.   It's always difficult to verbalize mechanics.  If it were merely a guide for the lathe center there would be no logical reason for it to be drilled clear through to the other hole.  

Anyone out there near enough to their bike that they can confirm yours are the same?  It's such a curiosity.  I've checked other forums and been met with silence.  Maybe I'll give MaxBMW a telephone call this afternoon now that I'm becoming mildly obsessed.

[Bob_Roller]

I know the axles on my'81 do not have the holes drilled in them, just the small concave depression, like it was the centering point for use in a lathe .

[Barry]

I think it may be normal for lathe turning centres to have a small (normally blind) pilot hole for tip clearance and to provide a lubricant reservoir. I never knew they went right through on our axles so just learn't something new - but what to do with it ?
I doubt they have any intended purpose
Rear axle is the same.

[montmil]

The six small marks radiating out from the hole may be headstock or something similar as toolmarks from a lathe. I'd betcha.  

[bjamesw]

Wow, mine does not have the teeth marks from the lathe center.  This may simply be the answer to the question.   But guess what Macgyver?  If you ever find yourself in the wilderness swapping in a new tire/tube, you can hang it all from the nearest branch via this hole and static balance your wheels just like those bubble level wheel balancers!   Works like a charm.

[Justin B.]

A center drill has a short point then a 60 degree chamfer.  The hole for the bar is close enough to the end of the piece that the point of the center drill intercepts the other hole.

Here are various center drills...