Hub Spoke Spacing

Perry Hudson said:

Hi all,

I'm fabricating a set of wheel hubs, using 20 inch rims for use on an ultralight aircraft. Is
there a quick way to lay out the flange spoke holes? Like a print out of dots I can center punch
directly on to metal. I will be using either 36 or 48 holes, standard diameter. Thanks for all
help, Perry

The best way to do this is with a "dividing head" on a drill press. Failing that, it could be done
by eyeball with no ill effects.

The only alignment is that the holes on the left flange need to line up halfway betwen the holes on
the right flange.

Sheldon "Hubs Are The Easiest Bike Part To Make" Brown +-----------------------------------------+
| The wind and waves are always on the | side of the ablest navigators. | --Edward Gibbon |
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Sheldon Brown said:

Quoted message said:

I'm fabricating a set of wheel hubs, using 20 inch rims for use on an ultralight aircraft. Is
there a quick way to lay out the flange spoke holes? Like a print out of dots I can center punch
directly on to metal. I will be using either 36 or 48 holes, standard diameter.

Quoted message said:

The best way to do this is with a "dividing head" on a drill press. Failing that, it could be done
by eyeball with no ill effects.

Quoted message said:

The only alignment is that the holes on the left flange need to line up halfway between the holes
on the right flange.

I think you can locate the holes accurately enough with a manual scribe and as you say you can
almost free hand this except that you ought to clamp the hub by its axle upright in a vise so you
can rotate the hub while putting the holes all on the same radius.

Jobst Brandt [email hidden]

On Fri, 09 Jan 2004 20:05:38 GMT [email hidden]

Quoted message said:

I think you can locate the holes accurately enough with a manual scribe and as you say you can
almost free hand this except that you ought to clamp the hub by its axle upright in a vise so you
can rotate the hub while putting the holes all on the same radius.

I don't think that even a perfectly constant radius would be necessary. I Once saw a wheel which had
been built up on a Campy record front hub, circa 1975, for which the spoke holes were clearly not
centered on the rotational axis. The person we had sold the hub to was complaining, but I really
couldn't see any reason why this would make a difference. The rim was still true and the delta r was
small enough that none of the spokes were either too short or too long.

You couldn't see the effect while riding, but it was easy to see when you held the hub in your hand
and spun the rim.

I've always wondered if that was an extremely odd occurance, or if it happens fairly regularly and
just never gets noticed. Has anyone else ever seen anything like this?

-
-----------------------------------------------
Jim Adney [email hidden] Madison, WI 53711 USA
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On Sat, 10 Jan 2004 00:01:51 -0600, Jim Adney <[email hidden]>

Quoted message said:

09 Jan 2004 20:05:38 GMT said:

I think you can locate the holes accurately enough with a manual scribe and as you say you can
almost free hand this except that you ought to clamp the hub by its axle upright in a vise so you
can rotate the hub while putting the holes all on the same radius.

I don't think that even a perfectly constant radius would be necessary. I Once saw a wheel which
had been built up on a Campy record front hub, circa 1975, for which the spoke holes were clearly
not centered on the rotational axis. The person we had sold the hub to was complaining, but I
really couldn't see any reason why this would make a difference. The rim was still true and the
delta r was small enough that none of the spokes were either too short or too long.

You couldn't see the effect while riding, but it was easy to see when you held the hub in your hand
and spun the rim.

I've always wondered if that was an extremely odd occurance, or if it happens fairly regularly and
just never gets noticed. Has anyone else ever seen anything like this?

-
-----------------------------------------------
Jim Adney [email hidden] Madison, WI 53711 USA
-----------------------------------------------

Yes.

I once saw on of the very cheapest China-made aluminum hubs with its inside axis skewed to its
outside axis. Don't know how that could happen; maybe the shell got fixed in the lathe wrong between
setting up for ID and OD machining.

Anyway, one end of the shell appeared to oscillate by several millimeters by my estimate, yet the
wheel was built up, trued, installed on the bike and works great.