RE: [CR]CUP REMOVAL

(Example: Framebuilders)

Content-class: urn:content-classes:message
Subject: RE: [CR]CUP REMOVAL
Date: Sat, 30 Dec 2006 12:24:17 -0800
In-Reply-To: <45969B43.6040200@pacbell.net>
Thread-Topic: [CR]CUP REMOVAL
Thread-Index: AccsNBNcxGaggeF6R/m4gUDlO2T7NQAFqamw
From: "Mark Bulgier" <Mark@bulgier.net>
To: "Bob Freitas" <freitas1@pacbell.net>, "classic rendezvous" <classicrendezvous@bikelist.org>


Bob Freitas wrote:
> The method I was shown was to take an Allen style
> wrench and grind most of the leg off leaving a flat ended
> stub which fits behind the cup. Place hub with cup to be
> removed on wooden bench or board and hammer away from the
> other side ,rotating the punch 180o then 90o.

I know this can work, but it takes a bit of skill and can damage the aluminum socket the race sits in if done clumsily -- if the race is allowed to cock to too much of an angle. It's also kinda slow.

You can make an approximation of the Campy "rocketship" four-pronged punch easily enough, I have done it. You need some 3/8" tubing, ideally some tough stuff like 4130 (Cr-Mo). (Yes there are places that will sell you as little as 1 foot of this*, see below). Fairly thick wall (like .058 or more) is best, but I used .035 which is kinda thin and it worked. 1/4" tubing might work too if that's all you have.

You make a hacksaw cut starting at one end, down the length of the tube about an inch and a half, then turn 90° and do it again, so you have 4 prongs. Bend each prong out, right near the tip, until the 4 prongs make a circle that is a little bit larger diameter than the hole in the cup. Note, when bending the prongs out, they will want to bend at their root (where your hacksaw cuts stopped), which won't work due to the confines of the space behind the cup. You need to apply leverage so as to get the prongs to bend out in the last 1/2" or less. Do not bend them any further than necessary.

Now the tool is ready to use: Insert the end you're going to hammer on (opposite the end with the prongs) through the cup you're extracting, and the prongs will have to spring inward to go through the hole - then they'll spring back out once they're through the hole - click! - and you're ready to hammer.

This kind of punch has to knock the race out straight.

Mark Bulgier Seattle WA USA

* Check out Aircraft Spruce or Dillsburg Aeroplane Works for 4130 tubing. http://www.aircraftspruce.com/catalog/mepages/4130tubing_un1.php 3/8" x .058" is just 95¢ ($0.95) for a foot, enough for two or three tries at this tool!

Aircraft Spruce also has a cool deal on a pile of miscellaneous short sizes, for only $30: "Starter Kit - An assortment of 4130 tubing, rod and bar in short lengths to practice welding. At least 20 ft. of tubing in assorted sizes and wall thicknesses." http://www.aircraftspruce.com/catalog/mepages/4130bargainbag.php