On Mon, 20 Feb 2012 08:06:59 -0600, "Pete C."
wrote:


Larry Jaques wrote:

On 20 Feb 2012 04:20:40 GMT, "DoN. Nichols"
wrote:

One problem -- I need the hub out of the failed one to complete
it. Unless I make myself a double-D broach to make them without the old
hub.

Don, how are double-D holes made? I just spent 5 minutes looking at
broachmaker sites and they don't have many pics. One listed it as a
round shape. Do they drill a hole and fit the broach in, moving it
up and down across an axis to cut the slot, or what?

Like most broaching, it will be drilling a pilot hole and then pushing
or pulling the broach through to finish the full hole profile. Each
cutter step of the broach will progressively start from the pilot hole
round diameter and expand out a few thousandths towards the final hole
shape. This is why specialty broaches are long and expensive, every
cutter stage is a different profile.

Thanks for the info, Pete. Broaches are almost as pricy as brooches.

--
The ultimate result of shielding men from folly
is to fill the world with fools.
-- Herbert Spencer