At 11:05 PM 11/16/2008, Jan Heine wrote:
>First, a technical note. Even though Tom thought the cantle plates
>were cast or forged, this is not correct. They are stamped. In fact,
>I cannot think of a part of a Brooks saddle that is forged or cast.
>Most of the parts are stamped. Of course, stamping dies aren't
>cheap, either, especially considering the thickness of the material
>that is involved on the frame pieces.
>
>Also, it may be that stamping ti wears the dies faster than working
>with steel.
>
>Beyond that, does Brooks use dedicated tooling for their ti saddles,
>or do they just place titanium in the place of steel when they make
>these parts? When you compare the dimensions of the cantle plates
>for Brooks ti and Brooks steel saddles, they are so similar that the
>tooling appears to be very similar.
Using the same tooling to stamp and bend steel and Ti will not produce identically shaped pieces.
Various metals and alloys all have varying amounts of springback when bent far enough to take a set. Lets say you wanted to put 90 degree bends on dimensionally identical pieces of 1020 and 4130 steel and Ti rod using a die with a 3" radius and some sort of follower. To get a 90 degree finished product, you might have to bend the 1020 95 degrees the 4130 100+ degrees and the Ti 130 degrees. (Numbers I pulled out of the air, but the proportions are about right) And the resulting radii of curvature would all be greater than 3', with the Ti quite a bit larger.
If the Ti and steel cantle plates are identical in shape I assume the Ti ones were done on a deeper, narrower die.
Mark Stonich;
BikeSmith Design & Fabrication
5349 Elliot Ave S. - Minneapolis. MN 55417
Ph. (612) 824-2372 http://bikesmithdesign.com
http://mnhpva.org