Friday, January 4, 2008

Rear stays and a bump in the road...

Hey folks,
I got an early start in the shop today after dropping the kids off for school, boy was it chilly. The thermometer said 10 degrees outside, but once I got in the shop I turned up the dial, started the mill, and got to work. Once moving, everything was warm and toasty!
I began the day by scallop cutting the chainstays and seatstays for Roy's bike. Once the scallop was cut, it was on to the bb and seat tube miters. I got a smoking deal on some Anvil fixtures a ways back but have not really been using them as I kind of fall under the old dog, new tricks pardigm. Regardless, gotta learn sometime :^) Set up on the chainstay fixture was a breeze. I measured the distance from axel to bottom bracket centerline and made one smooth cut...perfect fit!

Things were going smoothly, until I got to the seatstays.
The issue became quickly apparent. The fixture is designed to auto locate the dropout end of the stay on a conical post, so that each stay is symetrical with it's mate. The posts, however, are designed for the typical tapered stay with a small terminal end, not for the larger .75" diameter piece, thus the problem. The stay was looser than ____________ (put in your favorite analogy here).

The fun thing about framebuilding is having the tools to overcome such problems. I made up some new locating pieces for the Anvil fixture out of 304 stainless steel to accomodate the larger stays. First I turned down the od of the locating piece to match the id of the stay tubing. Then I parted off the two pieces, trued the ends and center drilled them for the fixing bolt that will hold them on the fixture axel with a 5mm allen bolt. Then it was off to the mill to drill the axel hole.

Center drill, then a few increasing drill bits, and finally finished off with a .624 end mill.

A little action with a 5mm tap and whalaa!

Now I have a more versatile piece and am ready to get back to the seatstays next day in the shop.
Had a few folks stop by today to talk custom work, Christi came down and we walked down to Muddy Waters for some hot chocolate, and before I knew it 10 hours had past me by.

Til next day,



steve garro said...

great work, man! the new anvil version 2.0 has a 3-bolt system to clamp the stays to reduce chatter. i hour-glassed the v-clamps as well so they wouldn't dimple the stays -esp. 30 x16's - when you crank 'em down. once again, beautiful fabrication! steve.

Rody said...

Thanks Steve...I'd love to have the latest Anvil stuff, but buying these were really not necessary, just justified the purchase due to the cheapo price. Still, nice stuff.