Friday, December 31, 2010

The frame with the still uncut seatstays, seat tube, and head tube weighs in at 4lbs. 5 oz.  Again, hoping for a sub 4lb. frame.  Devo came over and we mocked up for the seat stay positioning so I can possibly start cutting them tomorrow.  Of course, that depends on how tonight goes.

Tuesday, December 28, 2010

 Both chainstays are now brazed and in perfect alignment.  I put a small dimple for added chainring clearance in case Devo wants to run a larger ring and/or a bash guard.  Great crank arm and tire clearance also.  Very pleased. I have some bike maintenance jobs to get done before the week end, then I will fit up the s-bend seatstays.  I'm hoping for a 4lb. frame, it weighs 3lbs. 9oz. right now.  We will see.  I'm also contemplating head tube reinforcing rings to compensate for that big front tire and longer fork.
 Wouldn't want the head tube to ovalize.

Thursday, December 23, 2010

Sweet Tina had to work today, so I thought I would put a little time in on the frame.  I aligned and brazed the NDS chainstay on, then soaked the flux off, and realigned.  I'll now use that chainstay  and the installed wheel to align the DS chainstay.  It really looks good.  With the 56mm tire, it has 10mm minimum clearance to the chainstays without pinching.  When Devo runs a 61mm tire, he will still have 7.5mm clearence.  If he wants more, I can pinch them.  I also temporarily installed his crankset to check for any
interference with the chainstay.  So far so good.

Wednesday, December 22, 2010

The vent holes have been drilled for the chainstays.  I will attach them right after Festivus.  This year, I have done repairs on some other 'boutique" bikes and have noticed that there were no vent holes.  How do the welding gases and condensation escape?  You gotta have vent holes.  Also, the front triangle, with the uncut head and seat tube and all braze ons weighs 2lbs. 5 oz.  Not bad for a frame this big.  By the way, it won't fit in the blast cabinet.  And the fillets aren't finished due to my lacerated finger and five different seasonals in my fridge.

And just for fun, here's a pic of Dylan circumventing some mud at Nationals.  How long till cross season starts?

Monday, December 20, 2010

Here is one of Devins Paragon sliders silver brazed to the chainstay.  Took me most of the day to get this far.  My, pretty much non adjustable, fixture was designed around road bike type geometry and didn't want to accommodate the higher BB and longer chainstays. But enough manipulation and a smashed and cut finger, it works quite well.  I used a 45% silver rather than 50% or 56% as it should impart more strength to the joint.

Friday, December 17, 2010

After tacking the front triangle, the alignment check went well. The head tube was perfectly in plane and only 2mm off center. After the quick realignment, the brazing was coming along great until I ran out of gas and had to run down to the welding supply store for fresh tanks. I really need to buy spare tanks. I used the brazing sequence that I learned from Jim Kish and the triangle came out in perfect alignment. I'm doing over sized fillets per Devs request, it's a lot of extra work. The rule of thumb is that the fillet should be 3 times the wall thickness of the tubing. Beyond that it is purely cosmetic. Then I ran out of 80 grit emery cloth and spent considerable time trying to find some locally, but to no avail. So none of the fillets are finished. I will order my usual industrial sized quantity ASAP and work on the rear triangle in the interim.

Wednesday, December 15, 2010

Its been sanded, cleaned, fluxed, reassembled, and remeasured.

The tack brazing is now done. When it is cool, I will check for alignment and set as necessary. I only tack on the verticals so it is easier to take any twist out. I also rotate the frame as I braze to allow gravity to aid in the brass flow.

Monday, December 13, 2010

Devins 29er front triangle is finally fitted. The brake line bosses and water bottle braze-ons have been silver brazed on. I like to attach them prior to brazing up the triangle to minimize any stress that putting them on afterwards might induce. Also, the vent holes have been drilled. Wedsnesday I will sand and clean the tubes with lacquer thinner and braze it up. Cool.