Kirk Fat II.

Posted on December 3, 2014

Kirk Fat II

Today’s installment of the Kirk Fat miniseries picks up where yesterday’s left off and the first step is cleaning and prepping the mitered tubes to tack and braze. Typing this out with so few words makes it feel like it should be something that takes little time. Just three things really — clean, tack, braze. But this takes a number of hours to do. The amount of time with a torch in your hand while bent over and twisted at some odd angle can’t be dismissed. That said you can see in the photos that the brazing work is indeed done. The glassy clear and whiteish stuff on the joint is hardened flux and this is removed in a hot water bath where it dissolves.

Once the flux is removed the next step is to machine and face the BB shell so that the alignment can be done based on those parallel faces. The parallel BB faces are ‘home base’ so to speak and everything is referenced to them. If I’ve done my job well the frame will only need to be checked and not moved at all and my work here went very well. Once everything here is verified the wheel and fat tire are used to make a final checks to be sure that the wheel is perfectly in plane with the center plane of the frame. Lastly the clearance room for the tire to the chain and seat stays is double checked and here I decided to add just a bit with some shallow dimples in the tubes — better safe than sorry.

With the BB machined, the frame aligned and the tire clearance checked it’s now time to get into some serious sanding of fillets – More on that later.

Dave