It all starts when you decide you want me to build you a custom bicycle frame, at this point you only need a vague idea of what you want. Once you place a $500 non-trasferable down payment your spot will be save in the build queue. We can talk all about what you are looking for in your bike, you can also feel free to stop by my shop to see my current work and talk face-to-face. Shortly before your turn comes I will be contacting you to finalize frame geometry as well as the other options. I will then send you a BikeCAD draft for final approval and then the frame building starts.
After selecting tubing specifically for the riders needs the mitering process begins. The age old adage “measure twice, cut once” has new meaning when you are plunging a carbide hole saw into a stainless tube that cost $70. After measuring the butt lengths of the tube and finding the cut length the tube is secured in two tube blocks to ensure that the two miters are in phase with one another. A rough cut is made with a hacksaw and then the tubing is secured in the mill. After the mill is properly centered and the spindle speed and angles are set the cutting begins. Measure, cut, miter, and repeat…
After all the tubing is mitered with the milling machine each tube is fine tuned with a hand file to achieve a perfect fit. Since this frame is a lugged frame the next step is lug preparation. It is mandatory that each lug has the right fit on the tubing, if it fits to tightly the silver will not properly flow and penetrate the entire joint, and if it is too loose the joint will lose some strength. At this point I file the lugs edges to make sure it has elegant curves and a unique look, I also ensure that the edges or shorelines have a 90 degree angle for a crisp look and a cleaner braze. After all the shaping and filing work is done I clean the inside of the lugs with my trusted Dremel tool and a sandpaper flap wheel. After the final lug cleaning is complete (done for the last time just before brazing) I apply flux to help prevent any atmospheric contamination of the steel.
Next thing to be done is to drill the necessary vent holes in the head tube. Vent holes allow gases generated by the brazing process to escape and they help ventilate the frame and reduce the possibility of rust. I drill large 3/4″ holes in the head tube and the bottom bracket shell when building a fillet brazed frame. I skip the hole often found in the seat tube to top tube junction because the grease used for your seat post gets piled in the top tube with no possibility for removal, the last thing you want in you top tube is a big glob of grease!
The next portion of the build is the dry fit, this is time consuming but extremely important to achieve a strong frame that has no residual stresses. The frame is loaded in the jig and all the miters are double checked as well as the fit of the lugs. It is important that the fit is ever so slightly loose to accommodate the expansion creating by the brazing process. I also take this opportunity to double check all the measurements of your frame against the BikeCAD outline. The next step is to clean all the tubing and lugs very well one last time, apply flux to help prevent oxidization and finally load the main triangle into the frame fixture for tacking.
More to come…