Frame Jig I made from Warren Beauchamps plans around February 2004. The Jig is basically 2-2*4 steel beams acting as a base with axle and tube clamp posts extending from the base. These posts are clamped for support allowing you to move them within the base as needed. The project went well. Impressions follow, the thing is heavy you defiantly do not want to move it around much. This hopefully translates into a fairly dimensionally stable structure. The material cost wasn’t that bad. Around $90 for metal, $40 for sawhorses, and $60 for clamps. Total construction time was about 5 hours. Most of it was spent clamping and fitting various pieces accurately. The jig seems accurate enough. I was able to clamp everything to a large flat steel worktable so the beams are parallel (within the materials capabilities). The hardest part was fitting, the angle iron v-clamps accurately for both central location and alignment. The finished clamps hold tubing less than .001 centrally and within .002 thousandths over 6 feet for alignment. A little better accuracy could be had by machining the angle iron after welding, a step I may do if I like the jig after using it. The angle iron I used was quite thick so there is plenty of material left for this step. I also did the axle posts in a milling machine and they should be very close. The only problems I see are the weight issue and no provision for bottom bracket alignment. (Note: Warren added bottom bracket plans after I wrote this write-up. I have not tested his current setup).
The frame tubes are clamped in the angle iron v grooves with modified C-clamps.
The axles are held by metric allthread and nuts. Holes were accuratly machined with a milling machine.
Another view of the jig. The axle and tube clamp posts are all aligned with the base. C-clamps (not shown) are used to hold the axle and tube clamp posts in position for brazing or welding. The sawhorses support the whole Jig.
A final picture of the jig in use. (Note: The jig is a work in progress. The adjustability is
not optimum because moving one piece may effect the alignment on another piece
making precise setup difficult and time consuming.) If you are interested in more information on bicycle frame
building jigs there are two excellent resources I have come across. Stephanie Monfrey has an excellent website with tons of
information and pictures of several amateur and professional jigs as well as
other building information.
http://www.geocities.com/smonfrey/index.htm Choppers Handbook has some interesting information and
several nice pictures and plans for a similar twin rail welding jig. Scroll down
to "Welding Jig" and "Building a Frame Jig".
http://64.172.168.34/neatstuff/index.html
Page last updated 9-03-04