You can only make your frames as straight as the tooling and measurement equipment you use to build them. TIG welding frames adds an element of the organic due to the heating and cooling that takes place during the welding process. This makes them some of the most difficult types of frames to make and hold the tight tolerances required to achieve optimal performance and handling characteristics…
There are two major pieces of equipment that are the heart and soul of a frame builder’s shop: the frame jig and the alignment table. Today we are focusing on the creation of the alignment table that we built right here in our shop. Essentially it is a perfectly flat surface plate that various mechanisms and measuring devices can be attached to. It is used to check the frame at various points during the production process as well as to affix the frame to the table and cold set it as required to maintain our tight tolerances.
We started by designing and then ordering a 365 pound piece of steel that we then had cut and rotary surface ground (aka blanchard ground) to our specifications.
We ordered another couple of hundred pounds of steel tubing and angle iron for the skirt and base in order to properly support the top. We then used an old school precision horizontal band saw to cut all of the pieces to the proper angles and lengths.
Then the legs and table skirt were drilled on our Bridgeport to allow assembly after we welded the individual parts together.
The parts for the base were then laid out and affixed to the monster acorn fabrication table to be welded. What better way to build an alignment table than on an alignment table. The acorn table is the exact same kind of table I used back in the day, at Merlin Metalworks over in Cambridge, to align frames.
For this type of fabrication we used a different type of welding than you would use for making a bicycle frame. We used a MIG (metal inert gas) welder, this is not a delicate kind of welding, it is fast, furious and hot, ideal for heavy duty fabrication.
For the bottom of the table we decide on some heavy duty levelers to make the table sit flat, level and securely on our concrete floor. We drilled and tapped holes directly into plates that we welded to the bottom of the legs and then bolted on the levelers.
We attached the skirt to the underside of the surface plate and then bolted it to the legs, completing the main structure. Next we cleaned the hell out of it, oiled it down and loaded it up with our various precision measuring devices.
So much more to come…