Fritz Egli is a Swiss frame builder. In the late 1960s he took the most powerful motorcycle engine available at that time, the 1000cc Vincent V twin from the 1946-1955 and put it into a frame of his own design. He made about 70 of these Egli-Vincents before moving on to build custom frames for all of the major Japanese brands as well as race car frames.
Today the Egli-Vincents are a collector bike and a number of bike builders have built replicas.
I'm doing likewise, although my frame strays a bit from the original Egli.
I'm using SS 316 tubing, all .065 wall except the steering head and swing arm pivot tube.
Starting point was to machine up a steering tube to fit the bearings and stem for the front end I'm using (2003 GSXR 750) and cut appropriate shapes into the top spine (4" o.d. tube about 18" long) which is also the oil tank.
All welds and some cuts are done with an Everlast 205 multifunction.