Upper frames to e made from Φ1.5 brass rods. They had to have Φ1 holes to accept hinge screws. For this purpose I made this parallel from t1.5 mild steel plate. The groove on the top holds the brass rod in the vice. I drilled Φ1 hole in the rod, but the rod was too week after drilling and easily broken at the hole when I filed burrs. It seemed making a Φ1 hole in Φ1.5 brass rod was impractical.


So I decided to squash the ends of the rod by vice to about 2mm width. It should be done in several steps with annealing. Otherwise the brass rod might split.


Squashed rod.


The rod was held by special parallel and vice. It was drilled with Φ1 centre drill for the first hole.


Then the vice was loosen and the table and vice was shifted toward the other end of the work. Then second hole was positioned by DRO to ensure good accuracy.


By rounding the ends the beams were finished. The holes will accept hinge scres.


This job was really difficult and I made lot of waste.


パンタグラフの自作 scratch building pantograph

inserted by FC2 system