Production work, however, necessitates that dedicated, fixed position equipment be used to ensure accurate, repeatable results from piece to piece.
Today, I want to talk about the importance of "soft jaws". Soft jaws are replaceable tooling that hold a part for machining, often not heat treated, allowing the operator two distinct advantages; the ability to shape the jaws to perfectly fit the piece being machined. Secondly, the shaped clamping surface provides greater surface contact allowing for a less robust clamping surface, leaving no impressions on the finished part.
The example we are going to look at here is a set of jaws that were shaped to accept the spider interface for the Hot Rod cranks. In this case, the part is water jet cut to the rough dimensions and the center hole needs to be opened up to 24.02 mm and then face relieved a skoosh so that it is a tight slip fit over the bottom bracket spindle.
|The base part, before machining|
|The lathe jaws, ground to accept the part|
|The part clamped and machined in the soft jaw|