Since then I've had come up against a couple of situations that suggest further verification of the "trueness," the uniformity, the correctness of a given razor's condition. As a result of these situations, one of my concerns with a three-piece razor is the whether the key edges of the top cap are straight, parallel, and properly aligned with the baseplate.
The specific top-cap characteristics to be tested are as follows:
|Test one: sight along an edge to determine straightness.|
- Are the long edges of the top cap (that lie above the blade edge) straight?
- Are the long edges of the top cap in the same plane?
- Are the long edges of the top cap parallel?
- Is the plane of the top-cap edges parallel to the plane of the baseplate?
Perhaps an easier test two is to simply put a blade onto the inverted top cap. If the (unflexed and presumed-flat) blade settles evenly onto both edges of the top cap without any gaps along the edge, that would indicate that the edges are in the same plane.
|Test four: adjust the "tightness" of the top-cap screw so that|
the threads support the top cap and allow it to "float" just
above the flat razor blade.
If the threaded rod is too short to allow the completion of test four, then the safety tests in my earlier article on inspecting a new razor should be sufficient to complete the inspection of the entire razor and the top cap specifically.
These are the tests to determine if the top cap of your two- or three-piece razor is "in shape" properly hold a DE blade against the baseplate for a safe shave.