Missing Chrome Inside a Button

Q. Hello Mr. Taylor, we buy buttons for shift knobs/automotive industry, and noticed some areas missing chrome inside not visible to the user aproximately 1/2 inch away from A surface. Could that represent a risk of durability of the part? Or is this normal to get given the deepness of the interior cavity? Thanks in advance

A. What you're referring to is called "throw in". I'm not aware of your specific acceptance criteria for plating, but if you are referring to evidence of a plated coating and the depth or distance it coats into holes and recesses, there is a rule of thumb. If no other requirements, plating should be present at least to a depth equal to 1/2 the diameter of the hole. If the hole was .25 in diameter, the plating should throw into the hole at least 1/8th of an inch deep from the edge, unless otherwise specified.

Irregardless, in my opinion, as long as there is 100% coating coverage on the exterior, and little or no plating coverage inside the hole, the risk of durability is fairly low. The risk of corrosion will be slightly greater if the plated coating terminates at the edge of a hole and would increase if the termination of the plated coating is outside a hole.

Good Luck,

Randy Taylor