Spot Welding

Questions and Answers

A universal holder is a simple non ejector style straight barrel holder. Instead of a taper for electrode attachment it is threaded for use of threaded adapters. The threaded adapters allow welding in line with the barrel length or at right angle or 30 degrees.

High pressure holders are required at forces above 2400 lbs..  Tapers are no longer practical at these levels per RWMA Manual Fig 18.3. At these high forces the electrode tapers fail because they are continually forced deeper and deeper into the holder taper. High pressure holders use mechanical attachment that mount by means other than a taper and this is not an issue.

A straight cap shank is the most common. However in some applications one cannot reach into the proper location on the part without some adaption of the cap shank. A double bend cap shank solves many of these applications.

Cap shanks are small holders that the female or male cap is attached to using a taper. This shank usually has a full size RWMA taper on its other end which is used to attach it to the holder mechanism on the machine, cylinder or servo.

In order to minimize weld cost it is often prudent to make several welds with one stroke of the machine. If time is of the essence, this can be done with a dedicated machine design. Multiple cylinders would all operate at nearly the same time. Their timing is usually spaced slightly to reduce power demand. If multiple welds are in a modest space multiple cylinders may not fit. Then specialized multi spot equalizing holders might be the solution.

Have a Question?

Do you have a question that is not covered in our knowledgebase? Do you have questions regarding the above article? Click here to ask the professor.