Automatic Center-punch - American Welding Society

By aevald Date 11-04- 04:16 Hello everyone, I have some pictures to include with this and will post them tomorrow when I get back to my other computer and resources. Many of you may be familiar with this particular tool, especially if you do any machining to speak of. Simply put, this is a center-punch that is spring-loaded and once you have located the point that you would like to punch you apply pressure to the body and it will compress until it triggers the release and it leaves a "small" punch mark. Generally, as is the case with transfer punches, you will then use a regular center-punch and hammer to enlarge this punch mark to allow for further processing.
     In many of today's fabrication facilities there are a large number of drawings that are generated with various CAD programs. In many instances these drawings will detail connection plates and other complicated shapes that can then be exported to burn tables, plasma tables, laser tables, and water-jet tables for processing. Generally the water-jet, laser, and some of the plasma tables have enough accuracy and ability to put holes in these parts and not require secondary processes to provide the holes. In cases where they may not, for whatever reason, the programmers will often times include hole locations on these drawings. The drawings can be reproduced to scale and printed on paper to be used for patterns to locate and mark these hole locations by laying these scale patterns ontop of the parts and the automatic center-punch can easily be employed to mark these holes.
     For those who may not have ready access to these CNC type material processing systems there are some other possibilities: one is to print the pattern on paper and use a burn/plasma table that is equipped with a Linatrol or similar line-following eye system and then cut these shapes. Or simpler yet, produce the patterns with paper and depending on whether they can be sheared out or cut out with a hand torch/plasma proceed to cut them out. In the case of straight cut shapes that don't have inside corners you could use the automatic center-punch to locate the corners and lay-out the holes and then connect the dots so to speak and either shear or burn on these lines and then punch/drill the holes.
     Once I have included the pictures that I have for this topic, I believe it will make a lot more sense. As Mark mentioned about the transfer-punch thread, you do need to be sure that the pattern stays in place while you are doing any tracing or hole marking. The nice thing about using an automatic center-punch over using a conventional center-punch and hammer is that the impact remains constant and it doesn't tend to over-size the hole in your pattern and thus cause inaccuracies. Generally the divot produced with the automatic is such that it allows you to see where the point is easily enough and then you can upsize it according to the purpose that you have in mind for it. Since the automatic is a one-handed tool you can hold the pattern in place in many cases and it doesn't necessarily require clamps or other holding aides. I'll include the pics tomorrow. Best regards everyone, Allan