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Old 23-04-20, 19:09
David Dunlop David Dunlop is offline
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Join Date: Feb 2006
Location: Winnipeg, MB
Posts: 2,335
Default SEMS Fasteners

I have been taking a closer look at the panel mounting hardware on this Sender. A two-part reason for this.

Firstly, I want to know exactly what it is I have on this Sender, and secondly, once knowing that, I want to try and determine what is correct and what is not.

I started by numbering all 31 screws I had removed, on the foam board I transferred them to, and then I spec’d each of them out and recorded the data obtained. Apart from seven specialty screws, all others were 6 – 32 thread cutting of ¼, 5/16. 3/8 or ½ inch lengths.

I made some inquiries about possible specific names for thread cutting screws, in the process of which I stumbled across references to SEMS Fasteners. When I looked these fasteners up on line, it turns out pretty much any screw or bolt can become a SEMS Fastener. This fasteners claim to fame is the fact the shank of the screw, directly under the screw, or bolt, head is machined down slightly thinner than the following thread. A split washer is then fitted in that space and essentially held captive there.

With the exception of the previously mentioned specialty screws and two other in the panel, this type of fastener was what was being used as the panel mounting hardware. When I went into the Hardware Listing for the 52-Set, I found them listed as SEMS Fasteners. The big advantage of this hardware on an assembly line is the amount of time saved at stations where the workers do not have to fit individual screws and washers together before installing them. Both pieces are automatically together.

The other interesting thing in the Hardware Listing was that only two lengths of 6 – 32 SEMS Fasteners were used installing the front panels: 5/16 and 3/8 inch. So the ¼ and ½ inch ones I have present are clearly substitutes. That is a big help at this point.

David
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