At 09:07 AM 3/31/2011, Justin Richards wrote: >I have been trying to work out exactly what "cinch" refers to from=20 >the context. > >I have come to the conclusion that it is some type of lead >manipulation to help make the lead fit tight in the hole. Perhaps >with a hammer or pliers to flatten the leads at the reguired position >so when the component is placed it will stop at the "interference fit" >point. "Clinch" used to refer to the process of cutting the lead fairly=20 short on the bottom of the board, then folding that little bit of=20 lead flat onto the pad. This provides mechanical support and really=20 good pull-out strength. It also makes for a very low profile on the=20 bottom of the PC board. I have some hand-operated tools that do this - the tip hooks onto the=20 component lead. Squeezing the handles draws back a chisel-like=20 cutting blade. When the handles are squeezed past the trip point,=20 the chisel is released and flies into the lead. This shears off the=20 excess lead length and folds the little bit sticking out from the=20 board right flat onto the pad. I have some other pneumatic tools (Simmonds) that are also called=20 'clinch' tools but they work differently. Tripping the tool causes=20 the jaws to close and cut off the excess lead length. The little bit=20 of lead sticking out of the board is squashed flat (in one dimension)=20 which increases its diameter significantly. That stops the lead from=20 being able to be pulled back out of the hole. However, the lead is=20 still sticking below the surface of the board, unlike the clinch tool=20 I described above. One of the benefits of both tools is that the surface of the lead is=20 cleaned very well. This used to help a lot with old-time resistors -=20 the surface oxide was removed and the resulting solder joint was excellent. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .