Friday, December 23, 2011

Cable Splicing Clamp - Holding Plate

 The presser bar pushes the cable loop and thimble securely into this plate, which does the actual holding while the loose end of the cable is secured.  It is made from a piece of 1/4" x 1" x 3" mild steel bar stock.
 The hole Locations are transferred from the base plate with duplicating punches to assure the bolts will align well.  The center hole is not drilled it is just a reference point.  The 2 bolt holes are drilled with a #3 drill and tapped with a 1/4" - 28 UNF thread to accept the 1/4" bolts.
 The opening in the center is to hold the loop of cable and the thimble so the hole is tapered to match the thimble.  From the AN100 drawing the sides slope 1:3 so rather than move my nice square table, and have to realign it, I made a hardwood block 1" x 3".  The plate is set on top of it and  held with the wrench while drilling.  The bolt is just there as a stop to keep the block of wood from sliding.  Think of it as a bench dog.  The holes are drilled through with a #2 (3/16) center drill.  Before drilling at the angle I drilled with just the tip about 1/32" deep 5/16" apart.  I chose the 3/16" drill because I plan to use this with 1/8" and 5/32" cable but this would allow up to 3/16" cable to set nicely in the round groove.

 All of the cutting and drilling is done with the bottom side of the plate up (visible).  The edge of all the cuts are more sharply visible on this side and the saw work is all being done by eye.
 The entrance slot and the relief for the thimble are cut next without ant taper.  This is just to get the shape.  From the top side you can see the angle of the drilled holes better.

 The band saw was used with the same 1:3 block to taper the thimble relief by placing the block next to the blade for good support.  The saw is being used more like a powered file than as a saw.  You just gently saw into the plate until the blade just kissed the cut edge.

I also tapered the entrance hole by turning the block 90 degrees to the blade and sawing along the edge of the cut.  Again you could tilt the table but that would have taken longer then making the cuts.  This came out really good and the cable fits perfectly.

The two 1/4" bolts were threaded down to 2-5/8" from the head.  It doesn't show here but they were cut off to leave 1/4" of good threads to screw into the plate.  The center bolt was threaded to give 1-1/2" of threads.  The head will get cut off from it later.

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