>Hi Ron: > >Some of our readers may not know that some factories use brass shims to >make sure the agraffes are tight when they come around to the right >position. Occasionally a factory worker on piece-work basis may elect to >just force the agraffe a little more (hoping it does not break). Using >split shims is faster than unscrewing the agraffe all the way out for >spot facing or placing shims on agraffe. > >Jim Coleman, Sr. > Hi Jim, Oh yea, a little information would help clarify things some, wouldn't it? Fair enough, I'll explain why I'm not too concerned about cranking agraffes a quarter turn past snug. The old agraffes had flat shoulders that contacted the plate from the outer edge of the shoulder to the outer edge of the hole in the plate. There was no compressibility built in, so If these things were forced a quarter turn past snug it would likely damage the stud. Modern agraffes we get from supply houses have a bevel relief cut in the underside if the shoulder so that just the outer perimeter of the shoulder contacts the plate. If one of these snugs up 1/4 turn short of square, you can bring it to square in four or five "bites" by advancing it fifteen degrees or so past where it last was, and turning it back to loose again. This scrubs down the narrow contact point around the perimeter of the shoulder and lets the agraffe turn further each time than it did last time without damaging the stud. You can feel what's happening and see your progress relative to where you want it to stop. When it gets to the right position on a tightening stroke... stop. If you try to crank one 1/4 turn to square in one pass, you're wasting that nice "auto fit" shoulder feature and possibly breaking the stud. Spot facing the bottom off the shoulder makes it tougher to square the agraffe up because it widens the plate contact area and you lose the "scrub" adjustment. I use spot facing and shims mostly for height control if necessary when I'm replacing an individual agraffe in the field. When fitting new agraffes, I usually take out every other one and try different agraffes in each hole until I get one that snugs up at about 1/4 turn short. I seat and square them up, take out the remaining old ones and do the same thing. I do this after the plate is finished, but I can see that it would be easier to do the finish with the agraffes out. I'm open to suggestion if anyone has a better procedure. BTW, you don't have to spend a bunch on a hollow end mill or spot facer. I bought a couple of carbide tipped, four fluted mills at a local surplus yard from the $2.50 lb barrel for about $1.75. It took a little digging and trial fitting, but time flies when you're playing with tools. Ask Harvey. Anyway, that's my take. Ron
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