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I'm not an expert on fillister head screws, but it appears to me that the screws above do not meet the ANSI spec for fillister screws. The applicable ANSI spec is B18.6.3. According to the spec, no taper in the head diameter is shown (or implied). The only concession made is the following:
"A slight rounding of the edges at the periphery of the head shall be permissible provided the diameter of the bearing circle is equal to no less than 90 percent of the specified minimum head diameter."
The permissible diameter of a #5-40 head is .205/.187, so if the diameter of the head is less than .168 inches at the top, then these do not meet the spec.
Mike
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Mike
1976 Euro 911
3.2 w/10.3 compression & SSIs
22/29 torsions, 22/22 adjustable sways, Carrera brakes
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