Flat head Socket Cap Screw Head depth?
Flat head Socket Cap Screw Head depth?
(OP)
On Master Carr a 1/2 head depth is .251 Link
However, when I measure mine its closer to .295. Isn't there a standard or am I measuring wrong?
However, when I measure mine its closer to .295. Isn't there a standard or am I measuring wrong?





RE: Flat head Socket Cap Screw Head depth?
It depends where they are made, China or ??
I have seen both and the sizes vary.
Chris, CSWP
SolidWorks '16
ctophers home
SolidWorks Legion
RE: Flat head Socket Cap Screw Head depth?
YMMV.
RE: Flat head Socket Cap Screw Head depth?
The standard of interest is probably ASME B18.3.
Typically the head is controlled by an angle tolerance, a maximum theoretical sharp diameter, and a minimum actual material diameter. If the standard provides the .251 dimension at all, it is likely for reference only.
The McMaster drawing shows the dimension to the line of tangency between the conical surface and the fillet, but I doubt that's correct. It should probably be to the intersection of the conical surface with the basic major diameter as 3DDave mentioned.
What exactly are you measuring? Perhaps more to the point, why measure this at all?
pylfrm
RE: Flat head Socket Cap Screw Head depth?
RE: Flat head Socket Cap Screw Head depth?
RE: Flat head Socket Cap Screw Head depth?
In fact, for very precisely controlled countersinks, it's quite common to call out a tight tolerance on the major diameter of the countersink and use a countersink/chamfer gage to read the major diameter size.
It will be a much more precise control to ensure flat head screws seat flush or slightly below. I think you'll find the diameter of the screw heads are predictable enough to plan your countersink sizes for them.