Anybody know the head Dia of a #2 button head?

J S Machine

J S Machine

Well-Known Member
I'm trying to counterbore something for a 2-56 and I'm not sure if a #2 counterbore will do it for a button head screw. I know a counterbore will work for a Socket head, but I'm not sure if a button head is the same diameter. Anybody have one laying around that they can measure thre head on for me?

Thanks
 
I now have some from two suppliers and they are not the same size. I will be turning down some heads to fit . Frank
 
Anytime you need a measurement like that, look on McMaster-Carr. They have technical drawings for almost everything. They even have CAD you can download for a lot of their parts.
 
Frank and Dave are both right.

And No, a socket head counterbore will not work, socket heads are in the .140" range.
"Button" heads that I have on hand range from .157" to .187"

The ones I like require an 11/64" counterbore.
 
Thanks guys.

I didn'y even think about turning the head. I'm in a position where I need to use a 2-56 screw and all I have are bottun heads. The space where the c/b needs to be is only about .215" wide, and that won't leave me much on either side if I stick it with a 3/16" c/b. However, If I turn the head, I think I may be able to get away with a little less of a c/b size and the walls of the material will remain intact instead of breaking out on either side.
 
The standard counterbore for a #2 screw is .156-.157", or 5/32", and it's pilot is .086" in diameter. I use a standard C-bore that I bought years ago. Haven't seen any for sale in a long time so I have to break out the diamond files and sharpen it occasionally.

The standard size for a #2 button head screw is just a little bigger. The last little bag of screws I got (from Tracy) were some of the most consistent I've ever used and were probably averaging .158" for the head's diameter. I turn the heads down on my lathe and have for years. These last ones just took a few thousandths to get them to fit.
 
According to the Machinery's Handbook, the max-min diameter for a #2 button head is 0.164" -0.154", head height is 0.046"- 0.038"

The range for the pilot hole is 0.094" (a.k.a 3/32") for what they call a close fit and 0.106" (a.k.a. no 36 drill) for a normal fit.

Ric
 
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