A hole in a surface which is large enough to enable screw threads and shank to pass through.
Source: http://en.wiktionary.org/wiki/clearance_hole
If you want it to grip, drill a 9/64 hole. For a clearance hole, drill 7/32.
When assembling two parts, if the shaft is larger then the hole, you then get an interference because the shaft won't fit. A clearance fit is an assembly where a part enters a matching hole with a slightly larger diameter for easy joining or easy removal.
For a clearance hole you need a 9/64 drill bit.
Clearance volume usually refers to the volume above the piston(to the top of the block) if the piston is receased( .30'' in the hole). + vavle relief in cc's+ the volume of the head gasket.
The size of the clearance hole for screws should be slightly larger than the diameter of the screw shaft to allow for easy insertion and proper fastening.
A through-hole in a component that enables you to snugly pass a threaded screw/stud (or shank of) without interference or loose fit.
That size is 8-32. The drill bit for a clearance hole is 11/64, or a #17 drill bit.
Whether it is blanking or piercing, size of opening in sheet is governed by punch and size of cutout piece is governed by Die. So, for piercing, Punch size should be same as required hole size and clearance should be given on Die. For e.g for a hole size Dia 8, punch size should Be 8mm and die size 8 + clearance For Blanking, DIe size should be same as size of blank and clearance should be give on punch. So for a blank of Dia 8, die size is of 8mm and punch size is 8 - clearance.
Valve clearance
A clearance fit constraint is commonly used to place a pin in a hole, ensuring a close fit between the two parts while allowing for easy assembly and disassembly. This constraint enables the pin to slide into the hole with minimal interference, preventing any unnecessary movement.
It is to mark it as either promo or clearance. On LP's they would clip a corner of the jacket. If the 45 Lp's have the small additional hole in the same location, though they are from different recording companies could there be another purpose for it other than to denote a promo record. Such as a alignment hole of some type?
For a 6-32 screw, the recommended clearance hole size is typically around 0.138 inches (3.51 mm) for standard applications. If you are tapping a hole for a 6-32 screw, you would generally use a drill size of 0.106 inches (2.69 mm) for the tap. Always consider the specific application and material when determining the exact hole size.