Screw Sizes

[Baldhead]

What size screw will I need to secure a bracket that has a 7mm countersunk hole?

BH

 

[Myfordman]

3.5mm. Screw shank is always half the head diameter

 

[Baldhead]

Myfordman, thanks for that. The actual hole is 7mm in diameter, so that would mean size 14? is that correct.

BH

 

[kostello]

4" nail

 

[Chrispy]

If the clearance hole is 7mm the you need a 7mm screw 6mm will be easier to obtain, 6mm screw should have a 12mm head according to myfordman

 

[Cheshirechappie]

If you have any 'old money' screws in stock, a No 14 has a shank of just under 1/4" diameter, which will fit a 7mm hole nicely. Depending on how thick the metal of the bracket is, a No 12 or No 10 might be better - the thinner the bracket, the smaller will be the OD of the countersink, so the smaller the screwhead you'd need for a tidy finish.

 

[Baldhead]

Thanks guys I got it sorted, No12's perfect fit.

Baldhead