How do you size a countersink bit?

You will want to choose a countersink that is larger than the bolt size of the hole. Countersink diameter = 1.5 x Bolt Size Hole Diameter. Example: 1/4″-20 Bolt – Multiple the diameter (. 250) x 1.5 = 0.375.

What drill bit do you use to countersink?

We’ll look at what it does, why you need one, and what size countersink bit you need….Countersink Size Chart.

Drill Bit Size	Screw Size for Hardwood	Screw Size for Softwood
⁹/₆₄”	#10	#12

How do you know what size countersink to get?

> A simple rule of thumb is to choose a countersink which is 50\% larger than the diameter of the hole. > Countersink diameter = 1.5 x Bolt Size (hole) diameter. > Example: For a 1/4-20 bolt, multiply the diameter (. 250) x 1.5 = .

Can you countersink with a regular drill bit?

Instead of using a drill bit that both drills the pilot hole and creates a countersink divot, you can opt to make a pilot hole with a regular drill bit and then swap your bit for a countersink drill bit to create the countersink. Once that’s done, switch the drill bit for a screw bit and screw in your screw.

How do you measure countersink depth?

> A simple rule of thumb is to choose a countersink which is 50\% larger than the diameter of the hole > Countersink diameter = 1.5 x bolt size (hole) diameter > Ex: For a 1/4-20 bolt, multiply the diameter (. 250) x 1.5 = . 375. This equates to a 3/8” countersink.

What size countersink bit for wood screws?

Wood Screw Pilot Hole Sizes

Screw Size	Hard Wood	Countersink Size
Tapered Bit
#6	9/64″	5/16″
#7	5/32″	5/16″
#8	11/64″	3/8″

What size countersink bit for #12 screw?

Wood Screw Pilot Hole Sizes

Screw Size	Hard Wood	Countersink Size
Tapered Bit
#10	13/64″	7/16″
#12	7/32″	7/16″
#14	1/4″	1/2″

What size countersink bit for deck screws?

The 8 and 10 are really for DeckMate size screws. #7 is for the composite deck screws. The smaller the number the smaller the drill bit is too.

What is the standard countersink angle?

82°
Countersunk-head screws that follow the Unified Thread Standard very often have an 82° angle, and screws that follow the ISO standard very often have a 90° angle. Throughout the aerospace industry, countersunk fasteners typically have an angle of 100°.

What size countersink bit for #10 screw?

Wood Screw Pilot Hole Sizes

Screw Size	Hard Wood	Countersink Size
Tapered Bit
#9	3/16″	3/8″
#10	13/64″	7/16″
#12	7/32″	7/16″