How to calculate a countersink hole

Updated February 21, 2017

Countersinking holes is necessary for many different wood working and masonry applications. It is similar to pre-drilling, allowing a hole to be made before the screw or fastener is installed. When countersinking a hole, the key is to figure out how deep the hole is going to be and determining the proper size screws to use. Calculating a countersink hole is a job any homeowner can handle with no problem at all.

Determine the length of the screws that will be needed for the particular application and inspect the screws to determine the size drill bit that will need to be used.

Find out the size of the head of the screw and attach a countersinking drill bit that fits that description to the drill. Move the bit up and down to the desired depth of the hole based on the length of the screw.

Secure the bit firmly to the drill and line it up at the proper spot where it is going to be drilled. Push down on the drill at a 90-degree angle and drill the countersink bit into the wood until it is all the way in. Pull the bit out of the hole.

Insert the screw into the hole to make sure it fits properly and the head is not sticking up too much. Verify also that the head is not sunk too far into the hole. Drill deeper into the hole with the countersinking bit if necessary. Repeat this process for any other holes that will need to be drilled.

Things You'll Need

  • Screw
  • Drill
  • Drill bit
  • Countersinking bit
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About the Author

Alexander Callos began writing in 2005 for "The Lantern" at The Ohio State University and has written for various websites, including Bleacher Report, Top Ten Real Estate Deals and Columbus Sports. He has published articles for CBS Sports, and other websites. He graduated in 2007 from The Ohio State University with a bachelor's degree in public affairs journalism.