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Gimlet Points on Lag Screws

Question: Are gimlet points (threaded points) required on large diameter lag screws?

Gimlet Point vs Semi Cone Point Lag Screw

Gimlet Point (left), Semi Cone Point (right)

Answer: A lag screw, also referred to as a lag bolt, is a heavy wood screw with a spiral thread and a hex or square head used for driving it into wood.

Large diameter lag screws typically do not require gimlet points because of the need for a pilot hole to lower the torque required to drive it into the wood.  When installing large lag screws, if you do not use a pilot hole, you run the risk of snapping the heads off the bolts due to too much torque needed to drive the screw.  With a pilot hole, no more than a semi-cone point is typically required on the bolts since it is no longer a self-tapping screw. The pilot hole will also help reduce the risk of splitting the wood as you drive the large lag screw. Refer to our Pilot Hole Chart for commonly accepted pilot hole sizes.

Portland Bolt typically provides a semi-cone point on the domestic lag screws we manufacture. If a sharper point is required for any reason, we can machine a full cone point for an additional cost.

Posted by Steven Wallenstein

Phone: (800) 598-4204 Email: steven@portlandbolt.com
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