Reinstall Screws and Bolts
Reinstalling screws and bolts into materials such as plastic, wood, aluminum and sheet metal takes a light touch to avoid stripping or cross-threading. Here's how to do it correctly.
Contents
Steps
- Verify that you have the right size screw for the hole. If it's the same screw you just took out, fine. If you are replacing the screw, a good check is to hold it up opposite the old screw. If the threads mesh and the lengths are the same, it's probably correct. Note that some common screws in different sizes have the same thread pitch (the threads will mesh). A common example of three are 6-32, 8-32 and 10-32. So check the diameter of the screw too. If you cannot verify the size of the hole, proceed very gently and stop at the first sign of resistance.
- Ensure that the hole is free of debris. Vacuum out chips, blow them out with pressurized air, or shake the part upside down.
- Insert the tip of screw or bolt into the existing hole. Make sure the screw is perpendicular to the surface with the hole. Often the cause of cross threading is that the screw wasn't aligned correctly before it was driven.
- With light pressure, turn the screw backwards (counterclockwise) with a screwdriver until you feel an indent or hear a click or both. This indicates that the screw is in the original thread.
- Give the screw one or two turns clockwise. If there's a lot of resistance, stop and start over. It may be cross-threaded. There shouldn't be much resistance. Continue until the screw is snug, but don't over-torque.
Tips
- If you have a lot of screws or long screws and are using a drill motor or power screwdriver with a clutch, start the screw by hand with a screwdriver as above, then use the drill motor with the clutch set at its lowest setting. Seat the screw and snug it down with screwdriver and readjust the torque setting until the clutch breaks from that screw. That should be all the torque needed. If you don't have a clutch, stop just before seated and finish with a screwdriver.
- The finer the thread and the smaller the screw, the more careful you should be to avoid cross-threading or stripping.
- If needed, a dot of personal lubricant in screw hole helps. It's clear, odorless, water soluble, and it wipes clean if there's excess.
- To avoid damage to finished pieces due to tool slippage, cut a hole the size of the fastener head diameter into a coffee can lid or similar material and slip it over the screw when installing.
- Softer materials, such as plastic and wood, will strip more readily than harder ones, such as metal.
- If the female threads are stripped and the fastener will not tighten, it may be necessary to use replacement thread inserts.
Warnings
- If you are using an electric drill or screwdriver, understand its safe operation.
- Don't use magnetic screw holders or screwdrivers around sensitive electronics.
- Never use a screwdriver as a lever or chisel. They are not designed for this purpose.
