Helical Insert, 304SS, 5/16-18, PK12

Friday, May 16- If you want to buy the Helicoil 5521-H, you'll need to order a size 18 thread This form will take five and a half minutes to complete. A kit to repair coarse threads up to 18 inches. There are also appropriate drill bits, thread taps, and insert tools in that item. You are not likely to find this tap in a typical tap set as it is a specialized size. To install the helicoil insert, drill the hole with the bit provided, use the tap to provide threading for the outside of the insert, and then insert the helicoil with the insertion tool. You should use the insertion tool to break off the tab at the bottom of the helicoil when the helicoil is screwed in such that the outer end is flush or slightly recessed. As soon as you have the kit in hand, all will make sense.

I don't have any tools

Without a doubt. All the rocker cover and header / exhaust manifold threads in my car are threaded with heli coils. My rocker stand inserts are made from a mixture of steel and steel alloys. The heli coil inserts and time serts depend on the lift of the cam