Stop in for a cup of coffee

Rainy Day Auto said

Holy crap, my friend just showed me these.

She said "could you ever use these" I said, heck yea.

She bought a set for her dad but he doesn't know how to use them because he is the kind of guy who might hurt himself with a pair of pliers.

Either way, I think this is a sweet idea

Screw Tap Drill Bit 6PCS - $8.99 Free Shipping|GearBest.com

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That's a neat concept, but I think the two larger ones are wrong... Not sure if there is enough thread engagement/depth...

The general rule of thumb is that you should have at least one and a half times the thread diameter for thread engagement, but the two larger ones seem to have less and the shoulder on the larger one will limit the depth that you can make threads....

Example: If you have a 1/2" diameter thread, then you should have 1/2" + 1/4" = 3/4" of engagement...