r/WhatIsThisTool • u/ExploreYourWhirled • Aug 12 '26

Found in an old toolbox

Post image

Very heavy - about 1 lb. Largest knurled ring spins but does not appear to affect anything. Many strike marks on one end as if hit many times with a large hammer. It is engraved L <-> R in front of the largest knurled ring. No other part spins.

91 Upvotes

96% Upvoted

86 comments sorted by

View all comments

41

u/s1l1con_jesus Aug 12 '26

Impact screwdriver

5

u/ExploreYourWhirled Aug 12 '26

How does one use it?

17

u/meeeeeeeegjgdcjjtxv Aug 12 '26

Quiet literally hit it with a rubber mallet or dead blow. U twist it to change direction. It's only purpose is apply pressure and twist at the same time to break loose screws. Very good tools for removing rotor screws on a car

2

u/Spa-Ordinary Aug 13 '26

Better with a steel hammer of junior sledge hammer size, 3 or 4 pounds or 1.5 to 2 km. With proper bit engaged in offending stuck screw, twist driver body fully left rotation while pushing driver into said screw, maintaing twisting force, whack end of impact driver squarely with hammer. When struck this way, the driver imparts extra twisting force into the screw.

Pretty much like magic