how do the spec-s of an air impact wrench relate to the air compressor?
i need to loosen a crankshaft pulley bolt that is torqued at 134 ft-lb. i have a sears craftsman 1.5hp 4-gallon
4.7SCFM@40psi3.3SCFM@90psi air compressor. i don't yet have an air impact wrench. what should i look for in terms of psi when i go to
buy one, such that i can use that air compressor to drive the impact wrench to loosen the bolt? tia.

 

Most 1/2" impact wrenched are rated at CFM @ a constant 90 PSI. Good units with a 600-900 ft-lb of Maximum Torque usually require 15+ CFM @ 90 PSI. The lower rated units in the 300 ft-lb of Maximum Torque range still require 4-5 CFM @ 90 PSI. Your Craftsman will not drive a high torque impact but for a few seconds. I bought a 3-Cylinder "FARM HAND" compressor from Tractor Supply that will push anything I can feed it. It's made by Campbell Hausfeld exclusivly for Tractor Supply so it comes with a 3-Year warranty.

[IMG]local://upfiles/9061/3417BD84B53D49CE9B2F39145E4C9D38.gif[/IMG]