Craftsman electric impact driver help

[megotatractor]

Hi, would appreciate some help, not sure if this is the correct forum.
I have an old Craftsman heavy duty 1/2" electric impact driver that doesn't quite work the way I would expect. I think the cord has been replaced at some time and repairs were made to the hammer part a few years ago but to my knowledge (I inherited this a few years ago) it has never operated properly . This tool hammers merrily along forever and fails to loosen nuts that I can loosen with a large enough wrench. However the goofy thing is perfectly capable of overtightening a nut to the point of breakage with incredible efficiency and speed. It has a fwd/rev switch and I wonder if this is wired backwards and if so if that would effect the hammer? Or is the hammer backwards somehow? Also I would assume that "fwd" would mean "clockwise" and "rev" would mean "counterclockwise"???? or is the switch wired backwards because it operates the other way around; fwd=counterclockwise, rev=clockwise? the tool is about 30 years old and lightly used but doesn't work quite right. Any insights would be helpful, thanks.

 

[kcprecision]

I am not sure about the hammer part but I would assume that it should work the same in both directions.

The wiring would appear to be reversed and that could possibly be the cause if the direction is switched by some sort of electronic device. Now days they use electronics that I am not really familiar with. Now in the old days.

 

[JoeL4330]

I have one just like it ...fwd means "righty tighty" and rev means "lefty loosey".

You say it tightens just fine (presumably in fwd) but doesn't loosen (presumably when you switch it to rev), yes?

Does it rotate in the same (righty-tighty) direction irrespective of the switch? You should be able to tell the direction of the rotation easily by either (careful) feel, or visual observation ...it only really "hammers" when it meets resistance ...with no load, it should spin nicely ...in whatever direction.

If it rotates in the same direction irrespective of the switch, then (obviously) the switch is bad or it was not wired in when the cord was replaced.

I'm sure I couldn't locate the manual that came with mine and I'm reluctant to take it apart to draw a wiring diagram for you, but you should be able to find a manual online for any impact wrench and that would show the basic wiring scheme.

Incidentally, it only has so many ft-lbs of torque, which I have found is often insufficient to loosen a stubborn nut, which I can persuade with a long lever (pipe extension of my rachet, say). And, although I haven't tried it, I could probably tighten something with it that it would have trouble loosening ...if not right away, then after some time has elapsed.

Whenever I do use it on, say, lug nuts, I always use anti-seize on the nut/bolt ...in fact, every time I mess with a nut or bolt, it either anti-seize or locktite, depending.

 

[megotatractor]

Okay, thank you for the confirmation that I correctly intuited the rotation of fwd/rev which does correspond to logic; fwd=righty tighty, rev= lefty loosey. Yes the rotation does change with the switch and I verify this by touch before I put a socket on anything. So we can feel fairly sure that this tool is wired bass ackwards. Also thankyou for verifying the wimpy-ness of the tool in general though I must say it sure seems powerful when it quickly and easily breaks a bolt when tightening. Perhaps I should shop for a new one?

 

[Bird]

I've owned one Black & Decker and one Craftsman 1/2" electric impact wrench and one of my brothers currently has a Craftsman. All 3 were bought "reconditioned" and always worked perfectly. However, those tools were rated at 210 to 240 ft. lbs. My pneumatic 1/2" Ingersoll-Rand IR231 is rated at 425 ft. lbs. while several models are rated around 600; big difference. And all the impact wrenches I ever worked on were either rated for the same power in both directions or for more power in reverse. I only worked on the pneumatic tools; never worked on the electric, although the manuals I've seen showed the impact mechanism to be about the same. Under no load, just spinning free, does it sound as if it turns the same speed in both directions? If so, and I suspect it is, then the problem is wear, or something broken, in the impact mechanism and Sears should be able to either fix it or sell you the parts to fix it yourself.

Some of the newer electrics have a little more power, but not comparable to the air powered ones.

 

[megotatractor]

Bird, I checked it out, the tool turns significantly faster clockwise. IS it possible the hammer is installed backwards somehow??
I also possess a craftsman model 875 pnuematic impact wrench but have no air compressor anymore. I recall that this tool was capable of loosening lug nuts if I had enough air... I am seeing some high dollar electrics (almost $500) on ebay that are comparable to a pnuematic. the debate is which is less $$, a good air compressor or a good electric tool... first I will see if anything can be fixed on this tool then see how it performs...

 

[Bird]

There's a pretty wide variety of hammer mechanism styles and designs, so I couldn't tell you anything with any degree of confidence. It's possible something is installed wrong, but unlikely, if it had been working OK in the past. It's also possible the problem is with the electric motor. For just a wild guess, I'd suspect some piece is broken in either the motor or the impact assembly (maybe even brushes in the motor) that creates a drag in reverse but lets it spin smoothly in forward.

As for which is less $$, an air-compressor or a good electric tool, I don't know that either. But I do know that I just can't imagine not having a good air-compressor. I consider that to be indispensable, whether to power the air tools, a blow gun to clean stuff, to air up tires, etc. I think mine is used every day, if for nothing more than to blow the whiskers out of my electric razor.

The first electric impact wrench I owned was before I had my own air-compressor and learned I couldn't do without one. The second electric impact I owned was because we were full time RVers at the time and I had a generator in the fifth-wheel. Of course, I also carried a little 2 gallon air-compressor for airing up tires and blowing the dust out of things, but of course it was nearly enough to run an air impact wrench.

 

[megotatractor]

it spins okay in both directions, just a little faster in the righty-tighty direction. Brushes look okay. Hammer seems okay inside.

 

[Bird]

I wish we had a parts breakdown or diagram so we could see which style of impact mechanism it has. I once had one that you couldn't see anything wrong with it until I got it good and clean in the parts washer, then found a tiny crack in the hammer frame that allowed it to flex and that really cut the power. But I don't know whether you have a single or dual hammer style, hammers in a hammer frame, or hammer pins in a hammer cage.

 

[Skyco]

Bird is correct, same torque in both directions, or more in reverse, at least in a properly designed tool IMO. I learned way back that torque ratings aren't to be believed either. I bought and returned several low end import impact tools that were rated at say 240lbs but had real difficulty taking off nuts I'd torqued to 150 with a torque wrench. Finally coughed up the dough for an Ingersol Rand, that was 8 times what a cheapy costs, but it will do the job. IIRC it is rated at 400 forward and 600 loosening.

I'd guess something is amiss in the hammering mechanism.

I just bought one of the HF electric impacts on sale for $30 something, haven't tried it yet....