Impact-Drivers at very-low RPM... Still any good?

[Batpig]

Dear Folks,

What are these much-lauded Impact-Drivers like at very low RPM?
Do they lose their fabled usefulness?...

I ask the question, because I've noticed that they all seem to have fairly high max-RPM values, which doesn't seem to "gel" very well with their renowned ability for screwing and unscrewing...

For example, there's a little corded Makita that Bunnings sell, with a max-RPM figure of 3600rpm. For me, the typical application that an Impact Driver sounds like it could be very handy for, would be to undo the old painted-over slot-head screws that you usually find on old window-catches and latches that you're trying to remove off old hardwood-framed windows. A slot-head Bit in a normal Drill will usually just make a mess of the heads of such screws. But whilst the hammering action of an Impact Driver sounds like it would be very useful, their high RPM doesn't sound like the way to go at all. Instead, it sounds like a good recipe for well and truly burring the head of the screw before it's had a chance to "crack" and get moving...

Unless, of course, these Impact Drivers are still very useful at very-low RPM...

Another application that I could really use one for right now, is the removal of a sheared-off Coach-Screw that I broke when trying to fix a bracket to an old petrified hardwood stud in the Laundry downstairs (yes, I drilled a pilot-hole, and, used Vaseline...). I would obviously have to use a Screw-Extractor style Bit, but again I would have thought that low RPM in an Impact Driver was going to be the best way to go - as in about 36rpm, as opposed to 3600rpm .

So, do these things still have any grunt down at low RPM? (or do they become no better than a normal Drill...?)

Your thoughts please Gentlemen...

Many Thanks,
Batpig.<!-- google_ad_section_end -->

[Enfield Guy]

Yep, they work well at low RPM. Torque values don't change. I have a Panasonic impact driver and a Hitachi 1/2drive impact wrench. Where are you in bris? I might be able to come over with my machines if you like. PM me.

Cheers

[Batpig]

Dear Enfield,

That's mighty hospitable of you! . I'm out of immediate peril for now, because I undid the rest of the Coach Screws today in order to remove the piece of timber being fastened to the said hardwood studs, and was thus able to expose enough of the shank of the broken Screw to get at it with a Pipe Wrench (and those things don't let go once they get going...). So the broken Screw is out!

But going by what you've said, though, I might just grab myself one of those $99 corded Makitas that the BigB is doing next time I'm down there, because:
a) It's the only one around with a cord (I'm not big on "cordless"...), which really narrows the choice down very nicely for me,
and:
b) $99 is not the end of the world anyway. My $99 Makita Orbital Sander is a nice tool for the money, so I'm sure the Impact Driver will be useful too, given what you have said about the inherent torque of electric motors down-low.

I'll give you a yell, however, if I start having doubts again (I take it you're on the northside...)

Many Thanks,
Batpig.

[Fuzzie]

The lowest speed impact drivers are the old manual hit it with a club hammer type. My $99 Bunnings one is driving screws very nicely, but as there is no torque setting you have to judge when to lift your finger off the button yourself.

The manual impact driver will move frozen screws the electric one can only dream about.

[Harry72]

" undo the old painted-over slot-head screws that you usually find on old window-catches and latches that you're trying to remove off old hardwood-framed windows."

Clean out the paint from the slot and give the screw driver a sharp tap with a hammer to break the grip of the thread in the wood first. It can take a few blows to get them going.
A powered impact driver doesnt do this, but Fuzzies manual one can

[Batpig]

Dear Fuzzie & Harry,

Yes, you're quite right - it's hard to argue with one of the old manual Hit-With-Your-Hammer-types, and I do indeed have one. But they are a handful to use, because for starters you've got to make sure you've got the thing a little-bit pre-loaded (so to speak) using wrist-action, in the direction that you want it to turn when hit. It's always a bit tricky to get the preloading just right. Secondly, as they require both hands to operate, that doesn't leave a spare hand to support the window half-way up just behind where you're about to give it a fair belt with the Hammer and said Driver. This is not good for the windows.... But point taken - reality still rules at the end of the day...

Many Thanks,
Batpig.

[Fuzzie]

OK. I'll then go out on a limb and say the $99 one probably won't work for your frozen screws, but it would be an interesting exercise to actually try the limits of the tool.

I have replaced some screws on my jointer, that hold the blades in place, with hex drive machine screws that I hand tightened (very tight) with an allen key. The $99 impact driver won't undo those screws.

I have played with the $99 driver driving screws into hardwood and had good results, much easier than my battery drill, but I haven't used it for a real project yet. Wongo has used his in another thread to screw down a whole deck and he was very happy with its performance.

[Batpig]

We shall see how it goes in due course Fuzzie...

Many Thanks,
Batpig.

[Kyle]

OK. I'll then go out on a limb and say the $99 one probably won't work for your frozen screws, but it would be an interesting exercise to actually try the limits of the tool.

I have replaced some screws on my jointer, that hold the blades in place, with hex drive machine screws that I hand tightened (very tight) with an allen key. The $99 impact driver won't undo those screws.

Those corded impact drivers only have 100NM of torque. So anything tighter than that is it's limit.

Of interest it's cordless cousins have alot more grunt. The 18v cordless Makita impact drivers have 145NM and the impact wrenchs (which are only slightly bigger than the drivers) 230NM.

[Batpig]

Dear Kyle,

Yes - well noted. But with cordless, you're getting into Much-More-Serious-Dollar territory than the $99 Mak for starters, and then there's the issue of whether the Batteries are going to have any charge left in them when I go to use the thing up for the first time in two months (unless, of course, you're talking Lithium, which is in Very-Serious-Dollar-Territory...)

100Nm is still pretty grunty; That's about 10.2kg hanging down on the end of a 1m-long wrench...
To paraphrase a line often used in some of the Car mags; "In terms of Nm's per $, the little corded Mak looks unbeatable (at least on paper...)"

Best Wishes,
Batpig.