Cordless Dril/ Impact Driver Combo

[John Rumm]

That is true, but its not the whole story:

The main attraction is ease of driving screws from the operators point of view. Say I am sticking a 2" twin thread wood screw into softwood. A drill driver will do that without a pilot hole, and has more than enough torque. However you need to apply reasonably a significant amount of push to the tool to keep it adequately engaged in the screw head. That also means driving screws at arms length or in awkward places can be difficult.

The way the ID drives (in discrete rotational "punches") makes it much less likely that the bit will jump out of the head - so you can drive the screw with less physical effort from the operator. You get less torque reaction in the wrist as well.

[Tim Lamb]

There can be an issue where the screw is easily driven (pilot hole, soft material) leading to bit disengagement as the operators wrist fails to follow up.

[dennis]

I have three drills and an impact driver (ryobi one+).

I have actually put 12mm x 4mm screws in using the impact driver but it requires care. When you pull the trigger it rotates slowly and no impact action happens so it will drive small screws, but if you press the trigger too hard the thing will start impacting and that is a bit too much for small screws into soft wood.

I only used it because I had forgotten my little 3.7V screwdriver.

[dennis]

You are using the wrong screws, you need torque hex headed screws. They are much better than pozis.

[Bert Coules]

John, thanks for that. I see the advantages, but I'm not sure that the increased power and need for less force are necessary for most of the DIY work I do. It's silly to judge without actually trying one of course but "sledgehammer" and "nut" are the words that spring to mind.

[Bert Coules]

That's useful, thanks. Is it true of all makes and models? And does it mean that beyond slow/fast-with-impact they don't have variable speed?

[Bert Coules]

Thanks; you've just answered the question about variable speed which I asked in my previous post.

From what I've read here, I suspect I might be better off with two standard drill-drivers, one for pilot holes when needed, one for screws. But it's difficult to be sure without giving an impact driver a test run or two.

[Tim Lamb]

My impact driver is mains powered. Early days for battery powered versions and I needed something that would fix Tek roofing bolts.

I think the battery powered jobs are much more sophisticated.

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[John Rumm]

With a decent bit that matches the screws well I have never had a problem really - just avoid screwing too far off axis, and if you do start to chew up a head, bin the screw and start with a new one.

I have used Torx on some, but I tend to find the bit wear rate is worse than with a good diamond coated Pozi.

[John Rumm]

I think its like one of those hammer drill vs SDS type of experiences.

Yes the hammer drill will do the job in hard masonry - eventually, however having tried a SDS you won't want to go back to a hammer drill for hard masonry drilling.

[John Rumm]

Without a load, they are variable speed like a drill - but they only have one "gear", and the maximum rotation speed it higher (>3000rpm typically).

Once the load reaches a certain preset torque the impact action kicks in. Then the rate of impact is controlled by the speed. So with a gentle pull on the trigger you can get a slow impact rate - say a few strikes per second.

[John Rumm]

I would definitely recommend trying an ID and having a practice with it for a bit. I tend to find the combination with a drill is far better than two drills in most cases. The other thing is for a given torque you can get away with a much smaller and lighter ID.

[Bert Coules]

I see the advantage of course, but I suspect that the cost of hiring one, even for a day, would be steep enough to take a significant slice out of the cost of purchase. But I'll investigate.

[Dave Plowman (News)]

And that board could be mounted on studs. Also flammable.

[Dave Plowman (News)]

You can't have a chuck with an impact driver. A friction drive like a chuck will slip. Needs to be a positive drive like a hex or square.

Same sort of thing with SDS drills.

[charles]

just looked - it's straight on the wall. Most spacers I've seen elsewhere are ceramic.

[dennis]

I haven't had a problem with wear and the boxes of screws usually come with a bit. They are nearly all torx head in Germany IME.

[dennis]

It has continuously variable speed on the trigger.

[John Rumm]

Which kind of illustrates the point... I would normally expect to get through a few boxes of pozi on a single (quality) bit.

Having said that, I buy the common bits in bulk anyway, since you are going to shatter a few with an 18V impact driver.

Yup, Torx is popular there and elsewhere in europe... Robertson (square drive) is also popular in some bits of the US and especially Canada.

Although pozi seems rare in the US, where they still seem to use lots of philips - which are almost my least favourite screw to power drive.

[John Rumm]

Probably only viable if you can borrow someone's. Failing that buy a twin pack, and you won't lose any functionality over having a pair of drills.