To impact or not to
Greetings!
I have seen notions from local carpenters here in Germany that it is not beneficial to use an impact screw driver to fasten screws for framing work.
Explanation is that the pulse from the impact tends to loosen the connection of thread to wood – specially in the last moment when the head of the screw is in contact to the wood. It ‘s like the screw turning without going forward anymore as much as the thread would need to. The “go-to” way is to use a regular electric screw driver with the required torque to get the job done.
What the take here in this community? I have seen in some US youtube videos that screws were sometimes handled that way and wonder.
regards
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Replies
Framing screws have fins under the head that keep driving the screw into the wood until it's much deeper than necessary. I imagine a screw without this feature would indeed "strip" the threads in the wood it creates as it's driven in. I have had no trouble with framing screws installed with an impact driver in the almost 20 years I've been using them.
First off, if this is the local equivalent of stick framing, don't use screws. You are wasting your time thus money, get a framing nailer and nail it up. If you want more bite than regular nails use screw shank or ring shank nails. For anything removable I use Scrails although even there cutting nails with sawsall is usually quicker.
As for something like heavy timer or CLT. You have to look at how the fasteners are loaded. In wood you don't use the fastener in tension, in any place you need tension, you through bolt with nut and washer. So any fastener is in sheer or should be. This means load is handled by the shank and the wood fibers where the two pieces of the wood overlap.
The only thing the screw head needs to do is prevent the wood from pulling through, so a bit of damage from the wood fiber there is nothing.
I'm also skeptical of the whole impact damages the wood fiber bit. Most damage would come from install which is definitely easier with an impact.
There is a very good reason not to use an impact though. It is much slower. A regular driver with good power will get a screw in much faster but will also have a heck of kick when you seat the screw. You never see an auto-feed screw gun with an impact.
To my ear the supposition that impact points are not as tight seems silly without evidence.
The impact applies 3 times more torque to the screw so the joint is tighter and the battery lasts 3 times longer.
The only thing I dislike about my impact driver is how much noise it makes.
You might enjoy this YouTube video.
https://www.youtube.com/watch?v=43cuU0lP6To
Walta
You need a hydraulic impact, not quite as powerful but soo much quieter.
https://www.homedepot.com/p/Milwaukee-M18-FUEL-SURGE-18V-Lithium-Ion-Brushless-Cordless-1-4-in-Hex-Impact-Driver-Tool-Only-2760-20/300193508?source=shoppingads&locale=en-US&pla&mtc=SHOPPING-BF-CDP-GGL-D25P-025_009_PORTABLE_POWER-NA-Multi-NA-PMAX-NA-NA-NA-NA-NBR-NA-NA-NA-PortPower_NEW_LIA_TEST&cm_mmc=SHOPPING-BF-CDP-GGL-D25P-025_009_PORTABLE_POWER-NA-Multi-NA-PMAX-NA-NA-NA-NA-NBR-NA-NA-NA-PortPower_NEW_LIA_TEST-71700000120004386--&gad_source=1&gbraid=0AAAAADq61UeapmapmO5JS0shw-b2H5r-I&gclid=EAIaIQobChMIlc-6s-KuiQMVPgStBh0HgCogEAQYASABEgLK8fD_BwE&gclsrc=aw.ds
Hi Walta,
Thanks for the video. Pls check 2:50 - then the driver damaged the screw resp. the wood.
Beside that very informative. Thanks
wastl,
Sure, but only an idiot would use an impact driver on a 1/2" trim screw. It's like saying a Stiletto is poor at sinking brads.
The one thing not to use an impact on is hold downs and anchor bolts, but that has to do with concrete not wood. Seems a bit far fetched for framing lumber.
Thank you all!