Replies

1. 
   tsproul | May 11, 2004 06:06pm | #1

   the screw and the wood have no idea what tool was used to turn the screw...hand, driver or impact.

   Tim
2. 
   forestgirl | May 11, 2004 06:41pm | #2

   No advice here, just supporting your question -- seems reasonable that there could be a difference since "impact-driving" the screw might (might) change the character of the wood that adjoins the threads of the screw.  Looking forward to people's opinions.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
   Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   EdHarrow | May 11, 2004 06:49pm | #3

   I've only used an impact driver with ugly lag bolts and 2x construction of nothing fancy.  ;-)  Couldn't prove by me that there was any impact other than speeding up the assembly process (and the later disassembly process).

3. 
   Michmesquite | May 11, 2004 09:30pm | #4

   I also have the Makita.

   The problem with an "impact driven" screw is the Makita doesn't have a clutch and it is very easy to keep "screwing" the screw in until either the head pops off or the shank is twisted.

   I would not recommend using the impact driver with drywall type screws.

   _________________________________

   Michael in San Jose

   "Let no one be slow to seek wisdom when he is young nor weary in the search of it when he has grown old." Epicurus

4. 
   CRAIGCONEY_M | May 11, 2004 10:37pm | #5

   I have the Hitachi 12 volt and have used the Makita 12V.  For casework assembly I will predrill & countersink, use the impact driver.  Sometimes I won't predrill, but usually on rough framing on installations.  My experience is that the impact will pull the casework together more cosistantly than a drill/driver.  It is also alot easier on the hands/wrist. 

5. 
   yieldmap | May 11, 2004 10:46pm | #6

   I'll agree with tsproul, a properly torqued screw will hold the same in wood whether it's impacted or solid-torqued.  However, an impact gun will be MUCH more likely to either over-drive the screw or break the head off of a cheap screw.  For that matter, with nice furniture, I hand-drive all the screws.  Nothing like a mishap with a power tool to ruin a week of hard work!!

   I've got an air impact, and a 1/2" drive cordless impact that I use for lag screws in construction, but that's where they stay.  They're awesome for lag screws, and general mechanic work.

   yieldmap

6. 
   jazzdogg | May 12, 2004 06:21am | #7

   I have the 15.6 volt Panasonic and love it! It has a 1/2" square drive, to which you can directly attach [impact] sockets; it also has a 1/4" hex drive and a keyless chuck (which shouldn't be used in impact mode) that attach to the 1/2" square drive. Although it's a little heavier than the Makita, I bought it because of the much-greater versatility. 

   I've used it, in impact mode, to remove damaged 3" Phillips head wood screws from hardwood that couldn't be budged with a typical drill/driver, as well as for assembling a steel-framed barn, changing tires, and driving countless lag bolts, wood screws, drywall screws, etc.

   It has enough ooomph to snap the head right off of a brittle drywall screw, but you can dial down the torque by selecting a different clutch setting.

   As long as you don't overdrive, the wood won't know which tool was used to drive the screws.

   Good luck,

   -Jazzdogg-

   Whether you think you can, or you think you can't, you're right.

   
   

   ---

   Edited 5/11/2004 11:23 pm ET by jazzdogg

1. 
   mitch | May 12, 2004 05:03pm | #8

   impact drivers work by applying the impact force in the direction of the rotation of the screw- kind of like if you were using a hammer to tap on a wrench to tighten or loosen a bolt.  the impact force is NOT in line with the shaft of the screw like it would be with something such as a hammer drill.  therefore, it doesn't disturb the wood fibers any more than driving a screw by any other means.

   btw- i love my makita 12v 6916- once i got the hang of it- there is a bit of a learning curve to using one when you're used to a regular drill/driver.  for some applications, they're awesome for drilling large holes, too.

   m

1. 
   nikkiwood | May 13, 2004 12:55am | #9

   I bought a Panasonic 15.6 volt impact driver about two years ago, and it is the only machine I use now for driving screws of any type -- even mounting drawer glides.

   I had a chance to use a Makita 12v impact driver for about two months, and liked it way more than the Panasonic. The Makita is lighter, smaller, and very well designed ergonomically; as I recall, the torque rating (measured in foot/inches) is virtually identical with the Panasonic. In any case the Makita was able to drive 3 inch drywall screws into 2X4's effortlessly (and without pilot holes).

   Impact drivers do not have a clutch, but they don't need one. As you are seating the screw, the bit slows down, and you can stop exactly where you want. And even if you stop prematurely, it is easy to give the screw an extra quarter or half turn. Try that with a regular driver.

   The greatest advantage for me with the impact driver is avoiding what the tool people call "run out." With a regular driver you have to apply enough force in line with the machine to keep the bit from jumping out of the screw (i.e. run out). The impacting action provides enough force to keep the bit firmly buried in the screw. It is almost as though the bit and screw are "stuck" together. The practical advantage here is that when you are mounting screws in awkward positions (say, above your head, or the far back of a cabinet), you don't have to exert nearly as much physical force to drive the screw.

   Aside from price, the only downside to impact drivers is noise. They make a fearsome clatter as they drive the screw, and this will be annoying to many people.

2. 
   forestgirl | May 14, 2004 07:27pm | #10

   Mitch, thanks for making the important point about the direction of the impact force.  I've only used an impact driver once (cement) and did not realize that the force is in the direction of turning the screw, rather than down the core of the screw.  Am reading this thread with interest, and an impact driver may be in the future. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

1. 
   mitch | May 14, 2004 10:28pm | #11

   you're welcome-  i'm pretty sure about the impact direction issue, but if you really want some detail about how these things work you should ask next door at breaktime.  some of those guys are super tool wizards.

   m

2. 
   BenA | May 15, 2004 12:42am | #12

   Jamie: I think Impact drivers are one of the best ways to drive in screws since the invention of the cordless screwdriver. I use to sell  Makita tools, and when ever you show that tool , it will always sell . try it and you;ll like it. In a nutshell, the way it operates , theres a anvil that hammers clockwise against the shaft that gives you a rotational  impact force to drive the screw home. A hammer drill uses two knurled disc that operate against each other to create a force in a downward direction.  Not to confuse you more, a rotary hammer (1-1/2 inch and bigger) uses a piston plunger that hits the bit to make the chisel break ups the concrete. I hope this helps in understanding the difference. If you have any other questions ,just ask.  Ben

1. 
   forestgirl | May 15, 2004 01:05am | #13

   Hi Ben, thanks for the info.  My curious mind always wants to know!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

2. 
   robkelly | May 15, 2004 02:38am | #14

   I've got the Makita and not only is it great for screws, I use it to tap metal as well. I dril and tap a lot of cast iron to mount clamps and jigs on tool tables and it's perfect for that.

7. 
   mudman | May 16, 2004 08:16am | #15

   I have a Hitachi 12 v. and love it. I only use my drill/ driver for auger bits and that sort of stuff now. Impact drivers are amazing. Though you will still need a drill sometimes.

   Mike