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Last updated on July 25th, 2021
When you are doing auto repairs, what do you do when you encounter stubborn screws or bolts that won’t come out? I know you definitely grab the pneumatic or electric impact driver and bust the fastener out. But what do you do when you do not have such expensive tools around or if your air compressor has run out of air? Personally, I turn to my trusty manual impact driver. It is a great tool for removing stuck and stripped screws with more control and precision.
In this article I share about the manual impact drivers including how to use them and the 5 best you will find on the market.
What is a manual impact driver?
A manual impact driver is a handheld impact tool for removing stuck fasteners. It works much the same way as an air or electric impact driver except that it is slow and you have to apply the force manually. In other words, you have to strike the back of a handheld impact driver with a hammer to create the vertical force that is then converted to torque.
The tool has a mechanism that converts the impact force of the hammer into a powerful rotary force or torque to break loose the tight fasteners. Although the hand impact driver is used primarily to remove stuck screws, you can use it to apply extra torque onto bolts and nuts. However, when working on the bolts and nuts, you need to attach an impact wrench adapter onto the driver. For screws, the kit comes with a hex bit adapter and a few impact-ready bits.
How to use a manual impact driver
As I have explained, a hand impact driver converts the vertical force from a hammer force into rotary action. The rotary action then acts on the seized fastener to release it.
To use a handheld impact driver, you need five things: an impact drill, a pair of leather gloves, safety goggles, a hammer, and of course the impact tool.
1. Wear the safety gear
Wear the safety goggles to protect your eyes from any debris that may fly when you strike with a hammer. Also, put on some leather gloves to protect your hands from impact.
2. Spray the fastener with some penetrating oil
Spray a bit of penetrating oil to free rusted fasteners. You can use penetrants such as WD40 or PB blaster or any other that works for you.
3. Install the appropriate impact driver bit
Grab the appropriate driver bit and install it onto the hex adapter. The fit the adapter assembly onto the drive. Ensure that the bit is impact-rated to withstand the impact action. A regular bit will be damaged.
If you want to break loose a nut or bolt, attach the right size of impact socket onto the drive.
4. Set the direction of the driver
Pull the driver head away from you and the handle towards you while twisting it to either left or right. Twist left for loosening and right for tightening. That is, “Lefty Loosey Righty Tighty”. Some impact drivers require you to push the handle inside and twist. Others require you to turn the drive to the direction you want the fastener to move without pulling. So it is good to consult the instruction manual.
5. Set the impact driver onto the screw
With the right manual impact driver bit installed, hold and press the tool against the stubborn screw. Hold it perpendicular to the screw head and ensure the bit sits fully into the head. You can apply a little blob of valve lapping grease onto the head driver bit to ensure a good grip and prevent slipping.
6. Hammer the impact driver
Strike the other end of the impact driver tool with a hammer. The tool will convert the downward force from the hammer into a turning force or torque that will in turn try to burst the stuck screw. Don’t smack the tool too hard or you will damage the bit. Just a few small taps with a sledgehammer should work.
7. Undo the screw by hand
When the seized screw starts to turn, stop hammering and continue to unscrew with the impact driver or regular screwdriver until it comes off completely.
Best Manual Impact Driver Sets
Vessel Hand Impact Driver – Best for Japanese Imports Repairs
The Vessel manual impact driver is a very high quality tool from Japan. It is solid and sturdy and the bits that come with the kit conform to the Japanese Industrial Standards. Thus, the tool is perfect for removing over torqued fasteners on Japanese cars and bikes.
That said, you can still use the JIS driver bits on the regular American Philips screws but the opposite is not true. A regular driver bit will strip the Japanese standard screwheads.
The impact driver has a 1/2″ drive and a hex bit adapter. The handle has a rubber grip for a more comfortable grip. It also absorbs some of the shock generated by the hammer strikes but you still need to wear protective gloves. The molded handle has a lip at the tip to protect your hand but it is not impossible to whack yourself with the hammer if you are not careful.
The Vessel impact driver kit includes the tool, a hex bit adapter, and 5 impact-ready driver bits. It is the best impact tool kit overall for assembling and dismantling rotors and other auto parts, especially on import cars and motorcycles. You can twist the drive to set it to the right or left to tighten or loosen fasteners.
Mercars Impact Screwdriver – Most Versatile
Mercars impact screwdriver is a heavy duty hand impact tool for removing rusted bolts and frozen fasteners. It has a sturdy compact design but unlike the Vessel impact driver, there is no rubber overmold on the handle. So all the vibration on the tool when you strike with a hammer is transferred to your hands. Therefore, you must wear a pair of gloves to protect your hands and absorb some shock.
The tool has a 1/2 inch driver with pin detent for holding and locking in place an impact socket wrench or hex adapter. You can set the drive in both reverse and forward direction by simply pulling and turning left or right respectively.
Mercars impact tool kit includes an assortment of bits and drills. Among them is a screw extractor for removing stripped screws. The driver bits are long and short and include both Phillips head and slotted head. Lastly, the 12-pieces Mercars impact driver kit comes in a metallic enclosure for easy storage and transportation. It is also fairly priced.
Lisle 29200 3/8″ Hand Impact Tool Set – Best for Professional Mechanics
Lisle hand impact tool set is a great American-made kit for getting out those stubborn retaining screws on the brake rotors. The tool has great fit and finish and converts every hammer strike effectively into the shock torque you need to disengage stuck fasteners.
The kit includes an impact driver tool with a 3/8 inch drive, hex adapter, and 5 impact bits. 4 of the bits have Phillip’s heads of sizes #1, #2, #, and #4 and the fifth one is a flat blade. The only drawback is that the bits are not as great as the tool. They break pretty easily when you strike so hard with a hammer. Also, there are not many driver bit heads to choose from thus limiting the versatility of the tool.
However, you can readily find good replacement bits on the market. I prefer to use the Sear bits if those that come with an impact driver kit are not that great.
Lastly, you can use the impact driver to tighten or loosen fasteners. Simply turn the handle in the direction you need the screw to move. Another advantage of Lisle manual impact tool kit is that it comes in a molded case, which makes storage and transportation easy. The case has a slot for the tool and all the accessories. It is a great investment for professional auto mechanics and DIYers alike.
Tekton Impact Screwdriver Set – Best of home use & DIY
Tekton hand held impact tool set is another inexpensive solution for rusted and frozen screws. It is made of chrome vanadium steel and has 7 pieces in total including a molded case, 4 impact bits, hex adapter, the impact tool, and a carry case.
The bits have 5/16″ hex shank and include phillips head and slotted. The Phillip’s head bits are sizes #2 and #3 and the slotted head are 5/16″ and 3/8″. There is no torx bit.
Unfortunately, the bits are not the strongest bits you would find. The flat head bit, for instance, bends a little too easily and the phillips head tends to twist after a couple of heavy duty uses. So, although the tool is heavy-duty, the bits are not.
The tool has a 3/8″ drive but there is an option for a 1/2 inch drive. Both versions come with the same accessories, nevertheless. Also, both versions are reversible. In other words, you can set the drive to rotate either forward or reverse by simply holding the tool with the handle up then push in and twist the black adapter clockwise or counterclockwise.
Tekton manual impact tool has a solid metal handle with knurled grips to keep it from slipping from your hands. Unfortunately, there is no rubber cover over the handle to absorb some of the shocks from hammer strikes. So you must wear a good pair of work gloves when using the tool.
The major downside of this kit is that the bits are not hardened enough. Therefore, they are not the best for heavy duty work such as breaking loose the rotor screws on trucks. But you can use them to loosen stripped screws on door hinges and other lighter tasks.
However, if you put some quality impact-rated bits, you can use the tool on any assembly, repair, or dismantling job. But do not smack it too hard so that you don’t mar or dent the end. Anyways, the Tekton hand impact driver kit is a great inexpensive impact set for home use.
Klein Tools Hand Impact Driver kit – Best for the money
The Klein Tools manual impact driver kit is a great U.S.A-made impact set for disengaging corroded, frozen, or other stubborn screws and nuts or bolts. The tool is made from alloy steel and has a rugged design that can withstand heavy abuse in the garage or work site. You can whack it all day with an 8 lbs sledge hammer and it will ask for more.
The drive for the tool measures 3/8 inches. You can fit a hex bit adapter or a 3/8 impact socket to free seized nuts and bolts. The kit comes with four assorted hex impact-ready screwdriver bits and an adapter. 2 of the bits are Phillips tips (#2 and #4) and other two are slotted (5/16″ and 1/2″).
The Klein Tools hand impact driver is made to the American standard. It has solid internal construction that effectively converts every hammer blow to up to 200 ft-lbs of “shock” torque. You can use it to break loose those stubborn Honda rotor bolts. You can also use it to tighten fasteners by simply turning the drive a quarter a turn to the direction you want the fastener to move.
Unfortunately, the kit does not include a #3 driver bit that is very useful for working on brake rotors. So, you will need to buy the #3 impact bit separately if you intend to use the kit on rotor screws. Other than that, the kit is perfect for breaking free nearly any stubborn screw including those stubborn door butt screws and other fasteners. It comes in a reusable Vinyl enclosure that closes tight and has a hang-up grommet for hanging the kit on the wall. This is an excellent buy for any tradesman or DIYer.
Bottom line, it does not matter if you are a shade-tree mechanic or work in a professional garage. A good manual impact driver is a handy little tool that takes away all the drudgery when dealing with corrosively stuck screws. It does not matter if the screw is rusty or stripped, this tool gets it out in just a few taps with a hammer. It is a perfect rotor screw removal tool that every auto mechanic should have.
Factors to consider when selecting a handheld impact driver
When shopping for a manual impact driver, there are several factors you should consider so that you get the most value from your investment. The factors include:
When working with a manual impact driver it is possible for the hammer to come crushing on your fingers when you miss the target. So, some manufacturers have this figured out and include a protective lip as an extension to the handle. The lip ensures that the hammer won’t land on your fingers in case you miss the target. A good example is the Japanese Vessel handheld impact driver.
Bits and accessories
Manual impact driver kits come with bits and sometimes additional accessories such as adapters and sockets. So when choosing the best handheld impact driver kit, it is good to consider the one that includes the common bits and adapters you will need for your projects because purchasing them separately can be expensive.
However, consider the quality of the bits too. Some kits have many bits which are not hardened enough to withstand heavy abuse. So don’t get it twisted, the quality of the bits matters too and this is where reviews and feedback from other users matter.
Type of grip
You need a good grip on the manual impact driver when using it to remove stubborn screws. As such, a tool that has a non-slip handle provides a better grip and reduces the chances of the hammer landing on your fingers. Furthermore, rubber molded handles absorb some shock from the impact of the hammer strikes. That being said, it is still important to wear protective gloves when working with the tool.
Everyone loves a tool kit that comes with its own storage case. So, it is an added advantage if you get a good kit that comes in its own durable carry case. A good package keeps everything together and prevents loss.
Although hand held impact driver kits are inexpensive, we all have limits to what we are willing to pay for any tool. What is important is to get the value for the money. ,