Hand impact tools; striker wrenches

Capt. Mike

Not all do-it-yourselfers have an air compressor & air-tools. The most used of any air-tools is the air impact wrench. Here's a couple of substitutes.

Striker wrenches: A striker wrench is the name for a box-end wrench that has been designed to be struck with a hammer. We've all heard about "cheater" bars to extend the handle and increase the mechanical advantage. However a heavy blow with a hammer imparts tremendous "momentary" power and can break free fastners that often an impact wrench can't handle.

The design is pretty uniform. You have a box end opening on one end for the size nut/bolt needed, and the other end of what is typically a very short wrench usually ends in a heavy pad or anvil to be struck with the hammer. Some may have a rachet wrench opening to add leverage -- the cheater bar.

SP tools makes two for the VW axle nuts, P/N 79300 for the 36mm size and P/N 79350 for the 46mm size. They have a hole for inserting a standard ½" breaker bar or rachet. In use, while applying arm pressure to the breaker bar. strike the tool with a hammer. Cost about US$12 each. Snap-On offers a full line of sizes but without the stigma of low cost! The 36mm is US$49 & 46mm, US$78. You can kick that up 50% for offset models.

Hand impact drivers: The other impact driver is a punch style that incorporates a rotational twist with every blow. They look like a very fat ratcheting screwdriver body with a ½" socket holder on the end. When the hammer strikes the end, it both forces the driver hard onto the nut AND gives it a twist, via internal cam, in the desired direction. Most can be set for "on" or "off" twist direction. The amount of twist is almost undetectable, but it offers tremendous mechanical advantage. It is used only to break fastners free or set them. Since the drive forces the socket deeper on to the fastner, there is less tendancy for it to lift off and round the head.

Again, Snap-On makes the high end line at about $150 for the basic set and nearly $400 for the deluxe unit that includes all sorts of impact sockets. For the light home user, Northern Tool sells the small set P/N 15825-C141 for US$9! I've used an inexpensive set made by Vessel for years with complete satisfaction. They are best with screws that are close to stripping out the heads! I even caught one at Harbor Frieght the other day for $7 -- yea, Chinese junk but for the dozen or so times you need one, probably sufficient. Most come with only screwdriver bits & holder, but can then use ½" drive impact sockets.


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Capt. Mike

I've now found a 3/8" drive impact Driver Set. Same design as the Hand Impact Drivers in the post above.

A recent MSC ( www.mscdirect.com ) catalog had a K-D Tools brand one on sale for $22, including 4 screw-driver bits and a 5/16" hex adapter. It would also use standard 3/8" drive impact sockets. List is $26.50.

Maybe not for axle nuts, but a more useful size in limited spaces. I'd expect its major use would be in frozen screws rather than major nuts & bolts.
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New member
In addition to Capt. Mikes info above I would add the following. I just purchased the Schley 46mm striker wrench for axle nuts from Bus Depot. The tool is reasonably priced ($13) and extremely effective. The tool easily broke loose an axle nut that was so tight that I bent a 3/4" Craftsman breaker bar trying to get it off.
Good luck with your stubborn axle nuts!

Mike Robinson

New member
I have just replaced the shocks and springs on my '82 Westy diesel and in doing so discovered the impact wrench.

I have no idea how I survived without one! No more siezed, rounded nuts. Pre-soak the nuts with a penetrating oil and then use the impact driver and off with no problems.

In Canada Canadian Tire have a battery powered wrench that goes on sale at $125.