Intro: Make an Impact Nutcracker
Every winter I enjoy eating Hazelnuts ( Filberts ) but my classic nutcrackers had me picking bits
of nut-meat out of the crushed remains. Now you can build an impact nutcracker that does a
better job. It is fun to use and makes a great gift for the right person.
This nutcracker works by striking a shelled-nut with a hammer ( moving 1" diameter 2" rod )
against an anvil ( stationary hex head 5/8 bolt ).
Step 1: Tools and Supplies
To make this project, you will need:
A measure tape.
A hack saw.
A drill and a 3/4" drill bit.
Hot glue gun.
You should be able to find one for less then$6 on eBay.
Two taps, drill bits and a tapping tool for an 8/32 and 5/16 x18 threaded holes.
You need a #29 drill bit for the 8/32 tap and
A 17/64" drill bit for the 5/16 tap though a 1/4" drill bit will do.
A Dremel tool.
Hand impact punch .
A Vice or
A Drive Socket Set.
This Nutcracker is built into a short length ( 11 5/8" ) of common one inch PVC water pipe with the flared coupling on one end. You do need to get the schedule 80 pipe for strength, because of the sliding hammer impacts.
Schedule 80 one inch water pipes are available in Lowes and Home Depots.
Hammer Group ; [ image #2 and #3 ]
A two inch length of one inch diameter iron rod.
Some stores sell iron rods that big.
I found mine as a discarded swamp cooler fan shaft.
A 3/8" diameter 4 5/8" free length compression spring that was in my bin.
You could use two, 2" compression springs.
The spring needs 11 Lbs to be compressed to a 1 5/8" length.
A 5/16 hex bolt 5 5/8" long with full bolt length threads.
A 1 1/2" in diameter 0.05" Thin Washer with a 0.35" hole .
A wood Pull Knob.
you can find knobs on eBay.
A round head 8/32 machine screw 1" long.
A 1/4" diameter 8/32 standoff 1/2" long.
Anvil Group ; [ image #4 ]
A 1 3/4" diameter 1/8" Thick Washer with a 7/8" or 3/4" hole.
A 5/8 nut and hex bolt 2 1/4" long fully threaded.
A HEAVY Copper 1to 5/8 thread reducer as extra impact rest mass.
You could use a half dozen 1 inch 11/16" hole washers and another 5/8 nut.
Step 2: Cut and Drill the Pipe
Here you begin making the Nutcracker body by cutting an 11 5/8" length of pipe tube.
Be sure the end with the flair coupling is included in the body [ image #2 ].
Use the hacksaw with a fine tooth metal cutting blade for a smooth easy cut.
Now draw a ( center ) line along the full length of the cut tube.
For reference the flared coupling end is going to be called the Bottom .
Place a mark on the line at 2 3/4" from the bottom ( flared end ). The impact punch will make
an excellent mark.
Drill a pilot ( 3/16") hole straight through both sides of the tube, then drill a 3/4" hole through
each of the pilot holes [ image #3 ].
These holes will admit the shelled nut into the cracking zone on top of the Anvil and will be
enlarged in a later step.
Step 3: Cut the Tube Slots
Thin Cross Slot ;
Mark ( draw ) a circular line around the tube 1 7/8" from the top end, then use the hacksaw to cut
just less then halfway through the tube. I then used the Dremel to expand the Cross Slot to 1/8",
Wait a moment !
In typing this step I've just had an epiphany , which is; if your hacksaw can hold more then
one blade at a time, cutting this slot should be much easier.
Put two blades in your saw and cut the tube as before and the Thin Washer will fit snugly
into the slot [ image #1 ].
I just test tried a two blade saw cut on a scrap of pipe and it worked!
This is so much easier then using the Dremel to make the slot.
Thick Slots ;
Mark another circular line 1 1/4" from the bottom. Then mark 1/2" to either side of the
center line for the 1" slot dimension, then use a Dremel with a 409 cutting wheel to
make successive cuts for the 3/16" x 1" slot [ image #2 ].
Mark a 7/16" long slot directly opposite the front side slot, and use the same Dremel wheel
( probably smaller now ) to make successive cuts for the 3/16" x 7/16" slot [ image #2 ].
Later you will want the modified Thick Washer to easily sit across both these slots.
For now just check to see, if the Thick Washer easily slides into the individual slots.
Step 4: Cut the Bolt-Slide and Latch
Use the impact punch to place a mark at 5 3/4" from the Cross Slot reference.
Drill a single 1/4" hole at this mark.
Load a new 409 cutting wheel into the Dremel and make successive cuts to create a 1/4" wide
bolt-slide [ see the image ]. The bolt-slide runs from the Cross Slot to the 1/4" hole.
I hope you can make a better straight slot then mine. Don't worry, if the bolt-slide is not perfect,
it does not adversely affect the Nutcracker operation. The bolt-slide should be smooth.
Lastly, using a carbide bit , gouge out a 1/4" wide 3/8" deep Bolt-Latch at 2.5 inches from the
Cross Slot reference.
This Bolt-Latch slot is used to hold back the armed Hammer prior to cracking a nut shell.
Step 5: Make the Hammer Rod
The Hammer Rod is a 2" length cut from a 1" diameter iron rod [ image #1 ].
Use the hacksaw ( just one blade ) to cut the rod, it is not a critical dimension.
Now drill a 1/4" hole in the center of the rod ( any end ) 1" deep [ image #2 ].
Tap this hole for a 5/16" bolt ( 18 threads / inch ), Call this the Hammer top.
Use a #29 bit to drill a hole 5/8" from the top and a 1/2" deep [ image #3 ].
Tap this hole for the 8/32 Pull Knob machine screw.
Step 6: Making the Hammer Subassembly
Just make two pieces more for the hammer sub-assembly.
Thin Washer ;
Take and mark the Thin Washer as shown in [ image #3 ].
The first saw cut should be the middle flat. Mount the washer in a vice or locking pliers.
Use the hacksaw to make a straight cut 1/4" away from the hole edge.
Release the washer and make sure the the side marks will leave a 1/2" length in the
center after next two cuts.
Mount the washer in a vice or locking pliers again and use the hacksaw to make a side
cut 5/8" from the top center of the washer [ image #3 ].
Repeat this process finishing the Thin Washer modification which should look like the
left side of [ image #4 ].
Pull Knob ;
Depending on what kind of wood Pull Knob you find, you will need to drill a core into it.
The cored diameter should be 1/4" same as the standoff diameter, [ image #5 ].
Screw the standoff on the 8/32 machine screw. Leave 3/8" thread sticking out [ image #6 ].
Hot glue the screw with standoff into the wood Knob leaving about 1/4" of the standoff
exposed [ image #6 ].
Note the hammer parts properly put together [ image #7 ].
Step 7: Make the Anvil Subassembly
Cutting the Thick Washer ;
Mark 1 3/4" diameter 1/8" Thick Washer as a centered wedge [ image #2 ].
Mount the washer in a vice or locking pliers.
Use the hacksaw to make the cuts to create the wedge and lightly file the sharp edges.
Now, you should see how this Thick Washer wedge slides into the bottom slots of
the PVC tube and make any adjustments needed for this necessary fit.
Nut and Bolt ;
Take the bolt head and see how it does or does-not slide through the tube.
Hand file all six corners and use the tube as a Go / No-go test gauge.
Continue filing the corners and gauging the fit until it easily slides through the 1" tube.
Now repeat the hand filing of the nut corners until it also slide easily through the tube
see [ images #4 and #5 ].
See the up-side-down [ image #6 ] of the Anvil sub-assembly. Note the wedge thick washer
held in place by the copper massive nut.
Remember the copper nut mass can be replaced by multiple washers and a 5/8 nut.
Step 8: Install the Anvil
Bolt through wedge through tube ;
Prepare the 5/8 bolt and nut, they should be screwed tight together.
Insert the wedge thick washer into the two bottom slots of the tube. It should only go one way.
Keep the wedge centered by hand and slide the bolt and nut, threads first through the tube top
see [ image #2 ].
Enlarge the 3/4" hole ;
Now eyeball the front 3/4" hole and enlarge it with a round file until it looks like [ image #3 ].
Do this on the front side.
Be careful to only enlarge the hole in the vertical direction, because enlarging in the horizontal
will weaken the nutcracker.
This will necessitate sliding the Anvil bolt in and out, until the holes are satisfactory.
The back side hole should be smaller then the front side [ image #3 ].
Lastly, attach and tighten the heavy copper nut [ image #4 ].
Step 9: Install the Hammer
Bolt Pull ;
Slide the Hammer rod, smooth face side first, into position with the 8/32 threaded hole at the
bolt latch [ image #1 and #2 ].
Screw the pull Knob into the 8/32 threaded Hammer rod [ image #3 ].
Test if the pull Knob with Hammer can easily and smoothly travel the full length of the slide.
If it sticks anywhere, do some filing. Maybe add a small 8/32 washer under the pull Knob.
Spring, Washer and 5/16 Bolt ;
Position the pull Knob at the bottom of the slot [ image #4 ]. Drop the spring after the Hammer
and insert the Thin Washer into the Cross Slot. This traps the Spring in the tube.
Now you must insert the 5/16 hex bolt through the Thin Washer hole, through the Spring and begin to screw it into the Hammer top thread [ image #5 ].
This is where you adjust for all the small tolerance variations and any little errors in making
your Impact Nutcracker.
With the nut driver, simply tighten the hex screw head 2 or 3 turns [ image #5 ].
Next lower the pull Knob down to the slide-end-stop, with the spring fully extended [ image #4 ].
Hold the Knob all the way. You DON'T want to let the Spring push ( shoot ) the Hammer down
toward the Anvil, yet !
Now see if the Hammer is hanging on the Thin Washer and NOT on the pull Knob at the
If the Hammer is hanging on the pull Knob, you will need to pull the Knob up to bolt latch and
tighten the screw another turn. Repeat tightening the until pull Knob is not touching the PVC
tube slide-end-stop at full Spring extension.
If the pull Knob is what stops the hammer, you risk splitting the tube or damage to the small
The Impact Method ;
The Impact Nutcracker is designed to prevent the Hammer from ever touching the Anvil.
When a nut-in-shell rests on the Anvil, the released Hammer will strike and crack the
nut-shell but then go no further. This is what prevents crushing the nut meat.
This concludes the Impact Nutcracker assembly. Go on to the last step.
Step 10: How to Crack a Nut
Loading, Arming and Cracking ;
Arm the Nutcracker [ image #2 ]. Stand it up and place a Hazelnut on the Anvil [ image #1 ].
Now release ( fire ) the Hammer [ image #3 ] and remove the cracked nut [ image #4 ].
Two Handed Fast Method ;
Being right handed, hold the Nutcracker in your left hand fingers covering the back smaller nut
access hole. Hold the nutcracker at 45 degrees off the horizontal. Use the left thumb to push
the bolt Knob up just enough to drop a Hazelnut onto the Anvil, your left fingers keeping the nut
from rolling out.
Use the right hand thumb to draw the pull Knob up near the Bolt-Latch. While covering the top
hole with your left thumb. Now release the pull Bolt to crash the Hammer into the nutshell.
A ready to eat nut and shell fragments should fall into the fingers of your left hand [ image #4 ].
If the nut-meat is smashed, shorten the length you pull on the Knob for a softer hit the next time.
If not cracked, you want to pull the Knob further for a stronger hit and try again.
The way the nut rests on the Anvil will affect how it cracks open. See what works for you.
The two hand method is my favorite because it keeps nut shell scatter to a minimum.
The Impact Nutcracker is fun to use. It is a conversation piece on a shelf and can be a great gift.
Go have fun, try different kinds of nuts.