Nut cracker

[12bolts]

It started as a simple request. Could I make her a decent nut cracker please. One that was easy to operate and wouldn’t make too much mess.
Here in Queensland, our native nuts, Macadamias, are fairly prolific, but extremely hard. Pliers, hammers, crab crackers, are used with varying degrees of success. Pulverised nuts, pinched fingers, flying shells are often the result.
So I decided to do something worthwhile, but keeping to simple machining, and a work around of not having a rotary table or indexing head. And try to make it look nice for her.
I did a sketch to work from but it was a bit of a design in progress as far as the look of the finished product. I started with a pattern made from MDF and pine; shaped for draft, painted, and also a split mold.



30 minutes in the furnace and what used to be a wheel rim I found on the side of the road, (I still think if the owner wonders what happened to it), was turned into something more useful, (to me).


Cheers Phil

- - - Updated - - -

Drilled out on the mill to accept some brass bushes I had turned up on the lathe, and the “camshaft” from 4140.


The hole for the “pushrod” was too long for even my long series drill so I made an extension from an old printer roller shaft. I drilled a pilot hole, then went up in size to the diameter of the extension shaft to keep it centered for the next bearing block. Drill and repeat, but then I had to make an even longer extension shaft to reach the back bearing block.


The back bearing block needed a counterbore to suit the thumbwheel I had planned. So that was another tool to make. As accuracy was not critical here it ended up being simplest to make a boring tool of sorts with a ¼” HSS cutter, I assembled the bits and just using a hand drill to power it I pulled back on the tool until it had cut deep enough.


And some more brass bushes were machined up to suit the pushrod bearings.


Cheers Phil

 

[ricsmall]

Very nice start to a nutcracker! All you guys amaze me with your broad range of skills. Thanks for the post.

Richard

 

[PeteH]

Very nice indeed ! Do keep us posted as it comes to completion.

BTW -- here in the NE USA we have a similar problem with black walnuts -- delicious nuts, but the devil to crack, and you usually wind up with bits of shell in the meat. I use a bench vise.

 

[Bill Gruby]

I can't wait to see what this will look like. The War Department is watching this one also.

"Billy G"

 

[JoeSixPack74]

My mother grows those here in Florida. She uses a nut cracker similar to this one.

http://www.casa.com/p/hic-brands-th...625354&utm_content=pla&adtype=pla&cagpspn=pla

Will be looking forward to seeing yours.

 

[12bolts]

Thanks for the words guys.

A ½” grade 8 bolt had the thread and head cut off and I single pointed an Acme thread onto the shank, then milled a slot it for the grub screw which was drilled and tapped into the back bearing block from the underside. This screw prevents the Acme threaded bolt from rotating when the adjusting thumbwheel is turned. A small depression was machined in the end to give it a sharp working lip. A circlip groove was cut in it for a spring retainer. When the machining was finished I heated it red hot and quenched in oil. I left it as is with no tempering.


The thumbwheel is made from bronze, (a bit of left over sprue from another casting project), turned to size and shape, and single pointed with an internal thread. I have an old headstock and spindle, so that was pressed into use as a indexing head. I clamped it to the mill and bent up a piece of wire for an indicator. Locate the spindle so it lines up with the pointer, then tighten the split bearing hard on the spindle to lock it. I needed to hold the thumbwheel on the bolt to give me enough clearance between the chuck and the ballnose endmill. Mill a comfortable groove in the wheel, loosen the spindle, move a couple of teeth round, lock it up, repeat.

 

[12bolts]

Joe,
Whilst the operation of the cracker is a bit different, the ability to adjust for different size nuts is similar to mine.

Cheers Phil

- - - Updated - - -

The operating handle was some more 4140 that I turned to a pleasing taper, drilled and tapped the bottom for securing it and put a vague thread on the top for the knob. I drilled a 64th oversize hole in a steel block, put a screw in the threaded end to protect the thread from deforming, then heated it red hot, jammed it in the hole and bent it 90. I was quite impressed with how sharp and neat the bend came out. I then milled some sides to the handle to prevent any tendency for it to rotate in use.


The cam shaft then got a flat milled in it to lock it to the handle.


The cam lobe was plotted on a piece of paper as a graph, then transferred to a piece of plate and shaped with an angle grinder.

Cheers Phil

 

[12bolts]

All the bits'n'bobs that make up the guts of this contraption.
The pushrod is a piece of chromed rod from a printer, cut to length, a circlip groove was cut in it for the spring return when the handle is raised. The cam and camshaft were cross drilled for a pin to lock them together. A small felt pad was glued to the ally base below the cam for an oiler. Each operation of the handle presses the face of the cam against the felt pad. I just soaked it in gear oil, eventually I suppose it will dry out, but I don’t think it will happen real soon and I’m not even sure it was necessary. I don’t plan on cracking nuts at high speed for extended periods.


Cheers Phil

 

[12bolts]

The 3 wood pieces that hide it all, along with the cup for the nut, and a matching inlay for the handle. The bottom piece was routed out to the thickness of the ally base plate. The middle piece was pretty simple, just cut it to clear everything. The top piece needed careful planning on where to cut the openings for the cup and the operating lever, and also the top of the bearing blocks, but then also a bit more to clear the top of the cam, and also as an afterthought the bristle brush that was used to conceal the opening of the operating handle. It was getting pretty thin in a few places and it started to split with all the work being done to it so I inlet a couple of pieces of ¼ X ¼ oak across the grain to lock it together.


A dry run shows how it will all go together.




Cheers Phil

 

[CoopVA]

Well done so far! Looking forward to seeing the finished project in action!


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