Nut-cracker puzzle !!

[johnbs]

I hope no-one thinks this is off-topic, as the question below relates not to the nicely-turned bowl, but more specifically to the brass nut-cracker accessory.

Background: asked to fix this for a friend.

Description: Turned plane(?) = lacewood (?) bowl with brass nut-cracker mechanism in the form of a cast frame with a threaded brass screw:

The turned cross-handle has a stripped thread due to the torque required to crush the nuts/elicit a confession* :?

Now, you'd think that the designer would have the brass "crusher" disc (which appears solid from the nut's perspective) free to rotate, to reduce the friction when turning the cracker.
Also, the cast frame is just that: one piece, so the disc must have been added after the screw thread was dropped (screwed) in from the top.
However, when I attempted to remove /free the disc, I found that it was completely solid. A couple of downward taps with a soft drift had no effect, so I lubricated the main thread, stuck a couple of PTFE rods between the disc and underside of the frame, and then attempted to screw the screw up & out to drive the disc off the end. No joy.

Finally, I wondered if the disc was itself threaded onto the end of the primary screw, so I bored a hole just larger than the OD of aforesaid disc in a piece of 9mm Tufnol sheet, split across the diameter with the saw, and used a long 4BA screw to clamp the Tufnol around the circumference of the disc. Then attempted to "unscrew" the disc from the primary screw. No joy (LH or RH).

Does anyone happen to know how this might have been assembled in the first place? It may be that the brass assembly was some proprietary bought-in part.

Many thanks in anticipation!

John

* CIA version

 

[StevieB]

Heat the brass crusher disc and see if that releases it? If it was put on hot and then allowed to cool and contract onto the threaded spindle you would struggle to remove it cold.

To repair the mechanism why not just araldite (other glues are available TM) the wooden handle to the top of the brass thread. Alternatively drill a hole in the top of the threaded brass mechanism and rivet/screw/bolt the handle onto the thread. In this way your rivet/screw will take the strain from turning the handle rather than the glue if you were to glue it back in place. I am not entirely clear why you want to disassemble the mechanism?

Steve.

 

[Jamesc]

Hi John,

No experience with nut crackers but from a clanky engineers point of view the solutions to fixing the disk could be an interference fit, basically make the hole too small for the spigot and force it in (probably with the thread) or some form of glue like loctite. If it is either of these and you can remove the brass from the wood some gentle heat may help.
I wouldn't recommend playing a flame on it unless you really like polishing brass but a hot air gun or even pop it in with the sunday roast.
Most metal glues will release with moderate heat and if it is interference or even very tightly screwed on the act of heating and then cooling often gets things moving.

Regards

James

 

[Blister]

Hi again

I made one of these and my brass fitting bolted in , see photo

and from the top it looks like this

all i did was to turn a small plud and glue it in to cover the bolt hole

Probably of no help at all but I though I would show you just in case :lol:

 

[johnbs]

Firstly, thanks for all the helpful responses & suggestions.

I am not entirely clear why you want to disassemble the mechanism?

Steve: good point: it could be fixed "as is", but I suspect the problem would recur: with the whole of that disc trying to rotate atop a particularly resilient Brazil, it puts a massive torque on the relatively fragile joint between the wooden cross-handle and brass screw. The attachment thread (was) 1/2" Whit by the way. Glueing alone ain't going to hold it on.

My plan was to remove the disc (which has no hole or any other sign of two-partedness on the hidden face btw) and re-attach with a central stud (fixed permanently to the disc) which can rotate inside the body of the primary screw. Might have to abandon this if the disc won't come off!

I will now try a bit of heat

 

[jpt]

HI John

I made one of these about a year ago, you can still buy the mechanism HERE

Not sure how they are put together but the bottom plate should turn freely.

john

 

[johnbs]

John: That looks pretty much identical: the disc is a bit thicker.

Update: Heat gun didn't seem to work. So, gave up and decided to repair the 1/2" Whit thread (onto which the handle was screwed), but I don't have a 1/2" die. So I cut three longitudinal grooves in the threads of a 1/2" Whit steel nut, and in the process of winding this on and off (holding the disc as before with me Tufnol clamp), I happened to notice that the small gap between the disc and the shoulder of the principal screw (see photo) had closed (lot of torque needed to restore the brass thread). So, I drilled a 3/32" hole thro the steel nut (from flat to opposing flat), tightened it onto the brass screw, then drilled thro the nut & brass spindle and inserted a rolled-steel pin. Then holding the main brass frame in the vice, I managed to unscrew the disc from the spindle. The disc has an integral male thread (3/8" Whit this time) which was loc-tited into the main spindle thread.

John

 

[DaveL]

Well the thread in the wood never stood a chance with any nuts other than peanuts. :evil:
I think a long roll pin though the shaft that sits in a groove cut into the handle, held in place the epoxy should do the trick. :-k

 

[johnbs]

Dave:

I was thinking on similar lines. As there is no thread at-all-at-all left inside the wooden handle, I've tapped a brass collar with a 1/2" 12 tpi thread to glue inside the handle, but I don't want to rely solely on the glue joint.

 

[bugbear]

Totally OT (to the OP), but speaking as a fan of freshly shelled nuts, I consider this BY FAR the best design for the tricky nuts (e.g. brazils, walnuts, almonds)

The C.J.Rimes "CrackerJack"

e.g.

http://cgi.ebay.co.uk/VINTAGE-3-IN-ONE- ... 286.c0.m14

Overkill for filberts and hazelnuts, but sheer magic for anything else.

I have a particular hatred for the screw operated ones (as per this thread), since the retract time is immense - unless some knows a Quick Release model!

BugBear

 

[Paul Chapman]

The C.J.Rimes "CrackerJack"

My Mum used to have one of those. It worked really well. Don't know what happened to it :?

Cheers :wink:

Paul

 

[johnbs]

We bought one just like that not that long ago.

Re thread retraction time: I'm rigging up the Bosch reversible drill to the main spindle as I type....

J

 

[DaveL]

Totally OT (to the OP), but speaking as a fan of freshly shelled nuts, I consider this BY FAR the best design for the tricky nuts (e.g. brazils, walnuts, almonds)

The C.J.Rimes "CrackerJack"

We have one of these and as Bugbear says its great. 8)