Apple shredder

[keith darke]

Last season we prepared apples for pressing by chopping with a spade. This method is not very effective and would like to make a masher/grater/shredder. Can anyone advise of a machine on the market or a plan for making a machine. Regarding quantity to shred, we would process 3 m3 of apples total in 3 different times in the season.

[Mervyn Mitchell]

Hi Keith,

 

I can well believe that a spade is not the ideal tool for shredding apples!

 

A few months ago I built a simple scratter based on an idea I found on-line (I have since lost the address so cannot give credit where it is due - apologies to the originator of this highly effective scratter).  This device produces apple fragments of about the optimal size for pressing about as quickly as I can shovel the apples in.  It also has a sorting tray which enables fast identification and removal of dodgy fruit on its way to the shredder.  This is really helpful!

 

The attached photos should give you a good idea of how the contraption works.  The 1/3 HP motor was rescued from a scrap heap and develops sufficient power provided the shredding head is rotating before any fruit enters the hopper.  The pulleys used give a 2:1 speed reduction.

 

The head itself is made of hardwood epoxied on to a 20mm iron spindle.  I used a length of iron rod, and had a friend turn the ends to fit into19mm pillow blocks, which are easily purchased almost anywhere (even in Tasmania, where I live).

 

The hardwood cylinder would probably be most easily turned on a wood lathe, but I produced mine by cutting 8 circles with a hand-held jigsaw from a plank of 25mm (1 inch) hardwood (gum, in my case, but oak would work just as well).  These circles were cut quite roughly and made slightly larger (approx. 160mm) than required to allow for final turning.  Each was drilled to fit snugly on the shaft, to which they were epoxied in pairs, glued together with waterproof carpenter's glue, and tightly clamped while drying.  The shaft was then mounted horizontally above a router table, with the ends supported by the pillow blocks.   A router bit was selected capable of cutting a flat face perpendicular to its rotational axis, and this was used to true up the cylinder while it was rotated against it.  For anyone who has a router table, this is a very simple operation.

 

I then drilled 80 3mm holes into the cylinder, spaced 10mm apart, in four rows arranged at 90 degree intervals (see photo).  Alternate rows were staggered to ensure that every screw, as the cylinder rotates, passes through the gaps created by the preceding row of screws. I used stainless steel, countersink 30mm 8 gauge screws to complete the cutting head, each screw protruding by precisely 10mm.  It's helpful to make a depth gauge to ensure that all heads protrude by the same amount.

 

The hopper was built from wood, lined on the inside with Formica offcuts scrounged from a cabinet maker friend.  The seams were sealed with silicone caulking - probably best to use food safe silicone, although I used a variant that is approved for aquarium construction on the principal that if it doesn't harm the fish, it's ok for me.

 

The final diameter of the cutter head was about 150mm, but this isn't at all critical.  I turned the ends to about half this diameter (with the router as described) so that they could protrude through the sides of the hopper and protect the iron shaft from attack by the acidic apple juice.

 

It is important that the shaft rotates so that the screws move downwards towards the vertical cutting face of the hopper. At their nearest approach, the screw heads should clear the face by about 2mm.  Changing this distance will probably vary the coarseness of the pulp, but I started with 2mm and found this works just fine.

 

A lid over the hopper will prevent apple shrapnel coating the ceiling of your shed and should keep fingers away from the cutting head - very important!  Keep children and adult dill-brains away!  A large bucket will catch the pulp as it emerges and a final spray down with a hose while the head is rotating should remove all traces of apples and pulp.  Allow the hopper and head to dry with the lid open to prevent mildew.

 

This is one of the few semi-experimental machines I have built which exceeded all expectations at the outset.  The cost of shaft, screws, pillow blocks (bearings), pulleys and belt was about A$130 (that's Australian dollars).  The wood I scrounged or had already on hand.  The motor is probably 50 years old!

 

I trust this helps.  Happy scratting!

 

Mervyn

 

PS   I originally intended attaching a stainless steel plate at the point where the rotating screws approach most closely to the hopper wall - to prevent wear of the plastic laminate, but after processing about 300L of juice I noticed absolutely no deterioration of the laminate surface, so this probably is not necessary.

 

 

 

Mervyn Mitchell

62 Irby Boulevard
Sisters Beach
TAS 7321
Australia

 

(03) 6445 1168
mkm...@bigpond.com

[vince wakefield]

Can I respectfully suggest you fit a guard over the belt.

 

Vince

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[Mervyn Mitchell]

Absolutely!

[Ray Blockley]

That looks very much like it's based on Ny's "Codling Grinder" which
he made some years back:

http://www.youtube.com/watch?v=QnI33VOZVFI

Ray

[Thomas Fehige]

Am Dienstag, 12. November 2013 10:07:07 UTC+1 schrieb Ray:

That looks very much like it's based on Ny's "Codling Grinder" which
he made some years back:

 http://www.youtube.com/watch?v=QnI33VOZVFI

Ray

... and which he describes in detail on the ukcider wiki.

Also have a look at Claude's scratter (pdf-presentation, pictures, short video.) A machine based on Claude's ideas is available as a beautiful piece of woodworking from Peter Eveleigh -- video and homepage .

The basic principle is the same as the other machines mentioned. Claude and Peter use a bigger diameter drum (30 cm) in order to reduce the angle between the wall and the drum surface with bigger apples. Otherwise they can "dance" on the teeth instead of being crushed against the housing. And he doesn't use screwheads but strips of stainless steel sheet metal for the teeth.

I'm not so very sure I completely trust the water resistant carpenter's glue someone mentioned, to laminate the drum together. I think I'll use some kind of epoxy glue.

I made an early sketch (below) of something to mount on my woodturning lathe. The blue rectangles are the lathe's main cross beams, the thin red plate on top of them is a piece (or several) of plywood or sheet metal to adjust the fineness of the pulp, i.e. the distance between the teeth on the scratter drum and the edge of the housing at the narrowest point. The green circles denote the path of the apples (max diameter c. 11 cm). The drum (maple, stainless screws as teeth, diameter 20 cm, 15cm wide) is mounted on a 15 or 20mm stainless steel rod, which is held in the lathe's chuck on the one side and in a funnel-shaped adapter for the tailstock on the other. The housing will be 18mm birch ply lined with stainless steel sheets on the inside. For that I'll cut up the leftover pieces of my chimney pipes. They are made of the same highly acid-resistant stainless steel that is recommended for all apple juice and cider gear. The whole contraption will consist of five pieces: drum with axle; housing with one side fixed; second side of housing; sorting tray with safety cover for the tailstock; safety cover for the chuck. The apples will not be fed from the right as shown, but the sorting tray will sit above the lathe's tailstock.

Cheers -- Thomas

[Ray Blockley]

Yes we know the ukcider wiki very well... I am just one of many who have made many contributions to that wiki... :-) In particular I spent many hours putting information on the Homemade Cider Press pages - before I deleted most of it...  

 

We have also discussed and looked at Claude's machine in the past - it is a very nice piece of work.  

 

As has been said many times, all of this information and past discussion can be searched and found through the archives.

 

Ray

--

[Peter Eveleigh]

Hi Keith
and thank you Thomas & Ray for the comments; Do please let me know if you want further information on my machine, I am currently assisting someone near Chepstow with turning his design into reality - if you going into a minefield - follow someone!

On Monday, November 11, 2013 10:18:52 PM UTC, keith darke wrote:

Last season we prepared apples for pressing by chopping with a spade. This method is not very effective and would like to make a masher/grater/shredder. Can anyone advise of a machine on the market or a plan for making a machine. Regarding quantity to shred, we would process 3 m3 of apples total in 3 different times in the season.

At around 500 Kg / hour the sort of machine I make will easily manage this sort of quantity
Best wishes
Peter Eveleigh

[Thomas Fehige]

Well, yes, one aspect that is not quite clear and afaik has not been discussed conclusively here or elsewhere is the optimal shape and material of the scratter's teeth. Most of the proud scratter-designers don't show their pulp in their presentations, so it's not easy to judge from afar what is best. Also, I need to mill not only apples but Quinces too, so I need to be able to adjust the fineness of the milling, I think.

Claude says somewhere that the screws as teeth are not the best solution, but doesn't really explain what's wrong with them. Screw users have them stick out of the drum from 3 to 10mm.

So, what's wrong with the screws and/or what kind of improvements can anyone imagine?

- play with the geometry of the apple canal, like Claude has done in his design

- sharpen the edges of the screw heads

- use thin angled sheet metal pieces like Claude and Peter (although I doubt if that's an especially acid-resistant material) and screw them onto the drum.

- use a circular saw to make slits in the drum and with epoxy-stuff glue stainless-steel blades in; sharpen them. To make a drum that looks something like this one by Rink.

Ideas?

Cheers -- Thomas

[Dick Dunn]

On Tue, Nov 12, 2013 at 11:01:12AM -0800, Thomas Fehige wrote:
...

> Claude says somewhere that the screws as teeth are not the best solution,
> but doesn't really explain what's wrong with them. Screw users have them
> stick out of the drum from 3 to 10mm.

As one who tried flathead screws: If you get good stainless screws, the
edges probably won't be sharp--they're intentionally rounded a bit to make
them safer.

> So, what's wrong with the screws and/or what kind of improvements can
> anyone imagine?

...snip...

> - use thin angled sheet metal pieces like Claude and Peter (although I
> doubt if that's an especially acid-resistant material) and screw them onto
> the drum.

The material Claude uses is stainless steel; he points this out right near
the start of his discussion of teeth. He's cutting his strips from what he
calls a "pipe collar" (I'd call it a "band clamp" here), sort of like a
large hose clamp. I've only ever seen these with stainless bands.

--
Dick Dunn rc...@talisman.com Hygiene, Colorado USA

[Claude Jolicoeur]

While I am in Fouesnant near Quimper, currently tasting a wonderful cidre de Cornouaille, "Menez-Brug", I read this...
First point, I never tried a grater mill that had screws as teeth, but I can't see how they could really work efficiently, considering the shape of the cutter such formed by the screw head. I suppose that if the apples are pressed against the rotor, they would end up ground however.
Here in Canada, we easily find these pipe collars or clamps in stainless steel. We do have some in chrome steel also, hence it is necessary to check carefully - if stainless, it is written such.

P.S. the Menez-Brug is really nice, medium, with a touch of MLF nose, nicely balanced for acidity and good tannins. A beauty...

Claude

[Mervyn Mitchell]

Thanks for the link to the website showing Ny's grinder.  This is definitely what I saw some years ago, and on which, relying on memory, I based my own apple scratter.

 

At the risk of prolonging a discussion that may already have been aired through this site, I'd like to respond to some of the criticism of using screws to produce a cutting head.

 

The obvious merit of the screw-head grinder is extreme simplicity of construction, but, of course, this would be instantly negated by inadequate performance.

 

It seems to me that there are two important performance criteria in any scratter, plus some subsidiary ones:

 

1.    Quality of the pomace (neither too coarse nor too fine)

2.    Speed of processing.

 

plus, secondarily:

 

3.    Ease of cleaning

4.    Ease and cost of construction

5.    Provision of a sorting tray upstream of the apple feed - but I'm sure this could be improvised for any mill

6.    and probably a few more.

 

Most of the criticism of screws seems to originate from people who haven't tried them. Certainly, my grinder was dead easy to build, and processes apples about as fast as I can feed them in.  I haven't managed to compare the pomace with the output of other machines, but it presses well, with reasonable yields (for a basket press) and seems to fit Andrew Lea's criterion (Craft Cider Making, p. 46) by producing pieces about the size of a pea -  some smaller too, but I suspect all scratters do that.  The pomace seems largely free of fine puree that might clog the pressing cloth.

 

Some critics seem to feel the rounded screw edges would be too blunt to cut the apples cleanly.  This is not my experience.  Perhaps a linear cutting velocity of nearly 6 m/s (as in my machine) combined with the inertia of the apples themselves are sufficient to penetrate the relatively soft fruit.

 

The suggestion that external pressure would be needed to hold apples against the cutting head again seems not to apply, perhaps for the same reason given above.  The weight of apples in the hopper probably helps in this regard, and certainly the last two or three left behind do bounce around a bit before finally passing through.  But pass through they do!

 

I feel that one advantage of this scratter design might well be (although I haven't needed to test it out) the ease with which the milling head could be adjusted to change the consistency of the pomace, by

 

1.    Changing the clearance between the rotor and the cutting face of the hopper (the pillow blocks (bearings) can easily be moved by slackening off the four retaining bolts).

2.    Tightening or loosening the stainless wood screws (probably in conjunction with 1.)

3.    Removal of some of the screws - either alternate screws within each row, or alternate rows.  For protracted use, the holes would probably need filling afterwards.

 

A couple of hours experimenting in this way should optimise pomace quality.  I may try that next season.

 

Ultimately, I feel, a machine should be judged upon its performance.

 

Mervyn Mitchell

 

Sisters Beach
TAS
Australia

 

(03) 6445 1168
mkm...@bigpond.com

[Thomas Fehige]

I tend to lean to Merv's side where the teeth are concerned, and to Claude's as to the shape of the apple canal.

The screws are a simple "technology" and create no additional joint where juice or pomace residue can hide, they look like they would be easier to clean thoroughly. Experiments as to tooth length and gap width are easyly performed. They need to be staggered of course so that the whole apple is caught.

Stainless steel comes in different qualities or grades. Would that matter for this pupose? I can buy screws of type 316 "marine grade" stainless steel. Would there be any advantage over the more commonly used type 304? (Over here, they are called "V4A" and "V2A".) This would also be interesting for the juice tray of a press and other stainless steel parts.

The speed at which the teeth hit the apple skin is mentioned by Merv, Claude and Peter. Merv's 6m/s is topped by Peter's 7.5m/s. Claude recommends a speed between 600 and 900 rpm, which on his 30cm drum comes to 9.5 and 14 m/s.

Claude says that the shape of the narrowing canal where the apple is squeezed between drum/teeth and housing is relevant. The narrowing should happen over as long a distance as possible, to minimize the angle between the tangent where the apple touches the drum/teeth and the tangent where it touches the counter-plate. The smaller that angle, the better the apple is squeezed and held, and the less dancing apples you get, even when you feed them into the machine only one at a time (cf. Claude's video).

Cheers -- Thomas