Sharpening grinder blades

[vice]

One point always emphasized in charcuterie texts is to take good care of your grinder blades and sharpen them regularly. I'm good on the first point, but pretty clueless on the second. Given the KA attachment blade's small size and awkward shape, I can't figure how I'd put a good edge on it with a stone. What are other people doing to keep your blades sharp (aside from generally ignoring that recommendation)?

[RobertCollins]

I wouldn't touch the flat that goes toward the plate - the one with the extrusion holes- but would take a small square stone and clean up the side that is somewhere near 30-45 degrees off the the axis of the screw auger.

In construction we used a triangle file on the wood bore bits we had and they - knife wise - are similar but for the extrusion plate.

I just took a look in Chad Ward's "An Edge In The Kitchen" and found no mention of grinder or food grinder blades.

[Chris Amirault]

I've rubbed the blade in a circle on one of my EdgePro plates now and then, but I can't say I'm very confident that it did much. Eager to hear ideas.

[Blether]

I cannot remember where I got it from, but I believe the way to do it is to lay the blade flat on a stone and move it in a figure-of-eight pattern. I haven't had to sharpen either of my grinder blades yet.

[dougal]

You need a FLAT abrasive.

I believe that the standard solution is to use abrasive paper on a stiff and flat glass backing.

And then (one at a time) rub the plate and blade on the abrasive, with lightish finger pressure.

You can use a variation of "the sharpie trick" by painting the contact side, and looking to polish off all the paint equally.

And, as usual, you can start with relatively coarse and progress to fine abrasive.

Its not a bad idea to begin by just using the sharpie (or 'engineers blue') and fine abrasive to check the flatness of plate and blade and see whether anything actually needs to be done.

I think that the 'figure of eight' motion mentioned by Blether is the popular way of equalising the abrading directions.

[vice]

You need a FLAT abrasive.

I believe that the standard solution is to use abrasive paper on a stiff and flat glass backing.

And then (one at a time) rub the plate and blade on the abrasive, with lightish finger pressure.

Thanks for the tips. I assume a waterstone would qualify as a flat abrasive, no?

Never having seen it mentioned elsewhere, I wouldn't have thought to touch up the plate in addition to the blade. Just to make sure I'm understanding, by plate you're referring to the die that determines grind size?

Edited August 28, 2010 by vice (log)

[dougal]

Depends how worn things might be as to whether or not the plate (the part with the holes) needs attention.

I think the steels used in plate and blade are typically of equivalent hardness - and so can often both show wear.

And sometimes the plates start out bent - with one side convex and the other concave.

The idea is to ensure that BOTH the mating surfaces are as flat as possible, so that the cutter 'leaves no gap' between itself and the plate -- both must be flat.

Begin by 'painting' the surfaces with a marker pen and testing them for flatness. See what you've got.

A waterstone might be flat when brand new, but they do wear - as particularly seen with the EdgePro. Instructions are given for 'levelling' worn EdgePro stones - but compared to the flatness of a well-supported (therefore not flexed) piece of glass, a re-trued stone isn't usually very flat.

Hence the use of a glass-backed disposable abrasive. Flat. Inexpensive. Accessible. Effective.

However, you could use the glass+paper to get a good flat surface on your waterstone ...

Or use a diamond (impregnated) stone. They seem to stay pretty flat!

The use of glass-backed paper abrasive for sharpening tools has been known as the 'scary sharp' method almost since the internet began (or maybe even longer). http://en.wikipedia.org/wiki/Scary_sharp

[scubadoo97]

As far as using a waterstone or the Edgepro stone, flatting your stone is quite important if you sharpening your knife or your grinder blade. You need to keep your stones flat.

[dougal]

As far as using a waterstone or the Edgepro stone, flatting your stone is quite important if you sharpening your knife or your grinder blade. You need to keep your stones flat.

As I said initially, for grinder plate & blade sharpening, you really do need a FLAT abrasive.

You aren't so much 'sharpening' as 'flattening'.

And if your abrasive isn't VERY VERY FLAT, its very easy to make things worse.

Its good to have flat stones for knife sharpening, but for working on a grinder there's a much greater need for a much greater degree of flatness.

Hence the preference for some nice smooth glass, either well supported or itself quite stiff, to get your abrasive flat.