Flattening sh***pening stones

[deema]

I use primarily either oil or Arkansas sharpening stones, and hate the process of getting them flat again after they start to wear, a process that takes me some time. I would welcome your thoughts and tips on how this can be done efficiently.....read no time at all!

 

[marcros]

Using a concrete paving slab is the method that i have heard referred to on a number of occasions,

 

[lanemaux]

To flatten most any stone , I use some very cheap diamond plates I got for 3 or 4 dollars (couple of pounds) that attach to my key chain. The plastic backing to the plates are surprisingly robust and stay very rigid. They are 3 inches long , so cover my stones from side to side (Go on and laugh at my tiny sharpening stones if you will ) . I just give a cursory few passes on the stones after a few uses so I don't need to have long flattening sessions. So far they have served me well.

 

[D_W]

Loose silicon carbide is the standard for flattening oilstones that are far out of flat. Otherwise you can rub them with a diamond hone.

You should be able to use most without any additional flattening, the exception being maybe a new carborundum stone (crystolon), which is probably going to be friable and hollow quickly.

Allow your sharpening strokes to overlap the edges of the stone and it will stay plenty flat for use without doing anything else.

 

[MIGNAL]

Unless you have some sort of powered mechanised way of flattening them it's never going to be quick, so be prepared for a bit of sweat. Arkansas and Oil stones are hard, they aren't going to give up their scoop or camber easily.
The Japanese waterstones are soft, hence why they go out of shape very quickly. They are very easy/quick to get back to flat but you have to do the flattening almost on a daily basis.
I suppose diamond stones are heaven sent for those who like their sharpening media flat.

 

[Bluekingfisher]

I have used a large concete slab in the past with lots and lots of water to flatten an old oil stone of my fathers which was badly dished. It takes an age and would not wish to do it too often........................so I invested in diamond plates. Way better in every aspect.

Good luck with it

David

 

[Doug B]

I bought a set of 3 for £5, 6x2" plastic backed diamond stones at a show which is what I keep this sort of job

 

[Phil Pascoe]

I don't use oilstones, but as above - if you ensure you use the whole stone they don't tend to dish badly anyway. It's probably more important with water stones (their being softer) but valid nevertheless for oilstones that you use the sides for narrow chisels - this alone saves a lot of dishing. They're easier to keep relatively flat than to get flat.

 

[tomasg]

Ive heard recently some people are using the backs of tiles for this purpose
As most tiles have ridges on the back for adhesion roughly like a mil or two of pattern..
Had not the time to check this out yet
checking flatness tolerance ,speed of cut and surface finish
anyone use tile backs ?
Seems like it would make things easy to spot a hollowed out or uneven surface with the ridges
if you know that the tile is truly flat
Tomas

 

[deema]

Thanks Everyone, some good suggestions for me to try. I grew up with the traditional media and have so far resisted moving to water stones....steel and water just don't like each other I feel .......or diamond stones that cost lots of pennies. However since the stones are in regular use the need to flatten them comes up far too often, if I can't find a more 'enjoyable' solution the ludite may have to join the diamond stone camp.

 

[D_W]

I presume this progression of oilstones involves an india stone and then an arkansas stone or two?

Overlapping the edges (if you're working freehand) should keep all of them sharp.

I've tried everything for entertainment purposes, and I don't think there is anything more practical than oilstones *unless* they don't cut the steel you're using because you've stepped up the ladder to some whiz bang modern super duper 65 hardness whatever.

For less-than-recent magazine war steel, oilstones would be my choice. They are lifetime stones, and the edge is comparable to anything else.

Diamond stones are OK, but they do wear over time and they and silicon carbide can be rough on some older hard carbon steel tools.

I think you have what you need, now the transition to be made is to modify methods so that you're not needing to flatten the stones as often. Stones need to be flat only to set up new tools. After that, they just need to be able to contact the wire edge on the back face of the tool and not be too concave across width. The grinder does the bulk of the work (or a carborudum stones if you're not fancy on the plugged in stuff). a stone hollow along its length can still work the back of an iron just by overlapping the ends and not letter the iron fall into concavity the wrong way (so as to add an unwanted back bevel). The finest stone is the only one the back of a set up iron or chisel ever needs to touch.

 

[Doug B]

if I can't find a more 'enjoyable' solution the ludite may have to join the diamond stone camp.

If you are looking for decent diamond stones it's worth a look at Buy Brand Tools I found them very reasonable for diamond stones & they quite often do discounts if you spend over £50

http://www.buybrandtools.com/acatalog/D ... eners.html

 

[No skills]

From my own (often odd) perspective, I found a brick rubbing stone a few weeks ago - first thing that sprang to mind was "I bet I can flatten sharpening stones with that", it's certainly very course - haven't tried it out as I don't own any water or oil stones.

 

[D_W]

Bricks have a good deal of coarse silica and alumina, so they will work OK so long as they are porous and the binder of the stone being flattened doesn't grab (shapton stones come to mind as something that doesn't like much other than diamond plates because the binder will seize particles of the flattening grit). Concrete blocks work better for soft stones, though, they're more porous and probably bonded together better.

Fired bricks would make a decent coarse stone if the grit in them was more uniform. You can sharpen something junky on them for entertainment, but they will scratch up the bevel of anything nice due to random particle sizes, so don't do it with a nice knife.

 

[Derek Cohen (Perth Oz)]

I use primarily either oil or Arkansas sharpening stones, and hate the process of getting them flat again after they start to wear, a process that takes me some time. I would welcome your thoughts and tips on how this can be done efficiently.....read no time at all!

Hi deema

If you only have a little work to do, that is, they are fairly flat and your aim is mainly to return to perfectly flat, then it makes sense to keep a diamond stone for this. This also serves to freshen the surface. Larry Williams (Old Street Tools) has a video of this (below). Alternatively, using loose silicon carbide (used on cast iron or plastic laminate sheets - available from Lee Valley) may be cheaper.

https://www.youtube.com/watch?v=Z0ClNp_Eknw

Regards from Perth

Derek

 

[Lons]

Bricks have a good deal of coarse silica and alumina, so they will work OK so long as they are porous and the binder of the stone being flattened doesn't grab (shapton stones come to mind as something that doesn't like much other than diamond plates because the binder will seize particles of the flattening grit). Concrete blocks work better for soft stones, though, they're more porous and probably bonded together better.

Fired bricks would make a decent coarse stone if the grit in them was more uniform. You can sharpen something junky on them for entertainment, but they will scratch up the bevel of anything nice due to random particle sizes, so don't do it with a nice knife.

You possibly misread the post D_W ?

This is a brick rubbing stone http://www.my-tool-shed.co.uk/p18587/Fa ... wgodWL8K4w there are several shapes and sizes and often used for rubbing down concrete floors. You can also hire a machine for that purpose which uses several stones and they are discarded after hire so if you can find a friendly company they are worth having as they can true up grinding wheels also.

Bob

 

[D_W]

Bricks have a good deal of coarse silica and alumina, so they will work OK so long as they are porous and the binder of the stone being flattened doesn't grab (shapton stones come to mind as something that doesn't like much other than diamond plates because the binder will seize particles of the flattening grit). Concrete blocks work better for soft stones, though, they're more porous and probably bonded together better.

Fired bricks would make a decent coarse stone if the grit in them was more uniform. You can sharpen something junky on them for entertainment, but they will scratch up the bevel of anything nice due to random particle sizes, so don't do it with a nice knife.

You possibly misread the post D_W ?

This is a brick rubbing stone http://www.my-tool-shed.co.uk/p18587/Fa ... wgodWL8K4w there are several shapes and sizes and often used for rubbing down concrete floors. You can also hire a machine for that purpose which uses several stones and they are discarded after hire so if you can find a friendly company they are worth having as they can true up grinding wheels also.

Bob

Ahh...never heard them called that over here ("brick"), and they're generally not used around stones here, especially not oilstones (which "remember" deep marks for a long time).

Stones like that are generally used for tile fitting, etc, over here.

 

[tomasg]

Hello again
What should i use for flattening this ....(washita ,i think ?)
Had a look at an old tile again , seems theirs less than 1mm of grid patterns on the back .
along with some cement ..
Does anyone use a tile for this purpose for oilstones ?
Not having money for a large diamond lapping plate ...could this suffice ..
Thanks
tomas

 

[G S Haydon]

I used a belt sander before on a what I think was a charnley. Worked well, make sure the you protect yourself and others from the dust!

 

[D_W]

I have flattened stones like that using a common belt sander and a cheap aluminum oxide belt. Wear a respirator or good dust mask if you do it, and do it outside.

The trick with a cheap belt sander is that you have to focus pressure on the drum on the end of the sander so that you have a line of abrasive doing the work instead of a large area. Once you get close to flat, you can do traditional lapping. If that doesn't make sense, what I mean is raising the sanding bed to vertical instead of horizontal so that you can press the stone right against the wheel/drum at the top on a contact point so that the abrasive can dig in. It doesn't work well on the flat/platen and could burn out a sander. Coarse loose silicon carbide should also work it well without ruining a diamond hone, for instance. I haven't tried sidewalk, but if you have a neighbor you don't like, I've heard of folks claiming good luck with sidewalks. The beauty of the belt sander is that it does most of the work. Smells like fire while it's blasting the stone off, though.

A stone like that which might have a good second side begs the question of whether or not it's necessary. I've done the above on stones where the back side was hand cut or part of it beveled off so that you wouldn't get a full surface.

For a stone like you're showing, if the alternate side is in pretty good shape, I'd put bowed side down in a box made to hold the stone and put something cheap and easy (like plaster of paris) in the bottom of the stone box to hold it firmly. Cost a couple of (insert currency here), and be a lot quicker than lapping the bowed side.