If you sharpen by hand, then you'll know that your benchstone loses material at the same time as it abrades the metal of the blade - it wears down, usually as a hollow in the middle. Eventually, the shape of the stone starts to influence the bevel of the tool.
How can you get a flat bevel on a concave surface? So you need to flatten the stone.
How often? Whenever you notice an issue.
I'm using a Norton Flattening Stone (web search for suppliers) in this lesson. It's normally used with waterstones but works just fine for Carborundum and Arkansas - in fact it was Norton who originally suggested it to me. But any surface flatter and harder to rub against will work and I have some other, lower tech ideas in my book, Woodcarving Tools, Materials & Equipment Vol.1.
Look out for old benchstones from flea markets or car boot sales, often a great bargain when restored. You can clean the old oil from them with paraffin (kerosene) or - for all you non-smokers out there - petrol. As for restoring the shape, in this lesson I'll show you how.
| 19 September 2017 23:37
Iria - Finish with fine sandpaper then wash the stone and all should be well. There are many natural stones out there used by our grandfathers and such that are just waiting to be reclaimed. I hope it proves to be as good as it sounds!
| 19 September 2017 15:28
Thanks Chris! Great news! And what about the sanding paper? Could it damage the stone or leave sand in it?
| 19 September 2017 11:03
Iria - If your grandfather used the stone to sharpen a blade with which he was going to shave, it's a good bet that it'll be fine enough to sharpen your carving gouges! You can clean a dirty stone with kerosene (paraffin) or gasoline (petrol) and this you should do when you have finished flattening it.
I'm afraid that have no experience of using granite for sharpening carving tools but I doubt it will do the job properly.
| 18 September 2017 18:35
Hi Chris, I was looking to buy sharpening stones and I discovered that my mum kept an old stone from my grandfather (he used it for shaving knives). Looks pretty smooth so I would like to give it a go as a fine stone.
The problem is that is pretty bad shaped from use. I am thinking to use a flat surface and sandpaper as I read someone here had but I am concerned that the sand particles will remain stuck on the stone and ruin the stone or the cutting surface of the tools I try to sharpen. Any suggestions?
The other option that came to mind is a garden granite table that is perfectly flat and not polished, so it is a bit abrasive, I hope. What do you think? Is any option worth trying?I don't want to ruin my grandfather's stone if I will not be able to use it later.
| 30 August 2017 10:52
Azucena - That's a good method for flattening benchstones. Some people will use an old saw blade instead of a glass plate. 90 is a good grit number and will do for both the Carborundum and Arkansas stones, there is no need to use finer. You can use 60 grit if you want to be a little bit quicker.
| 30 August 2017 06:29
Chris - If I am going to use a glass plate with an oil solution and silicon carbide powder, which grit would you recommend? Lee Valley suggests a 90x lapping grit for most applications. Also, would you use the same grit# when flattening a coarse Carborundum stone vs. a fine Arkansas?
| 18 June 2017 20:30
Jeff - Please see Karen's comment below and her recommendation of SharpeningSupplies.com. I have just been to their website and they have a sale of hard, translucent benchstones at the moment, which would be what you need They also have combination Norton India stones. And a guarantee 'of 100% satisfaction' - so do check them out.
I can't recommend either or diamond stones myself - and certainly not as alternatives to the translucent Arkansas. My limited experience has been that they are either too coarse or too fine for my taste. Having said that, there will be carvers out there who are happy using them I'm sure.
I'm sorry my help is so limited. I have no say over the distribution or quality of these stones but my gut feeling is that Karen's website find will be where you will get what you need - so you can get on carving!
| 16 June 2017 17:56
Just spoke with Joel in Brooklyn (can't make it to his sharpening class in 3 weeks, but he sends regards). Very difficult to get translucent Arkansas stones: the ones in boxes are in boxes to conceal the lesser quality side. Also difficult to get true Indian stones of the correct (not just convenient) composition, so have to be careful. Diamond stones leave scratches because they simply wear out very slowly.
I'll ask one more question before taking the plunge: have you ever tried bench ceramic stones? Or Shapton ceramic glass, even though they are very dear?
Mr. Pye, I'm being picky because at age 70, I don't have a couple of years to test a set of bench stones. I'll have to do the best I can, knowing that I managed to assemble a range of sizes of your slip stones.
When I told Joel that the last time I brought my wife to a tool store, she encouraged me to buy tools, Joel said he is is looking forward to meeting her. So, you see, my difficulty is just making sure to decide correctly. I have two of his saws -- incredible!
| 16 June 2017 06:33
Jeff - (and thanks, Karen, for the source info) - Your questions, in order:
1. Use the coarser side of the stone for shaping.
2. True Arkansas stones cost a fair bit but they really should be seen as, after tools, your main investment. I've had mine 40 years. Just think what you need if you are a woodturner!
3. 'Very Hard' might well do the trick here, especially if you can return it if doesn't feel like marble.
4. A width of 3" is good but more use for plane blades; the narrower stone will do just fine.
| 13 June 2017 20:48
I purchased my Chris Pye slip stones from Sharpening Supplies.com in Middleton Wisconsin, no issue in trying to purchase them. They are an excellent company to deal with, fast, courteous and reputable. My Chris Pye slip stones were shipped to Canada, so the US exchange killed me but the stones are quality and I have never regretted my purchase.
| 13 June 2017 19:48
(I mean it when I say the slip stones are hard to find. The folks at Norton couldn't give me an availability date.) Yikes!!!
| 13 June 2017 19:46
I'm about to order the bench stones. I possibly have one already, The old Carborundum stone, by the Carborundum Co., in Niagara Falls, NY. It ha two grits. possibly 60 and 120. It's in remarkably good shape for its age. QUESTION: which grit would be best for that first shaping step of a gouge?
Then, for the finer stone. The true Arkansas translucents are pricy, the "very hard Arkansas" seem more reasonable and they look much like the very light colored translucents. Does it matter much if stropping follows?
As for width, 2" or 3"? It seems that 3" wide for an 8" long stone would give me more room to roll the tool depending on the sweep and width of the tool? What size are the bench stones you and Bob Cosman used in your joint video?
I know I'm being picky, but having found the few remaining Chris Pye Slip Stones in stock in North America, the dog is getting nervous about my being able to afford his dinner.
Yes, yes, the first tools are enroute and I will be carving very soon. The stack of carving wood has a lovely smell to it.
| 30 January 2017 10:45
Liam - The Norton 'Crystolon' stones are made of silicon carbide (SiC); the other name is 'Carborundum'. Norton 'India' stones use aluminium oxide (Al2O3) as the abrasive.
Both abrasives are fine for use with carving tools, although I have read that Silicon Carbide is generally thought to be the more aggressive of the two. But so much depends on the size of the grains and the binder that goes into making any artificial stone - which is why you should always buy the best quality stones (such as Norton) and not cheap imports.
At the end of the day, try it and see...
| 28 January 2017 22:29
Hello Mr. Pye,
I recently purchased a new coarse benchstone from Norton. When I purchased it I didn't realize it, but this stone is a "crystolon," as opposed to the one I had before, which was India. Is there a difference between the two?
| 19 December 2016 10:48
William (Bill) - My own Arkansas stone is over 40 years old now. I've only ever just wiped it clean with a rag after use and before putting it away. It rarely has a chance to glaze over but, when it has (because I forgot to clean it), I've used more oil and that has simply loosened the gunge up so I could wipe off and start again.
I had some severely glazed stones once that I brushed with kerosene (paraffin) to unclog the pores. They needed priming a bit with oil, since the kerosene leeches oil out but all in all it worked a treat. So... that's me.
As to your own stone glazing over, it may need a thinner oil than you are using. (They are natural stones and do vary in pore/crystal size.) Normally we need something like 3-in-1 bicycle/sewing machine oil, nothing thicker.
I would try diluting your sharpening oil with say 20% kerosene. It'll give a brisker cut on the stone and hopefully eliminate clogging. Other than dilutingt, I'd keep away from the kerosene.
| 19 December 2016 10:36
Karen - You should wipe oil off your own stone before putting it to the Norton flattening stone, so you don't clog the pores of the Norton.
Flattening the stone shouldn't be a big deal. After all carvers have needed to do it for hundreds of years. To flatten a benchstone all you really need is another flat surface, one that is itself more resistant to wear, and an abrasive. The Norton stone is just something on the market: I used an old saw blade and the sort of abrasive paste engineers use for valve grinding for many years before now, and that worked really well. Some people use glass instead of the blade; even others I know use a belt sander - though there are health and safety issues here.
| 19 December 2016 00:20
Chris. I have a translucent Arkansas stone that has glazed over. This started early on. I have been diligently using ample oil and when done, using kerosene to clean the stone. Now I become aware that there are some knowledgable persons that advocate never cleaning the stone with kerosene. They advocate dabbing the stone to remove excess oil and detritus and then putting fresh oil on the stone for storage. Any words you might have as to the veracity of this method? Bill Solberg, Los Angeles.
| 18 December 2016 17:17
I appreciate this video Chris as I had purchased a Norton flattening stone a year ago but couldn't find anyone at my carving club who knew how to use it. Now I can see my bench stone is beginning to hollow so I will get to work. I wasn't sure from the video if the stone was completely clean before you flattened it.
| 26 August 2016 22:34
Vivienne - The way I sharpened my tools, for many years, was with a 'combination' carborundum and a translucent Arkansas benchstone. The combination stone, still made by Norton India, was designated 'coarse' and 'fine', and I really don't know the grits - but that's the one to get. And, yes, get a translucent Arkansas stone. I have not found anything really to match it. Mine is 40 years old and was one of the best carving investments I ever made. So live long and carve well!
| 24 August 2016 19:42
Brought a few starter tools from the market. They're good Sheffield steel with good handles. The heel on the v tool is nowhere near as shallow as your description of ideal, so I have work ahead to adjust it.
Also one of the gouges needs work for similar reason- angle of bevvel.
I intend to buy a Carborundum dual surface stone, have looked online at several ...
Here's my issue.
What grade of 'grit surface' should I get. They come in such a variety.
400/1000 - 3000/8000. - and many other combinations.
Secondly..do I also NEED an Arkansas stone.
Very new at this.
| 06 June 2016 17:50
Thanks again for all your help! I have one tool I have to re-sharpen, and then I plan to carve a relief of a falcon...
| 06 June 2016 14:58
Liam - India stones are made from Aluminium Oxide. Carborundum is Silicon Carbide. I think the general opinion is that the Carborundum, which is the one I've always used, is more aggressive than India but in our application I'm not sure how significant the difference would be.
One important factor is the binder - what holds the particles together. The poorer this is, the quicker the stones will abrade. That's one reason why you want to buy the best stones you can. Anyway, I hope you get your tools sorted quickly so you can get into the real business of a woodcarver.... :)
| 05 June 2016 19:21
Thanks for your reply! (I hope I wasn't too confusing!) My theory is that I am putting too much force on certain parts of my sharpening stone when I sharpen, and I am going to try and be less forceful in the future.... On the topic of flattening, the reasons I got a simple flattening stone were that, although I have a diamond plate, it is nowhere near the size to flatten my stone; also, the flattening stone seems easy and affordable compared to the diamond plates I saw. I suppose I shall just purchase another flattening stone, and be more careful while sharpening.
I do have one more question (sorry!): you say in your sharpening videos that your coarse stone is carborundum; my benchstone is what's called and 'India' stone. I read that carborundum stones are made from different material than India stones and cut faster (although not as cleanly as) than india. Do you know if there is any substantial difference between them?
Thank you very much for helping me! I really do appreciate your website and your videos; they're very, very helpful! (:
| 05 June 2016 17:03
Liam - Stones do need flattening now and then - hard to say how often because it depends how you use them. I suspect you are focussing on the middle of the stone rather than trying to use as much surface as possible and not running in the same line all the time. Five tools shouldn't make much of a dent in the stone.
In theory, the flattening stone has to be much harder than the benchstone. Again, it's really heard to say what's happening but obviously something's not working. Diamond 'stones' (plates) are harder and sure, if you have one do use it. The plate will wear eventually because at the end of the day the diamond dust is just sintered on.
For many years I flattened my stones by rubbing them on an old saw blade with a slurry of oil and valve-grinding paste (coarse carborundum grit - you can still buy it, online) It was actually quite quick and the advantage was that the blade never wore out.On the other hand, it was rather messy...
| 04 June 2016 17:06
Hi Mr. Pye,
I really apologize for bothering you again, but I have quite a problem on my hands at the moment. Let me explain: about two months ago, I purchased five carving tools, and then I sharpened them--all five, one after the other. My coarse sharpening oilstone (made by Norton) got worn pretty badly. I realize that I probably shouldn't have let it get so worn. Anyway, I got out my flattening stone a few days ago (also Norton's, the one you recommend) and flattened. But here's my problem. Maybe because of the serious hollow in my sharpening stone, or some other reason I don't know, but my flattening stone now has a convex surface, and it is not flattening my sharpening stone, it is just continuing to hollow it.
So now that I have stated my problem (hopefully you could understand it), I have a few questions for you.
1)You say in a comment below that your flattening stone seems extremely hard and is doing fine--why then is my flattening stone being affected by my sharpening stone? Is it possible that I somehow got a defective flattening stone?
2)Do you think something such as diamond would be a better choice to flatten my sharpening stone, or should I stick with Norton's flattening stone?
3)Is it normal for a coarse oilstone to need flattening so much (I've already flattened several times), or am I doing something wrong???
Again, I apologize for bothering you with all these questions, and I really do appreciate your all your help; I hope you understand my dilemna!
| 17 January 2016 21:25
Thank you, Mr. Pye, for your reply. The smallest tool I have right now is a 2 or 3mm v tool, which I think has caused the grooves. I will go ahead and get a flattening stone anyway, because I know I will eventually need it. And now that I don't have any more questions (for the moment), I'll try not to bother for a while. (:
| 16 January 2016 16:36
William - I agree, it's slower than one would hope, but there isn't any other dedicated flattening stone out there. The old saw blade and carborundum grit/oil slurry probably works just as well. The problem I have showing or discussing other methods of flattening stones - such as the belt sander, which works very well - is the health and safety issues. Seriously: inverting a belt sander into a vice and holding the stone to it's surface (or vice versa), while a fast way of flattening, has all sorts of safety issues: grit, dust, danger to fingers etc. I know sensible people would do it outside, goggle and dusk mask up, and wear gloves but there are lots of cavaliers out there, so I can't recommend it...
| 16 January 2016 16:24
Liam - The chances are you're working and wearing just one part of the stone. (You are also right in that the narrower the tool and greater the pressure you exert the more you'll wear the surface.) Make sure you spread out over the whole surface - or at least as much as you can without coming off the edge - and it should last very much longer. And if you just have a single stone (as opposed to a combination stone) you can of course turn it over and use the other side before thinking about flattening. I just use an old cotton rag for wiping.
| 16 January 2016 14:58
I have found the Norton stone method dissappointing. If there is anything that will discourage compliance with your marvelous hand-sharpening technique, it is your suggestion to use the Norton stone. Would you consider discussing machine methods of flattening stones? For example: (1) random orbital sander; belt sander; etc.
| 14 January 2016 00:05
Hello Mr. Pye,
Sorry to bother you. I just have two quick questions. I bought the coarse benchstone from Norton a few months back, and I have sharpened six carving tools on it since. But I can already see (or rather feel) a few grooves in the surface. My thinking is that, since my tools are very small, they are causing this to happen. Anyway, I would assume I need to flatten my stone before I use it again? Also, what is the best type of material to wipe or clean the stones after use? Polyester or cotton, for example?
| 13 April 2015 11:06
Peter - You can certainly use water or oil on either. The water, or oil - the liquid part - is all about rinsing the debris out of the pores of the abrasive and keeping the cut fresh. On an oilstone, water will give a 'sharper' cut whereas oil will be smoother - and to my mind more pleasant. I'd use water with the diamond plate and when you have finished flattening, re-prime the Arkansas stone with lots of light oil until it'll take up no more. Also make sure you thoroughly dry the diamond plate.
| 01 April 2015 10:15
Hi Chris, I am new to your workshops and have already learned a lot from watching your sharpening videos. I have a coarse diamond plate that is supposed to be used with water when grinding or flattening. Do you think it would be alright to use water to flatten an Akansas stone? I don't know if you can use oil on the diamond plate or if I should use it dry. Thank you, Pete
| 05 January 2015 15:02
Eric - I guess everything wears out eventually! So the answer must be, yes. But what, ideed, to flatten the flattening stone on? And on what to flatten THAT one when it too wears out?! Before I disappear in a puff of logical regression let me say that the Norton stone seems to be extremely hard. The one I've had for many years now still looks good, so I'm happy to let the problem float 'downstream' to someone else..
| 02 January 2015 19:48
Hello Chris, I have recently registered on the web site and just finished viewing the entire videos on sharpening.
The use of the Norton Flattening Stone begs the question - does the flattening stone eventually need flattening?
| 18 September 2014 18:18
Dermot - There have been many different materials used for stones in the past which is hard to list and, when dirt, hard to recognise. The one thing to identify though is whether the stone is natural, in which case it is very likely to be good for final sharpening, or manufactured, and thus coarser - for rapid metal removal. If it's a natural stone, in good shape and cheap, it's worth a punt. You can always pass it on.
| 16 September 2014 19:58
Great lesson, thanks.
I have come across a few old oil stones in markets etc.
I didn't buy them as I didn't know what Material / Grades they might be.
My thinking being; If I don't know the stone how can I sharpen effectively.
Is there a way to identify stone Material / Grade ?
Any other observations you might share?
| 22 January 2014 09:21
Michael - There are lots of ways of doing this - as I say to Reginald above. Having just one flat stone is about as easyas it gets, but of course is more expensive than glass and sandpaper (and, actually, when I think of it, the glass technique is pretty simple!). What I hope I made clear in the video is that you really shouldn't wait until your stone is badly worn. Oilstones won't wear anything as fast as waterstones so you won't need to flatten as often, juts when you start to notice it. It's a part of general maintenance.
| 22 January 2014 09:15
Reginald - Yes! All you really need is a hard dead flat surface (thick glass, old handsaw blade) and a harder abrasive than the stone (carborundum grit, sandpaper) - see my book, as above. I have found sandpaper to wear very quickly and diamond paste smears rather than cuts, but do experiment and once you've found something simple that works, job done!
| 22 January 2014 08:02
Hello Chris! I took a sharpening class at our local Woodcraft store recently and we learned a similar technique using a granite flat plate and self stick 220 grit sandpaper. The process takes some time, but works well. Thank you for showing us the Norton Flattening Stone, this seems much more efficient a method!
| 21 January 2014 03:50
Chris, if you don't have one of those flattening stones, could you maybe substitute something like sandpaper glued to something flat like plate glass, or MDF ?
| 20 January 2014 17:07
Once again you make it Simple and Magic free, thanks