Unable to sharpen plane iron, sharpening equipment suggestions needed

[William Fretwell]

Yes I'm one of them, bought a 10" slow water cooled wheel thing for Cdn$200. It gives you your whole life back! You can actually get back to wood work. It's very annoying that these crazy thick blades are such a pain to sharpen without such a machine. I'm keeping my bevel up jack just for shooting but I've replaced them all.

[Mike Holbrook]

I hear you William,
I used a Tomek, 10”, slow speed, water wheel for a couple years. I thought I could “grind” with it, and I guess if one is very, very, very......patient. The difference between the Tormek and my current 8” Delta, variable speed grinder with diamond wheels, has allowed me to “get back to wood work”. I am now able to camber and hollow grind the entire edge of a LV BU plane in 30 minuets or less, something I was not able to achieve with: stones, diamond plates or a water wheel ever. I should also add that I typically regrind plane blades at 30 degrees rather than the typical 25. Half of the time it takes me to do such a grind is spent checking progress with a magnifying light vs whatever model I am trying to copy. Eventually the “model” becomes etched in ones brain.

I am still a little paranoid about over heating blades. I do not allow plane blades to get more than warm to the touch during grinding. I suspect that someone less paranoid who regularly quenches their blade in oil or water could do the job faster.

[Patrick Chase]

I am still a little paranoid about over heating blades. I do not allow plane blades to get more than warm to the touch during grinding. I suspect that someone less paranoid who regularly quenches their blade in oil or water could do the job faster.

If you use a grinder then you need to be careful about your steels. A few examples suffice:

O1 is typically used at Rc59 or so, which corresponds to tempering at 500F. If you get a tool that hot on the grinder you will know about it, as that corresponds to a red-brown surface color. If you're grinding on an O1 tool at that hardness, then lack of discoloration means you didn't burn it.

Hock irons are also O1, but at about Rc62, which corresponds to tempering at a bit under 400F. As Ron himself has said in older SMC posts, that correponds to no surface discoloration or maybe a very faint straw color. You could grind one of his tools but notice no discoloration and think that everything was peachy, and yet still have lost a point or two of hardness.

Let's assume that some major maker hypothetically uses something very similar to Carpenter CTS-XHP, and that they hypothetically temper it to Rc62.5. That would again correspond to 400F (or ~250F if they don't refrigerate after hardening, though I hope that's not the case) and a similar caution would apply. On a totally unrelated note, I'm pretty careful about grinding my PM-V11 irons, because I suspect that by the time they discolor noticeably they've already lost a fair bit of hardness.

An extreme example is a Japanese tool with water-hardened HCS tempered to Rc65 or so. Rc65 corresponds to tempering HCS at ~275F, so those tools should probably never see a dry grinder, period. If you have a very light touch you can probably get away with it, but the fundamental problem is that unless you happen to have a Versitron hardness tester laying around you'll never know for sure (and you can't really measure the edge anyway, so you'll never know even then).

As I've said here before, this is one of those situations where there is practical value (in terms of protecting your investment) in knowing what steel you're using and ideally how it was processed, though unfortunately the latter is impractical to determine analytically. Enough value to justify sending out a sample for XRF if you happen to use a whole lot of a particular "mystery steel".

[Brian Holcombe]

CBN wheels really help with that, but still you need to be careful with them as well. With full steel irons (not laminated) I remove the wear with 800 grit, then grind a hollow until the edge is thin then go to 3000 grit. I finish the process by lifting slightly on the finish stone then taking the burr off with a finish stone.

Grinding is a careful process, the best advice I can give is never grind to the edge. If you grind to the edge it will take multiple sharpenings before the blade acts correctly again.

I never work the back with a rough grit stone, it’s usually a good way to ruin the existing flatness .

Check diamond plates and check them every so often, I’ve had a few that were not flat and drove me a bit crazy for a day or two.

[Stewie Simpson]

Brian; I would assume the best advise wouldn't be to hollow grind the primary bevel on your Japanese laminated plane irons and chisels.

Stewie;

[Patrick Chase]

CBN wheels really help with that, but still you need to be careful with them as well.

Yes, CBN wheels reduce heat dissipation into the steel by a significant factor (~4X IIRC in one paper I've read). Ditto for flat diamond lapping discs as George has advocated in the past.

Grinding is a careful process, the best advice I can give is never grind to the edge. If you grind to the edge it will take multiple sharpenings before the blade acts correctly again.

You probably know this, but sometimes you need to grind to the edge, for example to repair chipping, and in that case the key is to present the edge perpendicular to the wheel. In other words grind the edge straight back to wherever it needs to be, and then regrind the bevel separately instead of trying to do both at once. That technique works because it ensures that the edge that will be "kept" after grinding is ground for the bare minimum amount of time possible, and only then as part of a relatively "tall" vertical face such that it's amply supported (preventing fracturing) and has plenty of cross-sectional area to dissipate heat. When I regrind the bevel I then avoid grinding all the way to the edge, i.e. I leave a tiny vertical part at the tip that I only remove by hand, during honing. That adds some time to the process, but it keeps the performance reduction to a bare minimum.

Check diamond plates and check them every so often, I’ve had a few that were not flat and drove me a bit crazy for a day or two.

Every diamond plate I've ever owned that was not an Atoma was out by at least a hair, and even some of the Atomas were a tiny bit out of flat (their spec is +/- 1 mil, and all of them have met that, but most are quite a bit better). The only "diamond plates" I own that are bang on are my cast iron laps, mostly because I periodically lap them using a class-A surface plate (with a sacrificial plastic film to protect the plate, of course).

[Brian Holcombe]

Brian; I would assume the best advise wouldn't be to hollow grind the primary bevel on your Japanese laminated plane irons and chisels.

Stewie;

I don’t, I was very clear about that in the post.

[Brian Holcombe]

I agree, Patrick, there are times when I do it but typically to fix something and at that I may re-hone a few times.

I have one Atoma plate that is now dished and really can’t understand why that happened all
of a sudden but the other two are very good.

[Patrick Chase]

I agree, Patrick, there are times when I do it but typically to fix something and at that I may re-hone a few times.

I have one Atoma plate that is now dished and really can’t understand why that happened all
of a sudden but the other two are very good.

Is it dished in the middle, or closer to 1/4 or 3/4 of its length?

If you look at how Atomas are made, they consist of a relatively thin and flexible steel-backed abrasive sheet laminated to a thicker aluminum blank. The abrasive sheet is attached to the blank using 3 strips of Nitto 5015 double-sided acrylic tape (great stuff, provided you don't care too much about ease of removal) at each end and in the center. If you hone tools on it then the abrasive sheet can "sag" in between the pieces of tape. That's why Stu advises never using the same Atoma plate for both stone-flattening and tool work.

I did have one Atoma go out of flat like that even though I didn't grind tools on it. I suspected at the time that one or more of the pieces of tape had "crept". In that instance I was able to delaminate the abrasive sheet from the underlying blank without bending it (a chore), clean it (even more of a chore), and tape it to a sheet of float glass using Nitto 5015 (I have a couple rolls). I still have that plate in service.

EDIT: The trick to removing Nitto 5015 is to be aware that most acrylic adhesives let go at about 200C, which is too low to do anything to the diamonds or the metallic bonds that retain them (the fact that similarly-bonded CBN grinding wheels work is testament to this).

[Brian Holcombe]

Ah, interesting that could certainly be the case it was the only plate I had used for tools for a time. Thanks for your insights!

[Mike Holbrook]

In regard to grinding hollow edges, I am not sure I understand the logic of grinding the narrow side of the bevel flat/dull and then using stones etc. to work that edge into a sharp surface. I understand the idea that the narrower edge heats up faster. I am all about speed sharpening/grinding so I can get back to woodworking. In my experience, grinding a flat edge and then working it on stones dramatically increases the time it takes to get the job done. Logically it seems one then has to work the back, less acute angle/edge of the hollow to get a sharp edge, assuming we are hollow grinding to create the two edges in the bevel that make finding and holding the bevel angle easier.

I tend to do the opposite, grinding down to the opposite surface all the way across the entire bevel. I find it faster to grind most of the bevel, down close to the other edge, then rest the iron until all the heat is gone. I just work slower and more carefully when I get close to the opposite side. My goal is to maximize the amount of work I do on the diamond wheel and minimize my time using the slower: stone, ceramic, diamond plate....I find it easier to adjust any issues on the thinner edge of the blade, which is easier to abrade away. If I loose a few degrees of hardness at the very edge I suspect it soon wears away with normal use and sharpening. One has to set priorities. I am mentioning this because the OP was asking about making the process easier.

Maybe Brian's rolling at the edge is how he achieves a similar result. Certainly different people learn specific techniques that work better for them and their priorities.

[Robert Engel]

Josh,

I have basically the same sharpening kit with the exception I have the larger Duo Sharp plates. I like the DiaSharp much better. I don't think the mesh plates last as long simply because there is not as much grit on them.

That being said, I have not been satsified with the coarse (black dot) plate. It wore out much faster than expected. The others (600, 800, 1250) seem to do fine. For flattening, I use a 250 grit water stone rather than buy a new coarse diamond plate.

Lubrication is very important with diamond plates, especially the mesh ones. I tend to avoid oil based lubricants. Soapy water, or window cleaner works fine but anything that keeps the slurry in suspension will do.

I also use the 4/8K Norton stones. I keep them flat with a Norton dressing stone (FYI don't trust it - I had to flatten mine before use). You don't need to go beyond coarse to flatten a water stone. I fear you will clog up a 600 grit diamond plate.

On a good quality iron, test the flatness first by marking the back with a sharpie and light passes over a fine stone. That being said, one Veritas iron I purchased took quite a bit of work to flatten, which surprised me.

Bottom line - I think your set up will work. I hollow grind the bevel on all my plane irons and chisels. This makes sharpening a much quicker, easier process, especially if honing freehand. I wouldn't invest hundreds of $'s in a power sharpening system. It is simply not cost effective unless you have a production shop.

[Brian Holcombe]

Mike, you lost me a bit in that description but basically I work away the wear on a rough stone (800 grit in my case) this removes the wear bevel. The hollow is minimized at this point but still typically visible.

Next I regrind the hollow, now I'm down to two thin landing strips. I work these on a 3k stone. Finally I lift the blade on the finish stone for a few strokes and then remove the burr.

This is a departure from most because I'm sure most grind first, then work the bevel. A hollow is, IMO, hardly needed for rough stones like 800 grit, but it is nice to have for finer stones, so I like to have the hollow there for the 3k stone.

Again, this is not for Japanese tools or laminated tools in my shop.

[Pete Taran]

+1 about sharpening using a Tormek.

I haven't found it laborious or time consuming to sharpen a plane iron on a Tormek. A week or so ago I had an new/old smoother iron I needed to regrind and sharpen. I spent a couple of minutes on a high speed wheel getting it square and partially creating the bevel. I left about a 1/16" of thickness at the cutting edge. It's really pretty hard to get a blade so hot that it ruins the temper if you are holding to with your bare hands. Think about it, if you touch a 400 degree oven pan, you get an immediate burn. Your fingertips will tell you long before it ever even gets remotely close to that.

Once complete, just use the standard jig to complete the hollow grind. When you grade the stone with the coarse side of the dressing stone, it cuts very fast. When you draw a wire edge, remove from the jig and flatten the back. You can finish by buffing the back and cutting edge with the leather strop, or put a nice secondary bevel on the blade with your favorite high grit waterstone. The entire process took me about 15 minutes. Once it's sharp, it is super easy to regrind the bevel when it dulls.

The tormek is expensive, but it really is worth it. All that jazz about various stones, flattening techniques, paper types, just forget about it. Sharpening on the Tormek is fun instead of a chore. It's really that good. The best part is the machine comes with a dressing jig to get your stone round again if you dish the center or want to expose a fresh surface after repeated use.

It's awesome.

[Mike Holbrook]

Brian,
I am sort of a mobile unit at the moment. I have a business and home that I need tools at. We bought another home about a year ago. I am working on getting one ready to sell and the other ready to move into. The two homes are about an hours drive appart. I have tools split between locations and a set of mobile tools. Once I get moved into the new place and can get my sharpening station set up...I am sure I will do things more like you mention. We have 8-10 dogs at the moment, some appear, disappear....at the whim of our kids/young adults now. Closing one business, starting a new one and moving all the gear and dogs, turns out to burn a good deal of a 68 yr olds time. I am also trying to harvest wood from the 12 acres to take to the new location. I wish I had more time to do the projects I would like to be doing, maybe soon...

Strictly from a time consideration, with a reduced set of two ceramic Spyderco stones, more polishing stones, which I typically have in my mobile kit. I try to get as much done on the grinder as I can. If I understand the more detailed information Brian provides above I think my routine is not far from his consdering the reduced # of stones I use. Most of my sharpening gear is either packed or not where I am. I need to build a sharpening station at the new place in a specific spot which will take some time.

Pete, I have had less luck with my Tormek. I should probably mention that I was trying to work the bevels on Lee Valley BU, thick plane blades, which totally frustrated me. I might also add that Contrary to what I originally thought I would do, I work a good deal of rough “green” wood. I typically regrind 30 degree, more cambered, hollow ground irons. I also own an old Tormek, that used a different system to lock the bar/rest in place. My bar can deflect quite a good deal, which I discovered relatively recently. I will give mine another shot after I repair the bar mount and get my new sharpening station made.