Grinding and shaping bevels

[Derek Cohen]

I like the idea of a very small micro bevel made via spyderco or arkansas stone too. I'm not sure the small micro bevel will suffice to camber and change a 25 degree BU plane blade to 40-50 degrees though? When we start talking cambers it seems to me we have to define how much camber too. Some apparently just lean on either side of their plane blade for the last few finishing strokes and call that camber, which is not at all like making a significant change in the radius of the edge.

Hi Mike

It does not matter whether you grind the primary bevel with a flat grind or a hollow grind - just make this 25 degrees.

Now use a honing guide set for (say) 50 degrees to hone the secondary micro bevel, and while you are doing this, add a camber by leaning hard on the corners. Done.

Wasn't that too simple for words?

Regards from Perth

Derek

[Mike Holbrook]

Apparently the Robo Rest comes in a version that works on a Oneway jig that is very popular with turners. I am trying to figure that option out too. Like Derek I am confused about a Tormek jig that might not work on the Tormek base.

[Steve Friedman]

Derek,

I agree with you, but sent an e-mail to Tormek (in Sweden) specifically asking about using three jigs with the Grinder attachment: the SVS-32 (Short Tool Jig), SVA-170 (Axe Jig), and the SE 76 (Square Edge Jig). Here's the response I got from them:

"The only reason we do not recommend using the other jigs is because of the grinding angles that are used. The risk of the tools catching the stone is imminent and can cause severe damage to the grinder and yourself. That is why we do not recommend it."

I don't really get it because the dog leg gouges actually have a lower angle than the regular bent gouges. I have never used a Tormek, but don't understand why the jigs wouldn't work.

Thanks.

Steve

[David Weaver]

Most of us would be better off doing grind work on gouges with a carborundum stone. It's something that should only ever happen one time per gouge, anyway, unless you drop a gouge.

[Steve Friedman]

My main purpose here is to define the technique and equipment necessary to make significant cambers precisely in BU plane blades and long curved green wood hand tools. The precision of the grind I see on my Hans Karrlson scorp would seem to suggest that the original work was done with some sort of rest to maintain the hollow in precisely the same place on a 8"+ blade curved to several different radiuses along it's length.

I don't have the scorp, but do have a couple of Hans' adzes and have always sharpened them by hand or with my 1 x 42 belt sander without problem. I have to look, but don't think they're hollow ground. You should ask him about the scorp, but I'm guessing he uses the Tormek turning tool jig because it lets you sharpen an edge that is not a perfect arc. The geometry of the scorp sounds similar to the dog leg gouges, where the blade flattens out in the center.

Based on Derek's comments, I'm starting to lean toward the Tormek platform just because of all the bent tools I use.

Steve

[Steve Friedman]

Most of us would be better off doing grind work on gouges with a carborundum stone. It's something that should only ever happen one time per gouge, anyway, unless you drop a gouge.

David, you're right in theory. But don't forget that some of use weren't blessed with the free handing gene. And some of us do drop gouges onto the concrete floors on occasion.

In all seriousness, most of the normal carving gouges I have seen have a flat grind and I find the 1 x 42 belt sander/grinder works great for them, The Hans Karlssen gouges all come with a hollow grind, slightly modified to flatten out the bevel. It's a very unusual geometry that's very difficult to replicate without using a grinding wheel to re-establish the hollow.

Steve

[Mike Holbrook]

My Hans scorp was purchased from Country Workshops. Drew Langsner actually calls it an inshave on his site. I use it on Windsor seats for a large amount of the stock removal. Mine definitely has a hollow ground bevel, much like his gouges. The "inshave" I have may be a unique design Hans does for Drew. Drew's info. at Country Workshops now states that Drew makes the handles for this tool here in the US. I know the Adze I have is a Drew design made by Hans. The inshave has a very gradual radius for most of its blade length, but at each end the blade has a much steeper radius. The one tool can shape the steep back area in chair seats and the less dramatic depressions in other parts because of the two different curves in the one blade.

Yes, Derek I understand that it would be easy to leave the flat bevel on a 25 degree BU plane blade and simply add a small micro bevel and small amount of relief at the corners. But what if I want a more dramatic curve to one of my Jack plane or fore plane blades? I believe the BU smooth plane comes with a 38 degree BU blade, maybe it can be ordered with a 25 but I did not know to do that. I think I know David's answer. I think David likes the old Stanley plane blades and chip breaker system precisely because the thin blades are much easier to grind a bevel on. So the suggestion then is not to use the high angle BU blades, but simply modify bevels on 25 degree blades? I believe I have two 38 degree BU blades, which I fully understand can be very hard to regrind. I am just wondering if it might make sense to hollow grind these higher plane blades if one has a CBN wheel? Want all the advantages apply to a hollow ground high angle plane blade once we get the hollow in it?

[David Weaver]

That's just one of the many things I like about the old stanleys. I could go on a long riff talking about all of the things I like, but they include:
* the iron loves a one stone system, and a one stone system loves the irons
* they are fast to grind and hone
* the cap iron setup is just a genius setup if the cap iron can be anywhere in the neighborhood of the edge
* the ergonomics and weight of the planes are ideal
* the fact that the planes are not perfectly flat means less friction in use (i never noticed this until relatively recently, though for really heavy work I'm starting to favor wooden planes - especially tight freshly made planes)

I don't mind a thicker iron on a jack plane, though, especially if it's laminated. I've always sharpened them by freehanding a hollow grind into them (something done easily if you let go of the idea of perfection and just go for geometry and grind it with knowledge that you can correct the grind later if you don't like it), and then sharpening them almost like the outside of a gouge on an oilstone.

I don't mind BU planes, but I don't like them if there is any significant level of camber.

I don't measure camber, nor heavy camber on roughing planes. I grind the corners of the iron off and fair a curve on them and use the plane and make adjustments from there. I think it just makes sense to do that.

What the premium planes have over the stanley planes is the irons hold the 1 thou shaving edge for a longer period of time, no doubt about it. And all of their parts lock down tight and the planes are just about silent in use and solid as a rock. Stuff on stanley planes clatters, especially adjuster levers and maybe the yoke? But none of the stuff that clatters matters if it clatters. It makes it feel as if something is not solid when that's not really the case most of the time.

The cap iron deal has pretty much eliminated my chasing the iron that holds a 1 thousandth shaving the longest. I just use an iron until the clearance goes away and resharpen, it's never a detriment causing tearout now and to the extent that the iron wears evenly, not to surface quality, either.

[Mike Holbrook]

I understand now that I was making my life very hard by trying to regrind bevels on thick Veritas BU plane blades. Certainly it took me too long to figure out that most of my fellow Creekers have better sense. Grind hollow grinds in Stanley plane blades and western chisels GOOD, grind hollow bevels in thick wood or BU plane blades and some Japanese(certainly HSS) chisels BAD! At least in the sense that GOOD equals quick & easy & Bad equals a PITA. I suspect another issue with hollow grinds on BU plane blades is guessing what blade angle you will end up with depending on the amount of hollow grind.

I suspect that faster cooler grinding CBN wheels will not challenge this logic for most woodworkers. Maybe I am still pressing the limits?

[Derek Cohen]

So the suggestion then is not to use the high angle BU blades, but simply modify bevels on 25 degree blades? I believe I have two 38 degree BU blades, which I fully understand can be very hard to regrind. I am just wondering if it might make sense to hollow grind these higher plane blades if one has a CBN wheel? Want all the advantages apply to a hollow ground high angle plane blade once we get the hollow in it?

Mike, since realizing that cambers on the thick BU blades would be difficult on all but a 25 degree primary bevel, my recommendation has been only get blades with a 25 degree bevel. You can nominate this when purchasing a new plane from LV. However, if you have blades that came with higher primary bevels, the choice is whether to grind them or not. I ground mine to 25 degrees.

Grinding a 38/50 degree primary to a 25 degree primary is easier than the other way around since the grind will take place at the rear of the primary, away from the thin steel at the sharp end. Yes, it will take some time, especially as you want to keep the steel cool, but it is not a big deal.

Regards from Perth

Derek

[ian maybury]

Guess I can confirm Mike from doing several in the last couple of months that honing a micro bevel at the required angle and camber with waterstones on a bevel up blade ground straight as Derek suggests on his sharpening pages at 25 deg is very straightforward - for moderate amounts of camber anyway. I used the method David Charlesworth has made popular - of using pressure to the corners and extra strokes on the waterstone to form the curve. It seems fine for a jack unless you run large amounts of camber (more than say 5 - 10 thou) - albeit that the micro bevel is signficantly wider out towards the corners. Derek also outlines a method for grinding a curved/cambered primary bevel on a scrub plane on a sanding belt which could be adapted to CBN wheels which is probably the next step if more camber is needed than can conveniently be achieved just by honing.

I used a Veritas Mk 2 honing guide fitted with the cambered roller so that tilting the blade is possible when forming the micro bevel and camber. The guide needed a little tuning to adjust the plane of the clamp so that it was exactly parallel with the axis of the roller - there was a small degree of casting error. I also as posted before upgraded the jaws to improve the grip on chisels - the stock powder coating is pretty slippery. (problematical I found with tapered Japanese chisels, but prob OK with plane blades) The camber roller is strictly speaking not cambered - it's actually a central cylindrical section with tapering ends - so it's necessary to be reasonably positive in controlling which part of the edge is contacting the waterstone as it will tend towards sitting on the centre section of the roller. No prob to produce perfectly formed cambered micro bevels though - with very tight control of the amount of camber.

Much like yourself I bought a bunch of odd/too steep bevel angle Veritas BU plane irons, and have had to reduce them to 25 deg. My bevels are flat. I didn't find it as easy as Derek as unlike him I didn't have a good grinding solution, and was very slow using a sanding disc. (because of the need to grind for only very short bursts and cool to avoid overheating) It entails removing a lot of metal per the 'heating' thread which is really about the search for a bevel grinding solution capable of removing metal fast enough to handle a job like this without burning, and at the same time be controllable, low heat and accurate enough to do small tools like narrow chisels. It seems very much like CBN wheels are the answer to this particular maiden's prayer - rapid metal removal, and minimal heating. (see the thread)

I reported a trial last night with CBN wheels on a low speed 8in grinder kindly made a available by a very experienced woodturning contact who has been using them for years in the 'heating' thread. I was more focused on the bench grinder, but he had a Tormek set up with a CBN wheel (not sure what grit or make of wheel) and demonstrated re-cutting the bevel on a 1/2in chisel. This it did in short order - I can't say how fast, but it seemed significantly faster than the stock Tormek wheel. (i have a Tormek) There is at least one CBN wheel out there for Tormek: http://www.cwsonline.com.au/shop/ite...-x-40mm-x-180g

I expressed some surprise, his comment was that he finds that the relative advantage of CBN is actually greater at low speeds...

[Mike Holbrook]

Thanks for all the great suggestions guys. So it sounds like I may actually have a use for my Veritas Honing Guide which I was about to decide would not get used because it was so slow. Micro bevels on BU plane blades with the Honing Guide and either water stones or my Spydercos makes much more sense. I have one A2 and one PM-V11 38 degree BU blades that will be a good test of the CBN wheel, if I take them back down to 25.

Great to know that the CBN wheels work well on the slow Tormek grinder. I imagine a 80 grit on a Tormek would be a good way to do the heavy lifting without any worries about temper or need to slow down. Not need to dunk or rest may actually make the Tormek relatively fast with a 80 grit wheel.

I have been studying the various tool rests: Robbo Hippy's, Oneways and the Veritas. I think the Veritas will handle everything I need to do for now, all I have to do is figure out how best to incresae the grinder space from 1- 1 1/2+".

[lowell holmes]

Me too!

I use the upside belt sander and a LV honing guide.

I use water on diamond hones.

[ian maybury]

Just to complete the picture - bearing in mind that this describes a slightly more complicated process used to grind flat bevels, and to hone chisels single bevel when required. Control of the angle of the primary bevel is less critical if you hollow grind, and then hone on a slightly steeper micro bevel as most do.

I used the LV Mk2 honing guide to grind the primary bevels as well as to hone - moving from disc sander (grinding the primary bevel on 80grit AlOx), to a quick but strictly speaking unnecessary rub on the top of WorkSharp disc (to improve the finish with 120 grit AlOx). Then on to the waterstones to polish the bevels on the Japanese chisels. All three steps without removing the chisel from the honing guide** (= preserving the originally set angle) - with the cylindrical/parallel roller set in the guide to ensure that the bevel is accurately aligned side to side. (it takes only a tiny amount of misplaced pressure to one side to cut a misaligned primary bevel and possibly overheat a corner given the speed 80 grit cuts at if the cambered roller is used), The roller runs/rests on the relevant work surface beside the disc. (see below)

This demands that the blade clamping surface on the guide is very accurately aligned with/in the same plane as the axis of the roller, and required some careful filing the mounting surface for the roller assembly (as previously described) to get it ready for use.

In the case of the BU plane blades I switched to the cambered roller and a slightly steeper angle setting to hone the microbevel and camber/the final cutting edge.

Done this way honing the single bevel on the japanese chisels becomes a very simple task provided the angle and flatness of the primary bevel is well controlled during grinding. i.e. if the bevel isn't ground flat or correctly angled, then it can take a lot of work on the waterstones to clean it up over its entire area.

As above the heavy grinding was done on a sanding disc with 80 grit self adhesive AlOx. (which works, but which puts quite a lot of heat into the work, so care is needed - flat grinding off the sides of some CBN wheels will probably replace this) The sander is set up with a DIY work table levelled carefully flush with the plane of the sanding disc to enable use of the honing guide, and with some feet so that it can be flipped on end so that the plane of the disc is horizontal.

This is the same principle as is used on the WorkSharp when working with the honing guide off the accessory top surface. It's important to ensure in both scenarios/on both pieces of equipment (WorkSharp and disc sander) that the work surface is accurately flush with/in the same plane as the disc so that the honing guide delivers the same angle in each case.

** the one exception to this arose if the original bevel on a blade was shallower than that being ground on to replace it. (the angles on some of the chisels were pretty haphazard) The resulting grinding away of some of the cutting edge on the disc sander actually very slightly shortens the blade. Moving it forward to touch the stop on the LV mk 2 honing guide returned the angle to that originally set...

[Mike Holbrook]

So I guess I need to get out the instructions and fiddle with my MK II, figure out how that puppy works and make sure everything is registering correctly. I believe I have a cambered roller too which may, if I understand Ian correctly, require a little more head scratching.

As I understand the Tormek BGM-100 Bench Grinder Mounting Set, one could be mounted in front of each wheel. The problem, however. seems to be that the two bars end up interfering with each other. The best option for someone wanting the same rest at both wheels is to mount a base at each wheel and share one bar.

I have a Veritas rest on order. I am thinking about buying a BGM-100 kit to place at the second wheel. I think the two rests could coexist at the same grinder with less strife. I am also thinking I will order the new SE-76 Square Edge Jig. I have the old jig but I have had trouble with it not wanting to keep tools square. I am wondering about two other jigs. The SVD-185 Gouge Jig appears to be popular as a turners tool, still I think it might be helpful for working my gouges. I am also curious if The Turning Tool Setter TTS-100 might be useful for setting up tools other than turners tools, relative to the wheel?