Bevel Up Plane Sharpening and Back Bevel Wear

[Erwin Graween]

Hi,

I have a question about the way to manage back bevel wear for Bevel Up planes. The question is not about bevel up vs bevel down (I'm not starting this kind of debate ). My question is for bevel up users.

As of today I'm only honing the regular bevel and not using the ruler technique. That takes me time to hone correctly. I'm also only honing straight edges, not using any camber.
In short, I'm using my bevel plane (veritas low angle jack) mostly for shooting and edges.

I now want to start exploring also other uses (jakc, smoothing, ...). For that I'm wondering about the back bevel wear. So my questions are :

1- Are you using the ruler technique to produce a back bevel on your bevel up plane's blades ? Do you find it useful ?

2- When you have an camber, since (i.e: read Derck Cohen's article on his site) you must put more camber, then on bevel down plane. do you apply the ruler tecnique like you would on any plane or is there a particulare technique ? I'm thinking about the fact that the greater curve might introduce the need for a wide back bevel then on bevel down blades.

Thank you for your inputs.

Regards,
Erwin.

[Robert Engel]

I think a back bevel would only work on a standard bevel down plane, right? You're not changing the cutting geometry in a BU doing anything to the back.

Like you, I mainly use mine for endgrain and shooting, so I've never thought about cambering or easing the edges.

[ian maybury]

Hi Erwin. THis is just one not terribly expert view. I have several BU Lee Valley planes, but not what could be called long term experience with them. Most of what I do is filtered from what others have reported, and so far it seems to work just fine. I have a block set up with a little camber as a small smoother, the big/wide smoother also with a little camber, a jack which is sharpened straight for shooting board use, and a jointer with light camber with an eye to use on setting up edge joints. (not tested on that application yet)

I have Shapton waterstones down to 12,000, and after years of more informal hand sharpening on old planes used for carpentry now use a tweaked Veritas Mk 2 honing guide. I've been using a WorkSharp with the wide blade platform and the honing guide for light grinding.

Derek Cohen's site is the biggest and best single resource i've seen for BU reviews and for reliable sharpening techniques. David Charlesworth's books for the fundamentals of waterstone sharpening in general. What i'm doing is close but doesn't necessarily replicate precisely what the guys do, but the key princples seem to click. (David would probably beg to differ on use of the ruler vs what i say below for example)

Be that as it may:

(1) The ruler technique may not be such a great idea (but it's definitely do-able) on a low angle BU because it reduces the just adequate clearance angle over the work surface and could (?) influence the feel of the tool and the rate of wear of the edge if reduced further. (it's not directly relevant, but metal cutting experience suggests that adequate clearance is important) My experience has been that the backs of the several (5 so far) LV irons are so accurately flat that they reliably clean up all over on a 1,000 grit waterstone in a few minutes - so to my mind there's not so much incentive to try it.

(2) Derek's suggestion to always use 25 deg irons and to then adjust the cutting angle using a microbevel seems to work well. It avoids the issue of needing to hone away large volumes of metal when adding a microbevel or camber on a thick iron - the low angle needs more than a more steeply bedded iron too.

(3) I'm not running heavy camber on anything ( i have a scrub, but use machines for most of the stock preparation i've done - so there's not so far been a big need to shift huge amounts of material), but it's easy to add camber as required with extra strokes on the 1,000 grit on the main bevel only to each side - say 10 extra to the corners, 5 at 1/4 and 3/4 or multiples of. (the technique David Charlesworth published)

First time through was harder work since I had bought some irons with steeper bevels than 25 deg and ended up grinding them back to 25 deg by various means (needs a lot of care to avoid heat damage), and there was some dialling in of the honing guide and figuring out of the details of technique. That said it's proven no problem to deliver and maintain edges which for me were a revelation - the smoothers went under 0.001in shavings on straight grained wood instantly, feel great and deliver a beautiful finish. (and believe me i'm picky)

I'll get in trouble in some quarters for saying this (and for sure the ruler has it uses in certain circumstances), but i'd so far prefer to do a little extra work on the bevel side to ensure that the wear bevels are fully cut away than get into using rulers and the like to create a back bevel. The topic was the subject of very heavy discussion recently, and there is probably some theoretical labour and metal saving (and this isn't to say it can't be done or that it might not be a good move in the case of a less flat back) - but as you point up i too would need to figure out how to handle it in a situation where there was significant camber….

[Jim Koepke]

Howdy Erwin,

My blades usually only get their back to the stones to remove a burr made when honing the bevel.

As with so many things, people have their own ways of accomplishing the same end.

Here is something of mine from a few years ago about blade cambering:

http://www.sawmillcreek.org/showthre...t-Finally-Came

The same technique works for bevel up or down.

One thing to consider with any kind of back bevel is there will be a lot of metal to remove if it turns out not to work as well as was wanted.

jtk

[lowell holmes]

I'm not one to analyze and theorize even a bit about such things, but I can tell you I use the ruler trick on all of my planes, both bu and bevel down planes.

I started using the trick at Robin Lee's suggestion when I commented my LV apron plane wouldn't perform like his. He posted that If I used the ruler trick it would help and it did.

Cambering the bu irons is another issue. I follow someone's suggestion and that is to slightly radius the corners of the iron. I never had much cambering a bevel up iron, but here are members of this group that do.

[Pat Barry]

My take is, yes, give it the ruler trick. This helps assure a sharp cutting edge with less bevel grinding / honing. Don't overdo i though - its just a tweak

[Reinis Kanders]

Ruler trick makes it harder to chase the burr though, so I only use it if blade is messed up by pitting or what not.

[lowell holmes]

Thirty strokes on a strop will eliminate the burr. I use green compound on a slab of mdf. I follow Paul Sellers method of thirty fast strokes and it leaves a very sharp edge.

[Derek Cohen]

Wear on a plane blade occurs on both sides. However, the act of rubbing a plane blade along a wooden surface does cause the steel to wear more in that area. In a BD plane, the act of honing the bevel removes this extra wear. In a BU blade, the wear is on the reverse side of the bevel, and is referred to as a "wear bevel".

Both BD and BU planes require attention to both sides of the bevel - one without the other simply leaves a serrated edge on the remaining side. Honing or grinding the bevel does it simply with the BD blade. There are essentially two methods of dealing with the wear bevel on a BU plane.

1. The first is to hone or strop the back of the blade frequently. How frequently depends on the type of steel (how abrasion-resistant it is) and the abrasiveness of the wood. Softer woods such as Pine are going to be very different compared to harder, silica-containing woods such a Jarrah. A2 is going to outlast O1, and in turn be outlasted by PM-V11.

2. When honing, do the "Ruler Trick". This places a micro secondary bevel (of about 2/3 degree) at the very spot where a wear bevel would encroach. This amount is not going to reduce the clearance angle (the bed is 12 degrees and anything past 7 degrees is pretty safe).

The downside of the Ruler Trick is that it is harder to maintain an edge by stropping. You certainly can just pull the blade along a leather strop in the usual way, and the "give" in the leather will likely be enough to hone the micro secondary already there. What I would rather do, to be sure that this area is being honed, is to "strop" on a fine stone repeating the Ruler Trick. It takes the same time as stropping but is precise.

What I have found over the years is that refreshing the (flat) back of the blade is usually enough to keep a plane going longer. This is the case for both BU and BD planes. It is just a lot easier to do this on BD plane blades since the BU blades typically have a high micro secondary bevel on a low primary bevel if cambered. Keeping this angle fairly accurate is more important on a BU plane than on a BD plane.

Regards from Perth

Derek

[Mark Almeidus]

I am not an expert into this to much, but recently i was watching rob cosmans sharpening technique.
https://www.youtube.com/watch?v=ZbInhTxtRcw
He is doing 3 microbevels on the bevel side and one microbevel on the back. I find it overkill with 3 microbevels and can be complicated, but i tried one microbevel on the front at about 4 or 5 degrees, and one on the back with a ruler just to remove the bur completely. I never achieved that sharp blades before. I am using sandpapers, (highest been 1200 girt). I dont see reason why not this work for a bevel down planes. Or you can try just with a microbevel on the bevel side handheld, about 10 15 strokes will be enough with light presure.

[Jim Matthews]

Fine Woodworking published an article addressing this method.

http://www.finewoodworking.com/tool-...do-it-all.aspx

[ian maybury]

Guess that's Erwin well and truly confused! It seems clearly as Jim that there's different ways to accomplish the required end.

To Derek.. I've been operating on the basis that while yes, there is a wear bevel on both sides on a BU (on a BD too) that (admittedly a little extra) honing on the bevel side to cut back through them eliminates both. What may not have been clear from the post is that while i haven't so far discovered any need to use a back bevel/ruler, i have as you say been 'refreshing' the back on the flat as well every time. i.e. on the basis that it's necessary to work both sides to create a clean/sharp edge.

Time will tell on this - it's clear for example that if even the slightest dubbing of the flat back caused either by a slightly out of flat stone, rippling in the sharpening film or touching the iron down edge first occurs that it may be time to head for the ruler - or get into a major re-flattening exercise since the resulting dub/accidental back bevel may extend some distance back up the iron. It's hard to over emphasise just how critical stone and hence back flatness are in this situation.

I'm not for one moment arguing the ruler doesn't work, just that my personal instinct has been to if possible avoid the added complexity. Less the first time through, more after repeated re-sharpenings. Especially when using cambers - a straight edge with relieved corners would simplify the deal. I guess what threw me a bit was the discovery of how few strokes it takes on a waterstone to create a micro bevel, and as a result how easy it is to overdo any back bevel….

[Robert Engel]

Ian I'm with you on the back bevel thing.
I still can't get my mind around why you would even do it on a BU - increase blade life? How can it affect the performance?
Bottom line I've tried it don't see an advantage for me.
I've always thought its for that little "extra" for sharpening I don't see how 1 or 2 degrees is going to provide any kind of "relief angle" effect.
If we're doing it to get around flattening the back, then I think its a mistake in the long run.
But it sure is popular so I must be missing something.

[Brian Holcombe]

Ruler trick makes it harder to chase the burr though, so I only use it if blade is messed up by pitting or what not.

Here is my recent experience and a disclaimer;

I generally avoid the ruler trick, I'd rather have a flat back on the blade.

My jointer has such a wide blade that it is a bit aggravating to work the back of the blade, so in using the ruler trick I'm bringing that huge area down to just the point that matters. I keep the same ruler handy and use it when tuning that blade. It turns a marathon into a dash.

Between full resharpenings I'll go back to the natural finish stone and strop a few times and once the edge really needs a makeover I go back to 1000 grit.

It does effect how I strop the back of the blade, as I have to raise the back of the blade ever so slightly to catch the wire edge and remove it.

[ian maybury]

As i see it the primary usefulness of the ruler trick (as Brian and others above) is when it's difficult to precisely flatten the back/'flat' side of either a BU or BD iron. (e.g. a slightly roughly ground iron can require an enormous amount of work to sort it out - the very precise flatness of the LV items seems to result from their being factory lapped)

The difficulty that arises in that case is that it becomes impossible (without this large amount of flattening work) to finish the 'flat' side right up to the cutting edge - because the full length of the area behind the cutting edge is not fully in contact with the stone.

I think it is easily possible (using a slightly steeper micro-bevel) to cut back the primary bevel enough so that as in the post above the wear bevels are eliminated from both sides, but if it's not cut back enough then some wear bevel may be left behind on the flat side that will cause an improperly formed edge (our two precisely formed facets meeting at an angle), and a problem similar to above. The difficulty though is that even if it is cut back enough to obliterate the wear bevels on both sides the less than perfect contact of a less than precisely flat 'flat' side with the stone will make it difficult to completely remove the wire edge by working the back flat on the stone.

Linking the usefulness of the ruler ttrick to less than microscopiscally flat backed irons may be controversial - it's got to be hard for a proponent of the ruler trick that represents an iron maker to be direct on it. Its got to be very useful in the case of both BD or BU irons though - it as others permits the finishing of a narrow strip of the flat behind/right up to the cutting edge without the need to very precisely polish the entire back flat. The tiny angle of the back bevel it puts on is not regarded as being enough to influence the performance of either type of plane plane.

The other scenario where it should prove very useful is when we don't manage for whatever reason to maintain a precisely flat back on our irons - and this seems likely to be the norm for a lot of us. As above even one episode of polishing the back of an iron while forgetting to flatten the stone in time (or an instance of even a small problem in our back flattening - maybe only due to something like wear in a plate) may dub the back of the iron enough to make the ruler trick a very useful alternative to a major flattening exercise. It's very easy to get caught this way - one of the classic 'i've honed it but it's still not cutting right' scenarios.

This could be one of the key benefits of stropping too - as a method it's not flatness sensitive.

My insinct is to shoot for flatness and precision, as my training is to feel that there has to be a catch (especially in terms of cumulative effects over time) to quicker methods. The day may well come when i'll be happy to use them though..

Pardon the length, but this isn't the same scenario as putting a significant micro bevel/back bevel on the flat/forward side of a trad BD plane iron to alter the cutting angle to deliver definite and very useful effects, or putting a steeper micro bevel on the bevel side of a BU plane for the same or similar reason. In both of these cases the cutting angle is significantly altered - which can be very useful to e.g. help reduce tear out. The matter of cap iron position kicks in in the case of a BD plane too - separating the effect of this and the cutting angle isn't easy/leads to lots of debate and is the subject of ongoing work by some here and elsewhere...