flattening LN blades

[sean_in_limerick]

Hi All - is it necessary to flatten the backs of new LN planes? The instructions that come with the hand-planes suggest all that is needed is a little honing?

 

[bugbear]

In my experience, the blades are flat. The backs can be further polished (if you like)

The bevels are ground; this may or may not constitute sharp by your own standards.

BugBear

 

[Scott]

I'll second that. My LN blades have all been flat enough not to need to bother about it. Hone the bevel and use DC's "ruler trick" so you only have to polish about a mm of the back

 

[MarcW]

Hi Sean,

I flatten LN blades backs on an 800 grit King Stone. Normally it takes 100 strokes to accomplish the job. Then follows David's ruler trick as Scott already mentioned. It works easily and takes all in all less then 20 minutes sharpening and honing the bevel included.

Flattening is a good thing because you can check if there is any fault in the iron, such as a bump or a bow. A fellow had this with a # 5 1/2 iron, that had both. Now I check every new blade first with a confirmed straightedge before I go to the waterstones. LN replaced the blade immediately for free as they do usually.

Regards, Marc

 

[sean_in_limerick]

the reason i ask this question is that i recently bought a LN 5.5 and took it out of the box, honed the edge and all i could get was dust! My 80-quid stanley cuts better than it at the moment! I'm sure my sharpening technique is sound - i use the DC 'ruler trick' but i was very dissapointed with the quality of the cut. I didn't bother flattening the back - but i will have a look at it tonight for bumps or hollows near the edge. What honing angles do you guys put on your standard bench planes - i go with a 25' bevel, followed by honing at 30' with 800-grit, and finish with a couple more degrees of a microbevel on an 8000-grit- all the time using the ruler-trick - the irons look good and sharp - is there some special technique required for the LN?

 

[Derek Cohen (Perth Oz)]

I have just received the #4 1/2 replacement iron personally from Thomas L-N. It looks just beautiful (quite different from the original, which was 6 years old and still new). I am sure it is representative of the rest of their stock (since I do own a number of their irons). The bevel was nice and clean and straight at looked like a 1200 grit to me. Importantly, the back was flat, even more so in the important area 1" behind the edge. This area looked like it had been smoothed to about a 6000 grit at best as scratches appeared when I ran it over my 8000 waterstone. In other words, regardless of flatness, unless you are using DCs' Ruler Trick, it is important to hone the back up to and including the final polishing grit you will use for your final bevel.

Regards from Perth

Derek

 

[engineer one]

sean, at the risk of teaching you your trade, are you sure that the
blade is projecting enough?????

sometimes i am sure that we all expect too much of LN and try to set
the cut too fine. i know when i first tried mine i was much happier
when i had moved the blade so that it took a bigger cut.

paul :wink:

 

[Anonymous]

Ruler trick is enough on a LN blade. If not, then it is below their usual superb standards and should go back

 

[hockeydad]

use DC's "ruler trick" so you only have to polish about a mm of the back.

What exactly is "the ruler trick"? I assume it is a piece of metal laid underneath the back raising it off the sharpening media to obtain a back bevel but how thick is it? How far back from the bevel edge, etc.. I have been using a piece of cardboard from a pizza box for years, ( I do change pieces frequently) but I'm open to a new technique.

George S

 

[Anonymous]

|George

loads of info on here

in brief, place a 6" metal ruler on one long edge of a waterstone (it will stick in the slurry) and then polish a very fine back bevel on the blade witht he back of the cutting edge on the other side of the stone. Works out at about 1 degree and so no impact on cutting angle, however, it ensures an absolutely perfectly flat mating edge.

David Charlesworth has published loads about it in books and mags

 

[sean_in_limerick]

Hi George - the 'ruler trick' comes from David Charlesworth, and English woodworking guru - when he is sharpening his plane-irons (not chisels), he places a thin 6" ruler at along the 8000-grit sharpening stone in order to obtain a slight back-bevel at the apex of the cutting edge - effectively only requiring the last mm or so of the back of the iron to be polished and saving a lot of work! He repeats this every time he sharpens. Can someone correct this if i didn't get it right!

 

[MarcW]

I flatten every back of a blade despite I use the ruler trick. The edge of the cap iron lies on the back sometimes on the slight microbevel i.e. the thin polished strip, but sometimes for coarse work on the unpolished back. So when the back isn't flat enough because of a minimal bump or hollow, the shavings stick in the gap on this area and make sawdust on the other places that have good fit.

Once one of my LNs made just sawdust. I realized after some time, that I'd planed with the cap iron.

Marc

 

[Alf]

DC does flatten the backs, the ruler being reserved for the polishing step, in case there's any confusion.

Cheers, Alf

Who hates back flattening - no good saying "but you only have to do it once" when you're a tool junkie.

 

[hockeydad]

re "ruler trick".

Thanks for the replies. I arrive at my back bevels with my, "pizza box", trick in a similar way that each of you use the 6" ruler. It was the thing that was at hand many years ago when I wanted something to use that was thin, available and repeatable. I was also in the process of switching from stones to scary sharp. Never thought of my 6" ruler. Think I'll give it a go.

However, I hone across the width of the blade on back bevels. It seems to me that if one strokes the length of the blade the size of the bevel can get quite large (long). If however the strokes are along the width, the bevel can be kept narrow, depending on the distance from the elevating surface and it's height. What am I missing??

By the way, I only back bevel blades that I'm having trouble flattening.

 

[Good Surname or what ?]

I learned how to do this on a training course with DC last year. I believe he would distinguish the "ruler trick" from a "back bevel".

The bevel produced with the "ruler trick" is insignificant and is NOT a substitute for flattening the back of the blade. It merely serves to speedup the process of polishing the back to 8000grit by ensuring you only polish the very smallest area behind the cutting edge. You must have already made the back of the blade substantially flat with 800 and 1200grit.

David - shoot me if I didn't learn that much!

 

[Scott]

The bevel produced with the "ruler trick" is insignificant and is NOT a substitute for flattening the back of the blade.

True but I hate flattening backs too. Every LN blade I've had I've given a quick wipe over a 1000 grit stone to confirm it's as flat as I expected it to be and then just used the ruler. Haven't had one so far that needed flattening as far as my standards go but I concede that DC's standards are very likely far higher than mine. LN blades are "substantially flat" enough for me.

In fairness to DC and his exacting and finely honed processes (which I admire enormously but rarely have the patience to follow to the letter) I really ought to rename it the "SL-lazy-git's-version-of-DC's-ruler-trick".

Sorry David. I know I'm a philistine!

 

[deirdre]

DC does flatten the backs, the ruler being reserved for the polishing step, in case there's any confusion.

Cheers, Alf

Who hates back flattening - no good saying "but you only have to do it once" when you're a tool junkie.

Amen, Alf. Nothing like getting 20-odd planes in 2 months to remind you how much you dislike back flattening, either.

 

[Derek Cohen (Perth Oz)]

The bevel produced with the "ruler trick" is insignificant and is NOT a substitute for flattening the back of the blade.

I think that it is worth repeating that the back of the blade must be flat and the back of the bevel must be flat and as smooth as the bevel. The Ruler trick is not a substitute for the flat but rather contributes to the smooth.

Regards from Perth

Derek

 

[engineer one]

ah but at least you are saved the trouble of flattening
the soles of LN and LV planes :lol: :lol: :lol: :lol:

just sharpened a couple more blades for my wooden planes on the tormek
and thought i'd try an extra bevel, so for the first time ever in living
memory, i used an oil stone, and a cheap guide. now i know why so many people get curved blades, because the blades are almost or slightly wider
than the stone, and the guide runs on a narrow wheel it is almost impossible not to get a slightly curved edge.

now that cuts well after a bundle of time setting the blade up. but how much easier is it with a bailey or LV/LN adjuster????? :?

still not sure how you set one for a really thin shaving when you get the wedge down hard.

paul :wink:

 

[Paul Kierstead]

Once one of my LNs made just sawdust. I realized after some time, that I'd planed with the cap iron.

Heh, just the other day I put the cap iron back on, was *sure* that I did it right and the thing make an racket that sounded a lot like scraping and produced dust, not matter what tweaking of projection I did. Turns out, the cap iron doesn't make a great scraper and an even worse blade....