Ruler trick - any reason not to use it?

[Greg Jones]

So in response to the original question-“Besides chisels are there any instances where the ruler trick should not be used.”, the answer appears to be no. At least that’s my summary of what I hear hear and what I apply in my personal practice. I’m a proponent of the ruler trick and I believe the 5 seconds it adds to the sharpening process is worth the effort.

[adamcherubini]

So in response to the original question-“Besides chisels are there any instances where the ruler trick should not be used.”, the answer appears to be no. At least that’s my summary of what I hear hear and what I apply in my personal practice. I’m a proponent of the ruler trick and I believe the 5 seconds it adds to the sharpening process is worth the effort.

Negative. I think it only works for irons with straight edges. For me that’s only fitting planes by definition. All of my surfacing planes/bench planes have curved irons which really can only be honed by hand.

I don’t know for sure and would like DCs response. He probably does something to eliminate plane tracks. But he’s also not nuts like me and probably prepares stock with machines and only finishes by hand. So the degree of curvature can be much reduced.

I’m not against using the technique. I’ve long stated flat backs are not a real woodworking requirement. Not even chisels need flat backs to pare.

[Greg Jones]

Negative. I think it only works for irons with straight edges. For me that’s only fitting planes by definition. All of my surfacing planes/bench planes have curved irons which really can only be honed by hand.

I don’t know for sure and would like DCs response…

David Charlesworth cambers all his bench plane irons, leaving the straight edges to shoulder plane blades, etc. Now granted, he’s not putting a scrub plane sized radius on them, but if one is using a scrub plane radius on a bench plane blade, I doubt they much care what the back of the blade looks like. Even at that, I would not be surprised if the ruler trick would still touch all the back edge of the blade that would ever be projected with a heavily cambered iron.

Now it is possible that DC’s ruler trick method of moving the back in and out may put on a slightly more aggressive micro-bevel that what one gets with the Cosman variation of moving the blade from side-to-side. I know Cosman does not camber his blades-just lightly eases the corners. Something to consider for anyone using a cambered blade.

[adamcherubini]

No, those of us who use cambered irons aren’t hacks scraping wood with dull tools.
. (I know you didn’t mean that).

I may have measured the curvature of my planes but I don’t remember those numbers so this could be wrong: I think my jack plane may have 1/8” of camber. That thing is as sharp as a scalpel. It doesn’t look good, but it’s really a superior plane.

For the ruler trick to work, I think I’d need a back bevel around 1/8” long. That’s not the tiny feature DC honed in the video. To be fair, the ruler trick is just a bit more aggressive than a strop. I think David said the stone he used was finer than the chromium oxide paste I use on my strop.

Not against the ruler trick. And for the record, I think the back bevel is so small, it would probably work fine on chisels. Think stropping does something very similar though.

[CStan]

The two faces that comprise a cutting edge are meeting when a burr can be flipped back and forth between the two. That's all that's really required for a perfectly serviceable edge. Additional polish of the faces is up to the user. The law of diminishing returns applies. If one is able to flip the burr without the ruler trick, i.e. the tool's back is flat enough vis-a-vis the honing media being employed, then there is virtually no reason to use the ruler trick or any other supposed 'short cut.' You're already there. There's nothing to 'fix.' There is no problem that needs to be solved. Move on to something else.

Most rank beginners are perfectly capable of producing serviceable edges with very little instruction. But they just can't resist the urge to futz, and to rub, and to basically keep picking at the metaphorical scab that will never heal. Hence "tricks," and jigs, and stones galore. Get off the merry-go-round.

If the thought of woodworking with an edge that's not in the 99th percentile of sharp sets you on edge (pun intended), then trust me there is more frustration than you can imagine awaiting you. Find a new hobby before it's too late.

[Handplanesandmore]

Looking back, I think Norm Abram has done the woodworking a great service not by insisting on wearing safety glass by not covering sharpening in his NYW. Paul Sellers has also done good public service by promoting his simpler diamond stones/strop method -- though I never tried it. Some woodworkers have made the topic of sharpening so complicated and complex that they're like telling an undergraduate that in order to do a thesis successfully at the Bachelor's level, he or she must first complete a PhD.

 
Simon

[AHill]

David Charlesworth cambers all his bench plane irons, leaving the straight edges to shoulder plane blades, etc. Now granted, he’s not putting a scrub plane sized radius on them, but if one is using a scrub plane radius on a bench plane blade, I doubt they much care what the back of the blade looks like. Even at that, I would not be surprised if the ruler trick would still touch all the back edge of the blade that would ever be projected with a heavily cambered iron.

Now it is possible that DC’s ruler trick method of moving the back in and out may put on a slightly more aggressive micro-bevel that what one gets with the Cosman variation of moving the blade from side-to-side. I know Cosman does not camber his blades-just lightly eases the corners. Something to consider for anyone using a cambered blade.

The very, very slight camber Charlesworth puts on his plane blades has a purpose.  It allows him to shift the plane from side to side to remove more or less material when jointing.  It takes some practice and a good eye to take advantage of that camber when jointing.  And, as mentioned, it eliminates the tracks you might get from a straight, uncambered edge when finish planing a surface.

[CStan]

The very, very slight camber Charlesworth puts on his plane blades has a purpose.  It allows him to shift the plane from side to side to remove more or less material when jointing.  It takes some practice and a good eye to take advantage of that camber when jointing.  And, as mentioned, it eliminates the tracks you might get from a straight, uncambered edge when finish planing a surface.

Alan, that advice is in at least ten British woodworking manuals dating back to the late 1800s/early 1900s.  It's not new, and it's not exclusive to David Charlesworth.  Nor is an *optional* slight lift when backing off a plane iron-- essentially the ruler trick without the ruler.

This all is starting to have the air of the close-set cap iron which had been in plain view in Planecraft since its first edition in 1934, amongst other sources.

[AHill]

Alan, that advice is in at least ten British woodworking manuals dating back to the late 1800s/early 1900s.  It's not new, and it's not exclusive to David Charlesworth.  Nor is an *optional* slight lift when backing off a plane iron-- essentially the ruler trick without the ruler.

This all is starting to have the air of the close-set cap iron which had been in plain view in Planecraft since its first edition in 1934, amongst other sources.

To be fair, I did not claim Charlesworth invented the cambered blade for jointing.  I just mentioned that it had a purpose and how he used it.

[bandit571]

Ruler trick, any reason not to use it........more likely, any reason TO even use it.     haven't seen any
...YMMV