Plane blades that get no secondary bevel?

[Andy Kev.]

As a rule I wouldn't think of putting a secondary bevel on blades for the following planes: Plough, Router and Skewed Rebate.

My reasoning is that they don't get hammered like bench planes and so stay sharper much longer and their smaller size (the skewed rebate is the biggest) means that it doesn't take more than a few seconds to sharpen the complete bevel.

What is the general view on this? Is there a quality advantage in terms of making the cut with these planes when they have a secondary bevel? I suspect not but then I don't have special technical/theoretical knowledge about blade angles. Hence the question, just in case I'm missing something.

 

[Mike G]

The only plane irons which get a secondary bevel in my workshop are woodies, and that's because of the thickness of the steel. My reasoning is that I am happy to spend a few extra seconds honing and thereby obviate the necessity to ever re-grind a primary bevel. Further, the actual honing (and stropping) of the bevel is only a small part of the process of sharpening a plane, with the majority being in the dis-assembly, cleaning up the back, re-assembly, and particularly, the re-setting............so a few extra seconds doing the entire bevel at once is neither here nor there. And yes, because of this, I use a honing guide.

My way is the very best way in the whole wide world....

....for me alone in my workshop at this particular time . Ask me again in 5 years time and you might get an entirely different answer. Chisels, due to their thickness, are an entirely different kettle of fish, and they get a secondary bevel, freehand.

 

[Raymedullary]

Sheer bravery.....
As far as I am concerned, the ONLY reasoning for a secondary bevel is that it means you are rubbing away less steel so it might be easier. Its the same in every other respect, its only the honing angle that can have any effect. I tend to do a secondary on everything just cos. I have never used (or even tried) using a honing guide.
Obviously a fine India stone with 3in1 and stropped on the palm of your hand is the way to go and shaving your forearm is the only permissible test.
Sweet or salty

 

[Andy Kev.]

I have to point out that my query was not about the S word nor was it an invitation to a blood letting about S.

However, I tend to use the Veritas guide for the plough and rebate blades. The secondary bevels on the bench planes get done free hand.

Mike, I find your point about it only taking a little extra to do the full bevel quite encouraging: I've let my Veritas LAJ go too long with just touching up the 2° bevel and now face the joy of removing about 1 mm of the length of a PVM iron to get the 1° bevel back. I'm beginning to think that I shall stick with only the 1° bevel in the future.

 

[Mike G]

........Obviously a fine India stone with 3in1 and stropped on the palm of your hand is the way to go and shaving your forearm is the only permissible test....

 

[AndyT]

Anyone using a single bevel can relax in the knowledge that the authors of "Planecraft" (ie the men in charge at Hamptons/Record, who must have spent much of their lives thinking about planes) advised that the cutters for their modern steel plough and combination planes should all be sharpened with a single bevel, and said the same for router cutters.

And remember, they cared so much for the idea of grinding at 25 degrees and honing at 30, that they used to mark the grinding angle on every Record bench plane cap iron.

(Diagram from https://www.recordhandplanes.com.)

 

[Andy Kev.]

Thanks Andy, that's crystal clear.

It then brings me to the final point: setting different wood grain types aside, is there any reason for not keeping a bench plane at 25° (assuming you don't mind spending a tad longer when honing) i.e. will it plane just as well as at 30°? I suspect that the answer is "no" and Mike's practice would seem to back that view up.

 

[AndyT]

The usual answer is that the edge at 25° wouldn't last as long as the edge at 30°.

But to be absolutely certain of that, you'd have to do lots of measured trials with your planes, your timber, your sharpening method etc, which I expect would be tedious and waste more time than you would save.

 

[Mike G]

Thanks Andy, that's crystal clear.

It then brings me to the final point: setting different wood grain types aside, is there any reason for not keeping a bench plane at 25° (assuming you don't mind spending a tad longer when honing) i.e. will it plane just as well as at 30°? I suspect that the answer is "no" and Mike's practice would seem to back that view up.

With a honing angle of 25 degrees and a primary bevel of 30 degrees, that's physically and metallurgically the same as a 25 degree single bevel. It's the opposite side of the iron which does the work, and that angle (the bed angle of the plane), doesn't change. There is no difference at all in practice (ie when planing) between the two set ups.

 

[Dr.Al]

As I understand it, anything up to about 40° is effectively equivalent on a 45° bevel-down bench plane. Above 40° you get a bit close to having no clearance under the bevel and obviously above 45° the tip isn't touching the wood any more. Below 40° the cutting angle is 45° regardless of the bevel angle, but higher bevel angles are likely to last a bit longer.

All my bevel-down planes have primary bevels ground (with a bench grinder) at about 25° and secondaries at about 35°, but I think pretty much anything will work, regardless of angle and regardless of whether you opt for a single bevel or two (or three, or four!). I guess if you sharpen free-hand (rather than with a honing guide) then ensuring that the angle doesn't gradually creep up could be more difficult, so a slightly lower angle might be better just to give more error-tolerance.

 

[Andy Kev.]

Thank you, gentlemen. I think that I'm going to have a go with just the primary bevels that my irons came with, irrespective of bevel up or down. I know that I won't mind going to the stones a little more often, unless it gets silly. I'll report back once I've got there.

 

[PAC1]

A compass plane is a good contender for no secondary bevel because the blade is incredibly thin.

 

[Eric the Viking]

Cor, you lot seem gluttons for punishment!
Most plane-ish irons I own have a secondary bevel, simply because it makes honing mid-job a lot easier.
On the one or two that might be considered bevel-up, it also allows me to tweak the angle for awkward grain.
I have one Boggs-pattern spokeshave and a scraper plane that don't have secondary bevels. The former has some special steel, either A-nought or "O", and so it keeps a wicked edge probably forever.
The scraper (Record #80) is factory-ground to 45deg I think to make raising a burr easier. At least that's how I treat it.
I'm also privileged to have a couple of Japanese Smoothcut laminated irons (for Bailey-pattern planes), and the edge retention is amazing. They have secondary bevels as they're also hard to hone, and the most likely reason for needing a re-grind is chipping the edge somehow, so the secondary bevel makes them a bit more robust.
I do get satisfaction from getting a "dry-shave" edge, but I don't like sharpening enough to want to do it all day!
E.
PS: The only other things with a single bevel, that I'd forgotten are the blades on my side rebate plane (because they're a total pig to do anyway), skew chisels and my marking knife. But I digress...

 

[Woodbloke]

I'm also privileged to have a couple of Japanese Smoothcut laminated irons (for Bailey-pattern planes), and the edge retention is amazing. They have secondary bevels as they're also hard to hone, and the most likely reason for needing a re-grind is chipping the edge somehow, so the secondary bevel makes them a bit more robust.

Is it one of these bad boys? I've been tempted but would be interested to know more- Rob

 

[Pete Maddex]

The square shouldered Record laminated blades are excellent I haven't found ant thing noticeably superior.

Best Crucible Cast Steel by Pete Maddex, on Flickr

Pete

 

[Eric the Viking]

Is it one of these bad boys? I've been tempted but would be interested to know more- Rob

Mine rotate around with the other irons, except when I'm doing something awkward, such as Sapele recently with a #4, when they hold an edge 3x or 4x longer than the original Record and Stanley ones. I also got a bit less tearout (at least to start with!). When there's a good polish on the bevels, you can see the laminations, too. Best plane upgrade ever? possibly, as no mods needed to the plane. I think they might be a gnat's thicker than the original irons, but not enough to need any fettling of the cast iron at all. Will check tomorrow.

Those ones from WH look pretty good value, considering I got mine about ten years ago for about the same price 2 3/8" (for #4 1/2, #7, etc.) was a bit more than for the 2" (for #4 and #5). Apart from the name they're very similar - same curve at the top, etc.

My "Smoothcut" ones came from Axminster, who sold them for a very short time, apparently. They do appear on the s/h market occasionally, but I recently Googled them and couldn't find any new ones. I was intending to buy a couple more (one of each common size). The cardboard slip cover sounds the same as in the reviews on WH site, too.