Bench plane camber choices vs. working practices

[ian maybury]

There's very little written about this. Lots about how to camber a blade (which isn't a problem), but big differences between writers in terms of what they (admittedly tentatively, and emphasising that personal preferences count for a lot) regard as a typical amount of camber for each plane type. Very little to say about why.

I'm relatively new to the structured use of planes, and have some initial/starting point choices to make.

Pondering the issue suggests that it's perhaps those planning to horse off large amounts of material using hand planes that go for the heavy cambers. Seems to me that as a mixed hand and power tool guy (having put a lot of time into accurately setting up a 16in jointer/thicknessser) that there's going to be far fewer situations where this is appropriate for me. David Charlesworth while not really being all that specific about camber amounts seems by his technique suggestions to use far less than many.

I'm for example thinking of keeping one block plane straight for trimming joints, and the other (wider) one set with a small camber for small area smoothing. Ditto the smoother where removing power planing marks (as an alternative to heavy sanding) is the main task. Also the jointer where board edges are likely to come off the machine pretty straight and require mostly fine tuning. The 1/64th mentioned in some places seems like an awful lot of camber for both these jobs though?

There's a choice to be made between a low angle jack or a bevel down to be kept straight for shooting. Then how much to camber the general use jack given that there's also a scrub plane for straightening wide surfaces. Some of the camber numbers quoted for jacks (1/32 in plus?) seem almost likely to take them into scrub plane territory - but that maybe makes sense in absence of a scrub plane. I'd likewise expect glued up boards to come out of the clamps relatively flat, and feel that a full 1/16in plus may be a lot for the scrub...

What strategies are people using, and what are the rationales?

[Prashun Patel]

My bevel up planes have eased corners; I wouldn't call it camber, though. I think of camber as a curved surface. My BU blades are indeed flat through their width, but eased on the corners only so they don't leave track marks (read, leave smaller track marks).

The trick to using a cambered blade for shooting is to use a concave square when measuring the result.

(I don't find that my eased edges affect the shooting accuracy).

[Warren Mickley]

The amount of camber is dependent on the shaving thickness. For each plane you want the camber so that the plane cuts almost full width, but the shaving thins out to nothing at the edges. Just rounding the corners is not the best because the rounded corners will still leave a bit of rounded track at the edges, and worse if the iron is not perfect with the lateral adjustment. A full gentle camber is more forgiving this way.

The sharpening stones will naturally become slightly dished and impart a slight camber. For a smoothing plane we want very little camber so we sharpen the middle of the blade over the left and right edges of the stone in order to keep the camber small and to even out the wear on the stone. For a jack plane we have to lean the iron a little to the left and right in order to keep the camber from flattening out too much from sharpening. So we are constantly managing both the stone surface and the camber.

[David Weaver]

I have never measured the camber on my irons...until a couple of weeks ago. I still don't know what any but the steepest are.

Your smoother should have enough camber or corner relief to not have the corners in the wood on a flat board when you're taking your final pass. What that is, I don't know, but you don't need to know the measure, either - you just need some repetition to figure out a process that doesn't involve measuring or delay that prepares your iron properly (which is exactly what warren has suggested).

I put a little more camber than that on my try plane, barely more on a jointer, and on jack and fore planes, whatever I feel like. My fore is probably set like most peoples' jacks and my jack is set very rank, something like a 4" radius (based on what I measured - out of curiosity because of discussions on ehre) on one. I don't typically use that plane for anything other than actually thicknessing boards.

I don't know what the curvature is on my irons, because I draw something on them by eye and manage them after setting them up by eye. If they seem too steep, then I let them flatten out some, and if the bottom of the iron seems to be getting off center, then I bias it back the other way when grinding it. It is one of the things that is better learned from experience than a spec sheet.

[Jim Koepke]

There's very little written about this. Lots about how to camber a blade (which isn't a problem), but big differences between writers in terms of what they (admittedly tentatively, and emphasising that personal preferences count for a lot) regard as a typical amount of camber for each plane type. Very little to say about why.

Purpose and personal preference is the reason for differing amounts of camber. A scrub plane will likely be the one with the most camber. Some measure in the depth of the camber others measure by the radius. For my few purposely cambered blades I usually just guesstimate. One plane that is purposely cambered is a plane used for scrub work. The camber allows taking a narrow yet fairly thick cross grain shaving without a lot of splintering the wood.

Seems to me that as a mixed hand and power tool guy (having put a lot of time into accurately setting up a 16in jointer/thicknessser) that there's going to be far fewer situations where this is appropriate for me.
[snip]
I'm for example thinking of keeping one block plane straight for trimming joints, and the other (wider) one set with a small camber for small area smoothing. Ditto the smoother where removing power planing marks (as an alternative to heavy sanding) is the main task. Also the jointer where board edges are likely to come off the machine pretty straight and require mostly fine tuning. The 1/64th mentioned in some places seems like an awful lot of camber for both these jobs though?

Though at times I have used a block plane for small area treatment a small bench plane seems to work best for me in this area. I have one block plane where the blade came with the back side worked deeper at the edges.

For smoothing a very light camber is used to make the shaving thin at the edges to help eliminate planing tracks. My tendency is to use a very sharp blade and make as thin a shaving as possible to keep from leaving tracks.

Here is another post about blade cambering:

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

There's a choice to be made between a low angle jack or a bevel down to be kept straight for shooting.

My choice for shooting is a low angle jack. For me this is because it goes through the end grain easier than a bevel down plane. My shoulder was messed up years ago in a cycling accident. Less effort used shooting makes for less discomfort in my shoulder. Also the low angle jack seems to leave a better surface on end grain than a bevel down plane.

Some of the camber numbers quoted for jacks (1/32 in plus?) seem almost likely to take them into scrub plane territory - but that maybe makes sense in absence of a scrub plane. I'd likewise expect glued up boards to come out of the clamps relatively flat, and feel that a full 1/16in plus may be a lot for the scrub...

A scrub plane is mostly used for hand dimensioning of rough sawn wood. If you have machines to do this, a scrub plane isn't as important in your case.

If you can find an inexpensive blade or two for experimentation you will be able to try different cambers to see what may suite your needs.

I am not sure if they stock it in your area but Home Depot here has a blade for a #4 or 5 plane that is inexpensive.

jtk

[Chuck Nickerson]

I am a blended woodworker but I do every fifth project hand-tool only (the small ones), so my hand planes are set for a wide range of tasks.
Also I like having tools so I have not pushed myself towards a small working set of planes.

My scrub blade is on a 3" radius and my jack on an 8" radius, what I read as the traditional numbers. That's quite a gap, so I have a 5-1/4 plane whose blade is a 6" radius and I find that useful enough to keep. Just because I like the radius ideal (and my degree is in math) my fore plane blade is on a 16" radius.

My jointer and smoother just have relieved corners.

[Sean Hughto]

A bevel up plane needs a significant radius to achieve the same effect as a slightly cambered bevel down plane. I have never cambered any of my block or other BU planes. I may knock off the corners a bit, but I don't bother to try to impart a curve.

On pretty much all my BD bench planes - jointers, jacks, and smoothers - I sharpen in a slight camber. This is virtually imperceptible from the back side, but is noticeable from the front because the extra strokes on the stone as I approach the corners from the middle make a bevel that is wider as it mores towards the corners. I like this camber as it minimizes tracks and helps in adjusting so that the blade starts its shaving from the middle. It is so slight that you can't notice any scallop on a panel or anything. My big jack I use for flattening after taking down really high spots with the scrub, has a somewhat more pronounced camber, but nothing like the scrub.

tiny camber.JPG

[ian maybury]

Thank you very much guys for coming back in so much detail. As is often the case reading across the posts paints the picture - and it more or less confirms the thinking subject to gaps in my experience. There's definitely some running with heavy camber that seem to be set up to remove a lot of wood by hand - Chuck, and David experimentally. Most others seem to be running quite a bit lighter. As Warren says - it depends on the shaving thickness. Which tends to point me towards running with lighter cambers until needs arise and a working style emerges.

The link is to a nice post showing what a (light) camber shaving looks like Jim. Can't imagine how you can get such performance out of a plane that's not all shiny though….


I think the situations where I could end up needing to remove significant amounts of wood with the scrub or a jack might be on stuff that's either too wide for the planer thicknesser, or rough/dirty enough that it's probably more attractive to risk blunting a re-sharpenable plane blade cleaning it up rather than an expensive set of HSS machine knives.

Sounds like it's the low angle jack for shooting Jim - I can drop another blade in it if it's needed for anything else anyway. Easing the corners is one way of shooting and using it for other stuff too Prashun. My planes just coming into use are all Veritias bevel up Sean - the plan is to run with 25 degree primary bevels, and then hone in any camber and or steeper angle that's required a la Derek Cohen. (plus i have some spare blades)

The Clifton is the exception and was my first 'good' plane, i bought it about 15 years ago and it's done almost everything that's come up in the interval. Sounds like it's heading into a new and rather more finely set up life….

The thinking in putting (just a little) camber on the bigger of the the block planes Jim is just that I have the bigger Veritas model that takes a handle and knob: http://www.leevalley.com/en/Wood/pag...182,41189&ap=1 The smoother is meanwhile quite big being the wide Veritas bevel up model. I bought a Veritas apron plane ( small block) to have something light and handy for general trimming jobs, and will sharpen that straight...

Thanks again...

[David Weaver]

I think the bottom line, if you experiment, you'll find that you like to have at least one plane set up to run like that (heavy camber) if you dimension by hand. If you don't dimension by hand, there's probably really no reason you'll ever need it as even moderate jack camber will take care (cross grain especially) of high corners or other things of the like that power toolers use as justification for scrub planes (aside from the fact that a scrub plane is an interesting sensation to use).

Doing a lot of dimensioning by hand, it's nice to have a plane with mild camber that can take a thick shaving as well as a plane or two with significant camber.

It's my opinion that you want these planes especially to be easy to sharpen because they will never need to take 1100 feet of one thousandth shavings, and you'll appreciate something like a carbon steel iron (which will be both tough and easy to sharpen, but not as wear resistant as wonder-steel).

But all of that is still best learned by experience. My favorite high camber jack planes are a funjii smoother (a very cheap japanese plane) and a $10 dutch continental smoother with a french iron (french people seemed to like soft tempered steel for some reason - both in knives and tools). I could get by with either, but have both because they're so cheap. They're both extremely easy to sharpen.

One other opinion - bevel down for highly cambered planes. You want a nimble plane for this kind of work, and when I had a jack, it never felt natural with a lot of camber. You can do it, but you have to do more work to the iron and it just seems bizarre using a pattern that was initially designed to smooth butcher block end grain (that's what stanley made the 62 for) to hog out long grain. It feels like you're wearing cast iron frying pan flip flops to play tennis.

[Tom M King]

holddownmoldinghead_001-507x392[1] (507x392).jpgOne of my three's is cambered this much. I don't know how much it is, but it looked about right to match some other boards in the 1828 house. They are the entry steps out of several year old air-dried treated pine. I could have measured the thickness of shavings, but it looked fine, so I didn't have any reason to.

I keep a couple of pairs of block planes like you mentioned. I never used them that much as intended, but I fell into great deals on NOS dark blue ones, and bought the Burgandy ones new a while back. I do use them as intended sometimes, but I have to plan ahead as to which one to keep in my toolbelt, and the one that gets used is the one at hand. They are pairs of 9-1/2s and 60-1/2s.

My smoothers have varying amounts of camber, down to the 4-1/2 which is probably less than a thousandth. I have two 6's with different cambers, only because I ended up with two for no good reason. It has actually worked out to be worthwhile to have both of them. I keep a 7 with small camber for surfaces, and an 8 straight for edges-although I'm sure the 7 would work just fine.

The 5 is set up, and used as a Jack is intended. A Scrub is used for scrubbing dirty beams and boards. The scrub will keep cutting even when the blade has a fairly wide flat at the cutting edge.

[Jim Koepke]

Can't imagine how you can get such performance out of a plane that's not all shiny though….

They are merely dressed in grunge camouflage.

The scrub will keep cutting even when the blade has a fairly wide flat at the cutting edge.

+1 on this, my scrub blade is just heavily relieved at the corners.

jtk

[Winton Applegate]

How much camber ?
That is perfectly straight forward . . . literally.
How much junk do you have in the trunk ?

What I mean is IF you have enough weight AND muscle AND traction to push what ever plane blade you want to through the hardest and toughest wood you will ever work at the cutting depth you choose to take off with the blade straight but the corners lightly relieved . . .
well brother
THEN you don’t need no stinkin’ camber.

You see ?

But if you are like some of us and on that big old plank of bubinga where you need to take off an eighth of an inch (I heard what you said about the 16 “ miracle machine but I ain’t got one) and I camber and I get too bogged down to get that plane to hog through the wood and then my floor is that very smooth kind of cement (I have to put down some grit just to get traction)

so I put on more camber, and maybe more camber again
until
finally
I reach an equilibrium where I am able to continue for long periods and take off significant depth
then
I have put on ENOUGH camber.
Purtty simple huh ?

If I am working softer wood and I am flying through the cuts with the greatest of ease with that previous bubinga camber
well
next time I sharpen I am going to straighten ‘er out some so I can get more blade width into the cut.
purtty simple huh ?

That’s about it really.

PS: first photo; bubinga; lots of depth not much width a butt load of camber. LN scrub.
Second and third photo bubinga very wide blade only a couple thou depth straight finish blade (no camber) relived corners. Veritas BU widest smoother.
Fourth photo those bags are almost all hand plane curls packed tight .

[Jim Koepke]

Fourth photo those bags are almost all hand plane curls packed tight .

Hope you know someone with a pet rabbit, hamster or guinea pig.

jtk

[Tom M King]

They are merely dressed in grunge camouflage.



+1 on this, my scrub blade is just heavily relieved at the corners.

jtk

I meant the flat behind the cutting edge when it's dull. It still has about a 1-1/2" radius. It'll still throw shavings three feet in the air even if it's dull since it takes such a big bite. I have to make the guys quit using it to sharpen it.

[ian maybury]

Cases where a picture is worth a thousand words! It actually comes as a surprise that a hand plane can strip off so much material. From gentlemanly smoothings to hard labour. Requiring just as wide a range of sharpening options - it certainly explains why writers tend not to be too specific in specifying camber amounts.

You're going to have to get published Winton!