Cambered Plane Iron, How Much?

Re: Cambered Plane Iron, How Much?

Dave Thompson


>I'm sure there's going to be varying personal opinion.... Here's mine. No camber on a jack or jointer plane and a tiny camber on smoother. How much? depends on the depth of the blade, i.e. thickness of shaving. If you're doing gossamer shavings with your smoother, then only an itty itty bit is necessary.

And for the reasoning....putting on a camber is an added complexity to the sharpening process. Having a well sharpened blade is paramount. If one is using a jack for surface jointing, then a camber adds no benefit. Putting a camber on a jointer increases the chances of getting boards not aligning as nice as they could, should the peak of the camber stray off the edge. It also adds no benefit.

Putting a camber on a smoother makes sense (IMHO) as it eases the transition to the edges. Though a final rub with some fine grit sandpaper after the smoother can have the same effect as the camber. (eek, did I say that???) The risk of not having a camber on a smoother is noticible when one varnishes.... all of the planing marks show up. With a camber on the smoother, the chances of this happening are reduced.

enjoy,

Dave

Re: Cambered Plane Iron, How Much?

steve knight


>depends on what your after. if your after no plane marks then you want as muich as the thickness of the shaving your taking is. then it changed of course for different planes.

Re: Cambered Plane Iron, How Much?

david charlesworth


>To illustrate the 'more camber needed for low angle bevel up planes' Try viewing a round disc, coin or plate say, when it is vertical, tilted away from you at 45 degrees and tilted at 12 degrees to horizontal.

It's too early in the morning for me to get my head around the trigonometry or drawing required to come up with a numerical answer!

Any offers? !!

More camber for squaring narrow edges, very little for smoothing.

David Charlesworth

Re: Cambered Plane Iron, How Much?

Dean J in MN


>FWIW my planes are set up as such: joint making planes have no camber (e.g. jointer, dado, rabbet, fillester, ...). All others (leave out molding planes here) have camber, and the rougher the work the more camber it has. Hence my smoother has a tiny amount, my fore has a ton, and try planes fall in the middle.

-Dean

Re: Cambered Plane Iron, How Much?

John Hoffman


>Chris did an article and a DVD about this titled "Coarse Medium and Fine" laying out specific recomendations. Here is the info he gave for the smoothing plane on the web blog www.woodworking-magazine.com/blog/. I found this one by entering "camber iron" on the search area; "the The iron should have a camber that is about .002" at each corner and in the dead center of the cutting edge (for smoothing plane). He also provides camber amount for jointer and fore plane which are more then the smoothing plane. I am on vacation now but if needed could send you the recomendations when I get home and find the article. I know he recomends an 8 inch radius for the camber. Hope this helps.

John H

Squaring with a camber?

Dave Thompson


>More camber for squaring narrow edges...

I'm glad you brought this up as it gives the opportunity to discuss...

Why would one want to square a narrow edge with a rounded blade?

Dave

Re: Squaring with a camber?

paul womack


>I'm glad you brought this up as it gives the opportunity to discuss...

Why would one want to square a narrow edge with a rounded blade?



That's not an opportunity to discuss; that's an opportunity to view the archive. To put it very mildly, this has been discussed before.

http://woodcentral.com.ldh0138.uslec.net/cgi-bin/archives_handtools.pl?read=52449

http://www.woodcentral.com/cgi-bin/handtools.pl?frames;read=85246 (recent)

BugBear

Re: Squaring with a camber?

david.marcus.brown


>This has been an oft covered (and oft debated) topic both in magazines and on the woodboards recently. It's been covered most extensively last year in Popular Woodworking.

If you are jointing the edge of a board with a straight blade, you must have the blade exactly square to the board to achieve your jointed edge. This is rather difficult. If you have a slightly cambered blade, the center of the blade protrudes from the mouth a few thousandths more than either side.

If the edge of your board is off-square, the cambered blade allows you to take a little off that side by moving the jointer off-center. It's easier to keep the plane a certain distance to one side of the board than hold it exactly square to the board. I use a fence when I'm jointing with a straight blade but the cambered blade makes it easier to joint when I'm freehanding it.

Re: Squaring with a camber?

david.marcus.brown


>Someone somewhere posted an animated gif of a man beating a dead horse.

Seemed rather appropriate . . .

Maybe that could be incorporated into the list scripted smilies that some forums use . . .

;-)

Re: Squaring with a camber?

Dave Thompson


>I don't want to bring up an over discussed topic and wear on the groups patience, so I will retract my question.

The summary presents a solution to a problem I don't encounter.

Regarding truing the edge, I don't use a clamp on fence nor have I used my #95 in ages. After creating a flat edge. I hold a small squared block just forward of the cutter to the bottom of the jointer. A few passes, and the edge is square. My jointers have no camber.

enjoy,

Dave

squared block

david.marcus.brown


>That's a cool trick dave! I'll have to give it a try some time.

You're on Vacation!?

John Clifford


>Man, you're a dedicated WoodCentraler. Thanks for the responses so far. The answer I was most looking for was how much more camber is needed for a low angle equivalent. Any takers? Mr. Charlesworth, your idea about the coin or plate tilted to the appropriate degree illustrates the need for more camber nicely but a quantitative answer might help my actual sharpening a bit more. Thanks to all.

John.

Re: Squaring with a camber?

Thom D


>A) the cambered blade squaring technique is a good technique;

B) The same technique is available to those using square blades and works in exactly the same way. As with all square blade technique you get tracks betweem passes. The tracks disappear on edge jointing if your through pass uses a blade as wide as your board, which it almost always does for jointing. The main advantage to curved blades is the lack of tracks and the easier cutting action.

C) For jointing and gluing up panels I think the matached endges technique is faster and simpler, an no more parts size sensitive than cambered jointing. But it isn't a squaring method per se.

D) There are many different ways of sqaring edges other than the cambered blade approach so it's anoying to be subjected to the opinions of those who think cambered is the only way. Ok, I'm over it.

Re: Cambered Plane Iron, How Much?

Thom D


>So here are the pictures of a coin at 90, 45, and 12.

In truth these are 1" radius circles. The flattest is reduced on the Y axis to a 12 degree showing. The shape is eliptical, however the radius shown over it is 3.7".

Re: Cambered Plane Iron, How Much?

david charlesworth


>Thom,

Thanks for the excellent drawing to illustrate the point.

Sounds like John Hoffman may find the answer.

Having largely resisted the current fashion for bevel up bench planes, being more than satisfied with the regular kind, I cannot immediately give a numerical answer.

However I like a curved blade in my low angle block plane for squaring the end grain of small components.

The light showing at the edges of the blade when offered up to a flat plastic surface suggests a gap of about 10 or 12 thou. of an inch at either corner. This might make a good starting point for a wider blade, depending on the planned end use.

I can only repeat our practice, in this workshop, more curve for squaring narrow edges and less for wider surfaces.

Delighted that some craftsmen square edges with a straight blade, anything that works is fine, but the cambered edge has many many applications, and makes an incredibly precise tool capable of removing high spots and adjusting surfaces, wherever desired, without leaving tracks, ever.

best wishes,

David Charlesworth

Thanks, but I can't take credit..

Dave Thompson


>I learned it from a contributor to Neanderthal Haven a while back. Don't remember his name. A European contributor who said that he was taught from his teacher to do it that way.

So simplistic, I wouldn't be surprised if it were a technique used for centuries... ?millenia?

enjoy,

Dave

Re: 12 degree math

Thom D


>Lets say the vertical projection you want (max perpendicular distance) is .002, then you need 4.7046 times that projection, on the curve for that to be full width (you may not want full width really). But anyway that is the factor. Now converting that into a radius is a whole other ball of wax, depends on the effective with of the blade, the width you actually want out there. It's easily modelled in CAD. In this case with 1.5" effective blade width, .oo2 perp proj., .0094 blade projection, you would need a radius of 29.92".

Picture shows 12 degree slope, 1.5x6" blade. 29 inch arc, that projects 9 thou.

Re: Cambered Plane Iron, How Much?

Thom D


>My pleasure.

Charlesworth DVD

John Hoffman


>I want to plug David's DVD that shows how using a plane with a cambered iron is a very, very precise tool. I enjoyed it and found it very informative. I have begun using stop shavings to flaten which is a great technique also shown.

Regards

JH

I second the recommendation

John Clifford


>I also have Charlesworth's DVDs, hand planing vols. 1, 2, and 3. They are excellent. I also have both of his books, and while good, do not explain nearly as well as watching the videos.

Re: Third it... but

Thom D


>I agree it is a very detailed exploration. I got the stop cuts from the Krenov tape many moons ago, Though I do it in terms of scrubbing out the center.

The squaring work is super and the curved blade part was new to me. On reflection I feel it is the same old same old in two senses.

a) it works just the same with a square blade, as mentioned above. All we are doing is lowering an edge, and then replaning it. Nothing unique to curved blades there, except they work without lines. Which is important though well known.

b)it basically works the same on large pieces and it obvious in that context. If you had a large piece of wood that was high on an edge you would just lower that edge. It seems magic when presented in the context of boards within the size range of the plane, but it is just the same principle while using the blade projection as a measure.

I just saw these tapes in the last few weeks. I have to say they are beautifully explained. I tried to explain stopcut technique on the UK board about a year back and created a minor incident. So it helps if someone with a gift for teaching is doing the talking.

Re: The real measure is

Thom D


>if one changes one's methods of work after watching a tape, and i have in some important ways. What more can one ask.

Re: Third it... but

paul womack


>a) it [squaring with a cambered blade]works just the same with a square blade

No; with the square blade you take a partial shaving on uniform thickness, making a stepwise approximation to your desired edge.

With the cambered iron you take a sequence of "full width" but tapered shavings, proceeded directly to your desired edge.

In essence, the non-square work piece has a tapered "error piece" that must be removed to leave a square surface. With a square blade this error piece is approximated by small rectangles. With a cambered blade the error piece can be created exactly from a stack of tapered shavings.

BugBear

Re: Third it... but

Thom D


>I don't disagree with your description, though if one is being that picky about the cut landscape on can't claim the final result of an edge jointed with a curved blade is square. Maybe we all have little "triangular" skeletons in our cupboards.

I'm not making a comparison of a cut surface, but a comparison of the method of using an offcenter cutting methodology to lower one edge. It's obvious there is a difference in what a curved cutter leaves behind and what a straight one does. Not all to the credit of either method.

How directly you can take off crescent shaped pieces to get directly to the concave surface you are after will depend on whether the angle and width of your surface are a good match to the plane you are using. There is a narrow parlour trick range where this would be a perfect fit. The same would be true for a square offset rebate from a square blade followed up by a full pass, there is a perfect match in there somewhere.

In essence, the technique for squaring an edge is just half of what is going on in the process of transverse flattening of the face of a board. There is a continuum in which the plane is wider than the surface, through to the surface being wider than the plane. In the face planing situation I think I would proceed identically with a square blade or a curved one. The results are just more pleasing with a curved blade when the stock is wider than the blade, and more pleasing with the flat blade when the blade is wider than the stock. Obviously if one chooses ones stock to suit the plane at hand it seems like some pretty radical stuff is happening, that's more the optimization than anything special about the method.