cambered chipbreaker

[Joe Rogers]

To get back to the OPs point about reshaping cap irons...I just recently experimented with the same drill. I found that a Clifton two piece cap iron has a wide enough contact facet to reproduce the irons camber with minimum additional work to maintain the gapless cap iron to iron fit.
And it made setting the irons projection with reserve yoke adjustment possible which was frustratingly tedious with the OE capiron. Performance was noticably improved in use.
Joe

[Brian Holcombe]

I think it's an exaggeration to assert that stock was always resawn for thinner pieces, or that pit sawyers regularly sawed stock thinner than 4/4 at all places and all times. Then, as now, a lot of stock ended up on the floor as chips and shavings when thinner parts were needed. That's why we read about jack planes and heavy cambers, and scrub planes in the Scandinavian and Germanic traditions. If you're only removing a fat eighth at the most (a 1/16"+ from each side), you need neither.

This is also why one of the first woodworking machines to be produced during the Industrial Revolution was the planer, and of course the Shakers had invented one as well. Again, not needed if all you're removing is an eighth or so.

Not sure where that was asserted? I read Warren's post simply to mean that if you have 1" rough sawn and are aiming at making something with it, then taking it to 7/8" is going to be just as well as taking it to 3/4" but without wasting another 1/8" for no purpose other than to hit a specific number.

Working by hand I almost always brought 4/4 stock to 7/8" thickness, I'm not going to knock off another eight without purpose. Working by machine now I almost always hit 3/4" with the same stock because I'm removing 1/32" per pass and once the stock is jointed flat It usually goes under 7/8". I like to hit a number when planing so .750" is it.

Working another 1/8" off of case sides is plenty of work, especially doing it accurately.

[steven c newman]

I don't change irons in a plane...
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4 "normal" #5 sized jack planes...top has the 8" camber.
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A large mouth to allow Olde Groats to pass through..
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Doing the Moxxon "Traverse"....I do have other jack planes..
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From the newest..
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To a #5-1/4 and #5-1/2....to
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That Sargent 3416 sitting in front of the Stanley #28 try plane. None have their chipbreakers ground to match the camber (if present) of the irons.

[Tom M King]

The only planes I have with matching breakers to iron cambers are my smoothers. I think the next thinnest shaving is one of my no.6's, and it takes something like a 7 or 8 thou thick shaving. Like Steven, I have multiples of a size with different cambers, but I bought them back when old ones were cheap, and use stock irons.

[Kees Heiden]

Technically speaking, you don't need a cambered chipbreaker, not even with a cambered iron. In the middle of the iron's edge the cut will be deepest, towards the edges it will be shallower and nothing will be cut at the very corners (when the iron is properly installed in the plane). The thinner shavings towards the corners can deal easilly with the shorter distance to the chipbreaker.

So, cambering the chipbreaker adds unneccessary complexity.

[Simon MacGowen]

So, cambering the chipbreaker adds unneccessary complexity.

10-4.

Some subject matters in woodworking fall into the category of hair-splitting. Cambering a chip breaker is one of those in my book. If you need to camber the c.b. to make your plane work, your camber is simply too big.

It is a different story if you want to camber your c.b. for a bit of fun, and not because of a functional need.

Simon

[Brian Holcombe]

I respect that Warren had gained considerable insight having hand planed since the early 70’s. I’m going to apply this to my chip breaker and find out first hand the effect

[bridger berdel]

I don't claim to be any kind of expert about cambered chipbreakers. I made one, it worked. It has a pretty deep camber for a smoother as i was trying for a textured surface. It was a bit fiddly to make, but not hard.

[Simon MacGowen]

I don't claim to be any kind of expert about cambered chipbreakers. I made one, it worked. It has a pretty deep camber for a smoother as i was trying for a textured surface. It was a bit fiddly to make, but not hard.

If the purpose of a deep camber was to hog out material (like a scrub plane) or a textured surface, the c.b. could be set away enough from the cambered edge, making a cambered chip breaker totally unnecessary.

Simon

[Vincent Tai]

If the purpose of a deep camber was to hog out material (like a scrub plane) or a textured surface, the c.b. could be set away enough from the cambered edge, making a cambered chip breaker totally unnecessary.

Simon

From the first post of this thread from OP I was pretty sure I knew what he was talking about. I felt that most people were missing the point and after today with his follow up I am a little more sure. He is not hogging out material, not fluffing around with a pretentious scrub plane. Think texture as in hollows and ridges. Valleys. Yariganna surfaces but with a plane and more consistent ("linear wise"). Like the surface from a medium set jack plane but with no tear out and glistening smooth. I have seen this effect and have done it before. Without the cambered chip-breaker.

There are plenty of hollows and rounds Japanese planes that come with matching chip-breaker. So for the extra cambered of smoothers there is plenty of reason to camber a chipbreaker.

For the usual small camber I see little to no reason to this. At least on a smoother. Derek's explanation doubly shows this.

There is that grey area of camber that allows you to take a little more of a bite but nowhere enough to be in a jointer plane or jack. Perhaps this area is where fine-tuning a cap-iron to be matching with the iron can be helpful. Perhaps Brian can experiment with this. I don't think that too many people would do this though or have reason too; though there are plenty of people who dimension wood completely by hand and will probably prove me wrong. Heck I'm one of those neanderthals...

[Simon MacGowen]

. Perhaps this area is where fine-tuning a cap-iron to be matching with the iron can be helpful..

I may have misread but whether it is Warren's or D.C.'s, I am not seeing any clue from their posts that they camber the c.b. for texturing.

I remain unconvinced that to texture hollows with a cambered blade, one needs to use it with a cambered/profile matching c.b.

Simon

[Vincent Tai]

I may have misread but whether it is Warren's or D.C.'s, I am not seeing any clue from their posts that they camber the c.b. for texturing.

I remain unconvinced that to texture hollows with a cambered blade, one needs to use it with a cambered/profile matching c.b.

Simon

Simon, The first post of this thread by Bridger is where he mentions his deliberate not so flat finish. This is followed up with him confirming the camber was deep; one can garner that the usual smoother camber was not enough.

Neither Warren or Derek have stated they camber the cap iron for texturing. I should have started another paragraph after mentioning Derek's explanation. But a close read and one can get the gist that the whole grey area part and there on after are just my musings, unrelated to D.C.

How would you go about making hollows without a matching cap iron, if the grain is reversing, curly etc? We are talking about very smooth finishes while having a not flat surface as the end goal, as stated by OP in the first post. Keep in mind the camber is deep. A proper round plane either needs to be made or bought, more money and time than shaping a chip breaker. In a normal frogged #4 the pitch is 45 and with the deep camber and a non matching chip breaker tear out is inevitable when the grain betrays you. There is no matching mouth to provide some aid against tear out like there is in a round plane. Again the modified chip-breaker seems like a sensible and quick enough solution. Perhaps a high angle frog if you have a Veritas or LN would be the answer but the old Stanley cap irons aren't too rare.

I am unconvinced with the idea of matching a chip breaker with a normal camber for a normal smoother. The math doesn't make sense to me. The grey area I am talking about is those thicker shavings one can get out their smoothers, more work done in one shaving; as long as the grain lets you get away with it that is. If the blade is a touch more cambered for this that is the grey area where perhaps the idea of a matching chip-breaker starts to creep in; for me at least. Even then I think it probably is unnecessary but perhaps - just perhaps.

[Warren Mickley]

A few more notes.

A cambered cap iron is easier to adjust for two reasons: the corners of the cap iron are not right up against the edge so there is less danger of going over, and also with a cap iron that mirrors the edge it is a lot easier to judge the distance the cap iron is set. In addition a cambered cap iron allows one to set the cap iron as close to the edge as desirable. The configuration shown by Stewie earlier in this thread looks like a shaving trap at the corners, which might be why he suggests large margins of clearance at each edge. Even though it is undesirable to have the corners digging in it is nice if a slightly crooked iron does not present clogging problems also.

The cambered cap iron is a sophisticated device. Though I have used it on all planes since 1976, I did not discuss it with anyone until earlier this year when someone on a forum asked me point blank if I used it. It does not belong on a beginner's check list of how to prepare a plane. It requires fairly careful work.

I have seen blogs, tutorials, videos and articles where the author barely knows how to use a plane, let alone a cap iron. Can you imagine someone doing a video of how to pole vault after a week of experimentation? And some guys only use a plane to skim a little off between the electric planer and sandpaper.

[Kees Heiden]

Indeed Vincent, that is the only task where I could see the value of a cambered chipbreaker. Usually you don't want the chipbreaker to protrude below the sole of the plane, as it quickly increases the pushing resistance. But in this case you could work it in steps with gradually a deeper setting of the cut.

My smoother and tryplane, where I use the chipbreaker effect the most, are both cambered and both have a straight chipbreaker. I had trouble enough to mate them perfectly as is, and I am not looking forward to create a gap less interface with a cambered chipbreaker.

[Simon MacGowen]

How would you go about making hollows without a matching cap iron, if the grain is reversing, curly etc?

If I were to "hollow" or texture with a cambered iron in a difficult grain situation, I would definitely switch the iron to a back-beveled iron (which I keep one honed at 10*, and can be re-honed with ease to 15* if necessary). Back bevel an iron -- cambered or not -- (you can do it by hand, no jigs if you have done it a few times) is 10 times easier and quicker than cambering a chip breaker to match a cambered profile on an iron, unless you make a jig to camber both the iron and chip breaker, something like Derek Cohen shows using a belt sander. Those who are unfamiliar with back bevels can easily work on the tricky spots with a card scraper (use a thin one to achieve the desired curvature).

There are easy ways to do things and there are complex ways to get things done. I am not saying the latter is wrong (it can be fun to over-engineer a solution as we sometimes see in Festool discussions), but it should not be presented as some more superior technique for a problem that simpler solutions do exist for.

Simon