cambered chipbreaker

[bridger berdel]

Thanks to Warren Mickley, I went to the trouble of cambering a chipbreaker to match an iron for my #4. It works nicely for the current project of a dining table with a deliberately not-totally-flat but very smooth finish.

I started with a cambered iron and filed the chipbreaker to follow the curve. This results in a chipbreaker that gaps at the corners. I tapped those down a bit then followed with files and eventually small stones, chasing points of contact. As differences of tension will open gaps either at the center or corners of the breaker it is necessary to do all of the checking with the chipbreaker screwed tight.

All in all maybe 20 minutes of careful fiddling about.

[Jason Martin Winnipeg]

Do you find it helps a lot with tear out compared to a camber iron with a normal chip breaker?

[Derek Cohen]

Bridger, I don't get this.

For most work, a smoother needs the chipbreaker around 0.4mm from the edge of the blade.

Now the average smoother shaving is around 0.05mm thick. The camber at the side is not much more than this. Therefore the reduced curve at the corners of a blade are around 0.1mm. This is not going to have any effect on the edge of the shaving. I do not see a need to camber a chipbreaker.

Regards from Perth

Derek

[Jim Koepke]

I do not see a need to camber a chipbreaker.

Need is seldom a limiting factor in the search for adventure.

jtk

[david charlesworth]

Camber may not be necessary, but it is good fun.

If C/B camber matches blade, it is possible to set 4 thou from edge without C/B going over the edge at the sides of the blade.

I have been cambering C/B for many years.

David Charlesworth

[Mark Rainey]

Wow! Sounds like quite a smoother! Bridger, can you be more descriptive of your technique for us slow learners? What do you mean by a chipbreaker that gaps at the corner? Tapping & chasing points of contact? Whatever more you can add would be helpful.

[Warren Mickley]

Wow! Sounds like quite a smoother! Bridger, can you be more descriptive of your technique for us slow learners? What do you mean by a chipbreaker that gaps at the corner? Tapping & chasing points of contact? Whatever more you can add would be helpful.

Because the cap iron rises up from the plane iron at an angle, when we round the leading edge the parts at the sides become higher and no longer meet the plane iron. In addition we undercut the cap iron somewhat so that it meets the plane iron at the front edge only. Because of the curve and this undercutting, we cannot true the true on a flat stone. It is hard to visualize, but this is why Bridger used trial and error to effect the mating, "chasing down points of contact" or carefully lowering the high spots until all was well.

I have used the double iron for tear out since 1973 and have rounded the cap iron since 1976. The rounding makes for easier use. After 30 years I noticed that Peter Nicholson also had the cap iron echo the plane iron camber. Nicholson apprenticed around 1776.

[Mark Rainey]

Thank you Warren.

[Stewie Simpson]

There is another option available that doesn't require the leading edge of the cap iron to be set within the distance of a bees scrotum. By adding a micro back bevel to the back of the irons cutting edge the effective pitch can be raised above that being governed by the planes bed. As an example, if your starting point is a 45 degree bed, by adding a 5 degree back bevel that will raise the effective pitch to york pitch (50 degrees) 10 degrees =middle pitch (55 degrees) 15 degrees =cabinet pitch (60 degrees).

On the following wooden jointer plane, the leading edge of the cap iron has a clearance gap of 1/16" (1.5mm). It has a 45 degree bed with an additional 10 degree back bevel to raise the effective pitch from common pitch to middle pitch. If tear-out was still occurring, I can opt to increase the back bevel by a further 5 degrees to cabinet pitch.

Stewie;

http://i1009.photobucket.com/albums/af219/swagman001/throat%20geometry/DSC_0147_zps8tpiklgp.jpg (http://s1009.photobucket.com/user/swagman001/media/throat%20geometry/DSC_0147_zps8tpiklgp.jpg.html)

http://i1009.photobucket.com/albums/af219/swagman001/throat%20geometry/DSC_0148_zps5stb5rfh.jpg (http://s1009.photobucket.com/user/swagman001/media/throat%20geometry/DSC_0148_zps5stb5rfh.jpg.html)

[steven c newman]

IIRC....usual area for a cambered jack plane to be used, is across the grain...either as a Traverse, or at the diagonals.....taking fairly thick shavings ( Shilling thickness?) taking down rough sawn stock to prep it for the longer, less cambered Try Planes....tear-out being the least of the worries. More like getting some 4/4 stock down close to the 3/4 stock most need. Traverse, and then the diagonals..paper thin shavings would be a waste of time and effort....save those type of shavings for the finish planes....

Most of the worries would along the lines of getting the shaving to fly up out of the planes, without clogging the plane up....they wouldn't be long thing ribbons, either....it being a bit hard when going across the board's grain, to get anything more than "chips"....like someone had dumped a can of Pringles on the board...

[Warren Mickley]

IIRC....usual area for a cambered jack plane to be used, is across the grain...either as a Traverse, or at the diagonals.....taking fairly thick shavings ( Shilling thickness?) taking down rough sawn stock to prep it for the longer, less cambered Try Planes....tear-out being the least of the worries. More like getting some 4/4 stock down close to the 3/4 stock most need. Traverse, and then the diagonals..paper thin shavings would be a waste of time and effort....save those type of shavings for the finish planes....

Most of the worries would along the lines of getting the shaving to fly up out of the planes, without clogging the plane up....they wouldn't be long thing ribbons, either....it being a bit hard when going across the board's grain, to get anything more than "chips"....like someone had dumped a can of Pringles on the board...

If you read the original Moxon text (1677, 1703) or Nicholson (1812), they both suggest that almost all planing with the jack plane is with the grain. Moxon says that if the board is badly cupped, you can turn the board crosswise on the bench (still loose, planing against the stop). Clogging is not a problem with a wooden plane that is nicely set up. And if you look at old work that is rough planed, you see stuff planed with the grain or occasionally at a very slight angle.

And speaking of old work, it is extremely rare to see stuff in the 3/4 thickness. The common thickness for casework or drawer fronts is 7/8, a little more or a little less. Nobody who is planing by hand wants to waste time (and energy!) planing an extra 1/8 inch of stuff when it is not needed.

[Charles Guest]

"Old work" is an awfully broad statement.

Drawer sides, backs, bottoms, door panels, etc.: this book is full of furniture with 3/4" (and thinner) components, both main and secondary:

https://www.amazon.com/Georgian-Period-Measured-Drawings-Colonial/dp/129547428X

[Brian Holcombe]

"Old work" is an awfully broad statement.

Drawer sides, backs, bottoms, door panels, etc.: this book is full of furniture with 3/4" (and thinner) components, both main and secondary:

https://www.amazon.com/Georgian-Period-Measured-Drawings-Colonial/dp/129547428X

I believe Warren is applying that to things that would have used 4/4 stock.

[Charles Guest]

I believe Warren is applying that to things that would have used 4/4 stock.

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.

[Warren Mickley]

Charles, I looked at the William Ware book you referenced, but the Part 2 volume in the link appears to have only architectural drawings. Maybe you are thinking of another volume that has furniture. At any rate I was talking about looking at 18th century furniture, not 19th century books.

Of course we see thinner pieces for drawer parts and backs, just not usually 3/4 stuff.

Faced with the prospect of planing away a half inch or more of material, I usually resaw instead. And you get two pieces for your labor, and the cost of your lumber, not just one.

[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...
396026
4 "normal" #5 sized jack planes...top has the 8" camber.
396027
A large mouth to allow Olde Groats to pass through..
396028
Doing the Moxxon "Traverse"....I do have other jack planes..
396029
From the newest..
396030
To a #5-1/4 and #5-1/2....to
396031
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

[William Fretwell]

Interesting discussion, not least because understanding that little sharp edge IS woodwork. I have cambered a smoother blade at the edges only to help avoid tracks. If the chip breaker is set correctly to provide the correct back pressure on the chip then logically where the blade is cambered it is too close which causes what I call ‘dusting’ as it scrapes more than cuts. You can get the whole blade to dust with the CB set too close, this lifts the CB off the blade.

So logically the CB should always be cambered to match. Sharpening becomes fidly at the edges but doable. I’ve never cambered the CB as I only have one for each plane and have lived with dusting at the edges.

Bottom line, you need at least two blades for many of your planes and two chip breakers! I have used a back bevel for difficult wood but recovering the edge after is lots of work, easier to buy another blade. Mostly I regret the difficult wood.

I have seen furniture with heavily cambered plane marks that was probably wire wool rubbed before the finish and thought nothing of it. True finish planeing with camber I’ve never seen.

I recently bought a high (60^) bed smoother to avoid back bevelling. It’s wood and needed some fettling but pleasantly surprised by the results.

Wonder if cambering ones low angle jack plane is the answer to relieve it of it’s paper weight status. Anyone turned it into a cambered scrub plane?

[Simon MacGowen]

I have used a back bevel for difficult wood but recovering the edge after is lots of work, easier to buy another blade. Mostly I regret the difficult wood.



Reason for keeping two blades for bevel down irons: one as a regular iron without any back bevel, one as a back bevel blade to handle difficult spots. The cost of an extra blade is minimal; anyone who tells me they can't afford to have an extra blade, i tell them to stop woodworking as a hobby, as they probably can't afford to buy lumber either which is a recurrent expense.

Reason for keeping two blades for bevel up irons: one (at 25*) as a regular iron in a low angle plane, one at a higher angle (38* or 50*) to tackle difficult grain wood. I actually keep three for my smoother, with the 50* used only once in a blue moon.


I try to make my woodworking life simple. Converting a back bevel iron back to a regular blade is self-torture in my book (some may enjoy it though).

Simon

[Tom M King]

I do a lot of surface finishing where the smoothing plane texture is the final surface. The old houses I work on have that sort of texture on every planed surface. It varies a lot from one of the houses to another, and I guess, depending on the person, and tool, doing the work.

I keep several Stanley 3's, and 4's with varying amounts of camber, so I can come close to matching a surface texture without fiddling with a plane. I bought all these planes long enough ago, when they were dirt cheap for ones almost ready to go to work, since few other people wanted them.

Having the breaker to match the iron camber helps a number of things when using them. If you don't need them set up like this, that's fine. It doesn't make it not worth doing for those of us who have found it to be useful. I thought I had some pictures of such work, that other people had done, of pieces that have all sorts of tearout problems with reversing grain, but can't find them easily. Some tearout might even be authentic, but I've seen some new replacement parts with Way too much.

Here's one of mine that I already had on these forums. I can't remember which plane I used, or how thick the shavings were, but you can only see this in a strong raking light. This was taken when the Sun just came around the corner of the house.

The new exterior step is on an 1815 house that doesn't have a straight smoothing plane track anywhere in the house. Historic Preservation is not really preserving history if your forgery doesn't match the original as closely as possible.

[John Schtrumpf]

A few more notes...
Thanks Warren for giving the reasons to camber a cap iron. I understand them and can see where sometime in the future I may want to do it.

[Mark Rainey]

Tom, you do beautiful restoration work. Your handplanes result in a surface that reveals the close connection between the craftsman and the wood.

[Warren Mickley]

Reason for keeping two blades for bevel down irons: one as a regular iron without any back bevel, one as a back bevel blade to handle difficult spots. The cost of an extra blade is minimal; anyone who tells me they can't afford to have an extra blade, i tell them to stop woodworking as a hobby, as they probably can't afford to buy lumber either which is a recurrent expense.

I try to make my woodworking life simple. Converting a back bevel iron back to a regular blade is self-torture in my book (some may enjoy it though).

Simon

I have used just one blade per plane in all my planes for my whole career. The only times I have used a new blade are when the old ones were worn down to nothing. I have never used a back bevel.

I don't see why learning to use a plane like this is beyond the reach of a hobbyist.

[bridger berdel]

I have used just one blade per plane in all my planes for my whole career. The only times I have used a new blade are when the old ones were worn down to nothing. I have never used a back bevel.

I don't see why learning to use a plane like this is beyond the reach of a hobbyist.

I have a few extra blade/chipbreaker sets. I have them set up with different cambers, not back bevels. I am still experimenting with planes (i may never stop), so any variation that i can think up and find a way to set up i'll probably try. It's not that i think i'm going to discover something "new", just that each thing teaches me a little bit.

[Jeff Bartley]

Reason for keeping two blades for bevel down irons: one as a regular iron without any back bevel, one as a back bevel blade to handle difficult spots. The cost of an extra blade is minimal; anyone who tells me they can't afford to have an extra blade, i tell them to stop woodworking as a hobby, as they probably can't afford to buy lumber either which is a recurrent expense.

Reason for keeping two blades for bevel up irons: one (at 25*) as a regular iron in a low angle plane, one at a higher angle (38* or 50*) to tackle difficult grain wood. I actually keep three for my smoother, with the 50* used only once in a blue moon.


I try to make my woodworking life simple. Converting a back bevel iron back to a regular blade is self-torture in my book (some may enjoy it though).

Simon

Simon,

If you want your woodworking to be simple isn't using the chipbreaker the most simple? With a back bevel there's no way you could get the chipbreaker close enough to control tear out. And a back bevel is an additional step in sharpening.

I had never considered putting chamber into the chip breaker but I think I'll try it on my #5.

Thank you OP and everyone else in this discussion!