The cap iron isn't just for smoothing folks

[Tom Trees]

Yet it seems some folks are still in the woods regarding the use of the cap iron for taking thicker shavings.

I will give two reasons why...

Not having honed ones cap iron steep enough, I like 50, or just over it to be sure, say maybe 52 degrees, I find this to be the minimum steepness I can get away with,

should I be working on a batch of lesser dense timbers, its nice to have camber, I've kind of settled for slightly less nowadays.

I can see why some might be worried about this being sacrilege, possibly de-valuing ones premium plane?
can't help you there... apart from suggesting to seek the right folks who tout the use of the cap iron.

Having the idea of the mouth playing a part when using the cap iron,
That is the big give away when someone mentions being familiar with using the cap iron, and goes hand in hand with the impression that the cap iron is only for smoothing.

That goes back to the first "hurdle" of being willing to hone the cap iron slightly steeper than most "gurus" suggest.
One won't be able to have the mouth close if they hone such an angle,
If they choose to try, they will be taking tissue shavings only, or have a half working scenario which is
extremely difficult to push, and not really working regarding tearout.

But ya'know, perhaps my iroko, sapelle sipo/utile,meranti,and so on, is just tame stuff or whatever you wish to believe,
I would call this productive working on this particularly dense batch of iroko

Try taking heavier shavings like below, whilst ignoring the outlined will result in...
A, Not getting influenced shavings,
If they're curling, then you'll be going to the stones every ten mins, and that's the best case scenario, not the worst (tearing out)

B, If one remains sceptical about having the frog back , flush with the castings that is, and keeps a tightish mouth...
Eventually something will come along and the cap iron will not be able to give the necessary influence required,
and those folks will be adamant that they have tried everything, yet they've never experienced the cap iron working to its real potential,
why, because they couldn't set it any closer.

And it goes full circle.

All thanks to Warren Mickley for informing those willing to listen, it got David to make multiple articles on the subject about a decade ago.

Plenty of folks like Derek have wrote much about this aswell,
Easy to spot a half working cap iron (wimpy shaving) compared to one working stout straight shavings which jump out of the plane.

Hope that might explain things.
Until the next time

All the best
Tom
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[Keegan Shields]

I’ll second the above advice. As a novice, I took this advice and honed my LN chip breaker to 70ish degrees and was finally able to get those straight shavings with my 4 1/2. It worked so well that I did it to my 7 and 6. Heavy shavings, no tear out. Thanks for all of the advice and coaching!

[Tom M King]

I don't use them all the time because I don't like straight shavings. I like shavings to curl up and fly away. When the surface requires it though, I deal with straight shavings-just aggravating to have to stop and pull too many off my arms. Sometimes, even with a tight iron, if I plane fast enough the shaving will fly away, but not all the time even then.

It seems like a lot of people only want straight shavings. I'd choose to have none if I could.

I keep multiple planes of several different numbers because I don't like to adjust one to use it. I think the no.7 and no.8 are the only ones I don't have multiples of. The number 8 was needed last Fall after I forget how many years since I had last seen it. When I took it out of its watertight toolbox, it was ready to go to work, and did.

[Andrew Hughes]

Once in a while I can get the shaving to shoot straight up i thinks its because of the camber. The shaving has to be just the right thickness.
Tom did you know Iroko wood is reported to be haunted. Because it can carry sprites not good ones bad ones.
Be careful
Good Luck

[Luke Dupont]

Once in a while I can get the shaving to shoot straight up i thinks its because of the camber. The shaving has to be just the right thickness.
Tom did you know Iroko wood is reported to be haunted. Because it can carry sprites not good ones bad ones.
Be careful
Good Luck


I have an old wooden coffin smoother with no cap iron and a huge mouth, which I put a fairly pronounced camber on to use as a scrub plane...

Oddly enough, I get those straight shavings you mention, and not nearly as much tear out as I expected. You'd think it should be a tear-out machine, but tear-out with it is fairly rare and mild.

I still don't know why this is. Maybe your point about camber could account for it.

[Jim Koepke]

The wedge on a wooden bodied plane can be made to work like a chip breaker:

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It can also be cut close to the action to make straight-ish shavings.

This wedge is also shaped to direct the shaving out the side of the plane.

In some cases a tight mouth does provide some benefit. Planing around knots in soft pine can be one of them. The squirrelly grain there is just itching to lift up even with a light shaving and a perfectly adjusted chip breaker. Just now thinking about it, it has been years since my budget required me to buy some of those cheaper boards to use on projects.

Most of the mouths on my Stanley/Bailey planes came with a somewhat square front. Filing this at an angle can help to prevent clogging with a tight mouth and a close chip breaker. A few of my planes have a tight mouth even with the frog all the way back and a stock blade.

jtk

[Tom Trees]

Keegan, takes a brave man to hone their caps to 70 degrees, from the horses mouth I take it, with the rounded profile.
I tried this for the craic after getting some damage of my cap iron, but went back to 50 near straight away being accustomed to my known distance of things @50,
I didn't account for that, as I was too ignorant and stupid not to set it back further, and depth adjustment was very sudden with my Bailey.
(I could have learned something from this, but didn't have time, and I'm a bit parsimonious regarding a not so consumable component to mess around with, if I don't need to)

Tom, not implying everyone needs to use the cap iron,
just clearing up some things regarding heavier stock removal on denser/interlocked/figured/knotted stuff,
which might indeed provide a lengthy workout if one omits using it.

Aye Andrew, though I feel like I'm somehow on good terms with that, saving the stuff from the mulcher.
Iroko is used on pretty much every wooden door in Ireland, including the shed...but UPVC for the house... that could just be the answer!;)
Not that my stock is intended for such punishment,
I'm even weary enough to keep these two around, which ended up under my guardianship! :)
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I do hope the Yoruba folk don't mind them seeking refuge here!


That's not to say this stuff is harmless, I had reactions to this before I learned to use the cap iron,
scraper planing deep tearout on some of those lengths was sweaty business indeed, you don't want the dust on your skin.
It's not easy like hand planing, that is, when the cap iron is set, and the edge isn't getting battered.

I've seen a good few planes take straight shavings without a cap iron totally involved, and also with some fillister planes IIRC.
Peter Follansbee seems to be able to take hefty cuts like that on somewhat wet oak.
I've noticed something similar on some bits of wettish ash without the cap iron set on my beater plane,
the shaving retains enough strength being more flexible than drier stock, is my guess.
I don't believe I've seen him discuss this, but he has a blog, perhaps he has the definitive answer to this.


Nearly/seemingly all my timber is similar enough to use two planes with the cap set, both honed @50ish
and seems to be good for any pine I come across either. (I have some tougher stuff again which is uber tropical, I've yet to experiment on to decide if going steeper is an improvement)

Below is the same distance set/camber as in my first pic, it's definitely under a 32"
You may notice the cap iron appears skewed, more so in the second photo, though unchanged, (you'll have to zoom in on the left piccy)
one would need to look up Derek Cohen's photos for a clear shot should they wish. (it's difficult to photograph)
that is... should they be wanting to hone their cap iron to 50 something degrees!

Just after a jack planing to get a flattish surface, most of this was soft resinous stuff, l'm guessing it's pitch pine.
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This is what is seemingly unapparent without the cap iron,
the shavings are being compressed and have a differing look to that of someone not using the cap iron, and is the same for all species I've came across.
It's like it extracts the oil out of the timbers, if you can make out the crinkly and waxy appearance.

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After the no.51/2 still needs some cleaning up with a no.4 smoother
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I ain't buying any argument about tight mouths,
It's a friction monster on a fine set jack or panel plane, and I reckon even with a filed mouth for the escapement wear profile for the shavings to eject upwards for enabling a tight mouth to be somewhat functional,
I'd still reckon a gun style thermometer would be able to tell one this fairly quickly.

Even if were not so, I'd still reckon you'd be back to the hone quicker than you would be if relying on the cap iron alone,
Those two things are pure speculation on my part, which I've not seen compared.
That might make watchable content for those youtuber's who like to test things.

That wasn't the point though, it's about the opposite, and not restricting the cut for the majority of the work, as many folks have the impression we're only talkin smoothing,

I often hear all too vague comments without being specific regarding the honing of the cap iron's leading edge,
and when queried about their opinion of the mouth, or anything to do with things, they seem to take offence.
Surely they believe their method should be able stand up to ridicule, should they give their recipe, and not just the ingredients?

All the best

Tom

[Lee Schierer]

I'm far from an expert on hand planes, but I ran across this interesting article regarding cap irons (https://smallworkshop.co.uk/2016/02/14/bench-planes-the-cap-iron/).

I've messed with my hand planes a bit and they work fairly well for my limited use. I guess I would need to spend some time with someone more knowledgeable to actually see the differences in performance of adjusting cap irons with my own eyes to really understand how to tune a hand plane to perfection or nearly so.

[steven c newman]

Sometimes...those shavings I get....like when edge jointing boards for a glue-up...will stand straight up, and then curl right around my left wrist....

As for chipbreakers....99% of my hand planes have the Bailey designed "hump"...and all I do is mate that to the back of the iron. I will grind it's mating surface to a knife edge, where it meets (and rests on) the back of the iron...I am more worried about shavings getting stuck between the iron and chipbreaker, and jamming things up. I also polish the front edge of the "hump", so that shavings will have a smooth ride, and nothing for the shavings to catch on.

I do have a 22" long Sandusky No. 81 Jointer...that the shavings will shoot straight up. Has the original Butcher iron and chipbreaker, BTW.

Cambered: I do NOT reshape the chipbreaker to match the camber, ever. Waste of time, actually....I will stop the Bailey Chipbreaker right at the corners....because I rarely would ever NEED that much of the iron to show in use. 8" radius...on a Jack plane's iron....we are NOT talking Smoother thin shavings..we are talking flattening work.

Normal space between the edge of an iron and the "hump" edge of the chipbreaker on the smoothers I use? 1mm.

[Mark Rainey]

I'm far from an expert on hand planes, but I ran across this interesting article regarding cap irons (https://smallworkshop.co.uk/2016/02/14/bench-planes-the-cap-iron/).

I've messed with my hand planes a bit and they work fairly well for my limited use. I guess I would need to spend some time with someone more knowledgeable to actually see the differences in performance of adjusting cap irons with my own eyes to really understand how to tune a hand plane to perfection or nearly so.

I agree Lee. I think an in person experience with cap iron technique would be invaluable.

[Rafael Herrera]

When preparing a piece of rough lumber, the objective is to do it quickly, with the least amount of effort and material waste. The cap iron helps with all of that.

In particular, if the piece of lumber is not perfect, hitting a knot can cause a deep tear out (I've had gashes as deep as 1/4" deep in the past). Now one has to plane the whole board to make the tear disappear.

Using the chipbreaker to control tear out comes into play at this early stage, not just when smoothing.

Preparing the chipbreaker is not difficult, takes at the most 10 minutes and you don't need to do it ever again. It's perplexing the amount of pushback one gets when advocating its use. It just makes the plane work better and accomplishes the objectives above.

For example, this board is dry soft maple, it has knots and it's a bit brittle. The surface is out of the mill. It took 15 minutes from rough to ready for final smoothing, no tear outs to erase. Used only the three planes in the picture.

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Intermediate stage, while jack planing, minimizing tear out.

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I recently found this video, from the looks of it it may predate the 1980s Kato & Kawai study, which was geared towards supersurfacers. It's self explanatory and it's specific to hand planes.

https://youtu.be/c0N5pV8N1H0

[Edward Weber]

This might be of interest for those following this thread
https://smallworkshop.co.uk/2016/02/14/bench-planes-the-cap-iron/

[Michael Bulatowicz]

Never again need to prepare the cap iron/chip breaker? I have found that I benefit from tuning it slightly from time to time; a “maintenance “ tuning rather than a full tuning, but certainly not nothing.

I agree with Tom that the largest benefit of the cap iron/chipbreaker lies not with smoothing but with thicker shavings. Today, I’m making a raised panel from cherry with reversing grain; the shavings are .018 inches at the thick side (see image; about 0.5mm) with no tear out in spite of the rising grain at the far edge. My cap iron is set close (?? inches: I didn’t measure, but looks similar to Tom’s or maybe a little closer if anything) and has a ~80 degree leading edge that smoothly curves back per Warren Mickley’s recommendation (or, at least, my recollection thereof). It works well for me.
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[Warren Mickley]

This might be of interest for those following this thread
https://smallworkshop.co.uk/2016/02/14/bench-planes-the-cap-iron/

I read this piece on the double iron; there were a number of errors, so here are some that I remember.

Thick irons were common in wooden planes in the 19th century, but when the double iron planes were being used in the 18th century, irons were thin.

The terms York pitch, half pitch, date from the mid 19th century. If they date from before the double iron era, I would be interested in seeing the evidence.

As mentioned by others in this thread, the cap iron doesn’t have to be extremely close to have an effect.

The accordion effect on shavings occurs when the cap iron is too close for the shaving thickness. Either moving the cap iron back, or taking a lighter cut will alleviate the problem. There is no such thing as too close a cap iron without consideration of the shaving.

[Chris Parks]

Yet it seems some folks are still in the woods regarding the use of the cap iron for taking thicker shavings.


Not having honed ones cap iron steep enough, I like 50, or just over it to be sure, say maybe 52 degrees, I find this to be the minimum steepness I can get away with,


I often get confused by discussion of cap irons and I wonder of others do as well. The old original type of cap iron had a curved face to it and the new irons all appear to have a flat bevelled face to them so what type are you referring to?

The question I then have is if it is the rounded type how do I put a 50 degree face on it, I doubt there is enough material to do that. I suppose the next question is what angle does the original rounded face equate to in practise.

I inherited all my hand planes from my father and his father so they do not have the straight bevelled cap iron.

[Tom Trees]

Aah, that's a very good point Chris
I believe everyone does the same though, as in treating the cap iron just like it is a flat piece of steel,
i.e, I think there's some photos of a fancy magnetic bevel box being utilized for honing the cap somewhere, IIRC.

You can make a small flat bevel if you want, though from what I can make out if going steeper, that might not act in your favour.
Folks like Derek Cohen has some writings regarding honing the cap irons on premium planes,
and he's done various profiles with them, it's likely googlable fairly easy.

One thing I will say about honing the underside is, it's wise to be aware of the sides becoming rounded, i.e cap iron rocking about in the middle.
If that happens one will need to remove only from the centre of the cap.
Easily done with a corner of a stone, or even better a narrow hone, or a little square of abrasive to hollow it out,
enough so the edges touch again, being careful to not repeat this again whilst doing a final stroke or two on the whole of the underside.

That's likely the easiest way to screw up a cap, and folks who work the entirety of the caps underside along the stone,
for the complete duration, seems like wizardry to me.!


David W's honing tip for making the camber very gradual, exactly as you like it...
I think it's in one of his videos, his term "directed pressure" I don't think is very catchy, but it's the biggest help regarding sharpening I've found.

If you've seen someone hone a scraper on the flat, with fingers splayed...and make note of the corresponding honed underside regarding finger placement,
then you're well aware of how it can effect things.
What I never took away from it is this can also help one hone their cambers with the most accuracy, regarding a graceful but tiny curve, which is totally equal on both sides.

Not his words, nor his methodology, but was just a passing comment, and I'm going to give you my hack version what I took from it to sum it up.
Basically putting a finger at the edge, in the oil, not just above like say Cosman for example ...
Rob's got his fingers pretty close to the edge, but I mean practically on the edge for when there is a facet like in the link,
or if one side doesn't match with the other,

I wasn't aware the little pressure from a single finger would play such a role honing the bevel on a stanley iron.
It's sort of a get out of jail free card.

Point and shoot if you like, it's really made honing easier.


Tom

[Chris Parks]

Aah, that's a very good point Chris
I believe everyone does the same though, as in treating the cap iron just like it is a flat piece of steel,
i.e, I think there's some photos of a fancy magnetic bevel box being utilized for honing the cap somewhere, IIRC.

You can make a small flat bevel if you want, though from what I can make out if going steeper, that might not act in your favour.
Folks like Derek Cohen has some writings regarding honing the cap irons on premium planes,
and he's done various profiles with them, it's likely googlable fairly easy.

One thing I will say about honing the underside is, it's wise to be aware of the sides becoming rounded, i.e cap iron rocking about in the middle.
If that happens one will need to remove only from the centre of the cap.
Easily done with a corner of a stone, or even better a narrow hone, or a little square of abrasive to hollow it out,
enough so the edges touch again, being careful to not repeat this again whilst doing a final stroke or two on the whole of the underside.

David W's honing tip for making the camber very gradual, exactly as you like it...
I think it's in one of his videos, his term "directed pressure" I don't think is very catchy, but it's the biggest help regarding sharpening I've found.

If you've seen someone hone a scraper on the flat, with fingers splayed...and make note of the corresponding honed underside regarding finger placement,
then you're well aware of how it can effect things.
What I never took away from it is this can also help one hone their cambers with the most accuracy, regarding a graceful but tiny curve, which is totally equal on both sides.

Not his words, nor his methodology, but was just a passing comment, and I'm going to give you my hack version what I took from it to sum it up.
Basically putting a finger at the edge, in the oil, not just above like say Cosman for example ...
Rob's got his fingers pretty close to the edge, but I mean practically on the edge for when there is a facet like in the link,
or if one side doesn't match with the other,

I wasn't aware the little pressure from a single finger would play such a role honing the bevel on a stanley iron.
It's sort of a get out of jail free card.

Point and shoot if you like, it's really made honing easier.

Tom

Thanks Tom, but what type are you referring to in your OP? That really is the fundamental question as it is not clear and it is something that never gets clarified in any post on the subject. Does everyone need to assume that discussion on cap irons is always referring to the bevel faced type these days?

[Tom Trees]

All of my cap irons are original regular Bailey types Chris, that's including vintage flat top ones, and upwards, some possibly slightly differing regarding the hump, but I notice no difference between any of them.
Hope that clears things up

Tom

[Rafael Herrera]

Thanks Tom, but what type are you referring to in your OP? That really is the fundamental question as it is not clear and it is something that never gets clarified in any post on the subject. Does everyone need to assume that discussion on cap irons is always referring to the bevel faced type these days?

No, he's no referring to the milled faceted cap irons. He's referring to the stamped, curved cap irons used on wooden planes, Stanley planes and its clones.

The angle talked about is imparted to of the cap iron.

Here's David's article from 2012. Directly from the horse's mouth and not steps removed like in the article linked above.

https://www.woodcentral.com/articles/?page=673&tags=handtools&search=&op=AND#gsc.tab=0

This picture is from the article, the angle (50 to 80 degrees) that's being discussed is illustrated here.

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This picture shows a 50 degree angle on the cap iron.

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Educational Video on “Influence of the Cap-iron on Hand Plane” (https://vimeo.com/158558759)

[Chris Parks]

I think the difference between the two types needs to be plainly made in discussions on cap irons.

[Rafael Herrera]

When preparing your cap iron, if you have a diamond stone, you could set it up like in the picture. Move the cap iron left to right until you have a uniform inner bevel. Use uniform or directed pressure to get the desired shape. Grinding the inner bevel back and forth could result in a convex shape and you will start chasing your tail trying to close the resulting gap.

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You'll end up with something that looks like this. This is a 2" iron from a Bailey pattern plane.

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[Tom Trees]

As to your other question Chris...

"I suppose the next question is what angle does the original rounded face equate to in practise. "

Sorry can't help you there, but I suspect there may be some untouched originals hanging around.
I wouldn't be surprised if some differed, since some being longer than others for a given plane, and tab slot not in the same location as on others.
I haven't heard the answer to that, but have read it brought up before,
Perhaps some others here actually have an/one answer for that?

Tom

[Rafael Herrera]

I think the difference between the two types needs to be plainly made in discussions on cap irons.

Although I don't have a sample of the beveled cap irons, it is my understanding that they can be prepared in the same way.

The purpose of the setup is to present an almost vertical wall to the shavings as they climb up the face of the iron. This is a very narrow strip and the beveled cap irons can be ground to that shape.

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Educational Video on “Influence of the Cap-iron on Hand Plane” (https://vimeo.com/158558759)

[Chris Parks]

Thanks Tom, is it possible to see an end on shot showing the 50 degree honed section.

[Tom Trees]

Sorry Chris, but I don't have a good photo of that, and I doubt I would be able to get a clear shot of things either, like Derek for instance.
Besides that, a lot more factors, my cheap diamond card hones glued to some granite aren't flat, so my rougher hones need a bit of familiarity to use,
All my caps are likely a bit rusty, dim lighting,
I have a fancy worn in 4000g fancy diamond plate, but showing on that isn't really going to show much up of a slurry.

Some planes like my 5 1/2, I originally used an Eclipse knockoff to hone @50 deg,
(might have changed it back to 45 at some point... as I failed to understand the mouth needs to be open whilst using the cap iron @50degrees)
likely touched it up at 50 again if so..
Damaged it with some grit, went to 70, and back down to 50somethin.
I won't be honing that particular cap iron needlessly, and I'll bet it looks a right mess if I were to look closely.

I can't say if one has nine lives or however many, but I think I may have went a bit heavy the first time with the honing guide,
so that small bit of geometry, if I changed it much, seems not to be absolutely critical to me.
I just gave any other planes I've gotten since the quickest lick, and never had to go back again due to not getting influence/straight shavings.

If you're wondering why I suggest 50 degrees being the minimum, as does most folks...
then that is because you might want some mild camber for your jack plane, i.e the steeper it is, the further it can be set back,
and you might not like my preference, and want more camber without the corners of the cap iron reaching the edge.
This is also a factor regarding the smoother, as most like the littlest camber/unnoticable by eye until paired with the flat cap.
Either way, for the toughest tests, that for me means 1/64" or under...

That might well be a little too close for comfort for some, if ones lighting/eyesight isn't the best
or for some on site honing on the fly on a wobbly trestle in the breeze might not give one as nice a camber like they would in the workshop,
or if doing some reclaiming timbers with cement/putty/grit or folks getting timbers with mineral deposits,
it makes sense to me to keep it out of as much danger as possible.


I reckon David W's channel has a few demonstrations of honing them, all of about 20 seconds per plane,
and I also reckon one might be able to pull a thicker shaving by following his methods,
which I believe to be fairly close to Warren's recommendation.

Tom

[Warren Mickley]

I often get confused by discussion of cap irons and I wonder of others do as well. The old original type of cap iron had a curved face to it and the new irons all appear to have a flat bevelled face to them so what type are you referring to?

The question I then have is if it is the rounded type how do I put a 50 degree face on it, I doubt there is enough material to do that. I suppose the next question is what angle does the original rounded face equate to in practise.

I inherited all my hand planes from my father and his father so they do not have the straight bevelled cap iron.

The cap iron is a rounded bevel and has been since the 18th century. Where the bevel meets the cutting iron it is quite steep (I like about 80 degrees), but rounds over, so that it is not a flat bevel. For the most extreme work, the cap iron is quite close and the steepest part comes into play, but a steep flat bevel that is too high would cause jam ups when too close. A very small steep bevel at the end of a shallow bevel would be ineffective for intermediate work.

I talked to Ron Hock at Valley Forge in 2009 about his cap irons. I told him they were too flat and needed a rounded bevel. He said they were soft enough steel that you could bend them in a vise to get more height and then true things up again on stones. He seemed to be in the dark about cap iron use.

Around the same time Lee Valley and Lie Nielsen came up with "Improved Chipbreakers". Chris Parks says he is confused, but these companies did not even know enough to be confused. They managed to render the cap irons ineffective while promoting them as innovation. Good marketing, not such good toolmaking.

[Rafael Herrera]

I asked him about cap irons as well, in 2019 or 2020, at a zoom meeting about his irons. I didn't get a satisfactory answer then, however their tear out mitigation function is now acknowledged in their product description.


"a thicker chip breaker (cap iron) can stabilize the blade's cutting edge reducing vibration and chatter. Set your breaker very close to the cutting edge to best prevent tear-out."
Bench Plane Blades and Breakers (https://www.hocktools.com/products/bp.html)

[Thomas Wilson]

I read these articles and watched the video many years ago. I was glad to see them again. It is therapeutic. I was inspired to go up to the tiny condo shop to plane a few scraps of knotty low grade pine. I have Lie-Nielsen planes with stock blades and chipbreakers. The chipbreaker is a milled bar stock rather than stamped metal. I think Lie-Nielsen introduced the milled design improvement for the chipbreaker. Based on the Japanese research, I set the chipbreaker very close to the edge of the blade by eye. I have no way to measure it but it is well less than a 1/16”. I can increase the depth of cut from transparent tissue thickness to sturdy tight curls without changing the chipbreaker setting. I measured the thickness of some of these with a digital caliper. Thinnest were 0.002”. The thickest were 0.008”. I could have gone heavier. No tear out even on the heavy cut. Most people like two things in my shop on first try, the planes and the nail guns. Me too.

[Derek Cohen]

One factor I am still puzzled about is the ideal shape of the leading edge of the chipbreaker. Should it be flat or rounded?

There have been arguments that it was always rounded from the days of Noah, so this is best. Both traditional woodies and Stanley bench planes are made like this. The question is whether the modern ones, such as Lie Nielsen, Veritas, Clifton (new ones - old were rounded) and copies by WoodRiver et al are flat since this was likely a result of easier manufacturing, and whether this is worth a damn.

Here is a Veritas blade with a re-worked LN chipbreaker …

https://i.postimg.cc/R4s1sGND/LN2.jpg (https://postimages.org/)
https://sawmillcreek.org/blob:https://sawmillcreek.org/d2279598-e092-4ab3-9670-3600ac622ac1

The aim here was to round the front of the chipbreaker …

https://i.postimg.cc/fZvfXMZZ/LN3.jpg (https://postimages.org/)
https://sawmillcreek.org/blob:https://sawmillcreek.org/a56cb44d-84da-431a-857f-ef2799650f49

I have done this with Veritas chipbreakers as well ….

https://i.postimg.cc/7DGyPxNV/2.jpg (https://postimages.org/)
https://sawmillcreek.org/blob:https://sawmillcreek.org/b0fcd907-408c-483d-81e8-7f07cabbd822

Here are chipbreakers in unmodified format (Veritas, LN, Stanley) …

https://i.postimg.cc/8N4tcnh8/LV_Chipbreaker_html_m514b0e82.jpg (https://postimages.org/)

https://sawmillcreek.org/blob:https://sawmillcreek.org/7a99260a-4ee6-4ed0-803c-e2b697b11fb2

The flat-to-the-floor of both Veritas and LN …

https://i.postimg.cc/dJ0nymBh/LV-Chipbreaker-html-m46227ae8.jpg (https://postimages.org/)

https://sawmillcreek.org/blob:https://sawmillcreek.org/40148f58-2f97-49a9-a75c-027aa17c294f

The (old) Clifton is rounded at the front but otherwise flat and also lacking in spring …

https://i.postimg.cc/mT6jNzX8/LV_Chipbreaker_html_m10b493fd.jpg (https://postimages.org/)

https://sawmillcreek.org/blob:https://sawmillcreek.org/dce63164-560e-4c4f-8ffa-1f0a8c7d1757

What I do with my LN and Veritas chipbreakers is add a slight bend in the middle to create some spring. This adds to their being tightened more securely.

The angle I give to the leading edge is around 70-80 degrees. Now this is the issue: does it make any difference whether the front is rounded or flat if this angle is added? So far I cannot say that I have noticed much difference at all.

Planing interlocked Jarrah …

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https://i.postimg.cc/YtPg3mpm/22.jpg (https://postimages.org/)

Regards from Perth

Derek

[Edward Weber]

One factor I am still puzzled about is the ideal shape of the leasing edge of the chipbreaker. Should it be flat or rounded?

There have been arguments that it was always rounded from the days of Noah, there this is best. Both traditional woodies and Stanley bench planes are made like this. The question is whether the modern ones, such as Lie Nielsen, Veritas, Clifton (new ones - old were rounded) and copies by WoodRiver et al are flat since this was likely a result of easier manufacturing, and whether this is worth a damn.



There's an old saying that goes something like,
Cut it with the edge or split it like a wedge.
This is the same "argument" about chisels. Some prefer the convex bevel that's associated with freehand sharpening. Some prefer a flat bevel that you get with a guide. And some go for a hollow grind from a wheel.
IMHO, it's all a matter of personal taste. Each approach has some benefits, but it winds up being what the user prefers.

[Rafael Herrera]

I think it's been pretty well established that the chipbreaker deflects the shavings upwards, allowing the edge to cut the fibers before they have time to detach and create tear out.

As long as there's a bevel to deflect the shavings, one gets the effect. That would be the case with both types of chipbreakers when taking thin shavings. However, if you move the chipbreaker back up, when taking more substantial shavings, the modern style chipbreakers may be too shallow to get the desired deflection.

This would have to be verified. If one mostly uses preprocessed lumber and only smothing it, then both designs would work.

Rafael

[Derek Cohen]

Hi Edward and Rafael

We are all on the same page. Chips/shavings are deflected by angles, and a round angle is at some point a flat to be an angle (so my logic tells me). But Warren has been the torch carrier here, and he will hopefully be along to to explain whether there is a difference. I respect his opinion, which is why I have rounded some of my chipbreakers (shaping them ala Paul Sellers sharpening method - freehand alongside a sliding bevel). However, I do not see a difference between flat leading edges (off a honing guide) and rounded leading edges. Is it worth the effort?

Regards from Perth

Derek

[Michael Bulatowicz]

Warren can certainly help clarify; my recollection of his previous comments is that the rounding allows more nuance to the use of the cap iron based on distance from the edge. If I recall correctly, he said the effect is not as on/off as with a flat bevel. I haven’t experimented enough with a flat bevel to comment—I simply went straight to the rounded bevel that was my recollection of his recommendation and it has worked well for me.

[Edward Weber]

Hi Edward and Rafael

We are all on the same page. Chips/shavings are deflected by angles, and a round angle is at some point a flat to be an angle (so my logic tells me). But Warren has been the torch carrier here, and he will hopefully be along to to explain whether there is a difference. I respect his opinion, which is why I have rounded some of my chipbreakers (shaping them ala Paul Sellers sharpening method - freehand alongside a sliding bevel). However, I do not see a difference between flat leading edges (off a honing guide) and rounded leading edges. Is it worth the effort?

Regards from Perth

Derek

Well, PS seems to think, from what material of his I've seen and read, that every chisel should have a convex bevel. I do not agree with that stance. I prefer a flat bevel on chisels and I honestly don't use western planes enough to have the background to comment, which is why I'm following the thread.
I understand the physics and geometry of it all, but have not near enough hands on time.
Japanese planes that I prefer usually have much thicker blades and don't suffer from the same issues as much as their western cousins.

[Chris Parks]

Around the same time Lee Valley and Lie Nielsen came up with "Improved Chipbreakers". Chris Parks says he is confused, but these companies did not even know enough to be confused. They managed to render the cap irons ineffective while promoting them as innovation. Good marketing, not such good toolmaking.

Confused was perhaps the wrong term, my "confusion" was meant to highlight the lack of clarity and separation of the two types in a discussion of this nature. I think the type of CB being talked about should have been stated for clarity in the OP but I have noticed over many years that it rarely is so I took the opportunity to try and highlight the point. My personal opinion is that the flat bevel type came about because it is easier and cheaper to make and no other reason.

[Rafael Herrera]

We are all on the same page. Chips/shavings are deflected by angles, and a round angle is at some point a flat to be an angle (so my logic tells me). But Warren has been the torch carrier here, and he will hopefully be along to to explain whether there is a difference. I respect his opinion, which is why I have rounded some of my chipbreakers (shaping them ala Paul Sellers sharpening method - freehand alongside a sliding bevel). However, I do not see a difference between flat leading edges (off a honing guide) and rounded leading edges. Is it worth the effort?


I asked Warren and David about non-smoothing uses of chipbreaker a few months ago. David had made some comments in passing and I was curious.

Warren's response to my question was that a rounded bevel results in the high angle deflection when the chip breaker is really close, the angle encountered by the shaving is shallower when the cap iron is further back.

If you were to have a flat facet instead of a rounded one, the thicker shavings would hit the steep wall. What comes to mind is would this steep wall make planing more difficult than necessary? Can this be tested?

Warren even quoted Nicholson:


"The basil of the cover must be rounded, and not flat, as that of the iron is." Nicholson 1812
Nicholson was very spare with his words; he would not have written this without it being important.


I don't have one of these flat bevel cap irons to try, though. Perhaps when they're back in stock at Ron Hock's store I'll get one.

Another though is, in the 19th century, specially in 1812, grinding a flat bevel on a grinding wheel and a sharpening stone would have been time consuming, but a rounded bevel a breeze. If the results are the same, why waste time with a flat bevel?

Rafael

[Rafael Herrera]

Confused was perhaps the wrong term, my "confusion" was meant to highlight the lack of clarity and separation of the two types in a discussion of this nature. I think the type of CB being talked about should have been stated for clarity in the OP but I have noticed over many years that it rarely is so I took the opportunity to try and highlight the point. My personal opinion is that the flat bevel type came about because it is easier and cheaper to make and no other reason.

We sometimes make comments with a lot of implied assumptions. The vast majority of old metal and wooden planes have a rounded chipbreaker, so when they are discussed it is safe to assume we're talking about rounded end chip breakers.

In any case, can the flat bevel chipbreakers be ground enough to get a small rounded bevel? It does not need to be big.

A story I read in the forums is that when they were introduced, they were marketed as improved due to their thickness. There was (and still is) a big deal made about the thin Stanley irons and chip breakers, their chattering problem. It was soon noted that one could not set these new chipbreakers close to the edge to get the chipbreaker effect if one wanted to try it. They were later modified. I don't know if this story is true.

[Chris Parks]

The bevel type presents no assistance to keep the shaving moving upward until the shaving has moved back from the cutting face of the blade where the rounded type immediately lifts the shaving and keeps pushing it upward out of the mouth of the plane. Is that an advantage...I think it is but that is only a gut feeling and nothing more.

[Chris Parks]

We sometimes make comments with a lot of implied assumptions. The vast majority of old metal and wooden planes have a rounded chipbreaker, so when they are discussed it is safe to assume we're talking about rounded end chip breakers.

I have read plenty of threads where the type of plane or age or even brand is not brought into the conversation and the OP was a classic example of this.

[Rafael Herrera]

The bevel type presents no assistance to keep the shaving moving upward until the shaving has moved back from the cutting face of the blade where the rounded type immediately lifts the shaving and keeps pushing it upward out of the mouth of the plane. Is that an advantage...I think it is but that is only a gut feeling and nothing more.

It can be observed. Here, https://youtu.be/c0N5pV8N1H0, or here, https://vimeo.com/158558759.

[Warren Mickley]

Fifiteen years ago it seemed like I was forever explaining the difference between chatter and tearout. Chatter occurs when the iron is poorly bedded and the iron starts vibrating, leaving a series of parallel lines in the work. Chatter rarely happens with a bench plane. Tearout occurs when the wood is planed against the grain and the iron lifts and breaks wood fibers.

A heavier iron is some help with chatter, but no help with tearout. Fifteen years ago people were promoting heavy irons and heavy cap irons as a means to prevent tearout. Amateurs were making 1/4 and even 5/16 thick irons and claiming they would prevent tearout. Makers like Hock, LV, and Lie Nielsen were making marginally thicker irons and cap irons and touting their superiority.

The Lie Nielsen "improved chipbreaker" had three features which were claimed as improvements: they were thicker, they were machined on the underside for better seating, and they were milled to roughly 30 degrees on the top side, supposedly help with clearance for the shavings. This last feature rendered them ineffective for double iron work. They had no idea how a double iron plane worked. And as if to emphasize the point, when they were first made they had a problem that the iron would not extend far enough to cut wood when the cap iron was set close.

[Chris Parks]

It can be observed. Here, https://youtu.be/c0N5pV8N1H0, or here, https://vimeo.com/158558759.

Thanks Rafael, I have seen both of those videos quite a few times over the years. What I haven't seen is a similar video showing the bevel type of CB in use.

[Derek Cohen]

I asked Warren and David about non-smoothing uses of chipbreaker a few months ago. David had made some comments in passing and I was curious.

Warren's response to my question was that a rounded bevel results in the high angle deflection when the chip breaker is really close, the angle encountered by the shaving is shallower when the cap iron is further back.

If you were to have a flat facet instead of a rounded one, the thicker shavings would hit the steep wall. What comes to mind is would this steep wall make planing more difficult than necessary? Can this be tested?

Warren even quoted Nicholson:



I don't have one of these flat bevel cap irons to try, though. Perhaps when they're back in stock at Ron Hock's store I'll get one.

Another though is, in the 19th century, specially in 1812, grinding a flat bevel on a grinding wheel and a sharpening stone would have been time consuming, but a rounded bevel a breeze. If the results are the same, why waste time with a flat bevel?

Rafael

Rafael, I get this, however I would like some evidence for one or the other. In this day and age, anecdotal evidence is a good place to start (thanks Warren), but we can do more now.

Regards from Perth

Derek

[Tom Trees]

There maybe an answer to this on some of David's recent enough postings Derek.

Tom

[Warren Mickley]

Another though is, in the 19th century, specially in 1812, grinding a flat bevel on a grinding wheel and a sharpening stone would have been time consuming, but a rounded bevel a breeze. If the results are the same, why waste time with a flat bevel?

Rafael

These cap irons were forged; if a flat bevel was wanted it would have been easy to forge a flat and true it up by grinding.

This reminds me of when Larry Williams claimed the double iron was invented to save labor. Todd Hughes wrote

"...Well if you think it was easier and cheaper for plane makers to make these double irons I sugest you forge a blade out, cut the slot into it for the cap iron, forge the cap iron out , make the cap screw, thread it and cut the threads in the cap iron and report back to us as how much easier this all is then to make just a single iron."

[Rafael Herrera]

These cap irons were forged; if a flat bevel was wanted it would have been easy to forge a flat and true it up by grinding.

This reminds me of when Larry Williams claimed the double iron was invented to save labor.

"...Well if you think it was easier and cheaper for plane makers to make these double irons I sugest you forge a blade out, cut the slot into it for the cap iron, forge the cap iron out , make the cap screw, thread it and cut the threads in the cap iron and report back to us as how much easier this all is then to make just a single iron."

I don't see the relevance to what I posted.

It was guessing that it would have been easier to manufacture them with a rounded bevel as opposed to a flat bevel. If the manufacturing effort was not an issue, then the rounding of the cap iron bevel had other reasons.

-----------

I read those debates, they were interesting. Larry seems to have discontinued his line of single iron bench planes he so vehemently advocated, they're retiring. It's interesting to note that I never see any of his planes in the used tool market, but instead I see a lot of LN planes, mostly unused, sold all the time in the classified section of this forum.

[steven c newman]

It was very simple and easy to do.....sheet of Mild Steel.....Stamped to the shape needed...(even those slots were stamped out) a couple twists of a tap into the stamped out hole....Stanley Chipbreaker...Done. They would even include the logo IF needed on the Chipbreaker....

One person to run the Stamping Machine.....Another to do the tap work...basket of stamped and tapped Chipbreakers then taken to the Grinding line.....One person to clean things up, match the bevel to a jig. Then over to the assembly line. Stanley would have had a machine/lathe line to turn out the bolts....ALL the bolts.

Sargent and Millers Falls would have had similar machines....

The "Hump" also acts as a spring.....note what happens as you tighten the bolt between the chipbreaker and the Iron.

[Rafael Herrera]

We're talking about the cap irons of wooden planes.

[Robert Hazelwood]

Regarding the Lie Nielsen chipbreaker, it works well for me in a #4 smoother. I only use this plane for thin shavings less than about 2 thou, so it does not have to adapt to a wide range of shaving thicknesses. Perhaps if I used it for rougher work as well the limitations of the LN chipbreaker design would become apparent. But for thin shavings its always worked very well. I prepared it by sharpening a small rounded bevel, using a rocking technique like Paul Sellers does with chisels. The bevel maxes out around 70 degrees or so at the tip (I don't measure the angle).

Honestly the LN chipbreaker seems more similar in shape to the Ward chipbreaker in my wooden try plane than either does to the stanley hump design. The Ward is taller than the LN, but there is a flattish bevel at a fairly low angle, and then a steeper secondary bevel at the tip with a rounded shape, versus the abrupt hump on the Stanley. I prepare them pretty much the same way.