bendy cap irons

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Carl P":z06l2iwz said:
On the curved cap iron, I had a couple of spar planes go through my hands a few years ago - they both had a semi-circle shaped cutting edge and a matching cap iron. Unfortunately as I didn't need them I released them into the wild waters of ebay but, although at the time I didn't know about the cap iron effect, I remember being particularly impressed by the ammount of care that had been taken to get an exact fit between cap iron and cutting edge.

Cheerio,

Carl

On the spar plane, that profiled cap iron is appropriate, since the sole of the plane follows the profile of the cap and an even depth cut can be had with the profiled cap.

I guess the best piece of advice is probably that the profile of the cap should match the sole of the plane being used.

For folks who want to camber the cap iron on a flat soled plane, I think they just need to think a little bit harder about exactly what's going on at each area of the wood, and if they think the cap is too close at the corners, a thought about what's going on at the middle of the plane at the same time needs to be had. Specifically, if the situation is such that the cap iron is 2 thousandths away from the edges at the corner of an iron and one is worried that it might be too close and wants to remove the cap, a second thought needs to be had about what's going on in the middle of the iron. At that point, for the corners to be in the cut, the cap iron would have to be no more than 2 thousandth from the center of the plane, and if the center is several thousandths lower than the corners, the cut depth would be too large for the cap iron set and the plane couldn't be pushed.

That's on a smoother cambered basis. The greater the camber, the narrower the cut and the less chance the edges are even in the cut.

(well, and for practical purposes, if one leaves the cap iron straight across, it's easy to find that it lacks nothing and the rest is overthinking).

But, the spar plane provides an interesting option for people who want to use the cap iron for very heavy work. It's not usually necessary to have the cap set so close as to provide resistance on a jack (though the cap does improve the function of the plane in general), but if someone wanted to, anyway, they could opt for a gutter style jack.

Thanks for bringing up the spar plane to stimulate the discussion.
 
D_W":3eftn664 said:
Bravo, Custard, for ignoring all of the discussions about where it may not work or what the patent may or may not have said.

There may be a little confusion, here.

The first reference to cap-irons (back-irons, cover-irons, double-irons, chipbreakers) was in an advertisement for a Philadelphia planemaker, Samuel Caruthers, in 1767, in which he offered "double-iron planes, of late construction, far exceeding any tooth planes or uprights whatsoever, for cross grain and curled stuff". In other words, using the cap-iron to control tearout. It isn't known when or where the idea was developed. The close setting of the cap-iron is mentioned in many texts since (eg 'Planecraft') but precise setting dimensions are not mentioned.

In April 2014, and article was published in Popular Woodworking entitled, "Chipbreaker: Theory and Use" by Kees van der Heiden and Wilbur Pan. (Kees is also 'Corneel' of this parish.) This references the work of two Japanese professors, Kawai and Kato, showing what happens at the cutting edge of a plane blade. From this work, cap-iron settings in the order of 0.1 - 0.3mm were shown to be effective at tearout control. I do not know if there was discussion about cap-iron settings on the woodworking forums before this article was published; Keesl could no doubt set us right. To the best of my knowledge, no patents arose from either the first use of cap-irons, or from the work presented in the 2014 article.

If anybody should take credit for spreading the word in the modern era about using the cap-iron to control tearout, it is Kees and Wilbur, and of course Professors Kawai and Kato for their research.

In 1867, Leonard Bailey was granted US patent 72443, which enabled him to use thin plane blades in metal-bodied planes. He did this by shaping the cap-iron in such a way that it pressed the blade to the frog surface at three points; the top of the frog, the base of the frog, and at an intermediate point between the two. This did not interfere in any way with the craftsman's ability to set the capiron close to the blade edge to control tearout, should he wish. It was a completely separate matter, intended to allow blades to be made from thinner stock without making them prone to chatter - a matter discussed in depth in other threads.
 
Credit belongs to Planecraft. If you follow the mathematical logic in the table present in every edition of Planecraft (8+) you come to a setting the in 1/128" range for "difficult timbers" -- .2 of a millimeter, rounded, dead center of the range suggested by K&K.

The progression in the table goes 1/32", 1/64", then 'as close as you can get it.' Easy math from where I come from. Granted, they would never have put 1/128" in the table -- just as ridiculous now as it would have been back then. Anybody not getting the point is rather dense -- it's not measurable in a wood shop and it's a setting by eye and judgment as it should be.
 
You're a little behind, Cheshire. I'll give you a brief history lesson on the American side.
* Warren Mickley, since at least 2006, took every opportunity to talk about the superiority of the double iron. We thought he was a troll. Todd Hughes, a blacksmith also told us we were in the weeds if we didn't think it was superior. Todd was a straight up troll sometimes, though (for real), and he didn't actually use planes. he just suggested that the cap iron must be awfully effective to go to the trouble of smithing it and paying for it in an evironment where money is very tight (he was right).
* Sometime around there, Steve Elliot and others got some data and stills from kato and kawai's study, it was mentioned on a few blogs and disappeared for reasons I don't know
* Early in 2012, after being goaded by warren over and over, I decided not to plane with anything other than a stanley plane until I figured out how to use the cap iron. I posted publicly to warren that he was right after I figured out how to use the double iron (took maybe a week or two weeks), and posted that I was ashamed to find out that the stanley plane was more capable at removing tearout than a 55 degree infill with a 3-4 thousandth mouth that I'd made not long before (thinking that such a plane was the most practical design for a do-it-all smoother). I told warren that he was right, I was wrong, and a few strings of posts ensued. Most of the people, including a few current plane makers told me that I was ridiculous and trolling with warren, and that they had only ever met one person other than warren who regularly used the double iron to control tearout.
* Bill Tindall saw my post on wood central (and I was trolling people on sawmill creek telling them to set the cap iron close at that time, too - with little success). He said he was interested in what I was saying because at the same time, he and Steve Elliot were trying to get access to videos related to the earlier mid 2000s discussion that fell flat. They were not available yet - to anyone. They weren't posted on any public server and Bill and Steve were working with non-English speaking folks about first, getting the videos and second, having permission to share them (given that they were originally made for marunaka to design a super surfacer that would plane without tearout - they influenced the design of the double iron on the marunaka)
* Bill and I talked back and forth a fair amount and relatively soon after, those videos were posted to a japanese server
* Bill enlisted the help of Mia Iwasaki to translate the captions and documentation that came with them. Mark Hennebury (who sells supersurfacers) posted the videos over here on his site
* Wilbur took a copy of the video and Mia's translations and put captions in the video, and posted it on his site
* Bill at the time wanted to pitch the cap iron thing to magazines, and shortly thereafter (this is in 2012), he forwarded an email from Bob Lang asking if I would write an article for Popular Woodworking. i said I didn't want to because I'm not a professional and I thought that such an article should be written by someone like Warren (who has been using the double iron in daily work for 35 years or so and doing most of his finish work with planes). I also wanted complete control of what would go in an article, so in april of 2012, I posted an article that was edited (and pictures provided by) by Ellis Wallentine, and i think STeve Elliot may have read some of it - he provided one of the pictures in it, too, ellis provided the other.
* I wrote an article because once the video came out, every Tom, Dick and Harry was an expert on using the cap iron and they were blindly following the video suggesting an 80 degree bevel on a cap iron (which is suboptimal in hand tools) and coming up with all kinds of ridiculous foolishness about measuring the distance the cap iron was set or making some contraption or shims to do it (it's very easily just done by hand and eye - kentucky windage, if you will).
* Fast forward a couple of years, Bill still was pushing around behind the scenes to get an article and Kees had written one and I believe Wilbur was added on to help push it through. Kees will never admit it, but the article content comes from Kees, not Wilbur. Wilbur's contributions (like annotating) have been ancillary, and not of the fundamental type in actually describing how to use the cap iron.

Wilbur was not included in the discussions between Steve, Bill and I (and Wiley Horne and Mia) until well later - the actual discussions predated the video. Video is powerful, though, and people won't believe what you say to even try it, but they'll believe a video.

Stateside, there were only three people that I can remember experimenting with cap irons before the video ever came out. At least in an educated successful way. Bob Strawn, me and Kees. Kees isn't stateside, but he participates in our forums. I don't know why nobody paid attention to Bob Strawn. He experimented with all kinds of stuff (sharpening on thin strips of steel, other metals, and cap irons, etc).

There was no mention of planecraft or any of these other texts over in the states until after we published an article. Bill Tindall and I joked that as soon as we put it on wood central, every armchair expert would probably be able to go find it in older texts and say they knew about it all along. That said, nobody ever agreed with Warren publicly.

I believe that there were plenty of people using a cap iron in England, but none of them ever came over to the states to say anything, and the English posters on our sites in the US didn't, either. Why Warren would repeat himself over and over when nobody believed him, I don't know.

So that's pretty much a summary of it up to this point.
* Credit Bill Tindall and Steve Elliot for finding and getting access to the video. They spent a lot of time doing it.
* Credit Kees for looking at this stuff in a vacuum (and Bob Strawn, too) before anyone else.
* Credit Mia Iwasaki for doing translation work that was technical (and something that was probably a significant amount of work)
* You don't have to give me credit for anything, but recognize that I figured it out and was discussing it on forums before there was any video available to be distributed and before I knew of any of it. It's funny how much trolling I got at the outset for even suggesting it, and most of that evaporated when a video showed up. That shows a lot about peoples' rationality - refusing to try something that can be explained in a few bullet points on a forum post.

The editor of the wood central article wanted me to credit Wilbur. Nothing against Wilbur (I have had some back and forth with Wilbur selling tools, etc, and he's a fine person), but he was not a part of the core effort, just a tag-along, and I would've left the credit with Mia, Steve and Bill as far as the video goes.

I'd have never figured out how to use a double iron without Warren's goading, but Kees, Bob Strawn and I didn't need a video to figure it out despite never being taught anything about it. If you're wondering why we didn't figure it out from Warren, it's because warren's instructions on how to set the cap iron were usually something like "it's hard to explain, it's subtle. a craftsman's skill".

I am so ardent about it not because of the above, but because when you actually put it in practice, it works a treat - better than anything else, and its at the fingertips of everyone. It makes every part of a stanley or old wooden plane work better, reduces the reliance on constant sharpness in trouble areas, and eliminates the need for precision stuff like tiny mouths and perfectly flat soles. And of those two types (old wooden planes and stanley planes), it 100% of the time makes those planes something that will stop you in your tracks before they will chatter.
 
CStanford":3lofsgfm said:
Credit belongs to Planecraft. If you follow the mathematical logic in the table present in every edition of Planecraft (8+) you come to a setting the in 1/128" range for "difficult timbers" -- .2 of a millimeter, rounded, dead center of the range suggested by K&K.

The progression in the table goes 1/32", 1/64", then 'as close as you can get it.' Easy math from where I come from. Granted, they would never have put 1/128" in the table -- just as ridiculous now as it would have been back then. Anybody not getting the point is rather dense -- it's not measurable in a wood shop and it's a setting by eye and judgment as it should be.

Bill and I were thinking of you (me more than Bill, maybe) when we mentioned that there would be after-the-fact armchair experts who had never managed in a decade to mention it before - not when Warren was getting belittled, or any other time.

But after the fact, you didn't disappoint.

Bob Feeser referred to planecraft often, but he never said anything about the cap iron settings.
 
Glad to know you were thinking of me. I don't even know who "Bill" is. This is weird, David.

You and "Bill" can refer to me however you please. It doesn't change the contents of Planecraft and the fact that it predates "Warren" by decades, and presumably "Bill" too.

If your metric by which you judge woodworking information is my having 'discovered' it first I can assure you that you will be sorely disappointed. Let me make this perfectly clear.
 
CStanford":3qva3662 said:
Glad to know you were thinking of me. I don't even know who "Bill" is. This is weird, David.

You and "Bill" can refer to me however you please. It doesn't change the contents of Planecraft and the fact that it predates "Warren" by decades, and presumably "Bill" too.

Well, we didn't give you exclusive rights to trolling. I think I referred to you as "people like Charlie" :D

You've read wood central long enough to have seen Bill Tindall's handle.

Why Bill was so interested in the double iron, I don't know. He goes down some odd technical rabbit holes. Bill didn't believe me (even after the video) that much, either, and unknown to me, it was a long time later that he actually even tried to use the double iron.

When he tried it, though (after kees posted a video), it didn't take long for him to describe - very animated - where it's useful (risk free flusing of surfaces on furniture, etc).
 
custard":peiuzayt said:
I was fretting about blunting the edge by running the cap iron over the honed edge when setting it ... I actually did run the cap iron over the edge a couple of times, but in practise it didn't seem to cause any problems and the iron still cut well. I'm sure with a bit more practise at setting the cap iron extremely close this wouldn't happen so much ...
I've mentioned this elsewhere custard (another forum I think), but one technique you might try for close setting of the cap iron to the cutting edge is to loosely assemble the blade and the cap iron, with the cap iron set generously back from the cutting edge. Then gently jam the cutting edge of the blade perpendicularly into a softish wood, e.g., poplar or pine. Slide the cap iron down to the wood, and tighten the machine screw to lock it in place.

It usually works pretty well, and a bit of practice helps in determining how firmly you should jam the blade's cutting edge into the wood before adjusting the cap iron. I can't say I've noticed detrimental effects to a freshly sharpened blade through this 'wood jamming' technique, although there might be - I just haven't noticed any! Slainte.
 
D_W - I'm not quite sure where the patent you mentioned comes into this. As far as I'm aware, the only patent applying to cap-irons is Bailey's, which as stated is about using thin irons, not about tearout control. Is there another patent about using cap-irons for tearout control?
 
I never relied on a patent as impetus to figure out why warren was heckling me. I don't care much what was in the patents, because what's printed or not printed doesn't really change what is.

One of the reasons I was so pleased to see Custard nail it right on the head trying out the cap iron is because I'm sure it didn't take him weeks to learn it, he's already aware of the benefits of it, and he's not arguing about what was in an old text or what's in a patent.

It doesn't really matter. The only point I wanted to make about anything related to that patent is that:
* there hasn't been any subsequent metal plane cap iron design that is an improvement on Baileys (for any reason, really, performance or otherwise)
* the oft had discussion about flatness of the frog or the seemingly undesirable situation to some people where the iron contacts only at the top and the bottom is essentially a planemaker's dream. It's exactly how a good designer would have it.

I sure hope that in all of this, at least a half dozen other people who have never really appreciated their stanley or record planes too much will actually prepare and set a cap iron and work it.

Forget about the patent at this point for anything other than literary curiosity. It will not teach you 1/10th of what an hour of experimentation at your bench will.
 
D_W":26gkpzax said:
It doesn't really matter.

Well, that at least I can agree with. On another thread, I did say everybody needs to lighten up a bit - it's woodworking, not life and death.

The reason for asking about the patent was as stated. There still seems to be some confusion, but before the whole thing becomes a flame-war, I think I'll just leave it be.
 
Cheshirechappie":2ksblklm said:
D_W":2ksblklm said:
It doesn't really matter.

Well, that at least I can agree with. On another thread, I did say everybody needs to lighten up a bit - it's woodworking, not life and death.

The reason for asking about the patent was as stated. There still seems to be some confusion, but before the whole thing becomes a flame-war, I think I'll just leave it be.

I think most people ignore the patent when it's brought up, but it does come up on various forums from time to time. It's used relatively often as justification that Leonard Bailey didn't know that you could break chips with it (because he didn't say it explicitly), or as description that we're all setting our cap irons wrong if they don't touch at three points (though since you've brought it up this time, we did at least learn that the patent was made when the frog was an older style with a ledge and unsupported area, something all of the newer types have eliminated). There's no great reason for the caps on the later designs to touch at three points. Conceptually, it sounds good, but most people would probably bend the cap too far and have too little pressure on the edge of the iron where you really need it.
 
G S Haydon":srb2ltle said:
Nice vid David. Shows a very effective way of using a plane.

Thanks, Graham. And a plane that would be cast off by most. I think I said it already, but I hate to admit that while the iron's not quite up to par with the older stanley's, the plane itself feels as good as any smoother I've ever used. :shock: It hardly took anything to lap it flat and the whole thing locks up tight as a drum. The handle is inexpensive beech with a thick lacquer on it, but it's shaped nicely and oriented well in the plane.

Certainly a usable iron, though. I have a couple of more kitchen cabinets to make, and I will use this smoother and its iron to do them just to get a better idea of these modern irons in context (the cap iron makes their quality not so critical, though)

(I am kind of jealous of Custard's I.Sorby metal plane, though)
 
I continue to be intrigued by this thread. I do have a question however or possibly an observation that I don't think has been addressed. Last night, after watching David's YouTube video (I hope you don't mind me referring to you by your first name) I thought I'd do some experimenting. So I squared the end of an iron, which was previously a bit wonky and re-ground it at my grinder. Now on this occasion I happen to have misjudged my angles a bit and ended up with a lower angle on that iron than I was aiming for. I didn't think much of it and honed as usual on my oil stones and tried to set the cap iron as close as I could. As soon as I started taking test shavings on some pine I encountered the most exquisite chatter you could imagine! Ribbon upon ribbon of perfectly parallel little ridged shavings came off that plane - even when planing against the grain! I tried lube on the sole to no avail. The only thing that tamed it was going back to the stones and working a steeper bevel. I had never encountered chatter of any sort before this incident. This might be a false conclusion drawn by a too small sample but it does make me think that there is probably an optimal bevel angle for the cap iron effect. Does this make sense to anyone else as well?
 
D_W":1c6c7t5c said:
CStanford":1c6c7t5c said:
Glad to know you were thinking of me. I don't even know who "Bill" is. This is weird, David.

You and "Bill" can refer to me however you please. It doesn't change the contents of Planecraft and the fact that it predates "Warren" by decades, and presumably "Bill" too.

Well, we didn't give you exclusive rights to trolling. I think I referred to you as "people like Charlie" :D

You've read wood central long enough to have seen Bill Tindall's handle.

Why Bill was so interested in the double iron, I don't know. He goes down some odd technical rabbit holes. Bill didn't believe me (even after the video) that much, either, and unknown to me, it was a long time later that he actually even tried to use the double iron.

When he tried it, though (after kees posted a video), it didn't take long for him to describe - very animated - where it's useful (risk free flusing of surfaces on furniture, etc).

Ah, Bill Tindall. Of course. Lots of Bills in the world -- last names are good.
 
memzey":30ocs07e said:
I continue to be intrigued by this thread. I do have a question however or possibly an observation that I don't think has been addressed. Last night, after watching David's YouTube video (I hope you don't mind me referring to you by your first name) I thought I'd do some experimenting. So I squared the end of an iron, which was previously a bit wonky and re-ground it at my grinder. Now on this occasion I happen to have misjudged my angles a bit and ended up with a lower angle on that iron than I was aiming for. I didn't think much of it and honed as usual on my oil stones and tried to set the cap iron as close as I could. As soon as I started taking test shavings on some pine I encountered the most exquisite chatter you could imagine! Ribbon upon ribbon of perfectly parallel little ridged shavings came off that plane - even when planing against the grain! I tried lube on the sole to no avail. The only thing that tamed it was going back to the stones and working a steeper bevel. I had never encountered chatter of any sort before this incident. This might be a false conclusion drawn by a too small sample but it does make me think that there is probably an optimal bevel angle for the cap iron effect. Does this make sense to anyone else as well?

Certainly if the only difference is a long thin bevel vs. one that's not as long and thin, it would seem possible that would cause chatter.

I've always ground the primary high 20s or so and hand honed on something that's probably low 30s in degrees. I have also had wooden plane irons that were sharpened to a very long primary that didn't chatter, though (those irons, of course, came from sheffield). No clue what their angle was, probably 20 degrees or so.

Anyway, whether it's only the thin primary bevel or if it's a combination of things that the thin bevel is a part of, I don't think we could know.
 
Thank you David. I normally sharpen to similar degrees but for some reason didn't quite manage it this time. On a separate note I've also had trouble in the past with the mating surface between the cap iron and iron not being 100% and as a result allowing shavings to get jammed in the gap. Do you have any detailed advice (or possibly a video in the offing) on cap iron prep to get this where it should be?
 
Flat and straight stone and careful strokes with the edge of the cap iron running along the length of the stone until you raise a wire edge along the cap iron. Undercut about 5 or 10 degrees so that the cap iron end touches the back of the iron at a knife edge.

(remove the burr off of the front of the cap iron with a fine stone, and then strop or stroke the cap across wood if necessary to remove the burr on the cap iron).

If there still isn't a satisfactory fit, check the back of the plane iron with a rule to make sure that it's not bellied. If it is, you're in a pickle.

If the fit issue appears minor, you can roll the front off the cap down like your rolling a burr on a scraper and close minor gaps, but that kind of thing is not my first choice.
 
I worked the cap iron in the last video here at about 13:30, though it's not ideal to see it. the other end of the cap iron is below the level of the stone to get the undercut I mentioned.

https://www.youtube.com/watch?v=InbpoRcQyI0

This cap iron required considerable work, more than most vintage ones. It was pretty coarsely made and I had to grind the leading edge to get the stanley curved profile correct (and get the mill marks out of it).

I don't think I have anything better for the cap iron, but there must be dozens of tutorials about these types of cap irons that describe the same thing, as the requirement for the knife edge fit is there regardless of whether or not someone instructing the setup knows how to use the cap iron.
 

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