Scraper & cap iron: 2 peas in a pod

[MikeG.]

Two completely different approaches to difficult grain, you'd think. I've always reached for the card scraper, or scraper plane. Others scoff, and say a close set cap iron is the only answer. Well, I thought I'd draw them, and see what was what. Red is the plane, and blue the scraper:

Maybe this little drawing will stop the arch proponents of one from sneering at the other. The geometry, and the reason they both work, is pretty much identical (in principle). OK, I'll always argue that it is quicker and easier to do the job with a scraper, but I'll happily now concede that a smoother with a well set cap iron can solve the same problem, and possibly more comfortably for the user. I'll continue to argue that it is easier to set up the scraper. but have a think about this comparison before you suggest that your way is the only way..........

 

[Bodgers]

I'm sure @D_W will have something to say about this...

 

[Steliz]

Quote from the comedy programme 'Whose Line is it Anyway' -

Host: What's the best line to say to start a fight?
Comedian: Who wants a fight?

 

[MikeG.]

I'm approaching this more along the lines of trying to stop one rather than start one.

 

[NickM]

That's a useful way of visualising things. Thanks.

I've just got myself a scraper and I love using it. I had a bash at sharpening it and it went OK although I'm finding I need to hold it at a lower angle to get it to cut - i.e. in your picture I would need to have the scraper leaning over a bit more to the right. When I do that it produces good shavings on oak. I think the issue is that I've turned the burr/hook over too far which should be easy enough to fix when I resharpen it.

I'm also getting a Stanley 81 as I think scraping larger areas with a hand held card scraper will get hard on the thumbs!

(PS. I hope you're wife is OK and that she recovers quickly.)

 

[Sideways]

Outstanding
What a simple, clever illustration.
I like the finish you can achieve from scrapers and have been looking for a good used scraper plane. I'll keep looking but this convinces me to try setting up a spare #4 smoother as a cheap substitute in the meantime.

 

[That would work]

Interesting enough but if it were a scraper plane without a turned over edge, the the geometry would be quite different.

 

[D_W]

scrape some pine and plane some pine and let me know how the results turn out. This is a constant amateur answer "it's the same as a scraper".

It' isn't. A scraper can sometimes be like a cap iron that's set far too close, but it won't match one that's set properly.

Nice try, though, mike. You probably should just stop talking about this stuff until you actually compare things. Supposing something from pictures without practical experience is often inaccurate. You have experience with scrapers, but you don't know much about using a double iron properly.

Of course I say the part that you should stop talking in jest - that's what you tell me. I relied on scrapers and high angles for about 7 years before i got frustrated with how slow they are. On curved work and things like guitar necks where finishing is confined, of course, I still use them. I've never used one without a burr, and never found getting a good burr particularly hard, but I've seen people make it look really difficult.

 

[D_W]

Seriously, though - scrape some softwoods and plane them and tell us how the surface of the wood (and especially the edges) fares. One obsoletes the other more or less on flat work, even relatively thick veneers (very thin work is scraped for obvious reasons). It's not the scraper obsoleting the cap iron.

 

[D_W]

I'm sure @D_W will have something to say about this...

Of course, but it only matters if one is actually doing these things. A conclusion drawn from supposing is always quite successful of the use is only supposed, too.

 

[D_W]

I'll give an explanation about this for everyone else. I suspect Mike will keep trying to find other straw things, but anyone considering using a plane instead of a scraper (which is well advised for flat work, as you can change three steps to one and do a lot less tool preparation - those three are plane/scrape/sand, the typical order of operations can just be changed to ...plane, and you can sand if you're staining as a cleanly planed surface often doesn't absorb anything other than water stains well).

Here's the issue.

What's happening with the double iron plane is you're attempting to apply only a reasonable small force to the shaving coming off of the wood to prevent it from lifting. It's being cut by a sharp iron that's set at a very precise angle (which allows the surface to stay clean and bright, and even). If you set a cap iron too close, you can get into the same trouble as you'll see with scrapers to some extent - that is that the amount of wood being pressed back is too much for the space and it gets smashed down into the surface of a board and some of the wood is severed and others is stripped off by the held up fibers. This isn't particularly desirable and is why any significant cut with a scraper will often result in a fuzzy surface on softwoods. On hardwoods, the wood is too hard for you to get to this point most of the type (or to be able to physically apply the pressure to do it), so you sever a reasonable thin shaving off of the wood that's not too large for the burr.

The other issue with scrapers is that you'll have an angle in a relative range, but you don't have great control over it. In a scraper plane, the burr wears and one remedy (instead of constantly rerolling it) is advancing the angle some to continue to cut (the same way you may tilt a card scraper forward).

With the plane, nothing changes. But the plane has yet another advantage. The wood is being held in place, so it will continue to cut smoothly even longer than it would in terms of dullness without the cap iron. Cut a hair with a dulling knife without holding it in place and then hold the other end and cut it to sort of get the same effect.

Mike gets stuffed up because I often say that in the hand tool forum that someone who doesn't work entirely by hand probably won't be as good at understanding planing because it won't matter that much. That makes it so that Mike knows less about this than I do, especially in practice (I just have to add that, because he gets fired up about it :mrgreen: ). Here in the states, there are a couple of professional woodworkers who have done all of this by hand for pay. Sometimes, they get larger in business flow and they have to turn to machines, but every one of them that I know of who legitimately works by hand and doesn't make money off of teaching students or working for a college ends up going down this exact same road - they get to using the double iron and casting most of the other tricks aside because they're time wasters and the result is inferior.

But they only got to that because they were doing more than just removing machine planer chatter with hand tools, and in the case of both that I know of within a few hours of me, they do no sanding and at least one of them has developed a well-heeled customer list who understands and demands work that has both a planed finish and very little finish applied to it - no sanding.

 

[MikeG.]

.........Supposing something from pictures without practical experience is often inaccurate..........

You're hilarious.

 

[MikeG.]

.........That makes it so that Mike knows less about this than I do..........

Classic fallacy: argument from authority.

And you know so much about this subject that you've never bothered to draw the two comparable techniques.......because your obsession with the one at the expense of any other is blinding you.

 

[D_W]

Mike, I've seen this at least 3 dozen times. When I first wrote an article about using a cap iron, this was the instant reply over and over.

I have no idea why you'd think I wouldn't have seen it before. do you think that such a common thought would be only unearthed by you? It's probably even on this forum.

As far as whether or not I'd have thought of it myself, it's literally an essential consideration in matching the burr size on a scraper to the amount of work that you're going to do. Think about it. It'll garner some oohs and aahs from beginners, but you are thinking things I considered a decade ago, but instead of just supposing these things, I went on to actually test them. It was the ineffectiveness of high angle planes and smoothers that drove me to the double iron. AT the time I started to figure the one professional woodworker here in the states (who works by hand) was probably right because I had just scraped all of these panels with everything I could think of - a large scraper plane, a card scraper (then planed with a high angle plane at 60 degrees, which is absolute torture) and finally after they had cupped and the large scraper plane was not able to do any volume of work, I listened to the advice of someone on another forum who noted that the smaller scraper plane would follow a less than perfect surface better. It did, but that expensive little plane wasn't necessary, and neither was something foolish, filthy and slower like belt sanding the cupping out.

boards like these are easily planed to finish - probably in about a tenth of the effort. A friend and I had no power tools that would work them cleanly, so we glued them together and had them thicknessed by someone with a giant multi drum sander (a 52" beach thicknessing sander). Ideally, you like to join things and get them together so that they cannot move on you, but in this case, using other peoples' equipment hamstrung us. If you're not following, I had to get the cup out of the finished panels to some extent to be able to get a finished surface on them as a beach sander leaves deep long rasped lines in the surface of wood. That means more than smoothing, or perhaps an hour or two of such a thing (at risk) to knock the cup out of these panels. It was horrendous. Single iron planing is risky (at common pitch), or punishing (at higher pitch) for anything other than small material removal. .

Inability to use the double iron on something like this (Without buying something else like a shop drum sander) exposes incompetence in anyone who doesn't know how to use a double iron.

I would dimension these from rough without issue at this point. You have no idea how far behind you are, but it's almost comical that you'd think I haven't seen or heard of this "a scraper is doing the same thing as a double iron plane" bit before. The funny thing is, the first person I can recall saying it was wilbur pan, who I had a slight distaste for at the time because he has a horrible habit of thinking about things, posting the results of his thoughts and not actually trying them.

you could probably learn something here that would serve you well. I figured this out in isolation because there was no literature that was really that reliable on describing it and a few hundred board feet of dimensioning is the only place that you're really going to learn it well. Is it possible for someone who likes scraping and machine planers to get something from it pretty quickly? I think so, but it is easier for me to know it well because I"m not using anyone else's borrowed knowledge. You are.

 

[D_W]

Having suffered through dealing with these panels, I'm reminded of something custard said about using the double iron on a piece of furniture he was making. One of the other folks who trolled me replied "oh come on, you could do this a million ways", and custard pretty much replied, sure, but none of them work as well or as quickly as this.

Custard may be put off by me. I am so certain I'm correct on this, and you're so consistent at telling other people what they can say and how they say it that I realize partly that if I play like "oh, they're all great", it gets lost.

You're generating publicity for the method, that's fine. Custard uses it. Whether he thinks I'm a tool or not, that's what I'm going for. That's my lot, to get people to learn it and use it because it costs nothing for anyone who already has a common bench plane, it's easy to do, it doesn't depend on sharpness or tiny thin shavings and it's several times faster than scraping even for finish work. If you have to do more than just scrape, then the gap widens further.

It's not by coincidence that this type of plane pretty much obsoleted everything else for solid flat work all at once in a matter of about two decades (or less). Anyone disregarding it wouldn't have been able to keep up economically.

 

[MikeG.]

......... it's almost comical that you'd think I haven't seen or heard of this "a scraper is doing the same thing as a double iron plane" bit before........

It's highly amusing that you should think this thread was somehow directed at you. That is an ego-driven approach which we have discussed previously.

It's also quite revealing that you've produced lots of words, but yet no critique of the drawing. Do feel free to produce your own. As well as spending many tens of thousands of hours of planing including when I was a professional cabinet maker (all stock preparation by hand), as an architect I have a yen to draw diagrams which illustrate issues. When you've produced your own drawings, feel free to post them in this thread. Or, if you like, you can take mine into Photoshop and adjust as you feel fit. As with BODMAS, you just constantly asserting "I am right, I know best" doesn't actually advance the discussion.

 

[D_W]

It may or may not be, but it's incorrect. It's not the same thing (scraper vs. double iron) and it became humorous when you thought (this whole thing is my hobby - it's not something where i Just try to get through with minimum effort, it is something that I want to do as well as possible - the planing and plane making) I'd have never seen it.

It was brought up from the start, but it's not correct and the penalty is the same as it is for being incomplete everywhere else.

I'm not asserting anything with Bodmas, either, except that I have a degree in mathematics and I literally never ran into a case where someone thought defining the environment was bad (we did have some French professors on sybattical and they were pretty intolerable). I would have said that if I were betting, bodmas would be where I'd go. If I have a choice, I ask for definition as would any other person. That's beside the point - not to mention, this wouldn't have come up at university level, though it does in computer programming where order of operations is specified for obvious reasons, and programming is part of a mathematics degree.

I curated discussions on the cap iron not to match necessarily just what i think, but what turns out to be historically correct (which I was pleased to find out that my experimenting agrees with - all except for one thing. I don't know why nicholson insists on matching a smoother cap iron profile to the iron. that's it). You'd have not posted this thread without my input elsewhere, so you can back away from the assertion that you would have or it has nothing to do with my beating the cap iron drum. It is convenient that you posted it here to hide it from the hand tools section, and that's OK.

What you or I like is less important than what is definitively correct for everyone else here to learn (or choose not to, but at least have the chance).

I described the mechanism with the cap iron fine, we don't need to draw. The critical part that differs is you manage the situation so that the cutting angle is constant and no wood is severed by bunching, but rather than same cutting effect planing downgrain would have anywhere else - the wood is held in place, but the low actual cutting angle is preserved because it's important for cleanly planing soft or curly wood where a scraper creates a fuzz in the soft parts.

Of course you can do a lifetime of woodwork without it. You can do a lifetime of woodworking without ever learning to use a scraper for curved work (that would be a shame - you get what I"m talking about here - people who only sand inside curves and never scrape or plane so that details aren't lost to sanding).

But the option to do things the best way is also the easiest, probably to learn, as well as to execute a volume of work. It costs nothing to do - the last part is important to some.

(you forgot to assert that what's going on with the double iron is the same as a single iron, draw a picture for that and use terms like "type 1 shavings and type 2 shavings" to further make the discussion more overly complicated for a beginner. I left it at the easiest mitigation being to start by smoothing - set the cap iron right on the edge of the iron as close as you can get it without over, and then pull it back just slightly to see a bit more of the shiny iron back. That's all the more difficult it is.)

 

[woodbloke66]

DW - PM sent - Rob

 

[Ttrees]

No contest if you intend to have flat surfaces.
If that's not important, then it may not be an issue.

Scraper panes nor card scrapers cannot dimension timber efficiently, where a regular double iron plane can, and can well.
You can't compare the two with a drawing, as the double iron is adjustable, far more than the largest burr that you can draw, never minding the fact that the plane works as a whole also.
There would be a huge difference in time if you had to dimension the same timber
with a scraper plane or handheld card with a plane beforehand, vs two planes and had no other tools to do so.



Two irons for the one plane can be tuned to the timber your working on.
You could even get an extra double iron instead of swapping the cap iron, or better yet,
even another plane to save you swapping any iron's at all!

The camber on your iron dictates the setting, there is no difficulty in setting the cap iron if you
have an even camber.
Getting the camber right is absolutely the most difficult thing about learning how to use a double iron plane.
This I feel gets overlooked in discussion.
Even if it takes an age to get your iron right, it is still vastly superior time and effort wise than scraping is.

That's my two cents
Tom

 

[D_W]

Sort of a side discussion, but the cap becomes the fixture that determines how to grind the iron (which will torture people who rely on a square), and getting the camber right is a matter of first honing a ground iron to be parallel to the cap iron and then introducing the camber.

Keeping things in good shape is just a matter of remembering to check the iron once in a while to see if it's getting out of match with the cap (the same way one might check to see if a ground iron is getting out of square). It's very handy, because the need to check for square goes away!!