Cap iron setback and shaving thickness

Re: Cap iron sharpness

david weaver

I've not noticed any practical amount of wear on my cap irons. I don't know if the rounded shape has anything to do with it, or if there's actually a bunch of wear and I don't know it. Either way, they work well without ever sharpening.

I recall Warren saying long ago that he doesn't sharpen his, either.

Never noticed it before, either, but the cap iron mechanism that K&K used is strange because it's bedded against the iron all the way down.

If there is material rounding going on at the edge, it would eventually allow shavings through (so it would seem). The only thing that's ever gotten through my cap iron is very troublesome cocobolo (something few will plane to begin with). That'll go through any, though, and went through when my cap iron was pretty fresh a few years ago.

I think this is an area where reviewing the paper and machine-related characteristics creates a sense where we need to do something on hand tools that really offers no benefit.

Re: No tear stained defense needed..

david weaver

So many method names. I round the front of mine the first time I do it, same with the burr - you have to remove it. I either do it with a fine stone and then stropping or with dursol on leather (the latter is a lot easier), but I've never redone it on anything.

Re: Cap iron setback and shaving thickness

Bridger

I'm imagining doing something like:

File the front edge to match the camber of the blade.

File the bevel to match the front edge.

Tap out the center a bit to raise it.

Fit the leading edge to the iron by honing the relief on a very narrow or curved stone. I have some abrasive sticks in the 1/4" x 1/4" x 3" range. That should work in the usual manner of resting the back end of the chipbreaker on the bench.

When I get a moment I'll set up a smoother that way and give it a try.

Japanese planes

Patrick Chase

Brian (I think) has previously pointed out that the proper use of double irons was never lost to the same degree in the Japanese woodworking tradition as in the West.

I'm not qualified to assess the degree to which that's true, but your comment about Andrew Hunter's presentation reminded me.

Re: Pictures

steve voigt

Dave, I have no idea what those pictures mean, but they look cool!

The Dursol on leather is a good idea--I don't have any, but I can try green paste. I don't know why I've never tried that. The burr on a mild steel cap iron can be a real bitch, even after honing it on the HBA. I've always used the plain strop, but I'll try some paste on my next round of cap irons.

Re: The most likely

steve voigt

Hey Bridger, I meant to reply yesterday. That's a cool story, and almost identical to my own--learning at a younger age, hanging out a shingle, giving it up, hanging out the shingle again.Good stuff.

Re: Blackburn

Charlie

Strange to say the least in that others, on other forums, have reported that he planed difficult species to a beautiful finish.

He's presented at WIA two or three times, Marc Adams several times, North Bennett Street, and others. It appears that he's fairly sought after.

Maybe there's more than one way to skin the cap iron cat?

Re:cap iron sharpness and maintenance

Charlie

I just hone it to keep it clean, bright, smooth, and rust free rather than making its maintenance a separate step using other products and procedures. Rust is a persistent problem in Memphis. It has rained here for almost seven days straight and is so foggy this morning I can't see 75 yards down to the end of the cove I live on. Super humid and over 50 inches of rain a year. You can't glop everything down with 3-in-1 as it takes longer to remove it so it won't xfer to the wood than it does to buff off the flash rust with lamp oil and a rag, or just hone it off, depending of course on what tool has rusted and where. If it is remotely susceptible to being run across a fine stone that's what I do. Much easier than dragging out steel wool, sand paper, etc. I'm getting lazy in my old age, or maybe just finally 'efficient' and cutting down on the overhead whenever I can.

Re: The most likely

david weaver

I'll echo what steve said, I like to hear how people got here.

I wish I had a similar story, but my grandfather lived by the stick welder, the chainsaw and the plow. My dad grew up the same way, and though he worked wood when I was a kid, it is because my mother is a "crafter", so working wood meant a lot of lumberyard pine and a flat belt sander and sanding the edges so that my mom could paint it and peddle it.

Otherwise, nobody even knew how to sharpen things. We specialized in using stuff that was past worn out and not buying anything.

Re:cap iron sharpness and maintenance

david weaver

It sounds like efficient is doing more?

I've not had any real rust problems on the business end of a cap iron, and my humidity is about the same as yours, but for a different reason than just due to the local weather. My garage is mostly underground and moisture comes through the floor slowly. That's compounded by it being about 10-15 degrees cooler than outside, which drives the relative humidity up (I'm sure you know how that calculation works).

The magic point for humidity is something like 63% relative humidity. It's uncommon for my shop to be below that in the summer due to the RH outside and the temperature differential.

I don't have to deal with my shop getting to 100 degrees like you do, but the rust can be an issue - especially at the point of contact where the iron and cap meet on an unused plane (that's pretty easily prevented with wax for a plane that's going to see little use, though).

I've never used 3 in one in my shop for anything, but I haven't had any problems with rust on cap irons. I didn't think I had any filth on mine, but the pictures do appear to show some wood residue. Until it causes a problem, it's no problem. I've never used steel wool on the business end, either - that would be very undude.

I think you're solving a problem that doesn't exist, and that's supposed to be my specialty and not yours.

Re: Pictures

david weaver

Flat face on the end is the back of the iron, part that contrasts against it after the line is the cap iron. I was speculating that we might find the wear that Charlie mentions needing rehoning, but I don't see anything other than one picture showing that the washita scratches were perhaps never honed off on this cap. Maybe I was in a hurry!!

The line of contact (the white lit up line) is either scuzz from the harshness of the honing on soft metal or it's wear - not sure. Magnification is about a true 100X and highlights the quick nature of prep but lack of subsequent damage that would need rehoning.

K&K talk about wear after 200M of planing. I don't know how many meters this plane has seen but it would be a large large multiple of that.

re: the paste, autosol is a good compromise (or any other paste with a little aluminum oxide). The washita and the arks just tear up the soft steel because they can cut it too well, and the wire edge is really persistent without extremely careful thinning. The autosol (or dursol, I guess) breaks it up and cleans off the edge without having to fiddle with the underside of the cap. I have dursol only because the US importer of Tormek was thinking of offering it at one point. It's maybe marginally finer (but maybe not) and the solvent greasy stuff in it is more greasy and much stinkier.

Re: Cap iron sharpening

david weaver

I don't think they apply directly, but I'm not sure why. I looked at my cap iron with a loupe only this morning looking for some indication of visible wear, but I couldn't see any. I'm not sure I could tell where most of the contact of the shaving occurs - the part of the cap that apparently wasn't prepared that well hasn't taken on much wear. The part where most of the contact probably occurs doesn't show anything except for a few faint scratches from an india or washita stone - those didn't get fully polished off when I prepped the cap (which was probably no more than a 2 minute process).

If there was any significant wear, the shavings would remove those remaining faint scratches, or at least muddle them. I think you could plane most things for a lifetime without unnecessary care for the cap iron. I sure wouldn't take on the obligation of doing something about it before it proved to be necessary. Doing such a thing is sort of like rebuilding a good running motor for no reason. It might not be as good after the rebuild.

Re: Pictures

david weaver

I think I might have the left and right mixed up.

The center is most burnished, and not sure if that's due to shaving flow or initial prep.

The bright white line in the middle is the front of the cap iron. Above that is the back of the plane iron, and below that is the rounded (and polished) middle of the cap iron hump.

The projection of the iron shown is about 5 thousandths or 6 thousandths, so the total amount of cap iron shown in the picture is not much - just the leading edge.

No clue if the white line is wear or just the torn off bits left from the initial conditioning. It's a fraction of a thousandth.

Also not sure if the trash left on the picture labeled right (which is probably left) is partly wood dirt, or if it's a couple of thousandths of harshly honed area that was done either with the india stone or washita and not fully polished (could be). You can't actually see any of that with the naked eye and none of it has ever affected use.

This is my favorite plane, and my favorite smoothing iron, so I expect that it'll continue to get used a lot, and i don't expect to do anything to the front of the cap.

This sort of reminds me of the threads on the shaving boards where someone insists that you need to rehone a razor every two weeks to remove accumulated damage. That process is a little different, but with the right (non-abrasive) care, a razor doesn't need to be honed more than every 300 shaves or so (and isn't improved by it, perhaps the opposite is the case).

Re: "Planecraft"

Charlie

Most articles of woodworking with any interest at all have elements not susceptible to being planed with a No. 4 with a beautifully arranged cap iron. If left 'off the plane' or 'off whatever tool' this can result in a shocking incongruence under a clear finish. If it's all milk-painted Shaker, comparatively rough "American Country," Colonial reproductions, and the like then it doesn't matter. Otherwise, one has a decision to make. Some homogenization of the surfaces usually results in a better overall product.

Re: "Planecraft"

david weaver

Scrape and burnish.

I don't do much historical reading, but I can't imagine that scraping and burnishing with shavings wasn't pretty common to go along with planing flat work historically.

no?

I don't think people do much burnishing now, but you know the routine.

Heavy scraping (if needed), then light scraping, then burnish. You come pretty close.

If you like to scrape surfaces or can't plane them, this is a fairly good way to get something close at the start (especially if the finish will be sheer and absorption rates can be different). I'll yield to the stainers, as perhaps staining is more uniform with sanding, and the purpose on most modern stuff seems to be to hide the wood in general. Not my bag.

I do like the take in hasluck's book about resorting to sanding, something along the lines of it ruining the piece. Carving is different, but I'm sure there's no shortage of sanding in carving these days.

(I just got my copy of planecraft in the mail over the weekend - a version printed about 60 years ago. I'm eager to read it and plan to start tonight, though I'll take warren's point into account - that it's a bit of a modern take).

Re: Japanese planes

Brian Holcombe

That would be a bit of an assumption on my part. I assume so due to the fact that Japanese ww'ing shops very often have a super surfacer and use it, but someone like Stan Covington would certainly be able to provide more real insights rather than assumptions.

Certainly I was completely unaware of it until David, Warren and Steve provided the insights they have.

The big difference

Warren in Lancaster, PA

I wrote this last week:

The big difference between the Planecraft era and what we are doing today is the scraping and sanding. The use of the double iron is an art. If you are planing well, both scraping and sanding will degrade the surface.

Todd Stock wrote in 2004 in a thread about ditching the Bailey plane:

It's refreshing to see at least an attempt at a rational examination of performance issues, versus more theology.

That said, exactly how many times do we actually maintain the freshly planed surface intact for our tactile pleasure - versus scraping, sanding, filling, sanding, first coat, sanding, etc..?

How many times? I haven't used scraper or sandpaper since 1978. Not for planed surfaces, mouldings, turnings or carving. I do burnish turningsand sometimes mouldings. For carving, I run a cloth over the finished work. If the cloth catches on the tip of a leaf or something, I burnish. Nobody wants to dust carvings that are too sharp.

Re: Cap iron setback and shaving thickness

Michael Brady

One can only hope that this is not the first thread of postings read by a novice woodworker exploring the internet woodworking community. "How many angels on the head of a pin?" --really?

Re: Cap iron setback and shaving thickness

david weaver

that might be an accurate representation if there was no practical use for the discussion.

This board generally isn't a beginners board to start with, and perhaps there is some accuracy that we don't need to talk in thousandths (actually, I think it's detrimental, because we should measure by eye and sense), but there is one simple fact that's lost in all of this:

"it's just another tool like scraping, sanding, etc"

That much is true, but there's a missing variable. It's a far better tool. It is the link between getting rough lumber and turning it into something accurate quickly. A subtlety lost on many, but if 100% of woodworkers would put down all of the "extras" and force themselves to use a stanley 4 for a month with a single washita sharpening stone, they would come out 50% more productive at least, for the rest of their life, even if it was only smoothing that they were doing.

Of all of the things that we talk about that are a waste of time (what's the difference between naniwa stones and ohishi), this is one that's actually practically useful.

Cut depth, species, and wear

Patrick Chase

It occurs to me that the K&K data were for fixed cut depths and species, which means that the shaving would have been consistently impacting the cap iron in the same place. I don't think that's how any of us actually use our planes, and varying either or both of those would further distribute the wear across the cap iron face, and reduce both its depth and perceptibility.

In any case my point was and is that K&K provide an upper limit for wear, as all of the variables we know of going from that to handplanes would tend to mitigate it in one way or another. That upper limit is quite low, enough so that I think we can safely conclude that frequent cap iron maintenance is more a matter of habit than necessity. You need at most infrequent touch-ups, and like you I haven't even see the need for that in my planes.

If you're a beginner...

david weaver

...and you're reading this forum (and there are a few who don't post, I've gotten emails from them).

Don't be put off by the long discussion. The technique is easy, it's superior and it requires no inspection of anything other than what's going on right in front of your face.

When we start talking about what was in Nicholson, etc, then it gets pretty far out there, I guess. But it's the fine detail on the end in terms of being really great at using the cap. Just being good at it is far better than any other method. It only takes about two weeks to get "good" with it.

Re: Cap iron setback and shaving thickness

Patrick Chase

I'm of two minds on this (and I say that as the OP of this thread).

As you say it's probably a bit esoteric for a beginner. More significantly it might deter them or cause them to become measurement-obsessed at a point in their development when they should focus exclusively on results.

With that said IMO this is not Angel-on-pin-dancing stuff. The topic of this thread (setback in relation to cut depth) is a very important challenge in properly tuning/optimizing a double-iron. As I've said in a couple other threads measuring isn't the right way to approach it when starting, but all the same it can add useful understanding.

Re: And a quote....

david weaver

My proficiency for talking about relatively little an awful lot reached the UK before I found their forum:

Here's a quote from a professional woodworker there, and some of Charlie's handy work between.

Custard (a pro):

"Having said all this I'm convinced about the advantages of a finely set cap iron. It banishes tear out and permits a heavy shaving to quickly clean up tear out left by machines. And if I can get it to work on curves with a compass plane I'll be even more delighted and grateful ..."

Charlie:

Don't mess this up by pointing out real world scenarios. You've spoiled all the fun.

Otherwise, damning with faint praise comes to mind.

Custard's reply:

No faint praise from me. The ability to handle a highly figured piece of timber confident about tear out is a massive step forward. Furthermore, what's "real world" in my workshop may be purely hypothetical in another workshop.

Not exactly angels dancing on the head of a pin kind of stuff, but perhaps a bit deep for the average woodworker just looking to buy a high angle frog (that being the kind of advice that's more commonly given).

Re: Cap iron setback and shaving thickness

Sgian Dubh

This thread has become fascinatingly involved, and I have been highly entertained by all its twists and turns. However, the following quotation might be worth a read - perhaps knowledge of the use of a cap iron was never completely lost:

"All bench planes ... have double irons composed of the cutting iron proper and the cap-iron whose function is to stiffen the cutting edge and break up the shaving as it is raised so that, robbed of its stiffness, it does not tend to run ahead of the cut in a series of small splits in the surface of the timber. The closer the cap-iron is to the cutting edge the sooner the shaving is bent over and broken, therefore fine cuts or difficult timbers require a close-set cap-iron and a narrow mouth which, in the case of metal bench-planes, is easily adjustable. Practical experience will give the best setting of the cap-iron, which may vary from a hair's breadth for the final surfacing of difficult timbers to 1/16 in. (1.5 mm) for the first rough levelling. This use of the cap-iron means that the grinding bevel of the cutting iron must be underneath, therefore the cutting angle is dependent on the pitch or angle of the iron in the plane, irrespective of the grinding angle. Usually a compromise angle of 45º is used for bench planes, for raising the angle gives more of a scraping action and lowering more of a slicing action.” (Joyce E, page 28, (1970) The Technique of Furniture Making [third edition, 1980], Batsford, London.

My experience is that it can be rather time consuming even with a well set up plane as described by Joyce above to prep large a large square footage of a challenging wood surface polish ready, without recourse to alternative surface prep means, e.g., scrapers and sanding techniques. It’s time consuming because, in part, because it’s necessary to stop planing quite frequently, resharpen and set-up the tool which can get a bit old. Generally I’ve found speed is a priority in the work I’ve been involved with - there’s a customer and I’m working to a price and/or deadline - and a fair amount of the prepping I do involves a limited amount of plane work, and a higher proportion of the scraping and sanding options.

Having just said what I’ve said there will no doubt be those who conclude (as in the past) that I don’t know how to use a plane. I think I do know because I can make a plane work contrary wood pretty much flawlessly – not quite flawlessly usually because there’s nearly always something somewhere in a wood surface that wants to play silly buggers, so for anything but a smallish area attempted for a bit of entertainment it’s just too darned slow for my needs. Slainte.

Re: Cap iron setback and shaving thickness

david weaver

Working contrary grain flawlessly is something people should be able to do two weeks after they've started. The issue is that nobody seems to think that it's worth teaching new students. First, we have to get them to learn to sharpen over 14 weeks. Then, we have to run them through a 2 hour plane improvement cycle. Then 7 more weeks on various types of dovetails.

They might not have the dexterity on day one to sharpen well with a single stone, but a decent washita and a strop, and a #4 plane that has been set up for them (not in an idealized way, but in a "this hasn't been used in 4 decades, but we can have it ready in 14 minutes" kind of way) - that would be about all that's needed.

It might take about a half hour to teach someone to use a cap iron, and give them a few pictures of what they're aiming at for set. It should be very easy. Online, it's made to be very difficult and it requires all kinds of tools in addition to the 4. It shouldn't.

Then there are discussions about rounding the cap iron or not like this, and the answer is, who cares either way? It's not really important.

But there is one thing you mentioned that's awfully difficult to overcome, and that is planing over a large wide surface (because smoothing a table top wouldn't actually involve many sharpening cycles - my ash bench top required 1...one...uno (with a horrid stanley 70s iron)...anyway, the real issue here is that planing a large wide and long surface can be quite painful. If you're cutting furniture out of CNCs and it looks like half of it came from the jetsons, and the customer doesn't really care about any of this stuff, run it through a wide belt sander and scrape it (and I say scrape only because it's faster than sanding and involves ingesting a whole lot less).

For the average dude standing in a shop and who doesn't want to outlay much, doing it the way someone did it 200 years ago is probably going to be awfully useful. The really hard part is finding good material and designing something that looks really good. And layout, marking and clamping. The planing ought to be really easy.