I have about 50 bf of poplar that I am preparing for some shelves. My boards are about 40" long and about 6" wide. I've just face jointed about 10 such boards, using a scrub then a jack to get the boards reasonably flat, then my LN #8 to get the board flat. My problem is that the blade of my #8 only lasts about one or two boards before it gets dull with a definate burr on the edge. The blade is very sharp to begin, but I am taking a fairly heavy cut with it. I tried the same process on some other poplar that I got from a different lumberyard, and the blade didn't loose it's edge when taking a heavy cut. The difference is that this other wood is a lot closer grained and less porus than the poplar that is dulling the blade. Other than that I can see nothing in the wood that could cause the blade to dull; it's fairly clear and clean.
Are some wood textures harder on blades than others? I am not a rookie at planing, but have usually worked in harder woods ( maple ). This is my first time using poplar.
>That's interesting, since (I assume) your LN has an A2 iron. This "burr" you mentioned...is it on the bevel side? I've never experienced this myself; have you given the iron a lower angle than the standard 25 (making the cutting edge weaker)?
I'd let the jack do a bit more work prior to busting out the jointer. Then, of course, set it for a finer cut. My jointers are set for as fine a cut as possible, essentially they're just really long smoothers. For drawers, shelves, etc., I find that very little work is left for the "real" smoothers.
As an aside, I don't particularly care for A2, and use Hock high carbon when I can...I wish LN offered these as an option. I'm about to send Ron Hock drawings for HC replacements for both my LN 4 1/2 and #9. Standard 2 3/8" replacement is too thin, and the only iron I can find for the #9 is from LN (A2).
>Stephen ... if your poplar was kiln dried it may have been done improperly and you may have a "case hardened" material - this will definely blunt an iron - I just had a similar problem with some red oak just last week.
>In addition to RJs answer which is a possibility, remember that wood is a natural material. It varies in density, hardness, mineral content, and mositure content. All of therse variations can occur either in boards from different lots, from the same lot, or even in different parts of the same board. Full smoothing of both sides of 2 boards isn't really that bad of a result if the wood is dense and relatively hard.
>Hmm... interesting, 'case hardened' wood. The wood is indeed kiln dried. How would I know if the drying process was not done correctly? Incidentally, it is not difficult to saw with a crosscut saw, and I can dent it with my fingernail.
I had decided to attribute this behaviour to differences in wood, and resigned myself to take lighter cuts with the jointer. The jack seems to cut the wood just fine due to the camber on it's blade.
>While oak must be dried with great care it is near impossible to case harden poplar because it dries so easily.
Cucumber (Magnolia variety) is graded in with poplar on occasion and it is substantially harder. It looks very similar, but heavier. Also, poplar that grows rapidly in plenty of light can be considerably harder than the "deep woods" trees which can be buttery soft.
>Stephen ... case hardening is generally localized so the fact that you can saw it and dent it with your nail doesn't completely rule this out as a possibility. I am, though, less inclined to think case hardening is your problem.
One of the more common symptoms of this problem is the wood moves radically after a cut is made, thus releasing internal stress induced by uneven drying or seasoning. This symptom is not an absolute indication of case hardening but is at least an indicatore with kiln dried material that's been rushed through the drying process (too hot; too fast; not cooled slowly enough; etc). Generally a good lumber yard will take the wood back if you explain what's happening and what you think the problem is ... rj
I've learnt dat case hardening has nothing to do with the actual hardness of the wood. More so it is a "defect" of improper kiln-drying where the outer "case" of the board appears well and fine but then the inner portions of the board either hold a lot of stress or are honeycombed. If the board holds a lot of stress, it checks and/or warps as you mill it....if honeycombed, you'll voids and such inside that look like honeycombs.
Sure, no problem. Just didn't want to hijack the thread with an off-topic and go off on a lengthy rant...but since you asked ;) .
I have a number of A2 irons which came standard on my LN tools. They are high-quality irons, no doubt, but I find that they hinder rather than help my productivity. I sharpen/hone by hand about 98% of the time; no jigs or guides. I've even taken to grinding by hand (thanks Joel) and have gotten pretty decent at it. It's a liberating feeling to not need a "crutch". However, those darn A2 irons are tough, and I find that my hands/fingers start to cramp up after a short time. Then I have to stop and give my hands a rest. This isn't necessary with HC. The irons are only off the tool for a couple of minutes, tops. To become proficient in the shop means doing things quickly without thinking about them. A2 steel doesn't allow me to do this. It slows me down significantly, and I lose my "rhythm", so to speak. Don't get me wrong, I'm not in a rush by any means. I do contemplate and relax while in the shop, and safety is always paramount.
Also, I do believe that HC hones sharper than A2. I've read articles and such which detail the reasons why (composition, metallurgy stuff), but I'm basing my belief on actual usage. Maybe I'm wrong, not spending enough time honing the A2. But that's the point, I'm not going to spend (waste) any more time than I already am.
BTW, I mainly sharpen/hone using India and "translucent" Arkansas oil stones. I do have waterstones, but they're messy and I hate that they need to be constantly flattened. I will say that they do work great, when they're flat.
Maybe I'm not doing something right when it comes to the A2. I'm always willing to try something new in the interest of more proficiency, if anyone cares to make a suggestion.
>Tim .... that's pretty much what my observations and understanding had always been, but the random area's of extreme hardness were pointed out to me by a friend at a mill I frequent and he was their expert on operating the kiln and drying sheds. He actually demonstrated the defect with a test similar to Rockwell testing (of their own devising) ... rj
"BTW, I mainly sharpen/hone using India and "translucent" Arkansas oil stones. I do have waterstones, but they're messy and I hate that they need to be constantly flattened. I will say that they do work great, when they're flat."
I have read articles in woodworking mags that relate the difficulty in sharpening harder alloys with this system of India, Arkansas honing. I have noticed the same issues that you cite with some irons also because this is my system too.
I'm glad you found a workaround for the extra time requirement needed with A2 and similar irons.JR
>You're right, the A2 is TOUGH. A few tricks I've found are the following. They take a little time the first time out, but after that, they make successive sharpenings a lot easier.
1) Hollow grind the bevel first on a bench grinder. This is as simple as setting up the tool rest so that the stone contacts the middle of the bevel. It's also one of the reasons I like the thick irons. The benefits are twofold:
-You're only taking steel off of the two high points of the grind when you go to the stone, meaning less effort.
-You'll feel when both points at the top and bottom of the hollow hit the stone, and you'll have a tactile way of being to easily tell that you're grinding to the right angle.
-The hollow in the middle gives a place for the oil to go, meaning it's easier to get the iron to contact the stone.
Of course, you will periodically need to keep sharpening, and eventually you'll grind away the hollow. The 2 minutes it takes to re-hollow the bevel makes all the difference in the world. Feel free to grind with a really course wheel... the idea is to remove the material, not to put an edge on the blade.
2) Take the time to REALLY flatten the back of the blade. Yes, it'a a royal pain in the ass, but like you, I don't like to spend a lot of time sharpening. Once the back is flat, you really only need to work the bevel, and take the burr off the back.
3) Learn to sharpen with a draw stroke, instead of pushing the blade along. I find it's easier to keep the blade at the right angle that way, and if I pull too hard, I'm only pulling the edge off of the stone.
4) Take the time to get used to the waterstones. The friable surface means that the stone is perpetually as sharp as it should be. Personally, I find them to be cleaner than oilstones, and there's no oily residue on everythign when I'm done. There shoudln't be a need to flood the stones. I use a small spray bottle thatsprays a fine mist, not a stream. It's enough to wet the stone without making a huge mess on everything. I also keep a flattening surface handy right next to the work area, to periodically swipe the stones to make sure they're flat.
The downside to all of this? It takes time to learn, and the grinding and flattening stuff takes forever to do it the first time. The waterstones cut the amount of time down considerably, though. Basically all of this will take a while, and for some folks, it's too much effort when they already have a system that works for them.
I had to learn some of it, like the hollow grinding trick, at school. Other stuff I picked up on my own, but I will say, there was a eureka when it started to click. I'd been sharpening pocket knives to shaving sharp for 10 years, and out of the blue, I was way past that. All of my edges have mirror shines on them now, and just last week I took the mill marks off of the edge of some 6/4 cherry... all in one shaving. The plane made a brrrrrrrr sound, and there was an undulating shaving that was comrised of just mill marks. The surface of the wood was as smooth as anything else I've ever done.
>While I can easily argue both sides of the A2/ HC issue I routinely sharpen A2 and D2 on arkansas and india stones. The secret is to hollow grind more frequently. And since A2 and D2 are much much harder to burn and more forgiving (they may get a little straw with no ill effect) - (not that you should try to burn it) and you are free hand grinding as well as sharpening you can save lots of time with a regular hollow grind.
Thanks for taking the time to post. I should have been more thorough in my post, though. I am well-versed in the techniques you mention. My thicker irons (3/16", 1/4"; for my shop-made jack and Knight coffin smoother), as well as a couple of my larger chisels are the only ones I hollow-grind. I don't hollow-grind the thinner, "standard" thickness bench plane irons, unless I need to grind out a chip or a nick. I simply find it unnecessary to hollow grind thin HC irons, as they sharpen and hone quite easily. All of my LN irons came hollow ground to begin with, but I still found the A2 to be aggravating. Maybe I'm just stubborn and reluctant to change my habits, but it took a while to get to the point where my sharpening/honing skills were second nature; besides, I do think that HC hones sharper than A2.
Notwithstanding the above, I do recommend to newbies that they hollow grind, for the reasons you mentioned; it's a good first step towards jig-free honing, I think.
Regarding the waterstones, however, maybe I'll pick up a couple of the Shaptons everyone seems to be raving about and see how they work on the A2 Satan-alloy.
>It would make sense that honey combing and internal checking and the other defects associated should lead to spots of very dense wood. Given that the outside dimensions of the board are the same....but now the wood fibers and lignin occupy less volume, the wood must be more dense and it seems likely there would be "hot spots" where the case hardened wood is especially dense.
Though I don't think the OP mentioned anything about problems with the wood other than the iron dulling sooner than expected.
>Do you have any test data on burning A2 with no loss in sharpness? High speed tool steel is naturally hard and has less to lose during annealing. I don't think that holds true with high carbon A2.
>Barry Iles - who grinds things for a living - said to me that even modern carbon steels are a little more forgiving of a little overheating than the old water hardening carbon steels and A2, D2 don't loose their hardness in any meaningfull way if the edge goes to 500 or 600 degrees. High speed of course can go to almost cherry red before anything bad happens.
In my experience he is right And I still try to be careful but a tiny burn once in awhile (I'm not perfect) doesn't seem to bother anything and it means I can grind something in 60 seconds or less. without getting too compulsive about it.
It is not a reason to be sloppy but it is a reason to not be too compulsive about grinding. This is especially true when you have a proper, well dressed wheel on your grinder.
>An old article in FWW (11/91) gives a test for case-hardened wood.
Crosscut a 1/2 inch thick slice (preferably from the middle of a board). Then cut a lengthways slot from the middle of it (leaving the outside faces), so that it is a U- or tuning-fork shape. Toss it in a 200 degree oven. If the fork dries straight, all is well. If the tines close up, it was case-hardened (drier on the surface than the center), and if the tines spread, it was 'reverse case-hardened' (drier in the center than the surfaces).
Either condition can often be corrected at the kiln - by more 'conditioning' for case-hardened, or by more drying for reverse.
>What you have concluded makes sense and I couldn't agree more on the convenience of jig-less sharpening. Indeed A2 is considered more abrasion resistant than O1, hence, it would be more difficult to sharpen, expecially with your choice of abrasives. (note: Rc hardness is a measure of penetration resistance, not abrasion resistance. So, all Rc 60's are not created equal, as you have found)
There is sound data that shows that most if not all the tool steels can be sharpened to the same degree (see Elliot Web site for details). The key word here is "can". The highly abrasion resistant steels need a more agressive abrasive grain, and some require diamond to get an equivalent edge(again see Elliot).
>Both A2 and O1 will be tempered at about the same temperature for woodworking tools and that is around 400 F to get a Rc 60 (approx) hardness. Hence, one needs to have the same concern grinding either. Tool steels on the other hand will be tempered at about 1000 F to get the same hardness. No need to worry grinding these steels.
It occurs to me that I have this great list of links to WW info, but it's only worth a damn as long as the pages are maintained. Guess I ought to start saving this stuff offline, in anticipation of the time it all fades away ...