I’m working on a glued up mahogany plank that’s about 18×24 inches. It was resawn from a plank that was an inch and a quarter thick; I glued the two halves together and have thinned and flattened it to a half inch for a project. I am having a problem with tear out as I’ve flattened it.
I’m using a #6 plane (Clifton) to do the final work, and despite very
careful tuning of the plane and a razor sharp blade, I’m still getting tear out. I have the mouth of the plane down to about a 64th, the blade is at a primary bevel of 25 degrees and has a secondary bevel at about 27 degrees. It’s been honed to 8000 grit on a Norton stone.
Most of the surface of the plank is glass slick where the plane has passed, but narrow “stripes” of the grain continue to tear out even at the thinnest of cuts (less than a thousandth by micrometer). Is it possible to get a smooth surface on this wood with a plane without resorting to a card scraper? I’ve smoothed part of it that way, but it’s a bunch of work; I’d much rather use the plane if possible.
Ideas appreciated,
Cliff
Replies
Have you tried planing those "stripes" in the opposite direction?
Don
Measure, cut, cuss
Don,Yes. An area that was tearing out may start to clean up, but another area will start to tear out. It's pretty frustrating, and beginning to look like I'll have to use a scraper for the whole thing. I wish I'd known mahogany could be this difficult. I didn't have this much trouble with quilted maple and curly walnut I used a while back for a project.Cliff
Sounds like you are using African mahogany, not South American. This is one of it's characteristics, beautiful ribbon grain but each ribbon goes in the opposite direction, or so it seems. I grab the sander. I'm not sure if a York pitch iron would help or maybe a low angle, bevel up plane. You could experiment if you have a low angle block plane. Holding the plane askew can help.Beat it to fit / Paint it to match
Everyone has pretty much said what I was thinking when I asked my question about planing in the opposite direction! Good luck with it, it can be quite striking once finished so taking your time now will pay great rewards later. Don
Measure, cut, cuss
There are some pieces of mahogany that are "woolly", and are difficult to plane smoothly. I can usually tell if a piece is going to be like this, by the color and weight; they are often very light in color and weight.
It might help to hone a slight back bevel on the iron, which raises the bed angle of the plane and makes more of a scraping cut. This back bevel should be about 5 degrees and so small that it really can't be seen ( you don't want to interfere with fit of the cap iron).
Even with a very light cut, the back bevel, and taking care to go with the grain, some pieces just won't plane smooth. I had one piece I used for legs on a table that was even difficult to sand smoothly.
I suspect that this type of "mahogany" is not a true mahogany, but I lack the knowledge to say for sure. I now put this type of wood aside to use in circumstances where appearance isn't important, such as a veneered drawer front.
Rob Millard
http://www.americanfederalperiod.com
Cliff
Mahogany is meant to be an easy wood to smooth, but I have come across just what you describe, in which there are ribbons of grain that change direction. These ribbons can also alternate soft and hard wood. This is a stern test for any plane, and few master it. So-much-so I used a board like this is one of my plane tests. A well set up Stanley #4 1/2 (with Clifton blade and stay set) could not manage this without tearout. What I found was that it is best worked with a high cutting angle, preferably above 60 degrees. This is easier to achieve on a bevel up smoother (just hone the necessary bevel angle) but you can do it on a bevel down plane with a suitable backbevel (I would try one of 15 degrees first, and then increase this if unsuccessful).
Regards from Perth
Derek
Pretty much like Rob and Derek said. Your best bet is to try a back-bevel unless you have a scraper or scraper plane. Even those are a last resort for me at the leveling stage.
Adding a 15 degree back bevel--of maybe 1 mm--will increase the effective cutting pitch to 60 degrees. Take a very light cut.
I have also had success on ribbon striped woods such as Kaya, Bubinga, and Meranti [sold around here as Dark Red Mahogany] by going at a slight diagonal while leveling a surface. Note that I don't mean skewing the plane, I mean orienting the plane at a slight angle to the long dimension and pushing the plane straight.
You may also try a light coat or two of shellac as a last resort. It stiffens the fibers of the grain and the plane can shear them better--but again, it's a long haul if there is leveling yet to do.
Good luck. Mike
Cliff, that sounds fairly typical of an African Mahogany such as Khaya species, and Sapele sometimes.
You maylike to experiment with back bevels etc but you could also try planing across the grain. Obviously a very fine cut, using a slicing action. There is ofcourse the card scraper and some sanding...
That is what I have done on numerous occasions, using a #51/2. Seems that the more difficult stuff fights to the end, but always looks great in the end.
Thanks, Philip, and everyone else - I'll probably just bite the bullet and use the card scraper for now. If I had an additional blade for this plane, I might try the back bevel approach, but until I get another I'm reluctant to modify the one I have. It works well for most things (I used it to joint the edges of this plank); this is the first wood it has not been able to handle.This wood is gorgeous - I've had mineral spirits on it to bring out the grain and it is incredible, with an iridescence (chatoyance?) that is hard to believe. It is only a single plank, so the scraping won't be too bad. I suppose it can be considered good experience, but a different experience wouold definitly be more fun 8^)Cliff
A card scraper works very quickly to clean up even large surfaces. You sound as though you expect using a scraper to be laborous and time consuming, which it shouldn't be with a properly shapened blade and a little experience.
John W.
I agree in principle, John.
Except if there is a fair amount of tear out already [sounded like there was] it will be laborius and time consuming--but if that is how it needs to be done, it is what it is.
Take care, Mike
Mike (and John),You hit the nail right on the head. A couple of other posters suggested trying a light cut with the plane at an angle to the grain; that did help reduce the tearout a bit, but didn't eliminate it.I then spent about an hour and a half this evening with the scraper, and I now have the plank almost completely smoothed with all but a couple of very small tear out spots cleaned up. The existing tear out spots took a LOT of work to remove. I initially had trouble with even the card scraper tearing out a little when I was a bit too aggressive with it. The surface now looks incredible, with a sheen that you never see after sandpaper; the light even reflects off of it when you look at it on an angle. I plan on using oil for the final finish. It's almost a shame to cut it up now, but it should look good as the finished article.Thanks everyone for your comments and advice, they're much appreciated. I learned quite a bit from this. Maybe someday I'll be able to afford one of those fabulous planes Philip makes to use on wood like this and save a bit of the work. In the mean time, I'm glad the scrapers can do the job.Cliff
Cliff - if you bookmatched the panel, then the grain will run opposite on the two sides. John J
John,I did bookmatch the panel, but the reverse graining is within each half, in strips approximately an inch apart. It was an interesting experience dealing with it.Cliff
Hi All,Not that it matters one bit, but this is typically called 'interlocking grain'.I think that's what I read in a Jon Arno article. Typical of woods like purpleheart, African mahogany, satinwood, and zebrawood.I don't work with those woods very often, but when I do, it's with a sander.Best,Chuck
Cliff,
I hestitated to post as I am a planing newbie; but since you mentioned a Marcou plane....
As Derek and Co mentioned, a very high cutting angle in the blade helps a lot. So does a very thin cut with a closed up mouth.
I find also that the weight of the Marcou also has an effect. It provides momentum to the swoosh - a steady pace across the wood seems to contribute to the quality of cut. It is also easier to keep the plane down on the surface of the wood without undue pressure (again allowing a steadier swoosh).
Even so, the cut often leaves not tear out but a surface that has a slight knap - ie it is not glassy smooth. You have to sand it to get it smooth.
But here is a little factet that is surprising. This very same plane with a low cutting-angle blade in it will sometimes give a better cut with the "roiling" sapele and other mahogany-like grain than will a high angle blade! Almost at random (or so it seems) a glassy cut can be got. Other times, the tear out occurs and with a vengeange.
I emphasise "sometimes" and I have no idea why this is possible. I could guess that some of this roiling grain acts like end grain so responds better to the low angle? Maybe the very close mouth and weight ofthe Marcou is at work?
Lataxe
Lataxe,I have a Lie-Nielsen low angle block plane. I did use it during the flattening process and, as you mention, it did successfully handle the weird grain in some areas. Unfortunately it was unpredictable as to where it would work or not; the block plane also was not large enough for the final surfacing process. I've had good luck with the low angle in the past with woods such as quilted maple and curly claro walnut, but this mahogany (if that's what it truly is) is something else for sure.Now that I finally have the plank well surfaced I'm getting ready to slice it up today into the required components for a jewelry box for my wife. She's seen the plank and was pestering me about what it was for (since it looks so pretty), but I'm trying to work on it in parallel with another project so she doesn't know what I'm up to. She has a lot of interest in the things I do, which is usually a good thing, but for this it's a task to keep it secret.Thanks for the comments; they're much appreciated!Cliff
A little trick you can do for shallow tearout is to raise the grain some with an iron, water ang some tinfoil. I have done this onfigured mahogany and it works.
Frank
"This wood is gorgeous - I've had mineral spirits on it to bring out the grain and it is incredible, with an iridescence (chatoyance?) that is hard to believe."
Well that is what we like so much about the wood- if you can manage a picture or two it would be much enjoyed.Philip Marcou
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