Can I use a large piece of 1/2″-thick Corian to sharpen the sole of a plane? I have some thick glass that will work for a smoothing plane, but I need to clean up and flatten the sole of an older No. 5 and a No. 8 Stanley. Would be interested in hearing how this is done.
Thanks for the advice,
Brian
Replies
I used the table of my table saw for a #8 jointer plane. Use some spray glue (the lighter kind) let it dry for only a minute before sticking it on the table saw and don't use any water. I only went to 200 grit on my #8 and #6 but they are flat and work well. The 200 clogged pretty quickly without water but I had a bad experience with water on my table saw so I am paranoid. I used a little denatured alcohol to get the little bit of glue that did not scrape off with a razor blade. I think David Charlesworth mentioned this somewhere and not many know more than him about hand plane tune ups.
I think I would skip the Corian but I imagine you could check it with a good straightedge. I don't think it would flex easily.
"The 200 clogged pretty quickly without water but I had a bad experience with water on my table saw so I am paranoid."
You can use kerosene instead-it won't kill the glue , is good for cast iron surfaces and augments the abrasive action.Philip Marcou
Thanks Phillip,I had read that but never really thought about it. Now that I think about it I am not even sure where to get kerosene anymore. Shawn
I use a good grade of lamp oil. It is about the same thing as kerosene just a little finer refined. It has very little smell and comes in nice sized bottles.gpssam
Yes, you can use Corian, a piece of granite, float glass, and even your driveway - presuming all of them are flat. Unlike flattening the back of chisel or plane blade, it really matters that the sole of a hand plane is flat to within about 3 thousandths of an inch over its length. The reason is that you're typically taking shavings that are no more than 5 thousandths, and if the sole has a concave curvature greater than this, the blade will have to be extended quite far out of the mouth, be relatively unsupported, and will chatter in hardwood.
If the sole is convex, the plane will either not cut or stall as it digs into the wood, depending on whether you put more pressure on the front or rear tote.
Achieving this level of flatness is actually pretty easy, though it helps if you've a good quality rule that's precisely ground. The Starret (steel) rules are made this way - the 12" model is no more than one-half of one thousandth of an inch out of true along its length. You simply use the rule as a standard against whatever surface you want to use as the bearing surface for 180 to 400 grit sandpaper (the starting grit depending on how badly off the sole of the plane is at the start). Most float glass, table saw tables, jointer tables, and granite surface plates are well within the tolerance you need for flattening the sole of a plane.
Once you've selected the bearing surface, stick the sandpaper down with 3M spray adhesive or a light coating of oil (the surface tension will make the paper stick). Coat the bottom of the plane with a magic marker, or machinist's dye if you have it. Take a couople of light passes over the sandpaper, carefully maintaining even pressure on both the front and rear tote, and with the blade and frog in the plane and tensioned properly (with the blade retracted, of course). Turn the plane over and examine where the color is removed. If it's removed over a wide area, you probably don't have much to go. If it's removed in only a couple of small areas, you have a couple of hours of lapping to go.
Continue lapping the sole and occasionally re-coating it with magic marker to check your progress. When the dye is evenly removed at the front of the mouth, the toe, and the heel of the plane, you're good enough to use the plane, though having it uniformly flat over the entire sole is helpful in a long plane.
As taught at the Centre for Fine Woodworking in New Zealand, use double sided tape to secure sandpaper (180 grit) to one of the tables on your jointer. That is about a flat a surface as you will get in your workshop - at least it should be!
If your plane is too far out of alignment and you don't want to throw it away take it to an auto shop that mills cylinder heads flat (do they still do that in the USA?). Beware that you then have to square off the sides if you want to then use the plane for shooting
I find that people sometimes start with abrasive paper that's too fine, particularly if a plane sole is quite severely concave. Don't be concerned about starting with 80 grit or even 60 grit if quite a bit of work is required. I demonstrate this to my learners with an occasional horror plane a student brings in, bought cheap to get their collection of planes going. Getting a really badly out of flat plane sole flat enough to work generally takes between 20 minutes and at most 35 or or 40 minutes using aggresive abrasives.
I've never found a really significant advantage in a plane's performance if the sole is abraded to anything finer than about 120 grit-- there's some advantage, but it's not a huge one. If you simply want the plane to work then as flat as 80, 100 or 120 grit at the rim and around the mouth of the plane does the job: you can chase high shine later if desired when you've got time between more important jobs.
Super-dooper engineering standards of flatness of metal plane soles I believe is generally a bit over-hyped. I've come to that conclusion because from time to time I purposely bend and twist the soles of the longer metal planes slightly in use to suit specific purposes. Sso, therefore, how important can perfect flatness be so long as the plane sole isn't concave? Slainte.Richard Jones Furniture
A footnote - the degree to which a plane sole needs to be polished (i.e., how high a grit number you go to when lapping) varies according to the purpose of the plane. A roughing plane (such as a #6) that will have a heavily curved iron, a wide mouth, and is intended to take big shavings doesn't need a very smooth surface on the bottom at all (though it does need to be reasonably flat).
A smoothing plane needs a fairly high polish to the sole in addition to being the flatest of your set of planes. That doesn't mean you need a mirror on the bottom, but it should be relatively free of scratches. The reason is that a smoothing plane needs to take very thin shavings. If the sole has scratches left in it from 100 grit sandpaper, you may find (as I did) that the shavings that result are a set of loosely held together strings - those strings corresponding to the scratches in the sole.
If the sole has scratches left in it from 100 grit sandpaper, you may find (as I did) that the shavings that result are a set of loosely held together strings - those strings corresponding to the scratches in the sole.
Really? I guess the scratches would have to be scoring the wood ahead of the cutter for that to happen. I suppose that's plausible on certain species but I'd love to actually see it.
Edited 8/28/2008 2:54 pm ET by BossCrunk
Boss - the stringing I'm referring to is due to a very shallow set on a smoothing plane - the blade is exposed farther in the "valleys" of the scratches than the hills. I've seen this effect with settings that produce shavings that are quite transparent, slightly extending the iron makes the effect dissappear, though striations in the shaving is still visible when held up to a light.
I'd note also that this was only something I saw after dressing the soles of old Stanleys and british infills with coarse sandpaper, not on the newly manufactured LV and LN planes. I don't know what grit they finish these planes to, but my impression is they're quite good enough out of the box.
"the blade is exposed farther in the "valleys" of the scratches than the hills"
Still puzzling. For scratches in a generally level sole to produce "strings", the wood would need to be compressing generally and expanding locally to conform to the scratches in the sole -- like an extrusion. It surprises me that wood is plastic enough to do this.
Is it possible that the scratches extend to the throat, rendering it "serrated", and when the closely-set chipbreaker on the smoother does it's thing, the serrations on the tight throat cause this effect? (When you set the blade coarser, the shaving is too thick to be shredded by the serrated throat.)
Just wonderin' is all.
Mike HennessyPittsburgh, PA
Mike - The wood does compress under a plane sole, unless it's really freakin' hard (like the australian stuff Phillip works!). It's pretty easy to confirm this with something like mahogany or walnut - just plane normally with a very lightly set iron, then back off on the pressure and just use the weight of the plane. At least in my experience, this is the difference between getting shavings and getting dust (or nothing at all). At first I attributed this to flexing of the plane's sole, but that doesn't really make sense. Given that the pressure applied by hands on totes would make the sole concave, and backing off would make the sole more convex, doing so should actually increase the depth of the cut.
My thought about the serrations is, I think, what you mean about getting the scratches at the throat - perhaps you meant the edge of the mouth? Examined under a magnifying glass, the edge of the mouth leading the blade has what amounts to a "saw tooth" edge, and that dissappears once the sole is more highly polished - the "saw tooth" configuration is still probably there, just a lot smaller than my magnifying glass can pick up.
Of course, all of this is just an interesting esoteric discussion. I have a hard time imagining a woodworker interested enough to flatten the sole of his plane leaving it with 80 grit scratches...
I've seen something similar although on planes with a fairly nice polish to the sole. Like others, I attributed it to the grain of the wood itself (open grain like Oak especially), a bit of a ragged cutter or a combination of both.
There are at least three reasons for getting "stringy" shavings:-
1)blunt or damaged blade 2)type of wood and 3)if one is planing the quarter sawn face.An ordinary Stanley type iron can appear "damaged" after planing an abrasive (but fairly soft) wood such as Makore.
Who cares what the shavings look like as long as the surface is right and the work is done to satisfaction.
I can't see how any sole that has been sanded with a rough grit even as low as 40 grit can leave an imprint of this on any wood- unless there are actually miniscule grooves with their edges raised-as one would get when a sole or piece of steel has been (badly) surfaced with a shaper (metal work machine which has a reciprocating tool head).
This sudden interest in shavings is out of character for you so I take the opportunity to sweeten you up further by sending you some more....Philip Marcou
I agree and thank you.
Edited 8/30/2008 7:19 am ET by BossCrunk
dkellernc," not on the newly manufactured LV and LN planes. I don't know what grit they finish these planes to, but my impression is they're quite good enough out of the box."I believe the literature that came with the 4 1/2 LN suggested you could touch up the sole with 400 grit. Therefore I'd assume that is the grit they are shipped in the box.
I have to say, like Boss, I've never seen the 80 or 100 grit striations left on the sole of a smoothing plane I've flattened transfer their profile to any piece of wood I've planed -- but I've got to admit I've never needed to plane anything softer than perhaps lime or one of the softer cedars.
I'm not saying it can't happen, but I am saying that in the time I've been whacking wood for a living, and before that when I was an amateur schoolkid woodworker I can't ever recall seeing such a thing. Slainte.Richard Jones Furniture
Me either Richard. I'd like to actually see that phenomenon in action.
I've had shavings that had a sort of parallel string thing going on, but I've always taken that to be the nature of the grain on particular pieces, not scoring from the sole.
That's been my interpretation as well.
I get that (your term) stringing effect all the time, but it's not due to the scratches in the soles of my smoothing planes. It's caused by the iron requiring re-honing, after becoming slightly dull from working. When smoothing, especially table tops, I use this signal as the moment to go and re-hone the edge of my plane iron, or just switch to another smoother. Otherwise, these slight lines can show up in the finish.
I always keep my smoothing plane irons ultra, ultra polished for final smoothing, and that is why I have 4 of them. I hate to stop working in the middle of smoothing a table top to go to the sharpening station. I don't worry about it as much with the other bench planes, as they aren't creating the final surface on the piece of furniture I'm working on.
Jeff
I am a machinist at boeing. My employer uses a product called lapping cloth. It works very well for flattening when placed on a flat surface.I can find out where my employer buys it if you are interested. You can even get your planes surface ground ( at more expense ) at a local job shop. I surface ground my planes,but I'm a perfectionist.
Reece
Love to know more about it but at the prices you employer charges and pays for things, would it be available in small enough lots for mortals?BB
You bring up a very good point. But it never hurts to ask. I will talk to someone in purchasing and let you know by Wednesday.
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