Lapping plane soles and blade backs with a belt sander...

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Forum topic by Benvolio posted 05-19-2013 09:34 PM 7363 views 0 times favorited 19 replies Add to Favorites Watch
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148 posts in 2475 days

05-19-2013 09:34 PM

.... is something I’ve never tried doing.

At the moment, I happily don’t own a belt sander, but I get that they’re used for flattening the soles of planes and the backs of irons and chisels….

But I’m curious – what guarantee do you have that the `plate` of the belt sander is flat enough to give finely tuned hand tools?

Confucious he say: ``don’t use canon, to kill mosquito``

-- Ben, England.

19 replies so far

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Don W

19371 posts in 3111 days

#1 posted 05-19-2013 09:41 PM

I can’t speak for any one else, but I always finish on granite. The belt sander is only for the heavy lifting and only for the one way out of whack.

-- - Collecting is an investment in the past, and the future.

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810 posts in 2447 days

#2 posted 05-19-2013 10:37 PM

Not to be too technical, lapping is a whole other process, that is not related at all to using abrasive paper even on a granite plate.
Though the term is often used for sanding a surface these days.
I myself would not use a belt sander on the sole of a plane, or ever seen a plane that would warrant such abuse, no matter how rust pitted it may be.

I need to say about comments I make is based on part of what I do for a living, making metal objects flat.

I keep adding at alittle to this reply,
I have not seen any standard of how flat a plane should be. A Powermatic model 66 table saw was spec by the factory to be .010” max out for overall table flatness.
A #8 plane should be?

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Don W

19371 posts in 3111 days

#3 posted 05-19-2013 10:49 PM

just out of curiosity unbob, how many planes have you flattened? You’ve post a few post that seem to go again common restoration practice, not saying its wrong mind you, just different. I’m a little curious were your info comes from.

-- - Collecting is an investment in the past, and the future.

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Francisco Luna

969 posts in 3937 days

#4 posted 05-19-2013 11:03 PM

that is like taking a Rolex and give it to a Gorilla to replace the battery.

-- Nature is my manifestation of God. I go to nature every day for inspiration in the day's work. I follow in building the principles which nature has used in its domain" Frank Lloyd Wright

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810 posts in 2447 days

#5 posted 05-19-2013 11:17 PM

I have flattened 2 ea of #4, 5, 5 1/2, 6, 7,8 and around a dozen other types of planes.
But, I do have a close tolerance machine shop, and have described “the idea”of hand scraping a plane sole, much the same as needed for mantainance, on surface grinder ways or the crosslide on the Monarch lathe upper left, for example.
Now, what I say can only be based on what I do. I certainly cant say everyone should do what is the norm for me.
But perhaps part of what I do can be useful for some.
Now here is a thought, in the “old days”, a machinist would be able to draw file a #8 planes sole flat to .002”.

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3112 posts in 3324 days

#6 posted 05-19-2013 11:38 PM

Gently…if you have a machine shop, it’s a whole different ball game.
For myself and others who don’t, and/or can’t aford that then it’s something else.
I’ve done draw file flattening, long process if it’s a ways off. On HPOD posted a couple
planes, a Stanley #4 and a Craftsman #5 that were canted, both off by a full 16th inch
corner to corner. My stationary belt sander was the savior on those two, followed by the sandpaper on a flat surface method. Yes it “seems” like a bull in a china shop method at first, but then again think of a scrub
plane chomping the rough stuff , followed by the rest of the herd to get that final smooooth surface ?


-- Glen, B.C. Canada

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810 posts in 2447 days

#7 posted 05-19-2013 11:50 PM

ah, but here is the catch,
To repair the machine tool ways, much the same as the sole on a hand plane, all done by hand.
Since most are sanding the soles of planes on granite, they already have the reference surface. What they do not have is the hand scrapers. Those can be made of old files. A tube of prussian blue is needed also. As far as draw filing a #8 plane flat to .002” that takes some practice, but was required in the distant past for a machinist, on other objects of course. Apparently there is no standard for how flat the sole of a plane should be. For several years, buying old planes and reworking them, I found for “me” the better I can get them flat, the better they work for “me”. So, again, what I do, is not for everyone, just information from another angle.

Maybe this will explain my perspective, the plane is a metal object that should be flat, I can only approach that problem from the methods of a metal worker, not a woodworker.

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2839 posts in 2841 days

#8 posted 05-19-2013 11:59 PM

I do it by hand on a scrap of MDF and work my way up from about 220 grit sandpaper to whatever the finest I have on hand is (usually autobody wet/dry stuff). I only use the belt sander if the cutting edge of a plane is badly chipped and I need to get to sound material.

View Woodknack's profile


12929 posts in 2924 days

#9 posted 05-20-2013 02:06 AM

Never used a belt sander to flatten a plane but I’ve never had one that was really out of whack either. I start at 80 grit and work until the sole is flat, then smooth it a little on finer grits. Does polishing the sole really make a difference? I’ve always read it’s unnecessary. How flat is flat? That’s a big discussion. For me it’s as flat as my granite slab or tablesaw top or longer planes.

-- Rick M,

View mandatory66's profile


202 posts in 2674 days

#10 posted 05-20-2013 02:36 AM

This is very timely, for today I started work on a Stanley 5 1/4 plane and found the sole to be very uneven. I ran the plane over some 100 grit on my table saw top and the only part that touched the paper was about a 1/4 inch on each side. This is my 4th plane that I have flattened and none were this bad. Sooo I decided to use my Grizzly 6 inch belt sander with a 50 grit belt. I was worried that I would put pressure on the plane in an uneven manner and mess the sole up more than it was. Well it worked out very well The plane flattened very quickly, I went back to my sandpaper on the table saw top and worked through the grits to 600. This basically polished the sole. Along with other fettling & a new IBC blade I can get shavings as thin as .0015 full width. This worked so well that in the future I would do this again. Setting the plane down on the belt as flat and even as possible along with even pressure is the key.

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810 posts in 2447 days

#11 posted 05-20-2013 06:44 AM

Some thoughts on how flat is a plane. If a granite plate is available, most of the lesser cost import plates should be at least within a couple hundred millionths in 24”, or .0002”. On the plate, lay 3 narrow strips of thin paper, one at each end one in center. Can any be pulled out? Move them around and try again. With the plane resting directly on the granite, can a strip of paper be slid under the plane at any location? If the answer is no to the above, then the plane is pretty flat.

An out of true plane can still do a good job, its been done for more then a century.

Since, I would expect many would be checking progress with some sort of straight edge, and correcting progress along the way by going at angles, skewing the plane, or what is needed to get the board flat. A flat plane should produce a flat board across the width with a few straight strokes. Of course at times, skewing is needed to reduce tear out. Since, I have two of each size of the #4 through #8, I noticed one plane of the same size and make worked better then the other. Working on these, such as making sure the blade,frog, lever cap, and ect had good contact and fit. The last factor, and the hardest to deal with, is the sole. When that was delt with, the planes all work the same in each size. Then I had no favorites.

Ok, since there seems to be no standard for a hand plane, I had to decide on a basic acceptable tolerance for flat. .0005” in 24”, about the same as a milling machine table.
A jigboring machine table would be .00007” or seventy millionths in 24”, abit excessive for a wood plane, I would think.

View Tim's profile


3859 posts in 2505 days

#12 posted 07-07-2013 06:31 PM

Bob, hand scraping sounds rather interesting, but I can’t find much good information about it. Do you have any good links or videos that show how it is done and how the scrapers can be made? In fact are there any good metal working forums like an equivalent for Lumberjocks?

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7 posts in 2329 days

#13 posted 07-07-2013 09:16 PM

I have done a bot of work on a #4, but probably would not ever do it again. It took lots of time and lots os sandpaper. If the sole is too far out of whack to work well, I’ll look for another plane. I think the longer planes are difficult to do by hand, and you can very easily make them worse. I have 5 1/2 that someone else flattened. It is now slightly bannana shaped.

If you really want a plane sole flattened, check out Tablesawtom. He hangs out over on Woodnet. He will precision grind planes for a very reasonable price. I have never had one done, but everybody raves about his work.


-- “It’s good to have an end to journey toward; but it is the journey that matters, in the end.” Ursula K. LeGuin

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1591 posts in 4305 days

#14 posted 07-07-2013 10:25 PM

Coincidently, I have just re-furbed four hand planes. A Stanley #6, Stanley #3, Stanley #4, and a DE (hardware store brand) #6.

All of them had gotten pretty rusty. I removed the rust with a solution of citric acid and then I used My Shopsmith 6”x48” belt sander to “mill” the soles and sides. This worked extremely well and the soles are quite flat – I was pleasantly surprised. I used an 80 grit ceramic belt and the soles are pretty smooth. I might do a little more work with finer grit belts – but perhaps not.

I’ve done the “flattening” with various grits on glass plates. It’s a lot of work, and my results with #5 and longer planes was not very good.

I say go ahead and try the belt sander.

-- "Heaven is North of the Bridge"

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23994 posts in 3227 days

#15 posted 07-07-2013 10:34 PM

About all I use…

at the start (10” long #4 base), then after a couple minutes

check for any low spots. Sharpie lines come next. Belt was a 100 grit, but kind of worn down. Sides done the same way, checking for square to the sole as i go. Run the base from both directions, as well. Sander does have a flat, steel platten under the belt.

-- A Planer? I'M the planer, this is what I use

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