Ask the Staff
Question:
I've found trying to smooth and flatten wood with a hand plane to be a frustrating experience. Even with the blade as sharp as I can get it,
I can't produce those thin, uniform shavings like you see in the woodworking magazines. What are some of the things I need to
know to get a bench plane to work well?
Answer:
It's an unfortunate reality that most metal bench planes don't work to their full potential right
out of the box, and that a certain amount of tuning needs to be done by the end user. With apologies
to all engineer/machinist woodworkers, I will endeavor to explain how to tune a metal bench plane
without involving a machine shop or taking up vast amounts of your valuable woodworking time or
money. I'll leave out the small stuff like after-market blades and accessories. This is by no means
the final word on this subject, but maybe you can pick up a thing or two from my many years of
making a living with these wonderful tools. [If you find my methods rudimentary or crude, let me
paraphrase Jim Krenov who said at some point the engineer and artisan must part ways.]
1. SHARPEN THE IRON
If there's a given principle in woodworking, it must be sharp tools. If your steel isn't keen,
not much happens. Learn to sharpen and everything else in woodworking will begin to fall into place.
80%of all plane problems can be fixed by getting your irons as sharp as possible. There's a ton of
information about sharpening out there, but stick with the basics and worry about other stuff like
cambered edges and different bevel angles later. I recommend Thomas Lie-Nielsen's book
Complete Illustrated Guide to
Sharpening
(202299), or Leonard Lee's
Complete Guide to Sharpening
(200831).
Remember, even a new iron off the shelf isn't sufficiently honed for
fine work.
2. FIT THE CHIP BREAKER TO THE BLADE
Most metal bench planes' irons have a cap iron or chip breaker attached to the back of the iron
with a short screw. Once the blade is honed and at least part of the back, near the edge, is flat,
then you can make sure the chip breaker fits properly. The chip breaker has several jobs like
stiffening the blade and breaking chips into lovely curls. It also clogs with chips if it's not
tight with the back of the iron. Clogging causes all sort of unimaginable misery and at least 5% of
bench plane problems. It's easy to fix. Attach the chip breaker to the back of the iron about 1/16"
away from the cutting edge and tighten the screw. Now, hold it up to a light source and see if you
can see light between where the two surfaces meet. File, sand or scrape metal away from the cap iron
until they meet reasonably well. Don't obsess about it, because you'll never get it perfect. Just be
aware of it if problems occur, so you'll know how to fix them.
3. INSPECT THE FROG
The frog is the inclined plane that the blade assembly beds against in the center of your tool.
Typically it's held to the body of the plane with two screws and advanced and retracted by a screw
just below the brass depth adjustment knob. Remove the frog and run your fingers over it to make
sure there aren't any burrs, catches or paint that will keep your iron from mating nicely against
it. You don't have to get it dead flat or anything like that. Just file or sand away the rough edges
and any other obvious impediments. The whole process shouldn't take 6 minutes. Now lubricate the
screws and reassemble the thing. When putting the frog back, try to visually square it up with the
body of the plane. Also make sure front of the frog is no further back than even with the rear of
the mouth opening, otherwise the blade assembly will flex when the lever cap is applied.
4. LEVER CAP
The lever cap keeps the blade assembly (iron and chip breaker) fastened to the frog. It's held
in place by a screw. The lever cap should operate smoothly and shouldn't be so tight that it
requires great force to remove it. A snug fit is all that's required. If it's difficult to advance
the blade or move the lateral adjustment lever, then loosen the screw that holds the lever cap.
5. A FLAT SOLE OR NOT
From age 16 to 30 I worked with my planes every day at the bench and at the jobsite before I was
made aware that planes needed to be flattened. Suddenly they stopped working properly and I labored
night and day to get them dead flat. Checking constantly with an expensive straightedge and grinding
away with sandpaper on glass, I struggled and eventually gave up. What had changed between one day
my planes working and the next day them not? I must have read some magazine article or talked to
someone who had convinced me this was the way it had to be: flat soles equal flat work, etc. Then I
attended a seminar with Toshio Odate. He was taking beautifully thin, gossamer shavings with a
wooden plane that was purposefully out of flat, and my suspicions were confirmed. The only thing
that changed was my attitude and my planes suddenly worked again. They've been fine ever since.
Okay, how much flattening or sole conditioning do you need to do? The answer is, not as much as
you've been led to believe. First, find something that's reasonably flat like a tablesaw wing, a
jointer out-feed table or a melamine-coated piece of MDF, and stick some 120-grit paper to it. Next,
take a magic marker and color a 1/8" stripe across the sole of your plane directly in front of the
mouth opening. With the plane assembled and the blade retracted, take a couple of passes atop the
paper with your plane. Flip the thing over and inspect the mark. Is the abrasive cutting through the
marker line? If so, you're done. Or course, you could keep polishing and using finer papers until
you had a mirror finish on your sole. Many people do. For all practical purposes, as long as that
first millionth of an inch of plane sole hits the wood before the cutting edge does, you're good to
go. If not, keep going. Switch to a coarser paper if necessary, but don't spend more than 10 or 15
minutes on this. The worse case scenario is that your tool is concave along its length and you've
got to spend some time lapping before you hit the marker line. Remember that temperature and weather
affect these things, so if your tool is working one day and not the next, try the magic marker
trick. Sole flatness only accounts for 5% of plane unhappiness.
More important than sole flatness is skill. You guessed it – skill is the last 10%. To obtain
skill you must practice and gain experience by doing. Only then can you make sound judgments about
what's going on. Now wax (any wax, really) up that sole and get to work.
6. OTHER STUFF
Bad news, your metal plane probably is never going on Antiques Road Show for big bucks. Good news,
you can modify it in anyway you see fit to personalize it or to make it more comfortable. Go ahead
and strip off all the shipping lacquer, file the handles and edges, even paint it teal so you can
recognize it in the plumber's tool bucket at the end of the day. The bottom line is that it's your
baby. Get it how you like it and enjoy the journey and joys of woodworking. Lastly, try not to get
wrapped around the axle about something you read or something someone told you about the way things
should be. Planes have been around for 10,000 years and have been doing fine work long before
machine shops, straightedges, feeler gauges, dial indicators and micrometers came into being. Trust yourself and
your ability to problem solve and you might find you didn't have a problem after all.
— Chris Black
Visit Highland Woodworking's Online Hand Plane Department
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