Thursday, April 29, 2010

Learning to Plane - Part III

When Should You Regrind a Bevel?

You only need to regrind after you have honed your secondary bevel, say, six times, if it is taking a long time to get a good polish, the secondary bevel has grown large or if you've hit a nail or dropped the blade and nicked it.  Chris Schwarz grinds on sandpaper, starting with 80 grit and moving to 120 grit.  Grind until the secondary bevel is small, unless it has been damaged.  In the latter case, grind it off entirely.

If you need to regrind on a grinder, grind the point flat, because the point is the most likely place for the blade to burn.  Alternatively, you can quench the blade while grinding.  If you burn a blade blue, hone it and use it anyway.  It will need honing sooner than if it had not been burned, but otherwise it will be OK.

When using a grinder, Chris draws a square line with a magic marker--red shows up best.  Then he grinds the bevel flat using an 80 grit wheel.  He prefers the gray wheels over the white ones because the gray breaks down easier and stays cooler.

How do you tell if your blade is dull?  When you can see a bright line across the end of the blade.  If it's sharp, you can't see the end at all.

Cambering Blades

Some planes will have straight blades.  Others, especially those designed to flatten boards, should have a curve to them.  Jack planes, when set up as fore planes, should have a curve with an eight inch radius.  You would create this camber on the grinder.  Jointer or try planes can be straight or curved.  Chris prefers them curved.  They get a much smaller curve, about .006 inch from the center of the curve to the edge of the blade.  This would work out to a radius of about 37.5 feet.  Bench planes get a smaller curve yet, about .002 or .003 inch.  In case the case of jointer and bench planes, you grind the blade flat, then hone it curved.  The goal is to have enough curve to the blade to avoid tracks and still take a good shaving.

Chris's method is to use a honing guide that allows some rocking motion side to side.  He holds the blade square against the 1000 grit stone, putting heavier pressure on one outside edge, then pulling the blade 10 times.  Then he shifts the heavy pressure to the other side and pulls 10 times.  After that, he moves the pressure to the midpoint between one side and the center and pulls the blade 5 times, repeating that motion on the other side.  Finally, he puts the pressure in the center of the blade and gives it two pulls.  This sequence is then repeated on the 4000 and 8000 grit stones.  There is no need to repeat the ruler trick on the back of the blade.  Stropping is about like using the 8000 grit stone.  Stropping the blade is unnecessary after honing and may even lead to rounding over the bevel.

You also want to trim the corners of the blade.  This only needs to be done the first time you set up the blade and is done by pushing a fine file against the corner of the blade, using a rounding motion.  This helps prevent blade tracks on your work.

Thanks to Jeff Fleisher for these photos.  Next time I'll cover setting up planes.

Norm

Tuesday, April 27, 2010

Learning to Plane - Part II

Last weekend, my friend Jeff Fleisher and I attended a two-day workshop on hand planes at the Marc Adams School of Woodworking.  The class was taught by two leaders in the field of hand planes, Thomas Lie-Nielsen, founder and owner of Lie-Nielsen Toolworks, and Christopher Schwarz, editor of Popular Woodworking Magazine.  The classroom held 20 Lie-Nielsen workbenches and provided comfortable room for about 40 of us to do our work. 

The class was a combination of lectures by the two presenters, hands on work on sharpening, setting up and using our own planes and those brought by the presenters, watching a film about the Lie-Nielsen factory and the making of their planes and other tools and a planing contest.  Lie-Nielsen had a full complement of their planes on hand for us to handle and try out and took orders from those who decided to purchase one (or more).  Chris Schwarz also brought a lineup of his own personal planes that we were free to use.  And Chris's Lost Art Press had T-shirts, hats, books and DVDs for sale.

I brought all my planes, including a new Lie-Nielsen low-angle jack plane I bought only a week before the class.  During the class, Tom Lie-Nielsen signed tools of his manufacture with an engraving tool.  I had all six of mine signed.

Sharpening

A major portion of class time was devoted to sharpening.  Sharpening is, after all, the essential step in getting a plane to produce consistent, thin shavings of the type we all desire.  Our presenters taught a method based on David Charlesworth's, but simplified.  They did not argue that their system was the best, only that it worked.  Chris said all systems work and that we should pick one system of sharpening and stick with it for a while, that our edges would improve over time.  Don't be a "sharpening bigamist," he concluded.

An edge is when two planes come to a point.  The smaller the point, the sharper the edge.  Also, the more you polish the edge, the more durable it will be.  On the other hand, there is a tradeoff; the thinner the edge, the more fragile it is and the more often you will need to sharpen it.

Grinding

The back or face is the flat side of the plane blade, the bevel is on the other side.  Only the ends of both sides need to be sharp.  Except on high quality planes or on blades needing reworking, you grind the bevel.  The bevel can be flat or hollow ground.  Regrinding will be needed after a blade has been honed five or six times or the secondary bevel gets too wide.  It can be done on a grinder, but we used 80 and 120 grit sticky back sandpaper on a flat surface to shape our blades where needed.  Only one of my blades needed grinding. 

After grinding, the next step is polishing the ends on both sides of the blade.  First you flatten the back of the blade.  Chris does this on a 1000 grit stone and does not polish the back any higher.  There's no need to.  The goal is to assure the blade is flat.  Once it is, you move on.  

Back Bevels

Chris strongly supports the use of back bevels--secondary bevels on the back of the plane that increase the sharpness of the edge--on all blades except chisel planes.  These can be used with both bevel-down (traditional) and bevel-up planes.  He uses Charlesworth's "ruler trick" to create these.  This involves taking a thin ruler (he uses Lie-Nielsen's ruler), placing it on the near edge of the waterstone, then, with the edge of the blade a half-inch off the far edge of the stone and flat against the ruler, pulling it onto the stone and rubbing it back and forth a few times (say 10) on each of the three grits (1000, 4000 and 8000).

Secondary Bevels

Precision in setting the angle of the secondary bevel is not critical, but consistency is.  Chris uses a homemade jig to set the proper angle at which the bevels will be honed using a simple $12 honing tool.  Typically, the secondary bevel is honed at 5 degrees higher than the primary bevel.  David Charlesworth also advocates a tertiary bevel, but both Chris and Tom thought this to be unnecessarily complicated.  Chris uses each of the three grits to hone the secondary bevel.  He prefers Shapton stones because he travels a lot and they don't have to be soaked like the Norton stones do.  Another class member told me the Shapton stones also wear better than the Norton stones.  Chris uses a DMT diamond stone (coarse or extra coarse only; finer stones use a different method to adhere the diamonds that is undone by the waterstones) to dress his waterstones flat.

Honing Guides

He prefers the inexpensive type of honing guide that grips the blade by the sides.  These may require some filing to assure the blade is held flat.  But in his opinion they work better than the type (like the Veritas Mk. II) that hold the blade from the top because the latter can allow the blade to slip out of alignment.  Lie-Nielsen provides instructions on building a jig like Chris's for setting the angle of the blade in the honing guide.

Straight Blades

You begin sharpening by honing a straight secondary bevel.  You take about 10 strokes with the 1000 grit stone so you get a bevel that is consistent all the way across the blade.  You want all the scratches from the primary bevel removed.  Pull the blade across the stone with heavy pressure, then a few light pulls using the slurry created by the heavier pulls.

Next go to the 4000 grit stone and hone in a back and forth motion about 10 times.  The steel wool-like pattern from the 1000 grit should disappear and a bright line should appear.  Many woodworkers stop here.  The edge will be fine, but it won't be as durable as if honed on an 8000 grit stone.  When using the 8000 grit stone, a Nagura stone is not needed with Norton waterstones.  Lighten your touch with this stone.  Use a back and forth rubbing motion.

Next we learned how to create cambered bevels.  I'll cover this in my next entry.

Norm

Saturday, April 24, 2010

Learning to Plane - Part I

I've got the planes.  I described these in an earlier posting.  I've read the books.  Especially good are Christopher Schwarz's Essential Handplanes and Thomas Lie-Nielsen's Sharpening.  Now it's time to put what I've been learning into action.

 I started with a wide board of curly red oak that I wanted to use to make some cutting boards.  I set out using my Lie-Nielsen no. 7 1/2 low angle jointer to flatten the board, then my Veritas low angle smoothing plane.  To remove a peak in the center of the board, I first planed a trough in the center with the jointer plane, then planed across the board on a diagonal to remove the high places until the board was level.  Then I used the smoother to produce a surface that barely needed sanding.  The result was good if I do say so myself, considering I started with a tough board to plane. 

I learned a lot from the process.  One lesson was that I need to know more about sharpening.  A second lesson is that I need to know more about setting up my planes for optimal performance.

Fortunately, I'm having a chance to learn how to do both of these things.  As I write this, I am midway through a class on handplanes taught by none other than Thomas Lie-Nielsen and Christopher Schwarz.  The class is being held at the Marc Adams School of Woodworking in Indianapolis.  Already, I've sharpened and set up two of my planes and have taken a perfect thin shaving with my Lie-Nielsen No. 4 smoothing plane.  It was an exciting moment!

I'll have more to say about this class later, along with photos.

Norm

My SawStop Returns

After nearly two months of down time, my SawStop contractor's saw is finally back in operation. The tech guys at SawStop were great. They sent me a new control box, which had been upgraded, updated the software in my brake cartridges and sent me a new connection cable. I first installed the new control box, a somewhat tedious but not altogether difficult process. That didn't fix it. Then I tried the updated brakes. That too didn't work.

So I set to work on changing the connection cable. That turned out to be hard work, reaching down through the table top to get at impossible to reach nuts and screws. One I stripped out and had to remove by drilling it out with my Dremel tool. Another the instructions said was a #2 Phillips head screw turned out to be a hex screw. But it faced downward and I couldn't tell that, so I kept on turning and turning to no effect.

I finally hired a man who does repairs for our Woodcraft store to come and fix it for me. In about three hours, he had it together and operating.

It's a wonderful saw. I'm glad to have it back again.

Norm