Monday, February 23, 2015

The Art of the Perfect Stringer Curl

Is there anything more gratifying?  When thumbing through Instagram, if you happen upon a perfect stringer curl, its a guaranteed double-tap.  Its a bravo to the shaper who kept his blades sharp, maintained a steady hand, and lucked into some straight grain.

We asked a few stringer curl connoisseurs whats required to achieve Rapunzel-status.

Firstly, a word from the kingpin of color-dyed plywood:
Bradley Appelcore:  Super straight grain (vertical grain) material, whether from Bass, Cedar, or Redwood performs best.  The straighter the grain without interference from diverging branch grain are guaranteed perfect curlers!  It can be from fast growth (wide grain) or old growth (tight grain) as long as it is arrow-straight. Its easy to notice on Cedar and Redwood, but much more difficult to spot on the Bass.

Sharp tools are key, low angle, and a steady, even push, keeping your palm out of the way from inhibiting the emerging curl.  There isnt much you can do if the stringer is from solid wood and has divergent grain (grain rising away from the blank or grain diving into the blank) even with the sharpest of tools.

Essential Tools
Tim Stamps:  The best tool to get the curl is the block plane.  This curl came from the blade from my Lie-Nielson standard angle block plane.  This block plane was a gift to me several years ago from Rich Harbour.  Hes a tool fanatic!

Josh Martin: My vintage Stanley model 60 1/2 block plane is the best tool to get the perfect curl.  I hand grind the iron razor sharp.  Also, my Xacto mini spoke shave is the best for mini curls.

Nick Aleandro:  Each wood will work a bit differently so it of best to have a variety of planes or spoke shaves to choose from with various bevel angles.  I prefer narrow curved Japanese plane since I can use the same tool on the deck and base no matter the rocker.

Massimiliano Purchiaroni:  The tools are very important.  I used a normal David Combi plane, a spoke shave, and a Japanese curved plane.

The Best Wood for the Perfect Curl
Josh Martin:  Premium light Balsa is my favorite wood to get the perfect stringer curl, but it needs to be the good stuff.  The heavier it is, it tends to get stringy and produces the worst curls.  The good stuff produces the most golden and perfectly relaxed curls.  The best part for me is the sound produced when making them.  A light clean hissing sound that almost sings like a rubbed crystal wine glass rim.

Wade Tokoro: Basswood with the David block plane is the best combination.

Breno Basiliro:  Powerline Strignerz is a composite so it is even throughout the length of the board.  You will not run into grains, as with wood, which can break the flow.

Tim Stamps:  From my experience, the type of wood that most often gives the best ‘spiral curls is Basswood.  My guess is its the combination of the woods density, cell structure, and grain pattern.

Massimiliano Purchiaroni:  Red Cedar is my favorite for a perfect curl.

Todd Messick: Balsa is like Butter compared to the rest. Easy Breezy!

Technique
Wade Tokoro:  One long pass with a sharp blade.

Todd Messick:  The curl comes into play based on function.  I angle my planner to create a roll or curl,  as i cut across the blade.  This technique allows the cut stringer to curl off the side instead of rolling over on top of your pass.  Form follows function.

Nick Aleandro:  Sharp tools are the only option.  At a minimum you should be able to shave with the edge.  When sharpening I go to at least 8000 grit and use a Veritas honing guide to make sure I get consistent results.  What ever your method, a sharp tool and slow cut work best.  It is always better to do a few passes rather than to try to cut one deep one.  If you are digging in often in one section, try approaching from the opposite side or skewing your edge.  Wood sometimes just likes to be difficult, so dont get frustrated.

Breno Basiliro:  The curl is a reflection of how continuously youre able to run your hands and make micro adjustments, feeling the board and stringer as you move.  Again, sharp tools are still the most important factor.

Josh Martin:  I customize my plane irons so that they have a slight radius from corner to corner.  This is done so the corners dont score the foam as much on each side of a stringer but may affect curl quality as well.  Sharpness cannot be over emphasized.  Holding the plane at a slight angle to the grain direction seems to produce the best curls.  Dont be in a bad mood when making curls.

Tim Stamps:   To get that perfect curl takes three main things: a very sharp blade, a deep cut, and the proper skew angle. Ive shaped quite a few boards, and these spirals and curls are always things that brighten my day and get me stoked. Just like seeing a perfect wave peel down the beach!


Bradley Appelcore:  I actually carry a tiny cheap Stanley planer with a medium angle thats 1-3/8″ wide by 3-1/2″ long with a sharp blade loaded slightly on the bias and it works killer.  I have to check the glue line on all production panels so it sees some serious mileage.  However, when I want the kind curl for showing off my fancy stuff on Instagram, I use my grandfathers two handed plane from the 50s where I can control bias and angle with precision controls.  But that one stays on my workbench.

by David Lee Scales for US Blanks