Building a Toboggan..?
By Drew
Published: December 16, 2007

This Article is a planning tool.  It describes what is known about making Toboggans; discusses ideas & variations;  and also outlines supplies and time needed to build one.

What is Known about Togoggan Making:
  Source: http://canadianwoodworking.com/forum/showthread.php?=15127
  -Toboggans have a 8" - 9" radius curve at the front.
  -they're made from planks 2.6" wide, & 3/8" thick
  -They CANNOT be made from kiln-dried wood, as this makes steam-bending impossible.
  -The steam-bending jig consists of a table with an 8" pipe sitting atop a 1/2" spacer.  Atop the pipe is a horiz' board; and once the wood is bent around the tube, everythinhg is clamped into place..


  From the LL Bean Catalog, Toboggans' dimensions are:
  -Small  - 45" x 12-3/4"
  -Medium - 72" x 15-3/4"
  -Large  - 92" x 15-3/4"
 

Ideas:
  Mini Steaming Box.  Kind of like a magic act where the assistant's head & lets stick out; build a 4' long steam box that the planks run through, and seals off those joints where the wood sticks out relatively well.  The inside of the box you fill with hot steam.
Design Decisions / picking the design & technique:
  -Blend Ash & Maple to have multi-coloured sleds.
 Steam the wood in preparation for Bending:
  -Requires a Steam "Hot Box" 10' long.
  -Box should have slots that you can slide the planks into while keeping them held separate from one-another
  -Box has 1 hole in its' bottom to accept a pipe from a steam-bending kettle.
  -The kettle has to be a special unit, able to produce enormous amounts of heat; and have a safety feature that shuts off the heating element once the kettle is out of water.
 Steam Bending Jig.  At the heart of any steam jig lies the 3 stage clamp.  The Steadying Clamp snaps on quickly & steadies most of the plank while you work to bend the tip.  The Bending Clamp bends the current plank; while the Holding Clamp holds those planks that were already bent.  The Holding clamp often tightens the plank around the bending tube; ensuring an even fit for all of the planks.  For this project,
  -The Steadying Clamp will be (at first) a clamp holding the plank to the underside of the workmate (+ for the 1st & last plank, a clamp holding the bending tube to the workmate through the plank). The Steadying Clamp is replaced by bolting the plank to the cross-pieces as soon as the plank is finished bending.

  -The Bending Clamp will have 3 parts. 1st part is a Cam Strap that pulls the tip of the plank's top towards the underside of the toboggan.  For extra leverage, use a pair of bar clamps puling down a piece of wood balanced between them. 2nd part is a bar that goes across the front of the toboggan; which squeezes the plank against the bending tube; both ensuring a snug fit, and also securing the bending tube in place for the rest of the bend.
  -The Holding Clamp will be (at first) Cam Straps, but after the last plank is bent, a pair of bars will be bolted together around the tips of the top, and that bar will be pulled down towards the workmate's surface with a pair of bar-clamps.  

Supplies,
  Get the wood milled into 3" wide planks.
  -Small - 4x 77"( Toboggan length: 45" -4" for curved portion + 24" for the actual curve (pi*8") + 12" for flat portion on top + excess for jigging, & clamping)
  -Medium: 5x 104" (same calculation as abv)
  -Large:  5x 124" (same as abv)
  + Enough 3" plank to do all 7 of the cross-pieces.  1.5" x 128".
  -28x 1/4" x 3/4" recessed wood screws; or carriage bolts.
  -4x heavy-duty hook-headed screws
  -3' of stainless steel chain
  -23' of 1/4" - 3/8" climbing rope, as colourful as possible.
  -A very good steaming kettle.
  -Paste varnish - got it!
  -Wax.. What kind?
  -Scrap plywood (preferably 1/2" thickness) for steam box.
  -Epoxy paint to seal steam box, and prevent it from turning into goo when the high temperature action starts.


  Cross pieces:
   a) goes inside the sled at the back,
   b) is at 1/4 length,
   c) is at1/2 length,
   d) 3/4 length positions;
   e) goes inside right at the very front of the sled;
   f&g) are sandwitched together, and straddle the tips of the planks on top.
   A Grab Rope is needed to keep zie Occupants in the toboggan, so cross-pieces a-d need a 3/8" hole drilled through them at each end (hole faces from toboggan's front-to - back)
  -The Climbing rope is used both for 2x 5' Grab Ropes, plus also for a ca. 4' long tow loop coming out of the toboggan's front.

Costs:

Timetable: 1 week.
  -1 hour: Pre-drill holes at the 1/4, 1/2, & 3/4 length marks along the bottom for hardwood cross-pieces.  The Cross Pieces should be 1/2" high and 1-1/2" wide (so half a plank width by plank thickness).
  -1 - 6 hours: Steam the wood for at least an hour.  4 - 6 hours may be necessary (2-3 hours is my experience with 1/4" cherry).  I'm going to assume that the shorty-box idea was used.
  -While the wood is steaming; lay out all parts required for the steam-bending jig.  If a plastic or steel tube is used for the bending jig, wrap it in waxed paper or butcher's paper, to prevent staining the wood.
  -2 hours: Bend the wood in a bending/drying jig.  If a piece of wood is too stubborn to bend; splash some water on it & go over it with a steam iron.
  -3 days: leave to dry.  Keep air moving over it, preferably warm air.
  -While the wood's drying, prepare a few nice veneers to go in as a pattern, also sew a pad to sit on.
  -1 day: Cut excess from front of toboggan.  Sand & smooth toboggan to perfection.  Temporarily fit retaining chain.
  -1 day: paste Varnish toboggan many, many, many times.  And.. Don't forget to varnish in between the planks!
  -1 Day: Wax the Toboggan many, many times.
  -Dust off, and show off