Experimental Underbucking Tool

This is a tool I have made but not used extensively.  The purpose is to have a convenient and lightweight tool to use on a pulaski handle for underbucking with the crosscut saw.  I have used a similar tool made by a former master trail worker, and that is where I got the idea to try to replicate his tool.  This project is aimed to benefit wilderness trail workers who already have experience with the procedure of using a crosscut saw for underbucking.

Materials: (I purchased all items at the Darrington "Do It" Hardware.)pulley photo
*  1 1/2 inch swivel pulley made by National (capacity 420 lb.)
*  1 1/2 inch x 3/8 inch stainless steel bolt with one regular nut and one locking nut
*  2 inch cast C clamp or larger (the bottom flared face that opposes the tightening screw of the C clamp must be wide and  thick enough so that it can be ground and drilled with a 3/8 inch hole.
clamp
underbucking tool photo

Procedure:

  • Remove the spring pin that secures the pulley axle.  
  • Remove the pulley.  
  • Cut off the swivel eye that would be the hanging attachment for the pulley.  This will be replaced with the 3/8 inch stainless bolt.  
  • The hex head of the bolt will need to be ground so that the edges of the hex are rounded and the bolt can fit into the pulley shell replacing the swivel eye.  The pulley should be able to swivel on the bolt.  
  • Replace the pulley and spring pin.
  • Put the regular nut on the bolt so that it is snug but still allows the pulley to swivel.
  • Grind the outside of the clamping face of the C clamp so that it has a surface parallel with the clamping face.  The shoulder of the clamp will need to be tapered so that the attached swivel pulley can turn.  
  • Drill a 3/8 inch hole through the flange you have created in the grinding step.  Be very careful that the clamp is safely secured for drilling so that it will not catch and spin.
  • Attach the pulley as shown with the locking nut . cut the excess bolt flat with the nut.
 Notice the change in the photo showing
that the rolling saw guide pivots.
underbucking tool photo 2
  • A similar tool made with a clamp that is normally used for clamping camper shells onto pickup truck beds.
  • With this tool a wrench is needed for tightening the clamp.
 tool made with a different clamp
underbucking tool in use

Tool Use:  (photo courtesy Gary Zink, Washington Trails Association)

When an undercut with the crosscut is needed, you will also need a pulaski (or a long handled single bit ax) and a small sledge or a single bit ax (the tool you have brought for driving wedges).  The planned cut will need to be vertical.  Position the pulaski so that the handle is horizontal with the wide surfaces facing up and down, and the gripping end of the handle is below and directly out from the location of the cut.  Drive the pulaski into the log with the sledge.  WEAR EYE PROTECTION especially when hammering steel to steel!

Clamp the underbucking tool (over a leather sleeve if desired) to the handle so that the roller is above the handle and so that the saw back can ride on the roller and appropriately reach the cut.  The pulaski will need repositioning as the cut progresses.  Be aware that when the cut releases and the log moves, the pulaski and underbucking tool are vulnerable to damage.

BE EXTRA CAREFUL TO STAY OUT FROM DIRECTLY UNDERNEATH OR ABOVE THE SAW, THE PULASKI, AND THE LOG!!  THIS TOOL, OR THE PULASKI HANDLE COULD BREAK OR SLIP AND LEVER OR PINCH THE SAW AGAINST ANY ONE IN THE WRONG PLACE!

Please email me if you have comments or questions: geowinters@glacierview.net
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