- Apr 27, 2012 · (3) 7″ pieces (used for the “runners” on the bottom of the sled) (2) 8.5″ pieces (used for support on top of the sled) Step 3: Boring Holes. We’ll be boring 1-1/2″ holes in the 4×4 for our pipe. To do this job, you’ll need a 1-1/2″ hole boring drill bit. Bore the following holes: 36″ piece – 2 holes.