View source for LifeTrac II Build/Frame Construction Video Script


The LifeTrac Tractor frame is constructed from eighteen pieces of 4 x 4 x 1/4 inch steel tube.  These pieces are cut and drilled to make eight unique members that are then assembled with 9 x 3/4 inch bolts.

This video includes the most updated measurements from LifeTrac III prototypes on the Factor E Farm.  I will refer to the orientation of the frame pieces as if we were sitting in the drivers seat of the LifeTrac:  north is to the front end where the loader will be attached, south is behind us at the back of the tractor, west is on our left hand side and east is on our right hand side.  All lateral measurements of the beams are from left to right, all measurements of depth are from front to back, and all measurements of height are from top to bottom.  Each drill hole is measured from one end of the tube to accommodate for error in tube length.  Pay careful attention to only measure from this reference point.

We have recently developed a new jig for measuring hole positioning on the frame pieces.  On previous fabrication, a short square jig was used to mark transfer punch locations on the steel tube, allowing for accurate measurement simultaneously on both sides of the tube.  This jig was useful only on the ends of the pieces and would have to be applied from each end separately. The new jig will run the length of the tube, include every hole, and is to be applied from one side making its application straightforward.  We are currently developing and documenting this jig. 

First step is to cut the steel tube into the proper lengths for the 18 frame pieces.  Cut the steel tubes with either a cut off saw, cold cut saw, or a bandsaw.  A torch will work too.  Cut the three lower frame pieces identically, measuring 60 inches in length.  Cut the four bottom north/south frame pieces to a length of 76 inches.  The vertical frame pieces are fabricated in pairs.  The front, middle, and rear vertical pieces are different lengths.  Cut the two front vertical pieces to a height of 55 inches.  Now cut the two middle vertical pieces to a height of 52 inches.  Cut the two rear vertical pieces to a height of 59 inches.  Cut the two top north/south frame pieces to a length of 68 inches.  Lastly, cut the three top cross pieces to a length of 44 inches.

1- Now we drill the three identical lower frame pieces.  Drill 13/16 inch holes on the side of the first tube at a distance of 14 inches and 46 inches from the left end.  Rotate the tube 180 degrees and repeat on the other side.  Rotate the tube 90 degrees and drill holes on the top at a distance of 2 inches, 10 inches, 50 inches, and 58 inches.  Rotate the tube 180 degrees and repeat these holes on the bottom of the tube.  Once again, every measurement is from one end of the tube.  Repeat drilling holes on all three lower frame pieces.  

Lay out six blocks on the floor of your workshop upon which to assemble the frame.  Place the three lower frame pieces on the blocks.

2 - Next drill the two bottom identical inner north/south pieces.  On the side of the tube, drill holes at 6 inches, 9 inches, 13 inches, 30 inches, 63 inches, 67 inches, and 70 inches.  Rotate the tube 180 degrees and repeat these holes on the other side of the tube.  Rotate the tube 90 degrees and drill holes in the top at 2 inches, 34 inches, 55 inches, 58.5 inches, 62 inches, and 74 inches.  Rotate another 180 degrees and repeat holes on the bottom of the tube.

3 - Drill holes on the side of the two identical bottom outer north/south pieces at 9 inches, 13 inches, 63 inches, and 67 inches.  Rotate the tube 180 degrees and repeat holes on the other side.  Rotate the tube 90 degrees and drill holes in the top at 2 inches, 34 inches, 58.5 inches, 62 inches, and 74 inches.  Rotate the tube 180 degrees and repeat holes on the bottom.

Place the bottom inner and outer north/south pieces on top of the lower frame pieces on the workshop floor.  Adjust the blocks so you have access to the underside of the holes.  Align the holes you've drilled and bolt together loosely using washers on either side and metal lock nuts.  If the holes are not exact you may need to drill them out further.

4 - Drill holes on the front of the two identical front vertical pieces at 6 inches and 50 inches.  Rotate the tube 180 degrees and repeat holes on the back of the tube.  Rotate the tube 90 degrees and drill holes in the side at 2 inches and 46 inches.  Rotate the tube 180 degrees and repeat holes on the other side.

5 - Next drill holes on the front of the two identical middle vertical pieces at 6 inches, 24 inches, and 50 inches.  Rotate the tube 180 degrees and repeat on the back. Rotate the tube 90 degrees and drill holes in the side at 2 inches and 46 inches.  Rotate another 180 degrees and repeat holes on the other side of the tube.

6- Now drill holes on the front of the two identical rear vertical pieces at 2 inches, 21 inches, 29.5 inches, 47.5 inches, and 54 inches.  Rotate the tube 180 degrees and repeat holes on the back.  Rotate the tube 90 degrees and drill holes in the side at 6 inches and 50 inches.  Rotate another 180 degrees and repeat holes on the other side of the tube.

Mount the vertical frame pieces to the the inner corners of the lower frame with bolts, nuts, and washers.  Tighten loosely, leaving a little room for play.

7 - On to the top of the frame.  Drill holes in the top of the two identical top north/south frame pieces at 6 inches, 22 inches, and 62 inches.  Rotate the tube 180 degrees and repeat holes on the bottom.  Rotate the tube 90 degrees and drill holes in the side at 2 inches, 26 inches, and 66 inches. At 46.5 inches, mark a center point and then torch out a hole with a diameter of 2 3/8 inches.  This is where the tractor arms will connect.  Rotate the tube 180 degrees and repeat holes on the other side, including torch hole.

Mount the top north/south frame pieces to the vertical frame pieces.

8 - Lastly, drill holes on the front of the three identical top cross pieces at 6 inches and 38 inches.  Rotate the tube 180 degrees and repeat holes on the back.  Rotate the tube 90 degrees and drill holes on the top at 2 inches and 42 inches.  Rotate the tube 180 degrees and repeat holes on the bottom.

Mount the top cross pieces to the frame.  Tighten all frame bolts extra tight.

This completes the entire frame upon which the wheels, front loader, power cubes, motors, and valves can be mounted.  Furthermore, this frame is one hundred percent designed for disassembly except for the wheel motor mounts for which it is absolutely critical that they do not shift at risk of motor shaft breakage, for which reason they are welded.  However, in the future prototypes will consider a method that allows for an even easier way to mount the wheels and motors without using any welds on the frame.  For additional information and media on fabricating and assembling the LifeTrac frame, visit the Open Source Ecology wiki page.