Instructables

Rebuild the Adjustment Mechanism for a Nordic Track Achiever

Picture of Rebuild the Adjustment Mechanism for a Nordic Track Achiever
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NordicDanny sent an adjustment knob assembly for a NordicTrack Achiever to me. He was curious about how to disassemble it. I covered that in a previous Instructable. This Instructable is also mostly for him, but covers how I rebuilt the stripped mechanism with common parts from a hardware store. I really hoped I could accomplish a rebuild with only a little cutting, drilling, and grinding; but, I found I needed to weld some pieces to finish the job.

See the second photo. The screw mechanism in these assemblies wears easily. So does the plastic block that moves with the screw. The task is to build a new traveler block and a new screw, and make it all fit into the original case.

Step 1: Choosing a key part

Picture of Choosing a key part
I decided to use a coupling nut (see photo), but what size? The hex socket in the adjustment knob measures 7/16 inch, and a coupling nut for 5/16 inch threads fits the hex socket exactly, but 1/4 inch threaded rod will work better for some other considerations. 

Tools
  • Vise
  • Hacksaw
  • Grinder
  • Oilstone
  • 1/4 inch tap and 1/4 inch die
  • Electric drill and bits
  • Dremel tool and cutting discs
  • Wire feed welder
  • Calipers
  • Vise-Grip pliers
  • Screwdriver

Materials
  • 1/4 inch coupling nut
  • 3/8 inch steel rod
  • Threaded 1/4 inch rod
  • Thin flat steel for making a shim
  • Auto body adhesive
  • Wood for a burnishing tool
  • Motor oil

Step 2: Cut 3/8 inch rod

Picture of Cut 3/8 inch rod
I decided to use a short piece of 3/8 inch steel rod in place of the old plastic follower block. Grind away any burrs after cutting.

Step 3: Cut the coupling nut into two pieces

Picture of Cut the coupling nut into two pieces
The hex socket on the knob is 7/16 inch deep, too. Cut 7/16 inch from the coupling nut, which is just about half of it, including the width of the sawcut. Grind away any burrs.

Step 4: Prepare to weld

Picture of Prepare to weld
I clamped the short piece of 3/8 inch rod and the piece I cut from the coupling nut to a piece of aluminum for welding the two together.

Step 5: Chase the threads

Picture of Chase the threads
Some weld spatter blocked the threads at one end of the coupling nut. I restored them with a 1/4 inch tap.
 
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rimar20001 year ago
Phil, you are "the impossible repairs's man"!
Phil B (author)  rimar20001 year ago
Thank you, Osvaldo. Things like this are even more of a challenge when the tools and materials available are only what you can find in a home workshop and a local hardware store. Many new possibilities became realities when I got a welder. Many more things would be possible if I had a metal lathe and some experience using it. You know how that goes.