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

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. 

  • 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

  • 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
Phil, you are "the impossible repairs's man"!
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.

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Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying ... More »
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