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
- 1/4 inch tap and 1/4 inch die
- Electric drill and bits
- Dremel tool and cutting discs
- Wire feed welder
- Vise-Grip pliers
- 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
Step 3: Cut the coupling nut into two pieces
Step 4: Prepare to weld
Step 5: Chase the threads
Step 6: Grind and smooth the welded assembly to fit the case
Step 7: Make a cavity for the cable end
Step 8: Attach the cable parts to the case
Step 9: Threaded rod
Step 10: Making the screw axle
Step 11: Retainer
Step 12: Fitting the rest of the screw
Step 13: Secure the coupling nut on the screw
The second photo shows the completed weld. Grind the sides of the coupling nut flat again. This is a good time to add a few drops of motor oil to the screw for smooth operation when finished.
Step 14: Make the knob fit
Step 15: Cut the knob screw to length
Step 16: Attach the knob
Step 17: Glue on the top plate
See the second photo. It is almost impossible to remove the thin aluminum plate from the knob without creases and wrinkles appearing. But, some burnishing with a piece of wood from both sides of the plate removes most of these so that no one notices them.
This knob adjustment assembly for a NordicTrack Achiever Ski Machine works very well again, and will last a long time. While this process is feasible and the cost in materials is very low, I spent almost six hours making and fitting all of the parts. Still, if one of these absolutely must work again, what I have done shows it is possible to make a repaired version that is probably better than the original.
Here is a link to an Instructable that describes a number of modifications I made to my NordicTrack Challenger, some of which would be helpful for any NordicTrack.