>An easy conversion which requires only standard tools, K & S 3/16" OD tubing , a 5/16" or 1/4" OD washer and a 2 mm screw which can be cut down from extras in package.
Frame front end showing parts. Screw not shown for clarity.
Since the SPUD stud is about .201 ", enlarge mounting hole with a #6 drill bit and debur and check play and free turning. Try #5 or #4 until satisfactory . Place frame with rear wheel and SPUD stud installed in hole on a piece of track. Level frame, if necessary with shim to raise or filing to lower. Insert tubing and mark about .01" above the ledge. Alternatively measure with an inexpensive depth gauge. Cut tubing slightly longer for later adjustment with a file.
Reinsert spacer, place washer on top and measure depth with gauge. Screw should be not more than .060" longer. Insert screw and check play. Some play is necessary to allow for uneven track. If too much, file or grind off some tube length. Screw length should be about 1/8".
A more sophisticated mounting hole can be made using a countersink or end mill to provide a recess for a shouldered washer as shown in picture below.
Note: Adjust brightness and contrast for optimum viewing.
Top view showing nylon shoulder washer and screw head.
End view
Shell mounted. Wheel are not off center as glare seems to indicate.
