Figure 1 - Section through adapter
• Meccano thread
Ø A 4.1mm - Meccano axle clearance
Ø B 1/4" (6.35mm)
Ø C - 7mm to fit 144C shoulder - Use 7mm drill. See note 2 below for details
Ø D 3/8" Material - Brass CZ121
E 7/32" (5.5mm)
F 7/16" (11mm)
G 1/8" (3.2mm)
All drill bits used for brass should be ‘backed off’ at the front edges of both cutting tips to reduce the cutting angle and avoid ‘snatching’ which can be dangerous to the person and destroy the workpiece.
Note 2: The Ø 7 mm drill should also be ‘stoned’ on the ‘lands to reduce the Diameter of the actual cut of the drill by 0.001" for an interferance fit with Part 144C - Speed maximum - 300 rpm.
See Fitting and General Information Notes
ALIGNMENT JIG - Final fitting:
1. Cut a 7/16" length of tri flat axle to line up one flat with the threaded hole in the adapter, then
2. Squeeze the components together in the vice.
Figure 2 - 144C adapter assembly
Total length 5/8".
The machined groove is for a selector which
can be made by slotting any suitable strip according to requirement.
Figure 3 - Suggested method - 3-hole strip shown
Slot 1/4" Wide
The component can be used on keyway rods via keyway bolts in the usual manner.
Suggestion - For tri axle use, a grub screw
with a flattened end should be fitted in one hole with sufficient clearance
for sliding and secured by Loctite nut loc as this is non permanent and
will allow removal. When required to be locked on the shaft, fit another
grub screw in the opposite hole.
All 12 of my plastic road wheels with internal gear have been modified as shown below. The two inner webs on the drum section are machined off and a Ø 2mm hole drilled at the opposite end to the gear for the cable fixing as it makes a neat winding drum for cranes etc. and still allows the tyre to be fitted with no detrimental effect.