Meccano Boss Fitting by Dave Taylor & Roland Jaggard

Adapted from spanner. Original material provided by Dave Taylor and Roland Jaggard.Three Way Rod Connector With Boss, part 213b

Dave Taylor: I was a trainee toolmaker at MK Electric (domestic switchgear makers). Many switch parts were bossed just like Meccano. The bosses were not "pressed" but "spun" on a device like a drill press. The tool used was like a shouldered screwdriver, the shouldered part being radiused and polished. My first job was to do the polishing-hundreds of them! I presume Meccano did theirs in the same way. 

Roland Jaggard: The image below with numbering 7 to 12 shows some unmounted bosses and brass blanks.  An explanation of each part is provided, left to right in the table below:

The tops were countersunk at 90 degrees total included angle to leave an edge on the top of about 0.25mm wide. This edge was then spun over at high speed to give the finished profile. If you use a press it is possible that the edge may split due to work hardening of the brass.



9 10 11 12
1/2" diameter Boss for part number 19c, 6" Pulley Boss for 1" Pulleys, small gear wheels etc Part number 26b 1/2" x 3/4" gear blank Boss for part number 187, Road Wheel Splined Boss for use with Plastic Gears Handrail Support without grub screw threads

Below is a sketch of the small boss, it is made from brass rod. In the late 1970's in the UK it would have come as Free Cutting Brass Rod - S.A.E. Standard No72. There were three standard alloy property types: Soft; Half-hard and Hard temper. I don't doubt Meccano Ltd used the soft grade, cheapest, and easiest to work. If you have trouble peening over the boss try extending the 0."065 rebate a bit to say 0."070.  If you want a working drawing click on the image below and you will download a 666 x 577 pixel *.bmp image.

Click on image for a larger size *.bmp file (666 x 577 pixels)

Finally below is a curiosity and some Meccano parts without their boss mountings.



3 4 5 6
Meccano Ltd "Model Room" Spiral Helix parts. 2"    Unmounted Sprocket Wheel. 1.5" Unmounted Sprocket Wheel. Unmounted 3/4" Contrate Gear. Unmounted 50t Gear. Unmounted 1.5" Contrate Gear.

If you want to know more about 'Meccano" parts that never left the model room visit an article on the subject by Roland Jaggard.

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