Meccano Parts General Information
Do Meccano gears and pulleys come with the required fixing screws?
All the gears, pulleys and brassware are supplied without grub or set screws. These can be ordered separately. Most people prefer using standard grub screws (Part Number 69a), these are headless screws and give a nice tidy finish. These are available with either the standard slotted or more the recent 2mm Allen head. If you are in a situation where clearances around the boss are very tight a short or flush grub screw (Part Number 69c) may be used. These fit flush with the boss when tight. If you require extra thread length (for instance to connect some other part), or the part in question has a ½" diameter boss (Part numbers 95, 95b, 27b & 19c) then you can use long grub screws (Part Number 69b). Brass set screws (Part Number 69) may also be used in all bosses where clearances and appearance are not critical.
I want to order Meccano nuts and bolts, which should I choose?
The standard Meccano bolt has a ¼" (about 6mm) long threaded portion (Part Number 37b). These are tightened into a standard Meccano nut, which can be either square or hexagonal (Part Number 37a). This nut and bolt combination is suitable for joining up to 4 standard thickness strips. If thicker combinations of parts are to be joined then longer bolts should be used accordingly. The next size up is 5/16" (8mm - Part Number 111b), then ⅜" (9.5mm - Part Number 111c), ½" (13mm - Part Number 111a), ¾" (19mm - Part Number 111), 1" (25mm Part Number 111e), and 1⅛" (28mm - Part Number 111d). Some longer sizes, up to 2" (25mm) are also available. Standard Meccano nuts can be used with screwed rods (Part Number 78-82 etc.) which range in size from 1" (25mm) long, Part Number 82, to 11½" (290mm) long, Part Number 78.
What are the standard Meccano hole sizes, spacing and threads?
Plain holes in all Meccano parts are all 4.1mm in diameter, and are spaced at ½" (12.7mm), with some modern parts having twice as many holes to give a ¼" (6.3mm) spacing. Meccano axles are a running fit in the holes, and are 4.06mm in diameter. This is actually an old Imperial SWG (Standard Wire Gauge) size 8. All Meccano threads are 5/32 BSW (British Standard Whitworth). Again, this is an old imperial size, which is around the same size as an M4 metric thread, but the two threads are not compatible with each other.
What sizes are the Standard and Narrow Meccano strips?
Standard Meccano strips are ½" (12.7mm) wide. The length is the same as the number of holes multiplied by ½" (12.7mm). The Narrow Strips have the same hole spacing, but are only ⅜" Wide. The length is the number of holes-1 multiplied by ½" (12.7mm) plus 5/16" (8mm).
What Thread Sizes does Meccano Use?
All Meccano parts ever made, from the earliest 1901 sets right up to the ones still being produced today uses a thread size of 5/32 Whitworth. This is a very old imperial standard, originally found on cabinet door handles. There are 32 threads per inch (TPI) and the thread pitch is 0.0312" or 0.79375mm. A tapping drill size of 0.126" or 3.2mm is required.
A word of caution - this thread is dimensionally very similar to metric M4 threads - you can usually engage a Meccano thread and M4 threads for a few turns. Many of the look-alike kits with 10mm hole pitch have M4 threads - don't get the fixings mixed up!
Do you buy Second Hand Meccano?
If you have a large quantity of Meccano that you no longer require, or are trying to sell some Meccano on behalf of someone else, please get in touch with me, as I may be interested in purchasing it from you. You'll need to be able to send me some digital photographs of what's available, and ideally the parts must currently be somewhere in the UK.