No. 1 The Basics – Nuts and Bolts
When tightening bolts, we often hold the nut with a spanner and turn the screwdriver. This is fine for running the bolt up to finger tight. If we apply tightening torque with a screwdriver, it is very easy to damage the slot or have the screwdriver slip, scratching the Meccano or stabbing the back of your spanner holding hand. This is because as we rotate the screwdriver, it is very difficult to keep the screwdriver blade fully located in the bolt slot and apply sufficient holding pressure. To prevent this, hold the screwdriver and rotate the spanner wherever possible.
No. 2 The Basics – Washers
Placing washers under bolt heads and nuts helps to protect the paint finish on our precious Meccano but only if we consider the following:
Meccano washers up to the 1970s, usually contained burrs, caused by cheap manufacturing with worn press tooling and not tumbling the washers to de-burr them. These washers are usually conical and it is often said this was to allow for clamp distortion to maintain the ‘clamp load’ and stop the bolt and nut from coming loose. Using these washers is sure to mark the paint or zinc plate.
Washers from the 1970s are much flatter and should damage the paint less. If you look carefully at the washer, you will see that one face has an edge which turns down giving a flat finish. The opposite face has an edge that turns up and this is the edge that can damage your paint.
No. 3 The Basics – Parts with bosses
One of the difficulties with Meccano is that parts with bosses can be a problem as they can be distorted or broken. Examine the parts before you use them as you may need to take remedial action:. This may often be little more than a sharp rap with a hammer and suitable punch in order to tighten up the reamed connection.
Another point to remember is that you do not improve the holding power of a boss by inserting two screws in opposing holes. This can lead to a wobble as the boss is not held parallel to the rod and two bolts are twice as likely to work loose as one.