All our miners lamp middles have 6 wires or posts in brass or steel around the glass. There are five miners lamp standard wires which are fixed and there is one slide wire which as the name suggests slides up and down.
This is part of the safety lock.
To open a miners lamp;
- Turn out the fuel filler flap, if it is a magnetic lock you will need a miners lamp opening magnet.
- Then unscrew the vessel/base anti clockwise, as you turn you will see the slide wire drop down.
- When you have removed the vessel the slide wire will have dropped far enough for you to unscrew the top of the lamp, again anti clockwise.
- To close reverse the above procedure
It is possible to replace a broken slide wire, we include this as part of our lamp middle repair service.
Miners lamp standard wires are a much more complicated affair. At the bottom the wires are threaded and are screwed down into the middle base plate and treated with thread locker. At the top the wires are then pushed into the 5 holes in the brass ring or outside middle ring as we call it. They are then machine riveted. The riveting has to be done a little at a time and evenly on all 5. If not the middle will become deformed and the stress can cause it to fail when a lamp is tightened up and locked.
Miners lamps have had 5 wires around the glass since 1913. This stops a straight edge touching the glass, which could be a source of ignition for fire damp. Prior to the 1911 Act lamps normally had 4 wires and accidents had occured.