The Watkin orthodontic spot welder was invented by Harold Gladstone Watkin, a leading orthodontist who in 1930 started one of only three specialist orthodontic practises in the UK at that time.

Watkin had an inventive mind combined with technical skill. He designed many orthodontic components and tools including a variation on Angle’s Pin and Tube Appliance, the Loop and Tube Appliance.

The 1930s saw a revolution in orthodontic appliances with stainless steel and acrylic replacing precious metals. This revolution was aided by the introduction of the Watkin spot welder. Watkin had identified that the condenser types of spot welders in use were unreliable and susceptible to surges of power which burnt through appliances. He designed and built a spot welder with components found in his workshop – a carbon arc lamp, two brass rods, a transformer and a Bowden brake cable. It had timed contact and a wheel which allowed the size of contact to be changed for different gauges of wire. The spot welder was produced commercially by Elliots of Liverpool. It was a great success for over 25 years until the introduction of electric welders.