Estes Igniter Patent, 1968

I found this on Wayne Hill's Rocketry Blog HERE
The patent for Vern Estes improved igniter. HERE

When I started flying rockets in 1969 we would still find motors tubes supplied with bare wire nichrome igniters.
This newer patent igniter had milled and thinner wire "centers" made for a higher resistance that heated faster and hotter.
"To effect ignition, the portion of the wire at the fold is reduced in area to provide a heating section of increased electrical resistance."

The milled wire centers first had a blue coating then a brown coating.

The igniters came in one piece with four (one extra) then later with only three coated sections.
You'd cut them between the coated sections and fold them in the middle.
The new pyrogen coating made for a faster, more reliable ignition and also insulated the bent wire.
I remember a BIG difference when using the new coated igniters. Ignition was faster. Heck, you'd even consider clustering!

The catalog illustration showed them with a smoother coating, without the beaded drips!

Check out the 1969 price -

Today's igniters still use a thinner bridge wire at the top bend.
On the left are some Quest MMX igniters. These uncoated igniters do take a moment longer to ignite an engine. The thin bridge wire looks to be spot welded on.
On the right is the standard black pyrogen tipped Estes igniter.
The thin bridge wire looks like it is wrapped around the side wires.
The pyrogen coating helps hold the bridge wire in place.
I have seen a few of the new Estes "Starter" igniters but haven't used one yet.