Felt Dies

Said a lot but did not address solid dies.

Solid dies have their place. For high speeds they are very good because they don't open. Another thing about solid dies is that the holes and tapers can be as precise as drawing dies. They can be hardened, some have carbide inserts. They are more difficult to string up because they are solid.

Split dies are somewhat forgiving if you have a raised (flipped back crow foot, enamel blister, trash etc.) spot on the wire as the die will spring open if there is enough force. A solid die doesn't. If the defect is too great and the wire diameter too small the wire can break even with a split die. Like with extrusion, a 'bird nest" will break the wire.

Some other time we can talk about roller dies.

Richard

Since things are slow: Roller dies were developed by GE. They were often called GE roller dies. A company called Mohawk Development also made them. So did Waldon Die and Bettner Die. (Note: Howard Bettner's father started Waldon Die. Hope I am spelling it right)and Howard and his son Max started Bettner Die.

The GE roller die was shaped like a spool with generally 3 grooves in the barrel. The depth of the grooves varied depending upon the size wire you were trying to coat. The dies slid on a rod which was driven by a motor. For larger wires the rod rotated against the movement of the wire. for finer wires sometimes you drove it so it moved in the same direction the wire was moving. there was a bracket with a flat metal strip where we added a finger which rode on the die and this resulted in the wire being trapped between the groove in the die and the die finger. A triangle was formed by the vee groove and the die finger. By adjusting the size of the triangle you could control the coating on the wire.

The dies were mounted on a driven rod which was supported by a couple of blocks which were drilled and cross drilled so that enamel was pumped through the holding block and the rotating die carried it around to the wire.

If you're willing to educate, I'm willing to read on. Keep going. There's so much I don't know about the enamelling portion of the industry. I wish I could visualize some of these things. Any way to add some pics?

Hello again Tuber,

Unfortunately there is no way to add pictures to the WAI Forums. What I have done in the past is to create a web page with the pictures on it and link to that web site.

I am not clear if anyone manufactures the classical roller dies anymore and I cannot find any drawings or pictures at all.

If however, Spectre has some old small drawings and pictures, he could E-mail them to me and I could whip up a simple web page in a few minutes.

Sincerely,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Peter, I sent an email to Max Bettner and they still make them but not a lot of people are using them. for smaller wires and specialty products where speed is not an issue, they are a good way to coat wire.

richard

What an interesting discussion !

To expand on Spectre's expertise, GE conceptualized the doghouse die but it was not in a workable state. Howard Bettner retooled and perfected the die at GE's request,which became a standard in enameling in the 60's and 70's.

The primary goal at that time was to get around the need to thread the wire through solid dies.

From the doghouse (clip die) Howard and his father Carl developed the split dome die which had a more typical approach angle and helped create some hydraulic properties which helped center the wire in the hole, and also maintained the "clip on" appeal of the doghouse die.

As carbide began to be used in enameling dies, threading the dies on the oven became less of a problem because of the longer runs possible before wearing out the dies. However, the split dome die has remained popular for many vertical operations.

As far as the coating quality is concerned, there is not a lot of difference if the dies are used correctly.