kakuip

An older lure similar to this was the Lazy Ike Wiggly Crawler. It used a bladed head with a worm trailer . There is a discussion on this back on Aug 18, 2010. I did own one, but I haven't been able to find it as it was either borrowed without my knowing or lost. Hard to find now though.

I would check out nflcc -- National Fishing Lure Collector's Club. Online they can be found at https://nflcc.org. I used to be a member about 15 or 20 years back. Good place to get answers to these kind of questions, though I don't know if you have to be a member to post your question there.

My method was actually from an article from Tom Seward that was in Fishing Fact's magazine, way back in the day. Tom Seward was a great guy and responded personally to letters I sent him asking questions about lure designing and sent me his fingerling and bullcat lures.

I have never made my balsa baits with through wire, though I drill my center weight hole and then drill a hole from front line tie to back line tie, going through the weight hole. I then fill the weight hole with epoxy and blow it through to fill the holes to the line ties and insert my hardware. This gives me a solid core of epoxy. My line ties I either twist or twist back the ends so they are anchored in the solidified epoxy.

Just a minor correction -- r is the radius, which is half the diameter. r2 would equal (d/2)2 or d2/4, where d is the diameter (not the hole depth).

Herter's sold various types of lure molds. Their first ones were metal and used a plastic called Fleshex that came in squeeze bottles. The molds were filled and then heated to set and they had a softener to add to it. I still have the molds and plastic. These were one sided baits and ;the baits were fairly firm/hard. Later they sold resin molds and some very cheap light plastic molds that used plastisol, but really couldn't handle the heat of the plastisol. They started to sell two piece molds and injectors, but went out of business shortly after that. If you need more information on the metal molds, I still have their instruction sheets and can send you the information.