Hardy's was late to the game of fiberglass, being reluctant to move away from bamboo rods. As a result they had to scramble to get caught up with the new trend in fly fishing at that time. It wasn't an easy adjustment for them, but fortunately the company was able to catch up & began to succeed in the world of glass rods.
I find this video particularly interesting as they mention John Tarantino. He's the guy who gets the credit for coming up with the first really good glass rod blanks. You know all those brown shafts of older rods (sometimes referred to as "tobacco" colored)? Those were developed by him & Hardy's went to him to build their first glass rods on. These Hardy "JET" rods were very nice for the time &, to their credit, Hardy's gave Tarantino full credit for the blank design & manufacture.
One other interesting point in the video: around 2:21 Jim Hardy talks about how great a fly caster John Tarantino was. Jim was being humble & gracious with those comments. Not to take anything away from Tarantino's casting skills, but Jim Hardy was one of the greatest fly casters in the world - ever. Look up his tournament records sometime.
Anyone who has an old Hardy JET rod will appreciate this video - & they have a nice, collectible rod. As Hardy continued on with fiberglass through the 1970's their rods became better & better. Here is an interesting look back at how they got started in fiberglass.