STH Fly Reel POP1.5 & POP2 Cassettes

The Argentinian company STH made fly reels from the 1970s to the mid-2000's before going out of business. In addition to several first in the fly fishing industry, they were one of the first companies to bring to market a cassette fly reel system where the fly line was held on an inexpensive polycarbonate cassette instead of an expensive, machined spool. Their cassette system was innovative in the early 1990s, and STH produced several reels sold by other companies, including Orvis, the Cortland Line Company, and LL Bean. After their patent for the cassette system lapsed in 2010, the idea was widely copied (including by Hardy Reels). Whether the expiration of their patent was the proverbial straw that broke STH's back or not, I don't know, but the company ceased operation about the same time.

The reels are still easy to find on eBay and are serviceable to use. I have one of the few Sacconni "Turbine" reels (they also produced an innovative turbine drag system using fluid dynamics to adjust the drag on a fish throughout its run) that was produced and sold, but only have the two original cassettes that came with the reel. Since the cassettes are no longer produced, it is difficult to find one without purchasing it with a reel on eBay.

My original design copies dimensions from the "POP2"-sized cassettes that fit my reel.  THANK YOU to user @Rede2go_3565551 for providing measurements for the POP1.5-sized cassette, and for testing the scaled down version to verify it fit and worked in hir reel! I believe there was also a 2.5 or 3-sized cassette for very large reels, but I don't have any copies to make measurement; feel free to get in touch if you need a different sized cassette to fit your reel and I will see what we can do.  My version differs slightly from the original in being ported to allow the line to dry more rapidly (the original was solid PC around the entire line).

I've printed the single piece file on a resin printer (Anycubic Photon M5s) in an ABS-like resin.  The two piece files (male-female pairs) I have printed on FDM-type printers in a variety of materials, though I favor PETG or similar for this application.  The model does have a small lip around the central hole which requires minimal supports be turned on in either printing method.

Hope you find it useful and it helps keep your STH reel functioning for many fish to come.  Tight Lines!