Hareline Stonfo Interchangeable Hook Jaw For Vise

What it is

The Hareline Stonfo Interchangeable Hook Jaw is a quick-change jaw set for a fly tying vise that lets you swap jaws instead of fighting one jaw across every hook. The design is built for clean alignment with a secure, slip-resistant clamping grip that holds steady without twisting. It’s meant to stay stable when you’re really leaning on the thread or pulling materials down.

What to tie with it

You use it to hold hooks securely while you change hook sizes and hook styles, and to match the jaw to the job instead of cranking extra pressure. It matters most when you’re tightening thread hard, cinching materials down, or packing hair where a stable, anti-twist hold keeps the hook from rolling. Narrow “midge” style jaws are commonly used when you’re tying very small patterns and want a tapered jaw that fits in tight.

Flies and the fish they're for

This is a tying-tool upgrade rather than a material that shows up in a recipe, but it directly affects what you can tie cleanly and confidently. With interchangeable jaws you can comfortably cover everything from tiny midge and small dry-fly hooks up through big salmon-fly style hooks, which translates to trout work on small rivers and tailwaters as well as larger freshwater and anadromous patterns. It’s also a practical setup for tying sea trout patterns on the water, where fast jaw changes and a secure grip help when you’re switching hook styles at the bench or travel kit.

How it compares

Compared to a single jaw setup, interchangeable jaws are more adaptable across hook sizes and hook styles without forcing one jaw to do it all. That reduces the temptation to over-tighten on small hooks and gives a more secure hold on larger hooks.