Slotted vs Through-Hole Beads (When to Use Each)
Hole style decides how the bead sits on the hook. Slotted tungsten beads open to the side for jig hooks and many straight shanks. Through-hole and countersunk beads slide over a conventional eye. Here is how we pick on the Ilwaco bench.
By Josh Phillips · Spawn Fly Fish, Ilwaco, WA
Beads do two jobs on a nymph. They add weight, and they set the head shape.
Material decides how fast that fly drops. Hole style decides how the bead seats on the hook.
Most of the questions we get after “tungsten or brass?” are about slotted tungsten beads versus through-hole, drilled, or countersunk beads. Same fly. Different seat. Different hook.
We stock both. We use both. Match the hole to the hook first, then pick size and finish.
Material choice is a separate decision. Shop the live fly tying beads collection for weight and finish.
Slotted vs drilled, countersunk, and through-hole
Names get messy on packaging. Here is the shop shorthand:
- Slotted: A side opening lets the bead slip on from the side of the shank, not only over the eye. This style is common on tungsten slotted beads for jig nymphs.
- Through-hole or drilled: A hole runs through the center. The bead slides over the hook eye onto the shank.
- Countersunk or counter-drilled: A through-hole has a cone or bevel cut into one face. This helps the bead nest against the eye or around the hook bend.
For tying, treat countersunk and plain through-hole as one family. Both go on over the eye. Slotted is the other family.
Slotted beads keep more metal than a deep countersink of the same outer size. They often feel slightly heavier at the same millimetre. Many Euro and jig tiers use slotted tungsten for maximum sink in a compact head.
Jig hooks vs straight-shank hooks
Jig hooks with 90-degree or jig-style eyes are built for a slotted bead. The slot lets the bead sit flush. The hook rides point-up, and the head stays compact.
Straight-shank and conventional-eye hooks take either style:
- Through-hole beads give the classic Cyclops-style seat. Slide one over the eye, push it to the head, and lock it with thread.
- Slotted beads also work on many straight shanks. Open the slot over the shank and seat the bead without fighting a tight eye.
If the bead will not seat without force, you have the wrong hole style. Do not ream a through-hole bead onto a jig eye that wants a slot.
Offset and the lead-in-slot trick
On jig hooks, seat the slotted bead with the slot facing the bend. Keep the solid face forward. This keeps the head clean and the gap honest.
Some tiers leave a short lead of thread or a tiny wrap in the slot before locking the bead. This fills play, stops spinning, and prevents rocking.
Use only enough material to snug the bead. Do not build a lump that opens the thorax.
A slotted bead can sit slightly off-center on some shanks. That is normal. Rotate it before locking it. You can also drop a size if the bead crowds the hook gap.
Hook gap and bead size
A bead that is too big eats gap. A bead that sits too far back crowds the thorax and makes the fly look stubby.
Use these rules on the bench:
- Seat the bead flush behind the eye, or against the jig eye, without swallowing the thorax.
- Drop a millimetre if the point looks short or the gap looks pinched.
- Slotted tungsten often carries more weight than a deep countersunk bead of the same outer size. Do not blindly upsize when switching.
Size and weight: bead size chart for fly tying
Use this as a starting bead size chart for fly tying. Adjust for pattern and water. Pack labels in inches are the closest standard sizing. Makers round differently, so trust the millimetres.
| Bead (mm) | Pack label | Hook size | Typical flies | Slotted at this size |
|---|---|---|---|---|
| 1.5 | 1/16" | 20–24 | Zebra Midges, tiny Perdigons | Made, but fiddly. Through-hole seats easier this small |
| 2.0 | 5/64" | 18–20 | Small mayfly nymphs, midges | Yes. Smallest practical jig-nymph size |
| 2.4 | 3/32" | 16–18 | Pheasant Tails, Hare's Ears | Yes. Workhorse jig sizes start here |
| 2.8 | 7/64" | 12–14 | Standard and jig nymphs | Yes. The everyday jig-nymph size |
| 3.3 | 1/8" | 10–12 | Stoneflies, big attractors | Yes. Check the hook gap before you commit |
| 3.8 | 5/32" | 6–10 | Heavy nymphs, small streamers | Yes. A lot of metal. Gap check is mandatory |
| 5.5 | n/a | Streamer hooks | Spawn football beads | Slotted is the stock format |
| 8–9 | n/a | Streamer rigs | Spawn Fathom beads | Slotted is the stock format |
Slotted tungsten beads in the mid sizes, about 2.4–3.8 mm, cover most jig nymphs we sell out of Ilwaco. Go smaller for midges. Go larger only when the pattern and hook gap allow it.
Weight still comes from material and diameter. Hole style is about seat and hook fit. Pick tungsten when you need sink. Pick the hole that matches the hook.
When slotted wins
Reach for slotted beads, especially slotted tungsten, when:
- You are tying on a jig hook.
- You want a compact, heavy head for Euro-style or short-line nymphing.
- The bead must slip on from the side because the eye is awkward for a through-hole.
- You want maximum metal in that millimetre size.
On our bench, slotted tungsten is the default for jig nymphs and winter steelhead nymphs. It also works in faster Columbia tributaries where the fly must sink without a giant head.
When through-hole wins
Through-hole and countersunk beads still earn space in the jar when:
- The pattern uses a classic Cyclops or drilled bead on a standard eye.
- You want a clean slide-over-eye seat and are not fishing a jig hook.
- You are matching an older recipe, and the through-hole head already fishes well.
- A specialty shape uses a through-hole bore and gives the pattern its needed silhouette.
If a slotted bead looks crooked or pinches the gap on a straight-shank pattern, switch to through-hole before blaming the tippet.
Types of beads and specialty shapes
Round ball beads, slotted or drilled, cover most nymphs. Colors and plated finishes change the look more than the seat.
Specialty shapes change the profile and weight placement:
- Football and Fathom: A different silhouette than a plain ball. Spawn stock is slotted tungsten.
- Cones: A tapered head, usually with a through-hole or cone bore.
- Dumbbell and lead eyes: Streamer tools, not nymph ball beads.
Use specialty shapes when the pattern needs that silhouette. Do not grab them because the jar looks cool.
Comparing your options
Use the table below as the short version. Then shop fly tying beads for the finish and size your pattern needs.
| Spec | Slotted | Through-hole / countersunk |
|---|---|---|
| How it goes on | Side slot. Slips onto the shank from the side, then rotates to seat | Slides over the hook eye onto the shank |
| Hook match | Jig hooks (90° and 60° eyes); also many straight shanks | Conventional-eye nymph and wet-fly hooks |
| Ride | Seats flush on a jig eye so the hook rides point-up with a compact head | Neutral. The hook rides as the pattern was designed |
| Seat orientation | Slot faces the bend, solid face forward | No orientation to manage. Countersunk face nests toward the eye |
| Weight at same mm | A touch heavier. A slot removes less metal than a deep countersink | A touch lighter when deeply countersunk. Diameter and material still set most of the sink |
| Sizes in our packs | 1.5–5.5 mm, plus Spawn football and Fathom | Standard mm range, including Cyclops-style brass |
| Pattern families | Euro and jig nymphs, Perdigons, winter steelhead jigs | Classic Cyclops recipes, standard beadheads, cones |
| Watch-outs | Can sit off-center or pinch the gap if oversized | Wrong fight for most jig eyes. It will not seat flush and the fly loses the point-up ride |
| Shop default | Jig hook on the vise: slotted, no debate | Standard eye and a proven recipe: through-hole |
One line to remember: the hook picks the hole. Jig eye gets a slot. Standard eye gets a through-hole. Size and material are separate calls.
Fly tying bead FAQ
What is the difference between slotted and through-hole beads?
Slotted beads open to the side, so they seat on jig hooks and many straight shanks. Through-hole beads slide over a conventional eye. Match the hole to the hook.
Are slotted tungsten beads heavier than countersunk beads?
Often slightly, at the same outer size, because a slot usually removes less metal than a deep countersink. Material and diameter still drive most of the sink. Hole style mainly controls the seat.
Can I put a slotted bead on a straight-shank hook?
Yes, on many patterns. Seat it flush and check the gap. Switch to through-hole or drop a size if it looks crooked or pinches the point.
When should I use through-hole beads instead of slotted?
Use them on standard-eye hooks, classic Cyclops recipes, and patterns that need a clean slide-over-eye seat. Through-hole is the wrong fight for most jig hooks.
What size slotted tungsten bead should I use?
Match the chart on this page. Rough rule: 2.4 mm for 16 to 18 hooks, 2.8 mm for 12 to 14, 3.3 mm for 10 to 12. The bead should sit flush without eating the thorax or pinching the gap. If it looks oversized, drop a size.
Does hole style replace tungsten vs brass?
No. Material sets sink. Hole style sets the seat and hook fit. Pick both on purpose. Shop the beads collection for current sizes and finishes.
Shop fly tying beads
Browse slotted tungsten and through-hole options in the sizes we actually tie with. Start at the collection, then pick hole style, size, and finish for the hook on your vise.
Spawn's Super Tungsten Slotted Beads
Hareline Tungsten Cones
Start with fly tying beads, then build the rest of the pattern from the fly tying materials we stock in Ilwaco.