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Sienci AltMill & LongMill Dust Boot — 80mm Spindle | Magnetic Quick-Release CNC Dust Shoe
Sienci AltMill & LongMill Dust Boot — 80mm Spindle | Magnetic Quick-Release CNC Dust Shoe
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Built for 80mm spindles on the Sienci AltMill and LongMill.
Whether your AltMill arrived with Sienci's 2.2kW spindle or you upgraded your LongMill from the stock Makita, you need a dust boot that clamps to an 80mm spindle body and gets out of the way when it's time to change a bit. This one is a true 80mm screw-clamp fit with a magnetic brush skirt that comes off in about two seconds. No unclamping, no zip ties, no shims.
📦 What's Included — Yes, the Brush Comes With It
- ✅ Dust boot body — 80mm screw-clamp spindle mount, assembled and ready to install
- ✅ One brush skirt in the style you choose above — full or split, 3" USA-made nylon, fitted to the boot
- ✅ Hose adapter in your size — tell us at checkout, no extra charge
You do not need to buy a brush separately. Pick Full or Split at the top of this page and that's the brush that ships on your boot. The brushes listed in our store are optional spares.
- 🎯 True 80mm screw-clamp fit — clamps directly to the spindle body. No shims, no zip ties, no slipping halfway through a long job
- 🧲 Magnetic brush + anti-dislodge tabs — the skirt holds through aggressive passes but pops off in about two seconds when you need to see the bit
- ✂️ Brush included — USA-made 3" nylon, trim it to length with scissors to match your tooling
- 🔀 Your choice of full or split — see the comparison below; the split skirt flips open for a tool change without unclamping the boot
- 🔌 Quick-connect hose port — 4" standard, with an adapter from 1.25" to 4" included at no extra cost. Just tell us your hose size at checkout
- 🎨 Black by default — message us if you want a different color
🔧 Does This Fit My Sienci?
| Machine | Spindle | Fits? |
|---|---|---|
| AltMill MK2 — 2×4, 4×4 & 4×8 | Sienci 2.2kW ER20 spindle (80mm) | ✅ Yes — this boot |
| AltMill (original) | 80mm spindle | ✅ Yes — this boot |
| LongMill MK2 / MK2.5 | 80mm spindle upgrade | ✅ Yes — this boot |
| LongMill MK2 / MK2.5 | Stock Makita RT0701 router (65mm) | ❌ No — you need the 65mm v4 boot |
| AltMill with a smaller aftermarket spindle | Shimmed into the 80mm mount | ❌ No — order the v4 boot in your spindle's diameter |
Quick check: measure the outer diameter of the motor body — not the collet, not the collet nut. Wrap a string around the widest part of the housing and divide the circumference by 3.14159. Around 80mm means this boot. Around 65mm means you're still on the Makita.
💡 Still not sure? Send us a photo of your spindle and Z-axis. We'd rather spend 30 seconds confirming than have you waiting on a return.
Hose size options: 4" · 2.5" OD · 2.25" OD · 1.75" OD · 1.5" ID · 1.25" ID
🔄 Already Have the Dust Shoe From Your AltMill Spindle Kit?
Sienci's AltMill spindle kits come with an 80mm dust shoe, and plenty of owners run it happily. AltMill owners who switch to this boot usually do it for one of three reasons:
- Faster bit changes — the magnetic skirt comes off by hand in seconds, or choose the split skirt and never take it off at all
- Your hose, your size — a 4" port with a free adapter down to 1.25", so it works with a dust collector or a shop vac
- Adjustable skirt height — trim the bristles or add a ½" or 1" spacer for surfacing and long end mills
Made by CNC makers, for CNC makers — in small batches, in Lafayette, Indiana.
🔀 Full Brush or Split Brush — Which Should I Pick?
Both are the same 3" USA-made nylon bristle on the same magnetic mount. The difference is whether the ring of bristles is continuous or divided in two.
| Full Brush | Split Brush | |
|---|---|---|
| Shape | One continuous ring of bristles all the way around | The same ring, divided into two halves that part in the middle |
| Seal & suction | Best possible — no break anywhere in the bristles | Excellent — a thin seam where the halves meet |
| Changing a bit | Pull the whole skirt off the magnets (about two seconds), change the bit, snap it back | Part the two halves and reach straight in — the skirt never leaves the boot |
| Setting Z-zero / checking the cut | Skirt comes off to see the bit | Open the split and look in |
| Best for | Surfacing the AltMill spoilboard, long single-bit production runs, maximum capture | Frequent tool changes, V-carving, multi-bit projects, lots of Z-zeroing |
Not sure? Most customers pick split if they change bits more than once or twice a job, and full if they mostly run long single-bit jobs. Either way, the other style drops onto the same magnets later — you're not locked in.
🛒 Complete Your Sienci Setup
Optional extras — your boot already arrives complete with brush and adapter. What LongMill and AltMill owners add over time:
| Product | Why You Need It | Price |
|---|---|---|
| Spare Brush — Full or Split | Optional spare (one already comes on your boot). Trim a skirt too short once and you'll be glad there's one on the shelf. Also how you add the other style. | $27.99 |
| Brush by the Foot | USA-made nylon bristle, 0.5mm standard or 0.25mm fine. Cut to any length for a custom skirt height. | from $10.00 |
| Brush Spacers — ½" & 1" | Surfacing the AltMill's big spoilboard or running long end mills? Spacers drop the skirt for a better seal on deep cuts. | $22.99 |
| Hose Adapters — 1.25" to 4" | Extra sizes beyond the one already included with your boot. | from $7.00 |
| Dust Hose Support Kit | Overhead EMT mount keeps a 4" hose off the spoilboard and out of the cut on every pass — especially useful across a 4×8 AltMill. | $46.50 |
Frequently asked questions
Does this fit the Sienci AltMill 2.2kW spindle?
Yes. The spindle in Sienci's AltMill 2.2kW ER20 kit has an 80mm body, which is exactly what this boot clamps to. It fits the AltMill MK2 in every table size — 2×4, 4×4 and 4×8 — because the boot mounts to the spindle, not the frame.
My AltMill came with a dust shoe. Why switch?
You don't have to. Owners switch for the magnetic quick-release skirt (or the split skirt, which never has to come off for a bit change), the free hose adapter from 1.25" to 4", and the option to trim the skirt or add a spacer for surfacing and long tooling.
Is the brush included with the dust boot?
Yes. Every P2P dust boot ships with a 3" USA-made nylon brush skirt already installed on it — you do not buy the brush separately. Choose Full or Split at the top of this page and that's the brush that comes on your boot. The brushes listed in our store are optional spares for when yours wears down or gets trimmed too short.
What's the difference between a full brush and a split brush?
A full brush is one continuous ring of bristles — the best seal and the strongest suction. A split brush is that same ring divided into two halves, so you can part it and reach the bit without pulling the skirt off the boot. See the comparison table above. Both use the same magnetic mount, so you can add the other style later and switch whenever you like.
Will this fit my LongMill with the stock Makita router?
No — the stock Makita RT0701 body is 65mm. This boot is for 80mm spindles. For the stock router, order the v4 boot in 65mm instead.
Do I need to buy a hose adapter too?
No. One adapter in your hose size is included at no extra cost — just tell us your size at checkout. The adapters listed separately are for running a second hose size or replacing a lost one.
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