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AltMill 4×8 Front View on Angle Close Up

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AltMill 4×8

Name: AltMill 4x8
Brand: Sienci Labs Inc.
SKU: 078221
Availability: BackOrder
Rating: 4.50 (2 reviews)

Rated 4.50 out of 5 based on 2 customer ratings

(2 customer reviews)

$10,390.00

The AltMill 4×8 is the next generation of prosumer CNCing. Designed for power, precision and production, the 4×8 has the production reliability and rapidity professionals need, and the value and rigidity advanced users want. Built for sheet goods, the AltMil 4×8 is a turnkey CNC that makes large format cutting a breeze.

The AltMill 4×8 comes with a standard 80mm spindle mount only. It does not come with a spindle or an Automatic Tool Changer system, which must be purchased separately.

This product has a lead time. View current lead times.

Ontario, Canada Customers: Starting April 29th, we’ll be pausing sales for all sizes of AltMill. Please read further on specific plans for each machine – ESA Compliance.

Available on backorder

Description

Highlights:

- Production level cutting speeds (approx. 1,000 inches per minute)
- Closed loop motor system on all three axis to auto-correct positioning and auto-stop when necessary (reliable for production style work)
- Requires little maintenance during project production
- Advanced, production-style features including Y-axis auto-squaring; limit switches by default; and tram adjustment capabilities
- Cuts materials ranging from hardwoods to plastics, foams, composites, aluminum – even steel
- Support for 80mm spindles and routers
- 49.8″ x 104″ working area with a max Z-height of 8.3″ (1265 mm × 2640 mm × 210 mm)
- Footprint of roughly 66″ wide and 114″ deep

Lead times
This product has a potentially long waitlist, relative to demand and seasonality. For more info on expected shipping and delivery times, please see our Order Status page.

Additional information

Weight	87 lbs
Dimensions	38 × 11 × 12 in

What's Included

***Included with your AltMill 4×8***

SLB-EXT controller and emergency stop
Partially pre-assembled rigid frame
Inductive sensors for homing
Sturdy metal legs with the ability to add 4ft wide shelving underneath

***Not included with your AltMill 4×8***
Check out our recommended products tabs for an ideal set up, but note the following ARE NOT included with your order:

Computer or laptop
Spindle
End mills or bits
T-tracks
Waste board (e.g. MDF 4ft x 8ft sheet)
Set of metric Allen keys, standard bits or drill for assembly
LED strip lights (Learn how to install)

The AltMill 4×8 does not come with an ATC System or Spindle Kit. They must be purchased separately. Images may contain items for illustrative purposes, including but not limited to: spindles, ATC systems, caster wheels, t-tracks or additional shelving. There may also be cosmetic differences between the machine in the photo and the production version of the AltMill. Some photos may also be engineering renders of the machine.

Specifications

Specifications

Footprint: Roughly 66″ wide and 114″ deep
X, Y, Z Axis Working Area: 1265 mm × 2640 mm × 210 mm (49.8″ x 104″ x 8.3″)
Z-axis Maximum Stock Clearance: 203 mm (8″)
Rapid Traverse Speed: Approx. 25,000 mm/min (1,000 IPM) in Y-axis; 16,000mm/min (590 IPM) in X-axis; 6,000mm/min (236 IPM) in Z-axis
Repeatability: ±0.05 mm (±0.002″)
Motion System: Rack and pinion using precision gearbox reduction on Y-axis; 16mm precision ball screw on X-axis; 12mm precision ball screw on Z-axis
Linear Motion: 15mm profiled linear guide rails and bearing blocks on all axes
Drive Motors: High-Torque NEMA 23 Closed-Loop Stepper Motors. 3NM torque on Y-axis; 2NM torque on X and Z axes.
Control System: SLB-Ext 32-bit controller with grblHAL firmware
Power Requirements: 120VAC, Single Phase, 4A (Spindle power requirements listed separately)
Weight: Approximately 400lbs as assembled, not including weight of add-ons such as spindles
Spindle Mount: Supports 80mm spindles and routers
Frame Construction: Rigid frame and linear motion design using HGR15 linear guides and ball screws on all axis mounted to a custom-designed, machined aluminum extrusion; with sturdy metal legs with the ability to add 4ft wide shelving underneath for sheet goods

More information

Must Have Add-on: 1.5kW, 2.2kW Spindle or 2.2kW ATC Spindle

Unlock the full potential of your AltMill with a 1.5W or 2.2KW ER Spindle and Dust Shoe Kit, or, an Automatic Tool Changer Spindle Kit

Each 1.5KW ER20 Spindle & Dust Shoe Kit comes with:

80mm Dust Shoe
ER20, 80mm, 1.5KW 110V Air-Cooled Spindle
110V, 1.5KW, 3-Phase VFD
AC power cable and 5m spindle power cable
ER20 1/8″, 1/4″, 3/8″and 1/2″ collets (one of each)
Data cable to connect to the AltMill/SLB-EXT controller for remote speed control

Each 2.2KW ER20 Spindle & Dust Shoe Kit will come with:

80mm Dust Shoe
ER20, 80mm, 2.2KW 220V Air-Cooled Spindle
220V input, 2.2KW, 3-Phase output VFD
NEMA 6-15P AC power cable and 5m spindle power cable
ER20 1/8″, 1/4″, 3/8″and 1/2″ collets (one of each)

Each ATC Spindle Kit comes with:

2.2kW ATC Spindle
ATC Spindle Mount
Enclosed 2.2kW VFD and Mount Adapter
Clear Cut Dust Shoe
Tool Length Sensor
ATC Expansion Board for an SLB-EXT Controller
2.2kW VFD NEMA 6-15P Power Cord
10m Length 8mm Air Line Tubing
Male ¼” NPT to 8mm Air Line Push Fitting
ER20 Collet Wrench

**Each ATC Spindle Kit comes with a variety of tool holders, collets or racks (or no rack.) Read for more details.

Recommended Add-ons & Accessories

FAQs

What are the payment plans for the AltMill 4×8?
Full payment is required at time of purchase to get your order into the queue. We ship on a first-come, first-served basis. If you choose local pick-up, you are subjected to the queue order and cannot get your machine quicker.

Are there any power requirements?
We recommend allocating two 15A 110V/120V circuits — one for the spindle and dust collection system, the other for the machine and a computer.

The AltMill consumes 500W and runs off a 48V 10A power supply
The 1.5KW Spindle Kit consumes 1500W at max load
The 2.2KW Spindle Kit consumes 2200W at max load

If you live in a country with 220V/240V power you must use a transformer to convert to 110V/120V.

To solely run the machine, you need a rating above 500W
To run the machine and spindle, you need a rating of 2000W

What are the power supply specifications?
All AltMills use a 110VAC, 48VDC 10A power supply, consuming up to 500 watts. The power supply comes with a North American Standard Type B NEMA 5-15P plug.

Do you ship internationally?
We do not have distribution centers but we ship internationally from our office via UPS. Shipping costs vary from $300 to $500 in Canada and the US and up to a couple thousand for far reaching international locations. You are responsible for any taxes, duties and brokerage fees.

I would like to source my own spindle, what should I be aware of?

For spindles 2.2KW or above, you will need to install extra 220VAC wiring
The AltMill comes with an 80mm spindle mount, we do not have larger diameter mounts at the moment
The VFDs that may work with our controller are: Huanyang v1, Huanyang P2A, Yalang YL620, H-100, and GS20, however they are not plug-and-play — read this article for further information

What materials can the AltMill 4×8 cut?
If you can name it, the AltMill pretty much has it covered:

Woods: Softwoods, hardwoods, plywood and MDF
Plastics: Acrylic, PVC, HDPE, Polycarbonate and ABS
Composites: Carbon Fiber, Dibond and ACM
Non-Ferrous Metals: Aluminum, brass and copper (with appropriate lubrication/misting and cutting strategies)
Ferrous Metals: Carbon steel, alloy steel and cast iron (with appropriate lubrication/misting and cutting strategies)
Foams: High-density sign foam and insulation foam

Can I upgrade my 2×4 or 4×4 AltMill to match the 4×8 AltMill?
Unfortunately, no. The 4×8 is the next step in the evolution of the AltMill brand, which means it incorporates newly engineered components unique to its design. It is under consideration but it will not be a priority for us to provide an upgrade path. First, given that so many additional new components are needed to go to a 4×8, the cost difference between the upgrade kit and the full kit will not be that significant. Additionally, there is a significant overhead cost to do version tracking and ensure compatibility between machine versions that will add to the cost of the kit. It’s likely that it will be more cost effective and reduce waste if customers sell their existing machines and order a full machine.

Are you going to make a 5x10ft AltMill?
Not until we get the 4x8ft machines out the door first. But if we get enough interest or demand, we may consider it.

How much assembly is involved and how long will assembly take?
The 4×8 is big, so it’s going to take some extra time. Grab a partner to make assembly easy, and it’ll take roughly one day to fully set up. It will come with all major subassemblies, pre-assembled and precision components are pre-aligned. Check the “Assembly Instructions & Help Resources” tab for more info.

What else will I need to get started using the machine?
Our recommended and must-have accessories listed above are definitely what you need, but the must have of must haves is an 80mm spindle (like our 1.5KW or 2.2KW ER20s (or from a competitor) and definitely a wasteboard like ¾” MDF.

Will the AltMill 4×8 work with an ATC?
Heck ya. Our ATC system will be fully compatible with the 4×8 and all other sized AltMills.

What are the power requirements of the AltMill 4×8?
All AltMills use a 110VAC, 48VDC 10A power supply, consuming up to 500 watts. The power supply comes with a North American Standard Type B NEMA 5-15P plug. Users will also need to account for power use from the spindle, which have separate specifications.

How big is the AltMill 4×8?
The footprint of the AltMill is approximately 114″ long x 66” wide, and over 66” tall (when including spindle height).

I’m not sure what to buy, an AltMill or a LongMill? Help!
Check out this video for a summary of why each does an amazing job and can get the jobs done that you need, but have some unique considerations.

Warranty

The AltMill has a 120 day warranty once it arrives at your door.

We want you to have a great experience with your machine, so if any parts are found to be missing or damaged, please email us. We will ensure that you receive the support you need to restore your AltMill to operating condition or provide a full or partial refund.

You may cancel an order if it has not shipped yet, please contact us if you wish to do so. We do not accept returns for AltMills that have already shipped.

General Warranty and Limits of Service:

Effective March 11, 2024

Throughout this policy the words “we”, “us” and “our”, or “Sienci Labs” will be used to refer to Sienci Labs Inc. herein and “AltMill” or “machine” will refer to Sienci Labs’ Sienci AltMill. Additionally, the words “you”, “your”, “user”, and “operator” will refer to the original purchaser/customer, user, or viewer of any of the products or media provided by or through Sienci Labs.

Sienci Labs Inc. (the “Company”) grants the AltMill (the “Product”) a standard warranty within Canada and the US to the original customer to be free from missing parts, defects in material, and defects in workmanship for a period of one hundred and twenty (120) days from the date of receipt by the original purchaser. Sienci Labs Inc. will ensure that the appropriate support is provided to the original customer to restore the AltMill to operational condition or provide a full or partial refund under the sole discretion of the Company.

This warranty does not cover damage due to improper use or assembly, lack of maintenance, normal wear and tear, or modifications to the AltMill which are not produced or authorized by the Company. Consumables such as cutting tools and sample or stock materials which may have come with your AltMill are not included in this warranty.

This warranty will become void if the operator does not follow the Safety Warnings and Guidelines, uses the Product for illegal purposes, intentionally causes damage to the Product, or transfers the Product to another owner.

The original customer must contact Sienci Labs Inc. within one-hundred and twenty (120) days of receiving their order to make a warranty claim to be eligible for warranty service. Proof of purchase, tracking number, email address, or other material will be used to confirm the original purchasing date and the identity of the original customer. If damage was due to shipping, original packaging materials must be kept in the original received condition. Photos, videos, written descriptions, and other items may be requested to assess and validate a warranty claim.

In the case Sienci Labs Inc. requires the original parts to be returned, the customer is solely responsible for packing all items securely. Damage incurred during return shipping will not be covered by the warranty. A method of payment such as a credit card may be requested by Sienci Labs Inc. to cover shipping costs or damaged items if Products are not eligible for warranty service.

Instructions & Assembly

New CNC users, Read these Resources to Ensure a Successful Start. When assembling the AltMill 4×8, use the Resources as well as the Assembly Videos for a successful start.
AltMill 4×8 Overview
Machine Specifications
Unboxing & Assembly

Videos

Shipping

This product has a lead time. View current lead times.
Our products are subject to the USMCA and are not affected by the 35% tariff on Canadian goods. Read how we are handling the situation.
We will be shipping to US customers with UPS option only.

2 reviews for AltMill 4×8

4.5

Based on 2 reviews

5 star	50	50%
4 star	50	50%
3 star		0%
2 star		0%
1 star		0%

Rated 5 out of 5

Jordan Z. (verified owner) – June 15, 2026

True game changer in the industry. Couldn’t be happier with the setup and functionality so far.

(0) (0)
Rated 4 out of 5

Luke (verified owner) – June 15, 2026

So far I’m having a good experience with my new 4×8 machine, and would highly recommend it! I’m coming from a Carbide Shapeoko 5 machine, and Sienci has really won me over with their dedication to bringing new features and technology like the ATC to their lineup. They’re blowing away the competition in that way. The Sienci team also did a great job of documenting the build process with their videos and online documentation. My only less than positive experience thus far has been with the customer service. Every time I’ve exchanged with the CS team, responses are very short and curt, and I’m always left feeling like I’m a bothersome nuisance rather than feeling like I’m talking to someone who truly wants to figure out how to help me. Overall though, you can’t go wrong with this machine and company.

(0) (0)

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AltMill 4×8

Description

Additional information

What's Included

Specifications

Must Have Add-on: 1.5kW, 2.2kW Spindle or 2.2kW ATC Spindle

Recommended Add-ons & Accessories

FAQs

Warranty

Instructions & Assembly

Videos

Shipping

2 reviews for AltMill 4×8

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