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AltMill MK2 4×4

Name: AltMill MK2 4x4
Brand: Sienci Labs Inc.
SKU: AM4X4MK2
Availability: InStock
Rating: 4.77 (192 reviews)

Rated 4.77 out of 5 based on 192 customer ratings

(192 customer reviews)

$4,290.00

The AltMill is the pinnacle of hobby CNCing, bringing industrial-level precision to a price point and ecosystem for both beginners and advanced users. The AltMill MK2 4×4 is your go-to CNC when time, performance and precision are crucial.

The AltMill MK2 4×4 comes with a standard 80mm spindle mount only. It does not come with a spindle, which must be purchased separately.

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

***New to CNC? Read to ensure a successful start!
***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.

Description

Highlights:

Production level cutting speeds (approx. 600 inches/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″ x 49″ working area with a max Z-height of 5.5″
Footprint of 59″ wide and 62″ 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.

New CNC users, Read these Resources to Ensure a Successful Start. When assembling the AltMill, use the Resources as well as the assembly video for a successful start. The assembly resources have up-to-date information.

Additional information

Weight	76 lbs
Dimensions	38 × 11 × 12 in
Include Spindle and Dust Shoe Kit	Include Spindle and Dust Shoe Kit, Machine Only
origin-criterion	C

What's Included

Included with your AltMill MK2 4×4

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

***Not included with your AltMill MK2 4×4***
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 2ft x 4ft sheet)
Set of metric Allen keys, standard bits or drill for assembly

***Some photos may contain items for illustrative purposes, such as spindles, 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.

Specifications

Specifications

Rigid frame and linear motion design using HGR15 linear guides and ball screws on all axis mounted to a custom-designed, machined aluminum extrusion
Closed loop stepper motors for over 600IPM
Support for 80mm spindles and routers
49″ by 49″ working area with a max Z-height of 5.5″
Inductive sensors for homing included
Sturdy metal legs with the ability to add 4ft wide shelving underneath
Footprint of 59″ wide and 62″ deep

Must Have Add-on: 1.5kW, 2.kW 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

Choosing an AltMill vs a LongMill

Payment

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.

Power Requirements

Altmill with the 1.5kW spindle. We recommend allocating 2x 15A, 110V/120V circuits — one for the spindle, the other for the machine and a computer.

The AltMill consumes 500W and runs off a 48V 10A power supply, 110-120 volt circuit
The 1.5KW Spindle Kit consumes 1500W at max load, 110-120 volt circuit

Altmill with the 2.2kW spindle. We recommend allocating 1x 15A, 110V/120V & 1x 20A, 220/240 Circuit — one for the spindle, the other for the machine and a computer.

The AltMill consumes 500W and runs off a 48V 10A power supply, 110-120 volt circuit
The 2.2KW Spindle Kit consumes 2000W at max load, 220-240 volt circuit

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 1.5kW spindle, you need a rating of 2000W

Altmill Power Supply Specifications: Input: 100-130 VAC 50/60 Hz, 7-54 Amps, Output: 48 VDC 10 Amps, 480 Watts

International Shipping

We do not have distribution centers but we ship internationally from our office via UPS. Shipping costs vary from $300 to $1900 USD. You are responsible for any taxes, duties and brokerage fees.

- HS Code 8465.91
- Carton Sizes and weights
  - Package 1, 62x16x11 (in) 70 lbs (X rail box)
  - Package 2, 62x16x11 (in) 70 lbs (Y rail box)
  - Package 3, 37x10x11 (in) 65 lbs (Main box)
  - Package 4, 15x13x5 (in) 20 lbs (Spindle kit)

3rd Party Spindles

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

More Information

Check out our comprehensive FAQs for prospective customers, addressing questions such as power requirements, spindle sourcing, and bundle deal info.

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

Videos

192 reviews for AltMill MK2 4×4

4.8

Based on 192 reviews

5 star	85	85%
4 star	8	8%
3 star	3	3%
2 star	1	1%
1 star	1	1%

Rated 5 out of 5

Josh B. (verified owner) – April 20, 2026

Upgraded from a Millright Mega V. Now Enjoying the Altill experience!

(2) (0)
Rated 5 out of 5

David Wilson (verified owner) – April 13, 2026

I have 2 small no name desktop cncs and needed to be able to do larger products. I saw the Altmill on IDC’s you tube channel and started doing my research on it. I hesitated ordering early Dec 25 because of the long wait times but eventually pushed the button to order a 4×4 with a spindle. After having it now for 2+ months I have no regrets. With the videos the Altmill was easy to assemble and understand. I do a little bit of aluminum work also and my only regret is not getting the 2.2kw spindle. Spend the extra $100 for it.

(0) (1)
Rated 5 out of 5

Bradley King (verified owner) – April 12, 2026

Love the machine. Haven’t quite utilized the entire work surface, but I know if I purchased the 2×4 I would have needed the 4×4. Assembly was quiet easy even with the mode that have been made after the fact. Great innovations on the Limit changes.

(0) (0)
Rated 4 out of 5

Jason McDaniel (verified owner) – April 11, 2026

The machine is awesome, that’s why I bought it. But it doesn’t have enough z axis travel. I have 39 years of cnc and programming experience so 5 inches of z travel dosen’t work for me. I am redesigning the side plates for dual z ballscrews for at least 10 inches of gantry lift. Also the ring status lights work but the strip lights don’t work on my longboard ext.

(0) (0)
Rated 5 out of 5

Anonymous (verified owner) – April 7, 2026

Solide, déplacement fluide.

(5) (2)
Rated 5 out of 5

Mark (verified owner) – April 7, 2026

Everything went together and is working great

(1) (1)
Rated 5 out of 5

Russell McClanahan (verified owner) – April 7, 2026

this has turned out to be the best purchase I had ever made

(1) (0)
Rated 5 out of 5

Marc Landry (verified owner) – April 7, 2026

very nice.

(0) (1)
Rated 5 out of 5

Dillon Flahr (verified owner) – April 7, 2026

I couldn’t be happier setup and software was a breeze and functionality is flawless I am very pleased with my purchase!

(1) (0)
Rated 5 out of 5

Anonymous (verified owner) – April 7, 2026

Great build instructions and solid and efficient performance.

(0) (0)
Rated 5 out of 5

Daniel M. (verified owner) – April 5, 2026

The Altmil is a great CNC. I do recommend it. It does take some getting used to it! The company has been great to work with, especially with shipping as UPS has not been the best. I have had several repeat shipments from Scienci due to their mishandling.

(1) (1)
Rated 5 out of 5

Raman (verified owner) – April 3, 2026

The assembly docs were first rate, as was the entire boxing experience, so pleased.

(4) (1)
Rated 5 out of 5

William P. (verified owner) – April 3, 2026

Makes me smile every time I use it. Then I think about the quality and precision of the work I’m doing and how little I paid for this machine. That makes me happy too.

(1) (0)
Rated 5 out of 5

Thomas Mertz (verified owner) – April 3, 2026

I really enjoy the 48”x48” AltMill

(1) (0)
Rated 5 out of 5

Markus Vock (verified owner) – April 1, 2026

Had some issues with the control board and Sience Labs took quick care of it

(5) (0)
Rated 5 out of 5

Thomas Jaskulski (verified owner) – April 1, 2026

The Altmill was for the most part was fairly easy to assemble

(0) (0)
Rated 4 out of 5

Anonymous (verified owner) – April 1, 2026

So far everything has worked perfectly

(2) (0)