On August 5, 2026, SainSmart published "What Is ATC? Why PRONAX Is the Smart Choice for Your CNC Shop." The post is part lesson and part product sheet. An automatic tool changer (ATC) keeps several cutters on the machine and swaps them under G-code control, so a multi-tool job doesn't stop for a wrench and a new Z zero. SainSmart's version is the PRONAX line, and the changer is the NAX5, a five-slot box.
TMWB has not tested the PRONAX. The specifications and accuracy figures below are SainSmart's, taken from its post.
Which machines did SainSmart describe?
Two machines are described.
- Spark 6090: SainSmart lists a working area of 606 × 911 × 119 mm (about 23.9 × 35.9 × 4.7 inches), which it also calls 600 × 900 mm in the prose. It weighs 62.3 kg, about 137 pounds.
- Forge 8080: listed at 804 × 810 × 120 mm (about 31.7 × 31.9 × 4.7 inches), called 800 × 800 mm in the prose. It weighs 68.5 kg, about 151 pounds.
If I were building a fixture, I'd use the three-digit figures and not the round ones. Z travel is shared by the spoilboard (the sacrificial sheet under your work), the hold-down, and the stock. At those weights, plan on two people and a bench that stays put. These are bench machines with a real spindle, and they aren't sheet routers.
What are the motion and spindle specifications?
Both machines use a 2.2 kW air-cooled spindle, up to 24,000 rpm. A kilowatt is 1,000 watts, and air-cooled means a fan on the spindle body, with no coolant pump or radiator described. The August 5 post doesn't print a plug voltage, but a spindle this size is the reason 220 V should be on your checklist. I'd ask about the outlet, the breaker, and the cord.
Both use ball screws, 1605 on X and Y and 1204 on Z, on HG20 linear rails. Those codes describe the screws. A 1605 screw is 16 mm in diameter with a 5 mm lead, and lead is how far the nut travels in one turn. The Z-axis 1204 advances 4 mm per turn. A shorter lead moves less per motor turn, so Z can push harder for the same torque while its top speed is lower. HG20 is a profiled rail 20 mm wide, heavier than the HG15 rails on many benchtop machines, and chips in its ball circuit are a wear problem, so the rails want to stay clean. The post prints the codes and no measured backlash (the dead motion when an axis reverses).
The motors are closed-loop NEMA 24 steppers rated at 3.5 N·m. NEMA 24 is an in-between frame, larger than a NEMA 23 and smaller than a NEMA 34. Closed loop means the drive can see a missed step.
What do accuracy and control look like?
The controller is GRBL 1.1f, and SainSmart says offline operation is supported, so the computer doesn't have to stay tied to the job. A sleeping laptop is how a lot of tethered jobs die.
Accuracy is listed as ±0.02 mm (about 0.0008 inch) and repeatability as ±0.005 mm (about 0.0002 inch). Accuracy is whether the cutter reached the coordinate you named. Repeatability is whether it can find that spot again. Those are company figures, and they belong in the same sentence as the measurement setup, which the post doesn't include.
How does the NAX5 tool changer work?
The NAX5 holds five tools and changes them as part of the program.
A hand tool change is a pause, a wrench on the collet, and a new Z for the new stick-out. Five pockets is enough for a roughing end mill, a finish mill, a V bit (the pointed cutter for lettering and inlays), a drill, and a spare. It isn't a 24-tool magazine. Every pocket still needs a true tool length, because a wrong offset gets cut exactly as programmed.
SainSmart says the machines are semi-assembled and that assembly is under 30 minutes. It also lists an MPG handwheel (a pendant with a wheel for jogging), a fourth axis, a dust shoe, and a vacuum fixture (which holds sheet material with suction, giving back the margins clamps would use) as things the platform can take. The post doesn't say they're in the crate. Semi-assembled in under 30 minutes still leaves squaring, tramming, and checking the tool-change positions.
Software named in the post is Fusion 360, VCarve, gSender, and any program that writes ordinary G-code. gSender is Sienci's sender, so naming it is a small, useful compatibility claim.
How does it compare with other options?
Sienci had already priced an AltMill ATC in December 2025, at $2,890 for a six-tool kit on a machine you buy separately. TwoTrees was weeks away from talking about the ED1's five-tool changer on a much smaller desktop. The PRONAX is the middle object, a 600 × 900 or 800 × 800 router with the changer designed in, at a weight you can still move with two people.
SainSmart says it's for sign shops and small manufacturers that have outgrown a desktop. The roughly 120 mm of work height says the work is sheet and flat parts, and deep boxes and tall clamps will argue with that Z.
What's missing?
The August 5 post doesn't print a price, a power-plug requirement, or a ship date. It does give two work envelopes, a screw specification, a rail specification, and a five-slot changer. On August 5, the PRONAX is a specification and a shop argument: production-minded, full metal frame, five tools, and a spindle big enough that 220 V power belongs on your list.
If you're pricing a first ATC and you can wait to see the invoice, read this post and then the product page on the day you buy. If you need the price in the same paragraph as the screw size, SainSmart hadn't written that paragraph yet.
Sources and image credits
- What Is ATC? Why PRONAX Is the Smart Choice for Your CNC Shop (SainSmart blog)
- The post links the Spark, Forge, and NAX5 product pages
- Product images: SainSmart blog post
