Buying a used CNC machine: what to check before you pay

Should I see it cut before I buy?

Yes. Cutting a part puts the control, spindle, axes, tool changer and coolant to work together. Ask the seller to:

1. 1.Power it up and home every axis.
2. 2.Run a program that moves every axis, takes the spindle up to speed, changes tools and turns the coolant on.
3. 3.Cut a part in a material like yours. Measure it there, or take it with you.

If you cannot get there, ask for a video of that run, start to finish, in one take.

What should I check on the control?

• •Make and model. Read them off the machine and check they match the listing.
• •Alarms. Note any that show at power-up, and ask for the alarm history.
• •Backups. Ask whether the programs and parameters are backed up, and whether the backup goes with the machine.
• •Options. If you need one, such as rigid tapping or a fourth axis, ask to see it work.
• •Getting programs in. Load one the way you will load yours, and run it.
• •Screen, keys and handwheel. Check they all respond.

How do I check the spindle?

• •Run it up to top speed in steps and back down, listening and watching for vibration at each step.
• •On a machining center, check it takes the tool holders you already own, and change one by hand to check it clamps and releases cleanly.
• •Ask whether the spindle has been rebuilt or replaced, by whom, and for the paperwork.

How do I check the axes, ways and lube?

• •Jog each axis from one end of its travel to the other, slowly and at rapid. Watch and listen for any spot where it catches or changes sound.
• •Look at the way covers and wipers: all there, none torn.
• •Check the lube system runs and its tank is filled.
• •Ask whether the machine has ever crashed, and what was repaired.

For accuracy, go by a part you saw it cut and measured yourself.

Do the tool changer, coolant and chip conveyor work?

• •Load tools and run the changer through every pocket.
• •On a lathe, index the turret to every station, run any live tools, and work the chuck and any tailstock.
• •Run the coolant, and look in the tank.
• •Run the chip conveyor, if it has one.
• •Check the doors, guards and door interlocks are all there and work.

What paperwork should come with it?

Ask for:

• •The year and serial number, from the machine's own plate.
• •Hours, if the control records them: power-on, and spindle or cutting time.
• •The manuals and the electrical drawings.
• •Maintenance and repair records.

If a listing does not show the hours or the serial number, ask for them. That goes for our used machines too. Ask where the machine ran, on what work, and who will service it after the sale.

What does the price include?

Ask what it covers: tooling and accessories, loading, freight, rigging, installation. Then make sure everything that matters is in the written proposal. Under Section 16 of our terms of sale, the proposal signed by both sides is the complete statement of the deal.

On a used machine from us:

• •Delivery. Under Section 3, a sale is FOB Arlington, TX: you pay freight and insurance from Arlington, and any demurrage, rigging and unloading charges at the destination.
• •Taxes. Applicable taxes are yours to pay (Section 4). Provide a tax-exempt form and you will not be billed taxes.
• •Payment. Cash, check (it must clear before we release the machine) or any major credit card. Contact the office for payment options.
• •Financing and trade-ins. Ask about financing a pre-owned machine and about a trade-in: the quote form has a box for one. If you have a machine to sell, the evaluation is free.
• •Commitment. The proposal is not a binding contract until the advance is paid with the order and an officer or authorized employee of Eagle Machine accepts it (Section 13). Read Section 15 on cancelling before you pay.

What has to be ready before it ships?

• •Power. Check the machine's voltage, phase and load against your shop's supply.
• •Air. Check the pressure and flow it needs against your compressor.
• •Space. Check its footprint and weight against your floor, and measure the doors and the path in.

Under Section 9 of our terms, you must have power and air to the machine at its location before an installation, and we are not responsible for extra electrical equipment it may need there, such as a transformer, a breaker box or fuses. For power, air, floor and rigging, see what your shop needs ready before a CNC machine arrives.