A used wire EDM in the $20,000–$30,000 target range may fit small parts and loose tolerances, but a dependable automatic threader and the actual time spent cutting 3-inch stock decide whether the purchase works. Treat advertised machine capability as a starting point: the seller must run a representative test cut, and you must confirm service, parts, footprint, and threading before committing.
What work must the machine cut?
Translate the part description into a testable job before comparing brands. The stated parts are under 10 inches square and 3 inches thick, with size tolerance of ±0.001 inch and location tolerance of ±0.002 inch. Most jobs are described as “put and take”; clarify the actual operation with a sample drawing or part, because the phrase does not specify contour length, material, number of setups, or cut sequence.
For each representative part, document the stock material and thickness, maximum outside dimensions, longest cut path, smallest feature, required size and location, and whether the cut starts from a predrilled hole. Record how many parts run per job and how often jobs change. The absence of tapered walls removes one stated requirement, but it does not establish that a particular machine’s other capabilities or condition are suitable.
Use these requirements to define the acceptance test. One tiny sample may prove that a machine can cut; it will not prove that it can handle the longest production path, 3-inch stock, repeated jobs, or the required tolerance. Check: have a representative drawing and stock sample ready before evaluating any machine.
Will the machine fit the parts and the floor?
A part envelope under 10 inches square and 3 inches thick is not the same as a machine’s usable work envelope. Confirm the table travel, workpiece capacity, and clearance against the specific machine documentation and the seller’s actual machine. Check whether the machine can hold the full stock and fixture with room for the required cut, not merely whether the part’s nominal dimensions appear smaller than the machine’s listed travel.
Limited floor space makes installation dimensions part of the purchase decision. Measure the machine footprint and the access needed to load stock, open doors, service components, and remove parts. Confirm available power, installation requirements, and any required ancillary equipment with the manufacturer or qualified installer; do not infer them from another machine in the same product family. The source describes submerged and non-submerged candidates, so establish which configuration is being offered and what the installation requires.
| Check | Decision evidence |
|---|---|
| Part envelope | Seller demonstrates that the sample stock, fixture, and cut path fit the actual machine. |
| Floor space | Measured footprint plus loading, door, and service access fits the shop layout. |
| Configuration | Record whether the machine is submerged and verify associated installation needs. |
Check: compare the machine’s actual dimensions and capacity with both the shop layout and the largest prepared sample.
How much cutting time does the job require?
Wire EDM removes material along a programmed path; stock thickness, path length, and the machine’s actual cutting performance affect cycle time. A low linear cutting rate can make a large contour uneconomic even when the part fits and the tolerance is easy to meet. Ask the seller to cut the longest representative path through the intended stock thickness and record elapsed time.
A rough estimate in the supplied discussion used 0.020 linear inch per minute with 0.012-inch wire for 3-inch-thick work. It is only an informal estimate, not a verified machine rating. A 7.5-hour estimate at that rate implies a 9-inch path, so the stated square size and time do not agree. Use the actual programmed path and the seller’s measured test time to build the cost estimate.
Include operator time, threading interruptions, setup, and the number of parts in the run when comparing in-house cutting with alternatives. The source notes that thick, large cuts may not run quickly and that some buyers may prefer manual threading over paying more for automatic threading. That is a production-cost decision, not a universal rule.
| Screening input | What to verify |
|---|---|
| Cutting rate estimate | Confirm with elapsed time on a comparable path and stock thickness. |
| Square contour | Calculate perimeter from the drawing; a 3-inch square is 12 inches around. |
| Production economics | Compare machine time and operator involvement with expected job frequency. |
Check: require a timed cut on the longest relevant contour before relying on a seller’s cycle-time claim.
Does automatic threading justify its premium?
Automatic threading is a stated must-have, yet older machines can have problematic threaders. Treat threading as a machine function to demonstrate under the intended operating conditions, not a feature that passes merely because it appears on a specification sheet. Have the seller show automatic threading and then run a representative job that requires it. Record whether it completes reliably and whether intervention is needed.
If automatic threading fails or is absent, decide explicitly whether manual threading is acceptable for the expected work. The source describes manual threading as a possible way to avoid the price difference on thick, large cuts; it does not show that manual threading suits every production schedule. Compare the added operator handling and downtime with the purchase premium. Do not buy a machine that misses the requirement on the assumption that the threader can be repaired later without a documented diagnosis and cost.
Check: witness the automatic threader complete a test, and make the purchase conditional on passing if automation is mandatory.
Which candidate machines deserve an inspection?
Names mentioned for this application include Brother HS-70A, Agie Classic, Charmilles 290/310, Sodick, Fanuc, and Mitsubishi CX and FX series. These are leads for inspection, not a ranking or proof that a particular used unit meets the job. The discussion describes the Brother HS-70A as submerged with fast automatic threading and good support, and mentions the Agie Classic and Charmilles 290/310 as non-submerged options. Verify those configuration and performance claims on the specific machine being offered.
The discussion also flags older automatic threaders as a possible problem, reports concerns about Mitsubishi CX series machines, and cautions that a Mitsubishi FX has a traveling-column design whose moving mass may matter for close-tolerance work. Treat these as reasons to inspect and test, not as conclusive judgments about every machine in those series. The stated tolerances are ±0.001 inch for size and ±0.002 inch for location; a test cut on the actual machine is the deciding evidence.
| Candidate or feature | Inspection question |
|---|---|
| Brother HS-70A | Does the offered unit demonstrate the claimed fit, submerged operation, automatic threading, and support? |
| Agie Classic; Charmilles 290/310 | Confirm the specific configuration, condition, capacity, and available service. |
| Mitsubishi CX or FX | Check the actual machine’s service history, threader, and test-cut performance; for FX, account for its moving-column arrangement. |
| Sodick or Fanuc | Evaluate the individual machine; threader and support experience varies by unit and service channel. |
Check: shortlist by demonstrated test performance and serviceability, not the badge alone.
Can the seller support the machine after delivery?
Before purchase, identify who supports the exact model and what support costs. Confirm whether the manufacturer backs the machine, whether technical support carries a fee, and whether replacement parts remain available. Include support charges and likely parts exposure in the total purchase budget; an attractive machine price does not include the cost of keeping it productive.
Get the service arrangement in writing: supported model and configuration, available support channel, fee structure, parts sourcing, and any known exclusions. Ask for service and maintenance records and investigate unresolved faults, especially automatic-threading faults. If the seller cannot show how the machine will be supported, price that uncertainty as an operating risk rather than assuming another machine in the same brand has the same support.
Check: obtain a clear support and parts plan for the specific serial-numbered machine before placing a deposit.
What should the used-machine acceptance test prove?
Arrange the inspection around the job path: stock and fixture, machine condition, automatic threading, cutting, measurement, and support documentation. See the machine run and have the seller make a test cut. Bring the drawing and material needed to represent the actual job; a demonstration on unrelated thin stock cannot validate performance on 3-inch-thick work.
- Confirm machine identity, configuration, included equipment, and visible condition. Resolve any faults or missing items before the test.
- Load representative stock and fixture. Verify capacity and clearance, then demonstrate automatic threading if required.
- Cut the representative feature and time the operation. Observe interruptions, threader behavior, and operator intervention.
- Measure size and location against the drawing using suitable inspection equipment. Compare results with ±0.001 inch and ±0.002 inch requirements.
- Review service, parts, and support terms and reconcile the measured cycle time with production economics.
Budget guidance in the discussion is not a current-market quote: one view was that a decent used machine might fit the $20,000–$30,000 target, while another estimated roughly $50,000 for a more modern machine with a reliable threader. Verify current asking prices and condition directly; do not treat either figure as a guaranteed market value. Final check: accept only after the specific machine completes the representative cut, demonstrates the required threader, meets the dimensional checks, and has a viable support plan.
FAQ
How do I choose a used wire EDM for parts under 10 inches?
Check the actual machine capacity against the stock, fixture, thickness, and cut path, then run a representative test cut. The offered machine’s condition and support matter more than its nominal model reputation.
How do I verify automatic threading before buying?
Ask the seller to demonstrate automatic threading on the specific machine and include a representative threading-dependent job in the test. If automatic threading is mandatory, make a successful demonstration an acceptance condition.
How long does a 3-inch square wire EDM cut take?
Measure the actual job because the estimate is not a machine rating.
How do I compare a submerged and non-submerged machine?
First confirm the configuration of the exact used machine, then check that it accommodates the work and installation. The candidates mentioned include submerged and non-submerged configurations; the configuration label alone does not prove cut performance.
How do I know the used wire EDM is ready for production?
Witness a representative cut in the required stock thickness, confirm automatic threading, measure the part against the drawing, and confirm support and parts availability. The final verification is a passing test on the machine being purchased.