Machines get compared on capacity and price. Those are the two easiest specs to read and neither of them tells you whether the machine suits your work.
1 · Capacity, honestly assessed
Capacity is the largest hole the machine will drill with an annular cutter. It is quoted at the limit, in ideal material.
Specify from what you actually drill, not what you might. Look back at a year of work and take the largest hole you genuinely produced. Buying two classes above that is weight you carry every day for a job you do twice.
2 · Stroke and depth of cut
Capacity is about diameter. Stroke is about how deep the machine can go in one pass, and it is what limits which depth of cut you can use.
If you work in thick section, check stroke specifically. It is the spec that quietly stops a machine doing a job it appears to be rated for.
3 · The magnet, and the spec nobody quotes
This is the safety-relevant one.
- Rated holding force is normally quoted on clean, flat, 25 mm steel.
- You need roughly 10 mm or more to get near that rating.
- Below about 6 mm the magnetic circuit is too thin to develop full hold, and the machine can break away under cutting torque.
- Rust, paint, scale and an uneven surface all reduce hold, sometimes sharply.
If your work is regularly thin, that is a specification conversation before it is a technique conversation. And use a safety chain on anything that is not flat and horizontal, regardless of what the magnet is rated at.
4 · Feed: hand or automatic
Most machines are hand-fed. Auto-feed machines advance the cutter at a set rate instead.
Auto feed earns its keep when: the same hole repeats many times, the plate is thick, shifts are long, or the operators change often. Consistent feed is also what makes cutters last, so the benefit shows up twice.
Hand feed is better when: holes are occasional, positions are awkward, or the operator needs to feel the cut.
5 · Duty, weight and the practical stuff
- How many holes a day? A machine used continuously needs to be specified for it.
- Weight. It gets carried up scaffolding by a person.
- Power available on site. Check the supply before the spec, not after.
- Shank. Weldon 19.05 mm keeps your consumable options open for the machine’s whole life. A non-standard shank narrows them permanently.
- Coolant. Gravity bottle or pumped, and whether it works in the positions you drill in.
The two specs that never appear on a comparison sheet
Where the spares are, and who repairs it. A machine is only as good as how quickly it comes back. If the spares are overseas, add the freight and the waiting to the purchase price, because you will pay it.
The short version
- Largest hole you really drill, and thickest plate
- Thinnest plate you will sit the magnet on
- Holes per day, and whether they repeat
- Where it will be used, and what power is there
- Who fixes it and where the parts live
Tell us the work and we will spec the machine
Answer the five lines above and we will tell you which class of machine fits – and we will say so when a smaller one will do the job.
Email info@neweratools.com or call +65 6241 0908.