Core drilling machines — magnetic drills — are essential on steel-structure fabrication sites, civil works and MEP installations across the Northeast. Getting the wrong machine costs time, cutters and frustration. This guide explains exactly how to pick the right unit.
Written by the counter team at Multi Trade Combines — 35 years supplying NE workshops.
Across Guwahati's booming construction belt — from the Brahmaputra bridges to the hill-terrain NHIDCL projects — drilling clean holes in steel beams, RCC slabs and composite structures without losing a job-site day is a critical skill. Magnetic drills let one operator drill where a radial drill or column drill simply cannot reach: clamped upside-down under a bridge deck, sideways into an H-beam, or on top of a 30-storey slab with a 20-metre carry from the lift. In humid Northeast conditions, you also need a machine with good IP rating and sealed motor for the six-month monsoon season.
The single biggest variable in choosing a core drilling machine is what you are drilling into.
Tier your machine to your most common hole diameter and material.
| Application | Light site MEP / electrical | Structural steel fab | Heavy civil / RCC |
|---|---|
| Motor power | 600–800 W | 1000–1300 W | 1500 W+ |
| Drill diameter (max) | Up to 40 mm | 40–80 mm | 80–130 mm |
| Magnet holding force | ≥ 5 kN | ≥ 10 kN | ≥ 14 kN |
| Recommended model | BDS MABasic 60R | BDS MAB 100 K | Consult counter |
| Coolant system | Not always required | Built-in recommended | Mandatory |
Both are stocked at Multi Trade Combines, AT Road, Guwahati.
| Feature (MABasic 60R vs MAB 100 K) | MABasic 60R → MAB 100 K |
|---|---|
| Motor power | 650 W → 1050 W |
| Max drill diameter (steel) | 40 mm → 100 mm |
| Stroke | 60 mm → 100 mm |
| Magnet holding force | ~6 kN → ~14 kN |
| Reverse function | No → Yes |
| Best for | Light MEP, thin plate → Structural steel, rail, heavy fab |
The magnetic holding force must exceed the cutting thrust force by a safe margin. As a rule of thumb, never use a magnetic drill on a steel plate thinner than 6 mm — the flux circuit closes poorly and the magnet can release mid-cut. For overhead work, always use the safety chain supplied with professional machines like the BDS MAB 100 K. On job sites across Assam, Meghalaya hill terrain and Arunachal mountain infrastructure projects, unstable footing is common — chain anchoring is non-negotiable.
The machine is only half the system. Budget separately for:
Guwahati and the broader Northeast see 1 800–3 000 mm of annual rainfall. After every wet-season site day: wipe the magnet face with a dry cloth, blow out swarf from the chuck, and store the machine with the magnet face oiled with a light machine oil to prevent rust pitting that degrades holding force. Have the carbon brushes checked every 200 hours.
All BDS machines sold at Multi Trade Combines are genuine stock with manufacturer warranty and on-counter spares for annular cutters and brushes. We can demo the machine before purchase and advise on the right cutter set for your application.
A core drilling machine (magnetic drill) uses an electromagnetic base to clamp directly onto steel structures and cuts annular cores through metal, RCC and masonry. A regular drill press is bench-mounted and cannot clamp vertically onto steel beams on site. For on-site structural work, a magnetic drill like the BDS MAB 100 K is the right tool.
Yes, with the right cutter. Use a carbide-tipped or diamond core cutter with water coolant rather than an HSS annular cutter, which is designed for steel. For heavy RCC work above 100 mm depth, choose a machine with at least 1200 W motor and 35 mm+ cutting diameter capacity.
Yes. Multi Trade Combines on AT Road, Guwahati supplies BDS Maschinen magnetic drilling machines including the MAB 100 K and MABasic 60R, with annular cutters and accessories. Call +91 91812 13332 or WhatsApp for availability.