oztooltalk review the latest in metal cutting technology for site, the Bosch GKM 18 V-Li. It’s small, lightweight and super easy to use. Perfect for electricians and plumbers. Known in the US as the CSM180.
Metal-cutting circular saws are becoming more and more well-known by trades-people, and it’s easy to see why. Their ‘cold-cut’ produces little burring, fast cutting speeds, few sparks and of course, no heat. It should be of no surprise then that Bosch have produced a cordless, light-weight metal saw for the job site. The GKM 18 V-Li has a 136 mm blade, with a cut depth of up to 50 mm. It weighs only 2.6 kg with a high capacity 18V battery, and is extremely ergonomic in the hand.
Recommended building materials for use include: cable tray, uni-strut, sheet metal, threaded rod and pipes. The saw is equally capable in non-ferrous metals and steel. HVAC, electrical, plumbing and metal-fabrication workers on commercial building sites stand to benefit most.
It also does a great job cutting cutting plastic pipes, and for those wondering, yes it can cut timber too. However it is significantly slower in timber than regular circular saws, probably because the blade isn’t designed for timber.
Whilst the saw can be used to cut thicker metal materials, care should be taken to prolong the life of the blade teeth, as replacement blades are expensive. I tried cutting reinforcement mesh and destroyed several teeth by pushing too fast. The thicker the material, the greater the risk to the teeth.
For many tasks, a cold-cutting metal saw is superior to a grinder or reciprocating saw. A small list of the strengths and weaknesses of each for cutting metal is shown below:
Metal-Cutting Circular Saw:
- Fastest cutting
- Cleanest and straightest cuts
- Few sparks
- True one-handed tool
- Very loud
- Expensive replacement blades
- Larger space for cut required
- Cheap cutting discs
- Most versatile
- Fine metal dust
- Hot materials & sparks
- No sparks
- Wide range of blade types
- Lots of vibration
- Larger tool
One of the advantages of metal-cutting circular saws are the ability to make long straight cuts due to the conventional saw base, using either the included fence or a straight edge.
The hanging-hook and LED light are also very welcome features that will please regular users. The saw includes onboard storage for the blade-change hex key.
As these saws are very loud when cutting, hearing protection is an absolute must. The Bosch GKM 18 V-Li, like most of it’s competitors, lacks the ability to collect chips or make bevel cuts.
If you haven’t already tried one, it’s probably overdue to take the plunge.