One case, a complete sawing system: The KSP 40 is a 2.2-kg handheld circular saw whose Flexi-Rail can be rolled up and stored inside the T-MAX—1.4 meters of guide rail that no longer requires a Tetris-style fit in your trunk. Built for renovation and interior finishing: cutting doors to length, trimming panels, fitting countertops, installing furring strips and formwork—for jobs where a large saw is overkill and a jigsaw isn’t powerful enough.
Mafell calls it “four saws in one”: freehand, rail-guided, plunge-cut, and as a shadow-joint saw for joint widths starting at 13 mm—with a rip fence starting at 14 mm, and at full cutting depth starting at 18 mm, as specified in the operator’s manual. Plunge cutting is made possible by a feature not found elsewhere in this class: the riving knife swings upward during the plunge and returns automatically as soon as the gap behind the blade clears—the kickback protection remains intact, whereas other plunge designs do without the riving knife entirely. Additionally, the pivot point on the rubber lip features a single cutting line indicator for every angle, with or without a guide rail. It cuts 0 to 42 mm, 40 mm on the guide rail, and 29 mm at 45°—with 900 watts and 8,400 rpm. According to the operating manual, it is not approved for continuous industrial use.
Buying the Mafell saw at RUWI isn’t something to take for granted: We’re the manufacturers ourselves—tools for woodworking professionals from Fluorn-Winzeln, 4 kilometers from the Mafell factory in Oberndorf am Neckar. We carry only what we can recommend from our own experience—and when we say “complete system,” we really mean it: the guide rail, stop, clamping brackets, and dust extraction nozzle are all included.
Here's how to use it
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Cutting shadow gaps: Pull the hood in using the lever, position it, and push it forward evenly—for gap widths of 13 mm or more, with the dust extraction system running.
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Cutting doors and panels to length: Unroll the guide rail, mark the position, score along the trimmed chip guard, and saw.
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Dive right into the middle of the area: Press the dive lever, read the depth on the scale—the wedge moves out of the way and then returns.
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Parallel to the edge: stop on the right up to 65 mm, on the left up to 250 mm—can be mounted on either side.
Does this fit in your workshop?
The KSP 40 is the go-to tool for renovations: always on hand, ready to use in a flash, for cuts up to 42 mm. If you regularly need a 55-depth setting, a scoring function, and the full range of rails, the MT 55 cc is the perfect choice—and if you’re looking for a repeatable crosscut guide instead of the rollable rail, go with the KSS 300, its sister model from the same instruction manual. When opening the Flexi-Rail, be sure to hold it firmly with both hands—the rail angle is pre-tensioned.
You can read about why your vacuum should be Dust Class M in the knowledge article on wood dust extraction —and the Machine Advisor will help you find the right saw by asking you two or three questions.
All the details
Function and Applications
Design: Mobile complete sawing system, KSP 40 40-series handheld circular saw with rollable FLEXI rail in a carrying case
Applications: Cutting panels to size, cutting shadow gaps, cutting doors to length; for cabinetmakers, carpenters, and interior finishers
Performance and Cutting Specifications
Rated power: 900 W
Speed: 8,400 min⁻¹
Cutting depth without guide rail: 0 to 42 mm
Cutting depth with guide rail: 0 to 40 mm
Cutting depth with guide rail at 45°: 0 to 29 mm
Tilt range: 0 to 45°
FLEXI Guide Rail: 1,400 mm usable length, roll-up design
Saw Blade: Ø 120 × 20 mm
Dimensions and Weight
Weight: 2.2 kg
Safety and Quality
Origin: Manufactured in Oberndorf am Neckar
Warranty: MAFELL-Complete, 36 months after registration
Replacement Parts: 10 years from end of production (Mafell commitment)
