Mafell LS 103Ec Deep Slot Mortiser

  • Choice of chain sizes for 3/8" or 1/2" knife plates
  • Plunges up to 15-11/16" deep (SG 400) or 19-5/8" deep (SG 500)
  • Angles up to 45°
  • Powerful 230 V motor

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Deep Slot Mortiser
Mafell LS 103Ec Deep Slot Mortiser is available to buy in increments of 1

The Mafell SG 400 slot mortising attachment can plunge approximately 15-11/16" either at angles up to 45 degrees, or straight (typically used horizontally).  This is the ideal attachment for cutting knife plate slots in large glulam workpieces, as well as slots for high quality gusset plates in engineered lumber.

Its impressive mortising depth and angles are made possible by the exact coordination of the slot attachment with your chain mortiser.  With a special chain guide, cutting depth stop, and vertical edge spacing scale, the SG 400 guarantees precision with each plunge.

The SG 400 is best used with a 230 V chain mortiser, which has advantages compared to 120 V motors when plunging very deep into wood.

There is also the Mafell SG 500 that plunges as far as 19-5/8" deep and comes with a clamping device plus three guide pieces, but the SG 230 or SG 400 is usually a more practical option.

With each slot mortiser purchase, Timberwolf Tools will include a free grease gun and premium bearing grease that you can pump into the bottom of the bar, plus free chain lubricant for lasting performance.


SG 400SG 500
Mortising depth: 15-11/16" 19-5/8"
Mortising width: 1-15/16" by 11mm or 14mm 1-15/16" by 11mm or 14mm
Tilt range: -45 to 45° -45 to 45°
Nominal speed - no load: 4,050 rpm 4,050 rpm
Motor: 230 V 230 V
Current: 13 A 13 A
Weight with stand: 73 lbs 88 lbs

Standard Equipment

  • Chain, Bar and Sprocket
  • SG 400 or 500 Slotting Guide
  • Stop Plate
  • Two Allen Keys
  • LU202 Chain Lubricant
  • Grease Gun
  • Premium Bearing Grease
  • 32.8 ft Cord


  • Additional chains and replacement components are available below
  • We recommend 11mm chains for 3/8" plates and 14mm chains for 1/2" plates
  • For other chain sizes ranging from 10 to 17mm, please call us at 1-800-869-4169
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