Flap grinding wheel FAPI-CORE

Flap wheel FAPI-CORE with straight flaps is suitable for surface treatment. The fan-shaped radial arranged flaps adapt to the contour of the workpiece. The flap discs FAPI-CORE are manufactured with a plastic core. When using the tool, it is not necessary to work with a suitable pair of clamping covers, as with the flap wheel FAPI-RING, but can be installed directly on the machine.


Today, flap discs are used in many areas of surface treatment. In the metal as well as in the woodworking industry, flap discs are used for grinding.

The main applications for flap discs are fine surface grinding, concave and convex surfaces, edge processing, profiles, internal and external grinding of vessels and apparatus.

  • Materials: steel, stainless steel, aluminium, wood and plastics.
  • Machines: Hand sanding machines, stationary sanding machines, automatic sanding machines, sanding frames and sanding carousels, flexible shafts.

Picard tip:

For the machining of workpieces with flap grinding wheels, the contact pressure must be as low as possible. In order to maintain a constant grinding pattern until wear, counter-rotating grinding should be used if possible. The surface is refined by adding grinding oil/grease.

Notes for the practice

  • The flap wheel is very easy to profile and adapts continuously to the workpiece, even during use. Profile the flap wheel “backwards”, i.e. against its running direction. In this way you profile the fabric side and not the grain side and have the desired profile in the flap wheel within seconds.
  • The grain size of the flap wheel should be approx. one to two steps coarser than the grain size of the grinding belt.
  • Coarse grit on a flap wheel will produce a finer effect at high speed – fine grit will produce a coarser effect at low speed.
  • Select contact pressure sensitively but not too strongly, possibly use coarser grit.


High-quality abrasive cloth flaps with a base of heavy cotton cloth are arranged in close succession radially around a plastic or aluminium core. The dense arrangement of the abrasive flaps ensures maximum performance in the machining process. The optimum design of the flap discs guarantees maximum tool life and flexibility.

The body diameter, the facing length (flaps) and the packaging are the decisive influencing factors for the process.

Body diameter and fill length

  • Hard flap grinding wheel
    A large body diameter with many short lamellas leads to a high cutting performance and thus to a high material removal rate.
  • Soft flap grinding wheel
    A small body diameter with a few long lamellas leads to an even grinding pattern. Soft flap discs are also ideal for the surface finish.


10:1 Paketierung (Standard)Eigenschaften: sehr aggressiv und hart
3:1 PaketierungEigenschaften: mittelweich
5:1 PaketierungEigenschaften: hart
1:1 PaketierungEigenschaften: sehr flexibel und weich


outer diameter d1 [ in mm ] core diameter d2 [ in mm ] bore d3 [ in mm ] inner core diameter d4 [ in mm ] width B [ in mm ]
100 to 140 50 max. 25 solid core max. 100
150 to 175 72 max. 45 solid core max. 100
150 to 175 72 max. 35 47 max. 100
180 to 200 93 max. 55 68 max. 100
250 114 55 77 max. 100
300 146 110 97 max. 100
350 188 110 147 max. 100
400 214 120 168 max. 100
450 314 120 268 max. 100
460 314 120 268 max. 100


(click table to enlarge)