Understanding the Function of Marginalized Carbide Knives

As you may have noticed that on some Sheartak spiral cutterhead, the inserts on both sides are slightly narrower than the ones in between. Hope this blog can help you understanding the Function of the Arrow Marked Blades as shown in Fig.1 and Fig. 2.

All of the carbide inserts are angled for a shear-cut action, so the regular carbide inserts on the sides would extend about 2.5mm out of the cutter block on each side if the block were still the same length as the original cutterhead. For machines with narrow and compact spaces, such as the Elu EPT 1161 planer thicknesser, the regular carbide inserts will touch and cut the casting or housing of the machine. So we install narrower inserts to maintain the same cutting length as the original cutterhead. On jointers, these inserts serve for rabbetting. 

There is another solution, which involves spacing all of the inserts narrowly, but this would result in a cutting length that is about 2.5mm shorter on each side, a total of 5mm.  

Many people prefer to keep the original cutting length, so we have developed these special inserts for machines. 

We design and manufacture to custom sizes. Don't hesitate to contact us. We are always availalbe to help.