positions of tensioning device 16 and advancing mechanism 38 can be switched or both can be on the same side of the welding area 26 either before or after the welding area 26 moreover although as described above the spacing of the weld is generally every tuft length t see fig4 the spacing of the welds may be at an interval equal to x number of tuft lengths for example it is possible to weld only every 5 tuft lengths or 5t in this example the welding setup 10 would index the filament bundle a distance equal to 5t for each weld it is also possible to vary the weld length w see fig4 referring to fig1 tuft 140 has a weld 142 that is entirely encapsulated within a toothbrush handle 144 weld 142 is generally the desirable length for most applications however in some cases a longer or shorter weld is desirable for example filaments of a diameter smaller than the 0 008 inches described above are sometimes desirable because these thinner filaments can more easily reach in between teeth however filaments with diameters less than 0 008 inches tend to more easily bend and quickly wear at the lengths necessary to reach from the toothbrush handle to in between the teeth this problem can be solved by increasing the weld length to reach beyond the toothbrush handle 144 such as shown by tuft 150 in fig1 tuft 150 includes a weld 152 that extends from within the toothbrush handle 144 to almost half the length of the free end of the tuft 150 while it is necessary to keep the tuft long to reach in between the teeth only a portion of the total tuft length.