M2 High Speed Steel Straight (Ratchet) teeth** BSS122 and DIN1837 Form A Inch bores with standard keyway (BSS122). Metric sizes are usually provided without keyway. Cutting teeth on periphery. Hollow ground to centre. **Tooth form according to DIN1840 Form A.
*Some stocks of 30mm diameter – once popular — remain and may be offered. Please enquire.
Note on the number of teeth in saws (Inch sizes) The number of teeth in fractional slitting saws has not in the past been set down to a rigid standard, and was largely left to each manufacturer to choose which teeth would be offered, which has led to many different variations. The important feature - the pitch (distance between successive tooth faces) when standardised over different diameters resulted in odd numbers of teeth, or fractions of teeth, at the periphery. Older production machinery was also limited by the number of divisions in a circle which could be utilised. It is therefore possible to find saws which, generally conforming to the standard, have very slightly different numbers of teeth. We are currently using the number of teeth laid down by BSS122, the reference standard for all bore-type cutting tools and generally offer both a fine pitch (TRUBOR No. 517A) and coarse pitch (TRUBOR No. 517B). Nevertheless older stock will occasionally be different. For example, 3,1/2” diameter fine pitch saws have been normally produced with 88 teeth, whereas the latest convention is to make with 90 teeth. Therefore we will deliver according to available stock, even where a small difference exists. The above remarks do not apply to metric saws, where the convention has not changed at all over many years, and numbers of teeth are better established, with standards DIN1837 (Tooth form A - fine pitch) and DIN1838 (Tooth Form B - coarse pitch) relating to TRUBOR series numbers 517A and 517B respectively.
In both inch and metric sizes, unlisted numbers of teeth may be manufactured to special order, with quantity ordered determining the unit price. Setup costs for specials in this range are high, so that small quantities may be relatively very expensive.
