Zobo bits and Ti15

[ostwest]

I was doing remedials on the kitchen I fitted recently and one of the doors came without pre-drilled hinge holes, luckily i bought 35mm zobo bit in anticipation of such event stuck it into my Ti15 and started drilling laminated chipboard on speed setting 6 (full 2600rpm). it was kicking in impact mode now and then,  slowed down half way, but produced excellent hole, after i have done second one i felt bit being fairly hot and one of the blades that scores the edge having small black mark. i hope i didnt just burned my 40quid forstner bit...
in the description of zobo bits festool say they are "high speed" and dont state actual rpm's do they mean high speed on T/C's 1500rpm or high speed of PDC/DRC/DR/PD 4000rpm? Has anyone had experience running zobos at high speed into chipboard? whats max recommended speed?

 

[greg mann]

Zobo bits and most other quality steel cutting tools are made from what is generically called 'high speed steel'. This was terminology originally intended to differentiate itfrom 'high carbon steel'. HSS can be run significantly faster than High Carbon but today we have carbide tools that run much, much faster than either steel. This makes the term 'high speed steel' somewhat misleading, since it is necessary to run much slower than carbide.

I think your Ti15 is too fast for a 35mm bit. It did what you needed but i would use a T or C drill in low gear if you have one. If you have no choice take it in short intervals and give the bit time to cool, cutting two or three seconds at a time and letting it cool for five or ten seconds.