Drilling and Plunging

[knowlzy0791]

I have seen quite a few posts in the different threads I've cruised through. Seem to come across the statement that routers aren't supposed to be used for drilling or plunging.

What exactly does that mean? I run sheets with 100+ holes plus they get countersunk all day. What is this doing to my machine exactly?

Still pretty new to the more technical portions of the CNC world so bear with me

[signmarketingman]

Some router bits are not designed to cut while plunging or drilling. The bottom flat edge does not the correct blades for cutting all the way across.. Some cutters have a gap between the blades that will not cut.

Some router bits are designed to plunge or drill. Their blades are ground in such a way that they will cut or drill while plunging.

[Rcnewcomb]

Seem to come across the statement that routers aren't supposed to be used for drilling or plunging.

Some spindle bearings don't do well with downward force since they are designed for side loads. This is a concern for certain models of Colombo spindles. Usually a second Z with a drill was used

[Leo]

I sat with the technical people from CR Onsrud to talk about applications on routers.

The statement that routers are not supposed to be used for drilling is just not "entirely" true.

If fact you CAN do that.

The machines are designed to be cutting mainly in the periphery and not really designed to be a drilling machine. The router machine designers do understand that there WILL be drilling and plunging so the design of the machines CAN do that, but that is not and should not be the primary use for the machine.

In the spindle - more than in the machine - the thrust bearings are not designed to take repeated thrust as in plunging or drilling. Many hobby CNC machines use spindles that are primarily designed for very short duration use and designed to be hand held. The design intent there is that more than 90% of the time, the work is periphery work. Putting that same spindle on a CNC machine really violates the design intent, in that it will now be long duration use AND multiple plunging.

Still - hand held routers are certainly designed for SOME plunging.

I would not fear drilling of plunging. The most abuse is going to be in the spindle - on the thrust bearings.