Router bit basics

When CNC shoppers look into purchasing a new CNC router, they look into every aspect and detail of the machine they are putting there hard earned money into. And rightfully so.
Yet one of the most overlooked aspects when purchasing a machine of this magnitude is the tooling. The popular phrase "A man is only as good as his tools" is very appropriate when dealing with CNC routers. You can own a Rolls Royce of a router and have a low quality bit in it's spindle and you might as well use a hand held router to achieve the same cut.

The router bit material, finish, geometry and cutting characteristics along with durability and long life are essential when choosing the right tool.

Some CNC owners choose the cheapest tools they can get their hands on
and without realizing they are making the poorest cost effective choice as far as productivity is concerned. Another phrase comes to mind "A penny wise and a pound foolish".

OK, enough with the popular phrases I promise.

The only time to choose the low cost bit if you must is at the start up phase of learning to operate the router. You may run in to some learning curves which may cause you to break one or two bits in the very beginning.

I personally believe in high quality as much as possible in all things. Having quality assurance and design experience in my background I can attest to this.

When choosing a router bit I highly recommend the following basics one should apply when purchasing router bits. Note that these are common characteristics and do not apply to the material being machined.

• Use solid carbide or carbide tipped tools.



• Always choose the tool with the shortest possible cutting edge length to cover the thickness of the part with a slight overlap.



• Since the diameter of the tool increases rigidity, it is best to choose the largest diameter possible and again the cutting edge length should be as short as possible and not more than three times the diameter in a perfect world.



• Keep the cutting edge length and shank diameter the same whenever possible



• Select tools on productivity rather than cost. Choose the tool for the speed of cut and finish desired, i.e., single flute for speed and larger chip loads. Double or multi flute for better finish.

These are just the basics as far as choosing a proper router bit. There are many more factors to consider like material being routed, feeds and speeds, part fixturing, chip loads etc. Although there are many different applications involved when cutting on a CNC, don''t feel overwhelmed. Whith the proper advice and direction you will eventually find your sweet spot when cutting on your CNC router and you will reap in the benefits of good high quality production.