What is the minimum size of router bit you can use with a small CNC routing/engraving table?

Question

I considering buying a CNC router table (max material cutting size is 1200mm x 800mm x 90mm). The website indicates the blade holder specfications are 3.175mm, 4mm & 6mm. Does this mean that the minimum router bit size I can use with this machine is 3.175mm? Basically, I want to cut narrow straight slots in a sheet of MDF and I need them to be as narrow as possible. Does this mean that this machine cannot cut slots more narrow than 3.175mm?

Finally, the sheet of MDF would be 30mm thickness. If the machine was to router/engrave completely through the sheet e.g to a depth of 30mm, would the cut be straight and clean with no tool marks on the cut sides of the MDF? Would a router bit with a thickness of 3.175 struggle to do this?

Answer 1

The holder specs refer to the 'shank' size of the bits you use. Typically, you can find just about any 'cut' size of bit you want, in those different shank sizes. What it will physically look like to you, is the shank will be larger than the cutter.... this is actually quite common.

Other things to consider when purchasing bits.... spiral cutters, or even double spiral cutters to prevent chip out of the material. Something to consider if you are going to be using melamine products.

I would suggest that you ask some questions of someone who has one of these router tables -- the company should be more than willing to give you references.

Have Fun.

Answer 2

You don't need a CNC machine to cut straight slots. A simple jig will accomplish the same task for a fraction the cost. The shank size on the router collet is not the same as the diameter of the bit. The bit diameter can be smaller, or larger than the shank.