Rising Cutters archive

Even our own router guru Anthony Bailey Editor runs into trouble every now and then!

The title might suggest something quite positive but it is quite the reverse! If you are doing either freehand or table routing and the cutter starts to slip from the collet while machining, it will not only damage your work,

it can also be dangerous to the operator and needs immediate action to deal with it. Well, that is exactly what happened to me while machining the dovetail housings in the lid of a zebrano box project.

I was informed by a cutter manufacturer some years ago that rising cutters occur because the router collet is worn or damaged. However, I think I would beg to partially disagree. My experience is that too deep a cut with attendant vibration or certain types of cutter can exacerbate this rather alarming effect. In this case I had carefully set up a small dovetail cutter ready to use in the router table. Because the positioning and height of the housings that allow the lid to slide on and off the box were critical, I decided not to use a straight cutter to clear the bulk of the waste first. I would always do this with a large dovetail cutter as a matter of course, but its small size suggested it should be okay. I set everything up using MDF blanks the same size as the zebrano lid blank and made trial cuts very successfully.

Step 1

The even texture of the MDF meant the waste cleared easily and left perfect housings with the correct positioning width-wise, which I needed to know when machining the zebrano. What I should have done at this stage was to swap to a straight cutter and clear the waste in the zebrano, then re-install the dovetail cutter, but I didn't†- Unfortunately, the zebrano, with its somewhat fluffy nature, clogged the slot and I think it was that which forced the cutter upwards, as it could not progress forward as easily as it did in the MDF.

Step 2

The resultant breaking through the lid forced a design re-think, as the zebrano had run out and I couldn't get any more. The key things in this situation were having an NVR switch I could hit easily to kill the power and wearing safety glasses too, just in case. A salutary lesson not to ignore the basics and expect too much from a cutter!