And Then There Were Eight

Recall from my previous post that I am making a set of blocks for a Christmas project that each have four slot mortises routed on one face, and a circular extruded cut feature routed on the other.

The slot mortises were easy to rout using the CNC router, and since they will accept a matching tenon, they only needed to be accurate.

The circle features on the other hand need to be free of visual defect which I found more difficult to accomplish given the nature of the two woods I am using.

Padauk and zebrawood easily splinter, and the router bit also tends to burn both woods more easily than others. I found that slowing the speed of the router to somewhere around 12,000 rpm and increasing the feed rate of the cut removed any tendency of the router bit to burn the wood. It was actually surprising that this combination of speed and feed rate also produced an almost splinter free cut.

What a relief.

There were originally nine blocks. The problem of speed and feed rate did not appear on the initial test run using a scrap of medium density fiberboard. It only became apparent on the first block of zebrawood.

This unfortunately happens sometimes.

That first block of zebrawood is now a block of sacrificial scrap. It was used to perfect the cnc routing process for the circles, and will be useful to test a future process that might need verification before committing that process to the other eight blocks.