Efficiency Bites the Dust in Spectacular Fashion

Commissioned to build a small donation box and with carte blanche on the appearance, I decided to use Bling Box from Vectric’s free projects. http://www.vectric.com/cool-stuff/projects/2013/bling-box.html
I would do away with the medallion and put a money slot and text in raised letters in the recess where the medallion goes. “Without the medallion”, I thought, “this is a simple three-piece project. Straight lines with a 1/4” ball-end for the most part. It should be quick and easy."

So I loaded the Aspire file for the top of the box, added my text and money slot, and looked everything over. The roughing pass around the edges is with the aforementioned a 1/4" ball-end. I checked the bit specified by the file and saw that its feed rate was 100 ipm, stepover 10%, and pass depth 0.0625. Ordinarily, I would be happy with that, but just this week I’ve been dealing with jitter that ruined an earlier project. I"ve tightened the belts and v-wheels and done a lot of general maintenance, but I’m still skittish, so I set the feed rate to 60. It’s just going to be doing laps around the edges of the top; shouldn’t take long.

An hour later I noticed that it had barely made a dent in the waste to be removed, so I watched for a minute and realized that it was using 3D raster strategy. It wasn’t cutting horizontally around all sides; it was cutting from one side to the other across the entire piece, meaning that it was doing two of the sides vertically rather than horizontally. It was cutting a Roman ogee pattern, and the farther toward the bottom of the pattern it got, the less actual cutting needed to be done; yet with every cut it went up to the top of the piece and the start of the ogee shape, floated down without touching, and made a short cut at the bottom, then went back up to the top for the next cut.

Right about then I started kicking myself for not looking closer at the start. I could have used an ogee bit on my router table and had the whole thing done in five minutes.

Well, at that point there was no help for it; I just had to wait it out.

Best laid plans… I had to laugh… not so much for the mistake but the many times I’ve made similar ones.

I once spent days writing up this brilliant bit of add-on code… only to discover at the end that the interface it was designed for had changed and no longer supported one of the key functions my code abused to work.

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Yep. Spent hours writing a VB macro - it was a brilliant piece of work I’m still proud of today. Unfortunately, it neatly duplicated an existing feature I wasn’t aware of.
If you ever need the wheel reinvented, give me a call…