Lessons learned
With the first batch of the top drawers out of the way, it was now time to start on the rest of them. These are bigger, and I had learned a few lessons from the first set of top drawers:
Consistency and repeatability are paramount. This lead to fixture board end stop additions and minor redesign to remove most human error. I had some sides on the first batch which did not line up perfectly and I was lucky to be able to fix the fit by sanding the backs of the drawer fronts.
After the first roughing pass, the new stop fingers had been “modified” due to the low Z axis clearance between cuts.
Drawer and side thickness MUST be consistent. This time all of the boards were drum sanded to the same thickness. It is surprising how much variation even a large well tuned planer has (mine is a 20″ Jet). This made a big difference in the fit for the 18 drawers vs the earlier batch of 9. Planing single handedly does not help.
Scoring the faces of the sides to prevent tear-out is a must. The roughing cut sequencing of Joint Cam causes a lot of tear out. It would be better if the roughing cut was the same sequence as the finish / dovetail pass. However , scoring the face heavily with a marking gauge, largely mitigates the problem .
Fixture additions must account for bit profile differences between the roughing and finish passes. It would pay to run the finish pass air cutting to make sure the fixture fingers are not in the way or you could end up with a snapped bit or missed steps. I had to trim back the corners by hand to allow room for the dovetail shaft.
The new LED light ring around the front of the motor nicely illuminates the work .
This shows the touch plate I use for setting the Z axis zero. There is something funky with the Mach4 CNC controller touch functions. I now repeat each zero touch to verify the value does not change.
Now for cutting the dadoes and assembling the 18 drawers.