Tuesday, July 25, 2017

Beyond Plywood 2

9:39 AM Comments 0

Mirrored Bench

pichichero-rendering

We had a client on Long Island that commissioned us to build a small bench out of white oak, with metal bars joining the legs, and recessed pockets on the faces of the legs and top to accept 1/4″ thick antique mirrors.

Problem: Trying to manually route out a 1/4″ deep recess from the face of the legs and top would be incredibly difficult. You could easily build a template and use a flush trim bit to cut the outside of the recess, and then use a straight cutting bit to hog away the interior, but the closer you come to the middle, the more unstable the router would become, since it would be slowly cannibalizing its reference surface.

This is another perfect application for the CNC machine.

Pichichero CNc 1

We first milled, glued, and wide belted the top and two legs. The parts were flat enough that the suction of the spoilboard was able to hold them down. We programmed the machine to not only cut out the 1/4″ recess for the mirrors, but to also cut each piece to its final size, which would ensure the pocket was perfectly parallel to the perimeter.

Pichichero CNc 3

The white oak was 1.25″ thick, so the perimeter cut was machined in 5 separate passes, with the bit dropping down an additional 1/4″ each pass.

Flattening Slabs

Over the past year and a half, we have been using live edge slabs in commission work and in spec pieces. Very rarely do we purchase a slab that is free from any sort of cupping or warping, and one of the most time consuming aspects of using live edge slabs is the leveling and flattening process.

Early on, we would place the slab on a flat table and hot glue on shims to keep the slab from rocking and to build up any high spots. We would then begin the long and repetitive process of flattening the slab using our single-head widebelt sander and a 36 grit belt. The process worked just fine, but, as I am sure you could tell from my description, was not a fast process.

Even after having the CNC machine up and running, we continued to use this method for far longer than any of us would like to admit.

slab-flattening-1

We now flatten all of our slabs using the spoilboard cutterhead, which is a 4″ flycutter with carbide inserts. We wrote a basic program that is easily customized for the current slab dimensions. We prevent the slabs from shifting during the machining process by tacking down corner blocks to the spoilboard. Once one side is flat, we simply flip the slab over, modify the program for the slabs new thickness, and repeat the process.

Even though the set-up time takes longer, overall this process is quicker, and far more accurate, than the 100% widebelt method!

Greater 5K Race medals

Last Thanksgiving, my wife and some fellow teachers at her school, hosted a charity fun run to raise support for an 8th grader who is battling cancer. My role in this endeavour was to make all 300 of the participant medals.

The name of the run was “The Greater 5K”, a reminder to us that “He who is in us, is greater than he who is in the world”.

My challenge was to figure out how to design a medal that was pretty, could be machined en mass, and included the name in an easy to recognize layout.

g5k1

Pretty – Walnut never fails to impress and audience

Simple – Keep it simple with symbols and a “less is more” approach

En Mass – CNC and plywood is the only way to go

We designed and layed out a 4’x8′ sheet of plywood and were able to nest 200 medals per sheet! I chose to use an MDF core 1/4″ Walnut plywood, since the core of the plywood has a nice consistent look, and complements the color of the Walnut veneer nicely.

We first sprayed on a top coat of lacquer to the entire sheet, since that was much faster and easier than trying to finish the medals individually. The first machining step was to drill the 5mm hole that would accept the ribbon, then, using a V-bit, we machined in the >5K and the ring around the outside. Finally, we cut the perimeter of each medal using a 3/8″ downcutting bit, leaving just a small amount of onion skin, to prevent the medals from moving around.

greater-5k-5-2

After 2 sheets of plywood, we had 400 wooden medals! We lightly sanded the perimeter of each piece to remove the bit of onion skin that was left, and my wife cut and hand sewed on each and every ribbon!

In the end, the medals were a huge hit with the participants, and something that was only possible with our CNC machine.