It is hard to believe that it was almost ten years ago I witnessed a CNC router in action for the very first time. I was fascinated and simply had to have one! Although I had been in the creative end of the three dimensional sign business for most of my life I didn't really know what I would do with one of these machines - but I just knew it could do fantastic stuff.

Along with the CNC router I discovered the wonderful material called Precision Board and the glues, primers and other companion products they offer. Since then we have gone through many tons of the material using it in most signs and projects we tackle. This journal will chronicle our many adventures both past, present and future. I'll talk from the perspective of someone who pushes these products to the creative limit on a daily basis. I'll be adding to the stories two or three times each week. -dan

Saturday, January 24, 2015

Lectern - Part two

The gears were next up. These were fairly straight forward and totally done in EnRoute. I first drew two circles for the big gear. I then drew a rectangle with slightly tapered ends. I reproduced and rotated this rectangle to form the gear teeth.  The smaller gear was created by using the point node tool to shorten the tapered rectangle. this was then rotated to form the gears. 

Then I added the middle circles to form the hubs. The gear teeth were combined with the outside circles.

For the spokes in the big gear I drew new rectangles and used the point edit tool to round the ends. This allowed the spokes to be perfectly round then I made then into reliefs.

The first step in making the gear reliefs was to create use the add to command to make flat reliefs that were an inch and a half high, the same thickness as our Precision Board.

I then used the dome tool to create the round spokes.  As I looked at the result I decided the gears would look better if I added an inner round piece to the gear body. This was as simple as creating two offsets (one inside and one outside) These new vectors were made into a separate relief using the dome tool.

The last step was to build the hubs. These were separate flat reliefs that were two inches thick. I then used a new circle vector (not shown) to create a new zero height relief  I merged (highest) all of the reliefs to this new relief. The center hole was created by merging (lowest) a zero height relief.

I created three copies of each  gear (for a total of four) and flipped two since they had to fit to the back when they were laminated together. As I set up the router I purposely left a thick onion skin (1/16") for a couple of reasons. First it helped the vacuum table hold the small pieces in place during the routing. Once the pieces were finished being cut from the Precision Board I left the skin in place between the spokes and in the center of the axle hole. We use Coastal Enterprises one part PB Bond240 guess which expands as it cures. This means it oozes out a little. The onion skin kept it from doing this in the center portions. Cleaning up the glue on the outside is easy with the die grinder.

Once the glue had cured the onion skin cleaned up easily with minimal work or rather should have.
But this time I out-smarted myself. Although I had carefully lined up the gear teeth I didn't hold the gear up to the light to sight the lining up of the spokes. This meant the first pair of big gears was sent to the dumpster. You can bet I took more care the second time around and got it right too.

Next post I'll be working on the tapered base which was a little more challenging. Stay tuned...