William's Workbench

What do you get when you mix a large clumsy geek, a dark house, and a poor defenseless baby safety gate? An excuse to make parts of course! While blundering around in the dark I managed to shear off the hinges on the baby gate that guards the top of our stairs. I have repaired them a time or two but they were never quite the same and finally there wasn’t enough material left to repair. With time off work and some shiny new 1″ thick HDPE for Christmas I decided to make some new brackets. The design was done in Google Sketchup and exported as DXF. Vectric Cut2D took in that geometry and I created the tool paths. After an air cut to see what kind of mood the CNC was in (it has been idle for months) I let the chips fly. The posts the gate attach to were fabricated from a couple of sacrificial 5/16″ nylon bolts. In hindsight I should have left some thread on and topped it off with a flange nut. Should the gate decide it likes to pop off enough I’ll upgrade the posts.

Sketchup model

Repaired gate

Bracket detail

Here are some rough, unedited videos. Note that the router is very loud so you will most likely need to crank down your audio.

The air cut, some closeups of the CNC machine

Cutting the first bracket.

The CNC itself was used to cut the groove for the T-track. I only did one track so far because my cheap 20K RPM router and cheap HSS bit were getting too hot. I also completed a probe setup for automatically determining workpiece height but failed to snap a picture.

I was playing with my CNC tonight and came up with this:

The text is the demo g-code that comes with EMC Axis and was engraved using a 0.5″ 90 degree v-bit. I hand calculated the offsets and wrote some simple g-code to cut out the text from a large scrap of MDF. The bottom edge looks pretty rough because I needed to fine tune the feed rate. Initially I had the feed set at 30 ipm (inches per minute) but this was too fast for my el-cheapo 2 flute up spiral bit. 10 ipm worked much better but still chattered a bit. Each pass was taking off 0.25″ and that might have been too aggressive.

These images show that the CNC is fairly accurate and precise, at least good enough to make nice 0.75″ text.

I still have no good CAD/CAM software stack but at least I am making chips.