Binding in a closed CNC channel

[verhoevenc]

Hey guys. I've been doing some more tests with my CNC and wanted to share my latest fun. I had thought about doing this for awhile, but when I saw the folks at Kauer doing it I was emboldened to do my own tests. The basic principal is to mill out a channel for the binding as the very first step in the build. That way you just hammer the binding into a slot and CA it. No strapping tape; just easy.

The Kauer guys gave me some great advice and said to put holes every few inches along the channel to account for glue overflow. They also mentioned they've had better luck with a bead of medium CA in the bottom followed by a thin CA flood. However, since everyone's milage varies I wanted to see how this played out on my machine.

Step one was to mill the channel and the glue reservoirs. I purposefully did sections of both straights and curves. Once cut I did half with a bead of medium CA in the bottom and then hammered the binding in with a rubber hammer and flooded with CA:

I then waited for everything to dry and went and cut what would have been the "body" outline with a 1/4" end mill like I would in real life:

Once that was done I could bandsaw it out close to the line and do some sanding to see how everything worked out. Here's the top. As you can see both side were equally as good and easily pass quality control:

Next lets look at the sanded side where I did a medium CA bead at the bottom of the channel. I feel that there is too much gap here... it's visible. This does not pass my quality control:

Here is the, in my opinion perfect, thin-CA-only side:

Lastly, here's where they meet in the curved section. As I expected the thin CA side is great, the medium CA side left some gaps on the bottom edge:

It appears for my setup and processes that I prefer the following steps:

1- Mill channel to only .001 over the binding thickness (that plus the few thou in runout any machine has will be plenty to allow for thin CA.

2- Hammer in binding with rubber hammer and flood with thin CA.

3- After dry run your profile cuts.

4- Sand edges smooth like any binding application.

Hope this helps folks,

Chris

[ScottR]

Cool.

SR

[verhoevenc]

I can also now verify that the quality works just fine with a .063" channel and .060 binding. So the width of the channel can accommodate a little play without detriment to the quality.

Chris

[demonx]

 

I was messing around with something like that last year, didn't use holes for the glue though. It's a bit tricky, but if I can do it anyone can.