I had a stock4th axis (2’nd z axis) on the machine I purchased from CNC router parts back at the end of 2018. After their transition to AVIDcnc I purchased the recessed 4’th axis option and it plugged right in and just worked. I don’t do a huge amount of work with it, but when I do it makes a huge mess because I never spent any time to consider swarf containment.
A couple months back, I had finally had enough and decided to do a few minimal pickups. I’ll add some thin UHMWPE fences around the recessed rotary axis and a decent high volume chip tray in underneath.
This project started with a couple hand sketches on graph-paper where I walked around the machine with a decimal inch tape measure and grabbed some low detail measurements. From there it was off to drive CAD for an hour or so.
With CAD in hand it is incredibly fast to head to the garage, fire up the air compressor, air chiller/separator, plasma cutter and AVIDcnc.
These parts were cut from 16Ga mild steel which is always fun just because of how fast and how clean the cuts come out.
Still wet, sitting on the machine, no clean-up and one can appreciate the level of detail.
I never ended up cleaning up these parts. The construction methods applied just didn’t call for it, so after a quick wipe down to dry them off a bit it was straight into bending. The design lent itself to a nice tight fit-up.
I did not capture an image of it but once I had the two halves cut I did perform a good bit of fit/interference checking on the machine itself.
After this a good bit of aluminum trim, both flat and angle was cut. Note if one uses what is considered architectural angle extrusion instead of structural angle extrusion, you’ll find that 5053 grades are delivered without an inside fillet that are excellent for this kind of work.
With the long bends completed, only the very top bends needed to be welded up. Rather than trying to dial in the perfect weld for ~8ft of weld length on thinner material with the gap larger than the thickness of the material, it was easier to lay this in as a series of chain welds.
And then some powder coating… At every step I had to remind myself this is for swarf containment, this is not a car part that needs to look perfect and gleam, perfectly in the sunshine at a car show. I did some minor cleaning but not up to the typical level of rigor.
With that completed, it was on to getting all those holes match drilled and lined up. Clecos are definitely the right tool for this job.
I’m using rivet washers with aluminum rivets on this project. (visible in the photo below) The rivet washers allow me to use the plasma cut holes and to oversize them just a little bit, to help with the alignment of such a large number of cross drilled holes, while still ending up with a tight enough diametral tolerance to snug the rivets down tight.
Here is a quick look from the inside. Once can see with all this angle extrusion riveted down the sides and bottom all the way along, why I didn’t bother to weld up the slots used to aid in bending along the bottom of the part, and only welded up the top.
Those rivet washers are plainly visible in this image.
Getting ready for installation… It isn’t a perfect fit up on the trim work but all the joints are fully sealed and that’s what I’m after.
It fits in there perfectly and all gaps between the swarf tray and the various parts sticking down from the bottom of the machine (5 surfaces) are fully sealed.
Mentioned at the top, I’ll go back and add a UHMWPE swarf containment fence like the one in the background of this image, to the front edge of the machine in an upcoming weekend. I just need to make the mounting brackets and cut the material down to size.
This was a pretty fun project. It took longer than expected as it was interrupted by several other projects along the way. Having it completed will make this part of the machine much more useable.
Hope someone else sees this and thinks, Hey I could make that, or, … I could make that better and finds a bit of inspiration.
-Kenneth