CNC plugs are an expensive commitment for smaller boat builders so there was always a desire to “do it ourselves”. Not something I was remotely interested in but in August 2014 we drove to Florida and disassembled a 20x12x6’ PAR 5-axis gantry router. This thing was built in the early 90’s and had hadn’t run in a long time. Took 11 months to rebuild it back in Georgia with a new controller and servo motors. Some of the bearings were shot as well so new guide rails were installed on the gantry. I climbed this thing like a monkey for months rigging the new motors and it was second biggest challenge of my life just to get it to move. The performance was terrible, it had a single servo with a driveshaft inside the gantry that made the tool tip wobble about a 1/2 inch every time it did a 90 degree turn. Even after designing custom adapters and couplers for the gearboxes every one of them was completely done. The rotary axis’ on the head couldn’t be calibrated at all and the spindle could only take a 1/2 collet. We cut some EPS foam plugs with it like this; the 32 helm seat and windshield plugs, the 54 scale model and deck plug.
5-Axis cutting the ZRX windsheild trim lines (Above)
54 EPS deck plug, this was cut in four sections then assembled and finished out (Above)
Custom adjustable gearbox and servo mount, one on each side of the gantry (Above)
Foam plugs are not a good process and a disaster to finish out and it was never going to be able to cut anything remotely hard so the first upgrade was a slave servo and new gear boxes for the gantry, one on each end. I engineered an adjustable bracket for pinon engagement and an adapter for the planetary reduction box. All of the billet parts we machined in house on a HAAS VF4 vertical milling center. It worked really well the only issue being the non-hardened pinons from McMaster Carr wore out quickly and we had to install new ones every few months including broaching key-ways into them. I was also getting better at programming tool paths in Fusion 360 and found techniques to get better performance. After this we cut a full set of plugs and temp molds for a 24’ wake boat design (Never made it into production), 47 hatch plugs and the 47 deck temp mold with the later being done in under 4 weeks.
Helm seat outer shell plug (Above)
24’ Wake boat deck plug, the lower sections were machined separately and installed later (Above)
47 deck plug fresh off the mill and ready for sanding (Above)
The final upgrade was the biggest. The hull temp mold for the 47 and 54 was not going to be possible with the current Z-height and spindle. So a deal was had for a new spindle and rotary axis along with making a new mast which would add height to the Z and allow us to cut the keel. Thankfully most of the mast fabrication and machine work was outsourced and all I had to do was design another adaptor plate. We upgraded the 90 degree gearbox so at least the coupler wasn’t needed. The most time consuming part was installing and dialing in the guide rails. Performance was good and the new rotary axis were finally repeatable. Immediately started on the 47-54 hull temp mold. This mold was designed to produce both size boats with 2 different inserts. The 47 insert also had the transom and the 54 insert was just the bottom as the transom was part of the main tool. Hull machine work took about 6 weeks including the 47 insert. After that I completed the rest of the interior components (Dashes, coamings and rear seat/steps etc).
Fully upgraded mill with new mast, head and control system (Above)
New mast, head and gearbox adapter. (Above)
47 hull insert was machined in place inside the tool, removed here for final sanding (Above)
Finished hull tool ready for final detail (Above)
ZRX rear seat / step plug test fitting (Above)
Machine model was vital for 3+2 toolpaths (Above)