Another week and I made.... a tap handle. Just the one.
Setting up for a production run of handles is a little bit more complicated than it was for the other wood parts that were made with good old-fashioned non-CNC machines. For starters, I had to add two new circuits to the electrical panel and run them to the control cabinet of the mill. One is for the high-speed spindle and the other is for the shop-vac that powers the dust extraction system. I want to be able to control them directly from the CAM code. What's a few wires more added to this collection?
The magnetic contacter and SSR in the bottom left corner do the switching - no particular reason for those selections, just what was big enough for the job and that happened to be on the parts shelf.
The other gizmo required, if gizmo is the right word for this assemblage of almost garbage, is the dust extractor itself. I made this a while ago, but I'm not sure if I put a photo up here. Probably not as it is pretty embarrassing: scraps of (cracked) acrylic tubing, ABS pipe and nitrile rubber held together with epoxy and (two different kinds of) tape. But, boy does it work
The offset of the extraction tube creates a vortex in the main tube and not ONE speck of dust escapes. I make more mess making toast.
The CAM programming is all about getting the cutter bit to engage the workpiece with the right load and so that the fibres of the wood grain are cut towards remaining material to avoid splintering.
Clean as a whistle.
That was a test piece of maple. Mahogany is the real deal.
Once both the front and back bores are finished, the part goes onto a fixture jig and into the lathe for the exterior contouring. Before:
... and about 30 seconds after. This operation would take 45 minutes to an hour on the mill and the surface finish wouldn't be anywhere close.
Then, still on the same fixture jig, the part goes back to the mill for the final profiling.
And yes, as you have probably already noticed, this is a new design! I had a think about the old design. I like the form; which is why I went to so much trouble to make it. But it really is problematic. Apart from the fact that it takes a long time to machine, has to be finished by hand and requires a modification to the valve stem, it is also hard to install. The tiny retaining ring requires special retaining ring pliers that I happen to own, but are pretty unlikely to be found in your average shop, let alone the toolbox in the cupboard under the stairs or in the garage. Note that the retaining ring rides on a washer that I lost down the back of the radiator in the kitchen while I was taking the photo; so washer not shown.
This one is designed specifically for the modern Pavoni valve. The larger opening in the face allows a split or hairpin cotter pin to be used instead of the retaining ring. This is a much more robust design which installs without any tools at all (shown here before the final sanding and finishing).
Here are the two designs, both oiled, side by side. I'm going to have another go this week at refining the new design a little.
Which one do you like best?