I thought I'd revive this thread since I finally got around to completing a couple tops to the F-hole stage.
A couple things to remember:
- always make sure that the depth stop is set so it can't go lower than the pin. I was doing a test with scrap and the up-cut spiral milling bit pulled itself and the router rig downward and pushed and milled the pin right into the table. Of course this meant that the router bit was now following the pattern template with the obvious results. So why do we always test with scrap?
-- the fix is of course to set the stop. Further I made a piece of PVC pipe that I dropped down on the large shaft in the back so it can never go below that. 5-minute epoxy makes a nice repair to poly-carb template
- The screw to apply clamping pressure on the slider part only engaged about two threads. When I tried to tighten it it stripped out. I needed to purchase a longer M4 screw to get at more of the threads. Then it can be easily adjusted to snug the slider part.
- The clamp at the back that adjusts the overall height is fine for the intended drill press use, but almost inadequate for a pin router application. The issue is not vertical but rotational clamping. Since the lever arm from the shaft at the back to the mill at the front is rather long it was/is easy to bump it and make it lose it's position over the pin. For the time being I just really clamped it down.
-- the real fix would be to grind a flat on the rear shaft and then get a set screw into the slider clamp part. The set screw wouldn't have to be tight, just snug up to the flat, that would block rotation. There is no easy/obvious way to do this since it is pot metal and has little fins to make it strong rather than being solid. I may later do an metallic epoxy fill to make an area that can be drilled and tapped. A tight fitting keyway and key would be best but probably more work than the tool merits.
- The rig is designed to take a metric Proxxon tool. I made an adapter that is a piece of aluminum tubing and turned it to the right diameter. I then threaded one end to fit into a standard 3/4" threaded nut which also matches the Dremel or B&D RTX tools. I split the nut to reduce it's height and screwed it onto the tube and clamped that in the rig. The RTX just screws into that. The description is longer and more complex that the actual making of the adapter.
- I found that even with a brand new solid carbide 1/8" spiral cut mill bit and the B&D RTX cranked to high speed, the transitions between the sap bands seemed to be "jumpy". A non-climb cut has a tendency to want to rip out the wood along the grain when making the initial cuts down the center. If you are slow and don't push it it is fine, but you can't just go at it like you are killing snakes or you will pop a chunk off along the grain. Perhaps a downcut bit might make this a bit easier?? I ended up trying to make an initial cut down the center line, then come back with small climb cuts to just shave away the wood to the template. I followed that by going all the way around with a climb cut as a finish cut.
Overall it did a great job and is way more consistent and a better result that I was getting with my saw. Many thanks to Haans for starting this thread.
Alan D.
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