I finally finished the pen that had me threatening to throw my lathe in the river. The idea was (I think) a good one - a pen with a chess piece on the cap, and a chessboard on the barrel. I had a vision of the inlays being shiny chrome/silver to match the findings on the kit. So ...
First, turn a blank (I started with a stunning camatillo RW, but %$£@ed it up so ended with a bubinga) down to 16.5mm diameter. Tolerance is wide, around 1/4mm either way. Chuck it in the fourth axis of the CNC mill and take the pattern down about 2mm. (Which turned out to be spot on for the chess piece on the cap, but should have been around 3.5mm depth for the chequerboard on the barrel.):
Fill the voids with the inlay material. (As an aside this is no mean feat as we are dealing with the outer surface of a cylinder.) This is where things went wrong - I used atomised aluminium powder mixed into epoxy resin, but as you will see it didn't colour right and had other problems! :
Re-mount the blank on the lathe and turn down the excess inlay material, trying to maintain around 16.5mm diameter:
Fix any major voids now, pinholes may turn away and new ones appear at lower levels. Turn away excess inlay material again, then cut the cap and barrel blanks apart, drill, insert tubes and turn as normal from there.
This is the result:
Lessons learned:
1. Ally powder and epoxy doth not a silver-chrome inlay make. Any ideas what might? I thought of melting pewter and pouring into the inlay cavities next time?
2. Open-grained woods like Bubinga are not ideal when you are re-filling pinholes and voids, as the inlay material strays into the grain and looks poo ...
3. Just because you have a great idea, don't expect to nail it on the first attempt!
First, turn a blank (I started with a stunning camatillo RW, but %$£@ed it up so ended with a bubinga) down to 16.5mm diameter. Tolerance is wide, around 1/4mm either way. Chuck it in the fourth axis of the CNC mill and take the pattern down about 2mm. (Which turned out to be spot on for the chess piece on the cap, but should have been around 3.5mm depth for the chequerboard on the barrel.):
Fill the voids with the inlay material. (As an aside this is no mean feat as we are dealing with the outer surface of a cylinder.) This is where things went wrong - I used atomised aluminium powder mixed into epoxy resin, but as you will see it didn't colour right and had other problems! :
Re-mount the blank on the lathe and turn down the excess inlay material, trying to maintain around 16.5mm diameter:
Fix any major voids now, pinholes may turn away and new ones appear at lower levels. Turn away excess inlay material again, then cut the cap and barrel blanks apart, drill, insert tubes and turn as normal from there.
This is the result:
Lessons learned:
1. Ally powder and epoxy doth not a silver-chrome inlay make. Any ideas what might? I thought of melting pewter and pouring into the inlay cavities next time?
2. Open-grained woods like Bubinga are not ideal when you are re-filling pinholes and voids, as the inlay material strays into the grain and looks poo ...
3. Just because you have a great idea, don't expect to nail it on the first attempt!
Bl**dy 'ell, if I had a meltdown trying this, imagine the strop I'd end up throwing if I tried that!
