Hi Vic, last year we had a demo by an Irish turner called Joe Laird. He told us he had a contract to make 600 whiskey tumblers for a special whiskey made by Jamesons the Irish Distiller. I asked Joe how he made them & his method is below.
Finished size, 80mm highx75mm diameter. The oak has to have No flaws in it at all.
Turn your outside shape, sand & burnish with oak shavings to achieve a gloss. This is all the finish you need.
Turn the inside but leave a Good 12mm thickness in the bottom, sand to required finish. Dampen the inside with a damp paper towel to lift the grain. Now scorch the inside with a blowtorch until black inside. Be cautious when doing this, wipe again inside with a damp paper towel to cool it down, when cool very lightly denib. NO more finish is required. Now wipe out the inside with a clean dry paper towel to get rid of any soot. Check for any faults in the timber.
The scorching process makes it like the sherry casks the whiskey is stored in as the fire the inside before the whiskey is poured in.
The flavour this produces in your tumbler is brilliant. Make it, pour your whiskey in it & enjoy.
I'll add a photo of my tumbler to this thread when I've photographed it.