Probably a stupid question....

As a total newcomer to pen turning, I wanted to pick the collective brain of the board.

From my research it seems it's sensible to stop turning down before you reach the level of the bushings.
This makes total sense, as with sanding you'd be below the bushing level after final finishing.

My question is, how much material should I leave over the bushing diameter when turning, A: Wood blanks and B: Acrylic/plastic blanks?

Many thanks,
Karl

You are right... in a way it does make sense. BUT the amount of material removed by sanding depends on the sharpness of your tools and your competence in using them. So when I started I used to turn down until I could use 80 grit and then the rest to get there. Now I turn down to the bushings and use 400 grit to 12000 grit to finish. (and they don't remove much material)

So if you have to use the 80 edge skew to finish then perhaps your technique isn't right and if by the time you get to the bushing level your wood is shining and glowing then you may only need a sealer and a couple of passes of micromesh, followed by a buffing wheel.

So in general answer to your question .25mm coarse finish and zeromm fine finish off the tool how does that sound?

PS after edit it also depends on the quality and density of the wood ie some woods are open and dry others closed and oily so much then depends on your qualities as a discerning turner as to how you treat them.

Certainly by now you have measured with a caliper as well as relying on the bushings (notorious for small variations). One caliper is cheaper than a host of bushes, my habit is to use two calipers set for both ends every time. I hate surprises. Better to err on the slight oversize and small champher to the kit.

Peter.

It’s not a stupid question at all Karl. Peter is right though, best check with calipers as some bushings are more accurate than others and best used as only a rough guide in some cases.

All good advice and information.
Thank you.

I gave up on using bushes ages ago and now rely on using callipers to measure the components and transfer to the blank and even then stop using the tools with the smallest of material to be removed and normally start sanding at 240grit down to 600grit on wood and even finer for acrylics.
By starting to sand at 240grit allows for material removal to the final size without leaving deep scratches all other grits are then really used to get the finish that I require before applying finish. Remember that even a few coats of finish will very slightly build up the size a fraction

Thanks very much, I appreciate the advice.