Best dremel attachment for sanding and polishing the inside of a coconut shell?

What do the lathe-owning, bowl-turners use?

I was going to say you might have to make your own, but Andy's answer is

A die grinder might be another option for holding those "bits". They come in straight and 90 degree variants too.

That's a great list of possibilities, thanks. Some of them even provide their own rotation, which is more like what I need.

I'll look into those options too. Thank you.

dremels are small toys compressed air die grinders are the ants pants.

A lathe is the "best" answer but if you don't have access to one you could mount a drill securely and use that to spin the shell (presumably it's actually half a shell?) while holding a suitable scraper against the inside. An improvised tool rest and "scraper on a stick" would be better but needs to be secure. Obviously there are safety issues so: ensure everything is secure and that the shell is adequately attached to whatever arbour you use (a bolt?), that the scraper is sharp, that you can't get yourself tangled in anything, and that you wear safety specs. As a bonus, this would allow you to finish the outside to a much higher standard than you could achieve with an orbital sander. It would be a good idea to look at some bowl-turning examples on YouTube.

You are getting answers from people who obviously have never attempted this (neither have I). Best of luck with mounting the shell concentrically on the lathe. Even if it's perfectly round it will be a challenge. Bowl sanders are tools that are pressed against the (ideally concentric) work to make them rotate. If they don't rotate they are no more effective than holding abrasive against the work. Probably best to nest the shell on a cushion & use a right angled rotary tool of some description .... so you are back to your original qhestion. The only other help I can offer is that the smaller the sanding disc, the tighter the curve it can manage but the harder it is to keep from digging in. HTH

Horses for courses, they all have their uses. An "industrial" mains Dremel with a right angle head, as used by site metallurgists and NDT guys for inspecting welds etc. has all the oomph needed for coconut shells.

I have a USB rechargable tool the size of a highlighter pen that takes Dremel accessories, this has its place for small delicate stuff.

Main point, as just made by wasbit, is that a 90 degree head (like an angle grinder) is usually best if you are working on a surface because you have better grip and control.

Is it? Has nature created the perfect concentric coconut shell that will not wobbly like mad when attached to a lathe or drill.

Obvs it needs mounting carefully, and the speed needs to be kept quite low. I haven't turned coconut but I've turned nuts (eg Banksia) and lumps of wet wood this way and it allows good control and finish.

Following some of the suggestions here I've seen some interesting possibilities both commercial and diy. For a start I've ordered an abrasive mop which can be used with a Dremel or drill. I was definitely avoiding the option of buying a lathe and as you point out, mounting the shell effectively would be tricky.

Wouldn't I just love one of those to complement my wee flat.

I only recently managed to justify the purchase of a basic cordless dremel, which may help quite a bit. Still, with any luck there will be more birthdays and Christmases to come.

Some encouraging food for thought there. I'm working on more than half a coconut right now, with the remaining part planned as a base. This makes the entry narrower than the rest of the inside. As mentioned earlier coconuts are rarely symmetrical, so getting it spinning suitably on the end of a drill will be a feat worth attempting.

I wasn't suggesting use of a lathe, just similar tools that lathe-owners do ...

I can't see a lathe working well on a coconut shell either. The wall thickness is so small that you would need a very symmetric shell, let alone the difficulty of mounting. Also, I (sort of) assume you were after a "natural" shape rather than the perfect geometry you might want for a turned wooden bowl.

Due to a recent dietary change I've got quite a lot of coconut shells and not a one so far is near symmetrical in shape. They are really good looking when polished up though. And I do like the idea of utilizing the whole nut: milk, desiccated coconut and shell. The only thing I'm binning is the fibrous dust produced by the sanding. Looking for more storage space for the boxes of desiccated coconut though. After all I can only consume so many diy bounty bars.