Bringing a roughed bowl to round, and knowing when to stop.....photos

[odie]

Using a Prismacolor Ebony soft black pencil:

To bring a roughed bowl to round after seasoning, start by
covering the entire surface at a slow rpm like so:

This photo shows the last bit of pencil marks on the rim, when
the surface has almost been completely brought back to round.
You can feel it with your tool. Stop the lathe, and verify your
progress visually like this:


-o-

 

[Michael Anderson]

I like that idea of marking the entire surface, especially if removing the absolute minimal amount of material. Similar to pencil marks prior to sanding. I’m not sure what you’re trying to show with the last photo though. I just started drinking my coffee, so I might be a bit slow

 

[odie]

I’m not sure what you’re trying to show with the last photo though.

Hi Michael......it's just to show the last bit of pencil marks on this surface prior to bringing it to round. The photo is just to show that you're "almost" there, and can stop removing material. Yes, you are correct in that this is a method to bring a roughed bowl to round, while removing as little material as possible.

-o-

 

[Michael Anderson]

Oohhh okay, I see the faint marks on the rim. I was still looking at the interior. See, told you I was running a bit slow still haha.

 

[Larry Mercier]

Hi Odie, again you share a great tip.

-o-

 

[Alan Weinberg]

I’ve read and been told to leave a rough bowl about 10% of the diameter—1 inch for a 10 inch bowl. When I remount to finish the bowl, I then need to take a fair amount of material off—so the pencil won’t help, right? That’s only when you are down to needing just a bit more removed or am I misreading the advice?

 

[Brian Gustin]

I’ve read and been told to leave a rough bowl about 10% of the diameter—1 inch for a 10 inch bowl. When I remount to finish the bowl, I then need to take a fair amount of material off—so the pencil won’t help, right? That’s only when you are down to needing just a bit more removed or am I misreading the advice?

Oh No, you're misreading... I use the pencil first as soon as I have the tenon trued up and mounted in chuck - Some woods, it is really easy to not see where you're still out of round - even by feel or the gouge cuts , you can still have some spots where the cutting edge may be just barely kissing the surface and not cutting, but then you go to sand the bowl and you find you can't get some spots sanded down because they're low spots, so you need to do another cut or two (or three) and if you assumed your bowl was true round and went to finish the inside, it may then be so thin that making a good outside cut is gonna be extra difficult due to the wood flexing - So I'll do as Odie describes and roll bowl by hand and make sure I have pencil ALL the way around every surface on the outside, then I'll true it up and it's quick to see right away whether or not you got the bowl true round on the outside. - The parts where it is still out of round are gonna have pencil marks still, (and on dark woods, use a contrasting color pencil) so you'll be able to see right away and no guessing - once you have all the pencil/color turned away you know your outside is as true round as you're gonna get.