Bowl coring question

[ticklingmedusa]

I don't use one of these systems ...
someone asked me "Why a live centre is not brought up to the piece when coring?"
I thought about it & decided I needed some time to follow up with a response to the question. Even if a cup or cone was close it seems like it would keep the cores from falling or flying when they come free as shown in the video.
There may be a good reason or reasons but I'm flatlining at the moment
and at a loss.
I've seen more experienced users check frequently and when just a whisker thin
interior tenon remains they simply break it off by hand when the machine is off.
The video below is what prompted the question.
Thanks in advance for all responses.
tm

link to a short video
Woodturning Bowl Coring Blooper - Kel McNaughton System - YouTube

[hughie]

Hmm, dunno I would have thought to the discerning there would a change in the tone as the cut got nearer to the centre.

But with a live centre there would be a danger of as the cut frees the centre from the bowl it would jam between the bowl and the live centre, causing all manner of conditions for an under garment change.

[ticklingmedusa]

Hmm, dunno I would have thought to the discerning there would a change in the tone as the cut got nearer to the centre.

But with a live centre there would be a danger of as the cut frees the centre from the bowl it would jam between the bowl and the live centre, causing all manner of conditions for an under garment change.

I had a feeling it would be obvious once the answer was given.
My guess is the user in the video had some laundry to deal with.
She was pushing hard and did not seem to know how deep she was.
Thanks Hughie.
tm

[wheelinround]

How would you fit a live or dead centre and bring the tailstock up knowing the bowl corer swings where the tailstock would be in the way :?

You could I suppose fit one between the tool post mounting a support.

[wheelinround]

How would you fit a live or dead centre and bring the tailstock knowing the bowl corer swings where the tailstock would be in the way :? Sorry thinking, this Woodcuts system

Woodturning with the Woodcut Bowl Saver - YouTube



Must be that system

Coring a bowl with the Kel McNaughton coring tool - YouTube

You could I suppose fit one between the tool post mounting a support.

[robo hippy]

You can move the tailstock into place with the McNaughton if you are using the flatter blades. With the 2 smaller curved blades, the tool rest and handle are in the way. With the Oneway and the Woodcut, it is impossible. Main thing is to stop before it breaks out by itself. Main thing this does is it keeps you from having to bend over to pick it up off the floor. Generally you are coring at slower speeds, and I do stand out of the line of fire.

robo hippy

[corbs]

Wouldn't having the tail stock up against the blank put pressure through the blank increasing the risk of jamming or binding on the cutting edge?

[tea lady]

No one was hurt or wood harmed in that video! :shrug: What's the problem? :hmm:

[hughie]

[No one was hurt or wood harmed in that video! :shrug: What's the problem? :hmm:[/


Not for the want of trying.... :U

Its like you have to pay attention to what your doing, so you avoid these sort of incidents.

A turner recently in the USA had the bowl she was turning fly out of the chuck, hitting her in the head, she never regained conscious.An unusal accident and she was wearing a face sheild at the time as I understand. But it does high light what can go wrong in what appears a simple regular operational occurance.

[dr4g0nfly]

Whenever I've seen these used, they normally cut to almost the whole way around and then knock the inner blank to break it away from the outer. The lady cutting the inner all the way shows why you shouldent do that!

The one thing I've not understood is why they show cutting out the biggest blank, reversing the removed blank and cutting another tenon, chucking it and cutting the next smaller blank etc.

Why not cut the smallest first and work outward?

[APD]

Hi Dragonfly,

Working from the outside to the center gives you a spigot to mount the blank in the scroll chuck for every blank. Working from the center out leaves you without a spigot on the base.

Cheers

[WOODbTURNER]

Hi Dragonfly,

Working from the outside to the center gives you a spigot to mount the blank in the scroll chuck for every blank. Working from the center out leaves you without a spigot on the base.

Cheers

Dragonfly is on the right track imho.
If you cut from the outside-in, you have to cut another spigot on the new blank for cutting the next. I cut from the centre first and you always have a secure? spigot from the start and don't have to remount every time. I know you won't have a spigot on the inside blanks when you cut from the centre-out, but I use my vacuum chuck or bowl jaws.
APD's suggestion means that when you cut from outside-in, you will have to cut a new spigot to hold the next. His way means the original spigot will only be on the outside bowl.
Mike Mahoney has a good DVD on this and he also has a basic one on youtube.
Geez, a bit long winded and I stand to be corrected

[jefferson]

Ken Wraight was demonstrating the Bowl Saver system at the WWW show on the last weekend.

He cored from outside to in - for exactly the reasons noted above. That is, you have a fixing point each time you start a fresh bowl. His reasoning was that cole jaws or jam chucks were just too slow.

Seemed to make sense to me.

[ticklingmedusa]

Interesting discussion thanks for all comments.:2tsup:

[robo hippy]

Mike Mahoney some times does it both ways. If you rough turn, dry and then return, since you have to remount them anyway, you do not need a recess or tenon, and he starts with the smaller one, cores out all he wants, seals them, and then sets them off in the basement to dry. On his 10 piece burl sets, he will remove a few small ones off the top, and some times continue all the way down to the final one.

For me, I turn green to final thickness, let them dry and warp, then sand and finish. For initial mounting, I drill a recess, turn the outside, turn a recess, reverse and core the biggest one first. Once the core is removed, finish turn the one on the lathe. Then remount the core in the drilled out recess. Continue till done. No face plate, no removing the chuck.

The tailstock wouldn't put any lateral pressure on the bowl coring since it center mounts.

robo hippy