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View Full Version : First attempt at deep hollowing



Tangoman
3rd December 2014, 09:11 PM
G'Day Folks,

Having challenged myself with some hollow forms, i thought I'd have a try at deeper hollowing and share some of what I've learnt !

I went fishing at Fingal head and noticed a nice kind local had dumped some logs along the side of the track; what can a turner do but stop and pick some up ! The only piece I could safely lift was duly loaded and off home I went.
I trimmed the cracked ends and had a log 35cm long, totally out of balance due to a branch having grown off this bit and some rot. I turned the outside to nice profile deliberately keeping the entry large.
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Then I had to stop to make a Steady Rest out of Ply and kids roller-boot wheels.

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I then got the log gripped in the chuck, removed the tail-stock and installed the rest and set to with my old Exocet tool. I've had problems in the past using the Exocet but have learnt its all in the angle its presented to the wood, after quite a bit of mucking about adjusting the tool-rest height and angle I held the tool at I got it to cut very well, controllably and very cleanly - definitely worth persevering with !!! Its slow going but I got my walls down to about 10mm and quite even up to 5' deep, but then chatter and tool bounce started to set in, not unexpected really !!

At this point I stopped and made an extended tool rest that reached in to a depth of 5', this helped settle matters down really well and hollowing proceeded ! However after about another 4' inches tool bounce and chatter set in again !!!
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At this point I thought its time to trim the walls down before it gets too floppy !! So I stopped and made a laser hollowing guide - this is a wonderful idea and so simple. Just some 3/8th studding and scrap timber and a cheap laser pointer from Jaycar !
This makes judging wall thickness so easy and repeatable, I can see me using it on lots of projects !
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I carried on with a bit more hollowing but really had to stop as it was becoming unsafe and the constant leaning and controlling the cutting forces was having to be done by wrist and elbow which was getting to be painful !!!

So I stopped, rough sanded the exterior and there it will remain as it is beyond my current skills, equipment and, I believe, unsafe to carry on !

So what have I learnt ?

1. Deep hollowing is challenging, fun and rewarding.
2.Some specialist equipment is needed e.g steady rest, extended tool rest and Laser guide.These are easy to make and cheap too !!
3.The tools with guarded ring cutters are the go for working end-grain BUT you have to get the angles right and keep them razor sharp !
4. As always STOP if you are unsure and think through what your are doing, and STOP when its getting too far past your personal current skill level.

Next step - make my extended tool rest from steel and make some more vase/bottles but only go for about 25cm height; buy a cheap LED and tape it to my tool for some light inside !! -I'll keep you posted !!

Hope this has been of interest and some use to some of you.
May your tool always be sharp,
Regards,
Cam

dai sensei
3rd December 2014, 09:25 PM
You certainly jump right in :U.

It all looks good, except your rest extension, that just looks dangerous :o. I am amazed when you were getting chatter it didn't let go. The stresses on steel posts can break them, let alone timber.

hughie
3rd December 2014, 10:14 PM
Also the type of tip your using has a big effect on chatter, as much as possible you want a slicing action when going deep as it requires less force, oh and razor sharp wont hurt either. :D