Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 19
Thread: hollow form blow out!
-
7th October 2014, 07:18 PM #1
hollow form blow out!
Hi all,
I had a nice myrtle burl blank which I had turned
a couple of weeks ago, so I put it back on to hollow out
on the weekend , all going well and then I noticed
shavings coming out the side ,,,,,,, oooooooppppppsssss!!!!!!!
This is the second time i have done this and was
wondering if anyone could tell me what i am doing
or not doing wrong?
Put up a couple of pics,,, any help would be appreciatedCheers smiife
-
7th October 2014 07:18 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Age
- 2010
- Posts
- Many
-
7th October 2014, 09:28 PM #2
it is one of the most common areas for going through,
It has the sound of beign thicker than it acually is.
It is the old saying measure twice cut once.Jim Carroll
One Good Turn Deserves Another. CWS, Vicmarc, Robert Sorby, Woodcut, Tormek, Woodfast
Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds!
-
7th October 2014, 09:54 PM #3Senior Member
- Join Date
- Jun 2012
- Location
- Mosgiel New Zealand
- Posts
- 221
Just looking at the photo it has only come out on one patch looks to me you may have a bit of run out ( wobble ) as well as what Jim just said take it slower stop and measure often
-
7th October 2014, 10:39 PM #4
-
8th October 2014, 02:40 AM #5GOLD MEMBER
- Join Date
- Sep 2008
- Location
- North Carolina, USA
- Posts
- 2,327
Bore a hole in this one, put a contrasting tapered plug in it, and carry on.
Nice piece, nice figure, don't give up on it.
You could make or buy a laser guide. In the US one can buy a laser pointer for $5 - $10. Make a bracket to point at the end of your hollowing tool.
Expensive laser guided hollowing tools:
http://www.onewayeuropa.com/hollowing/
https://www.google.com/search?q=lase...w&ved=0CDkQsAQSo much timber, so little time.
Paul
-
8th October 2014, 05:52 AM #6GOLD MEMBER
- Join Date
- Jun 2010
- Location
- shoalhaven n.s.w
- Posts
- 1,240
It does look like one partial cut of the tool with some run out, did you have a catch? How fast was the rpm?
-
8th October 2014, 06:51 AM #7Senior Member
- Join Date
- Aug 2012
- Location
- Banora point,NSW.
- Posts
- 172
Oops!
Smite,
really wish I hAdnt seen this post, I've got a very similar one on my lathe which pushing my skills a bit too far ! Am terrified of blowing it up !! LOL.
i will be making a laser guide fitting soon for my tools, you can get a cheap laser pointer from Jaycar and Officeworks - fwiw.
Regards,
Cam
-
8th October 2014, 07:08 AM #8GOLD MEMBER
- Join Date
- Sep 2008
- Location
- North Carolina, USA
- Posts
- 2,327
Smiife,
The blank may have shrunk a bit in that area in the week it was off the lathe, or it may have shrunk more on one side and bent the piece over,making the opposite side thinner when you hollowed. The spigot may have shrunk more on one side making the piece go off center.
Or any or all of the above.
I have had "dry" partially finished pieces move all over the place when left in the lathe overnight. The more interesting the figure, the more they tend to move.So much timber, so little time.
Paul
-
8th October 2014, 08:12 AM #9
-
8th October 2014, 09:22 AM #10GOLD MEMBER
- Join Date
- Aug 2012
- Location
- Imbil
- Posts
- 1,167
I totally agree with Paul39 timber movement most likely way this happened with the time delay from start to finish. If you need to do in stages only rough out and leave plenty of meat to then finish the remaining cuts all at the one time.
Regards Rod.
-
8th October 2014, 08:46 PM #11
Hi guys,
In a general reply to everyone,
as to movement i bought this blank quite a long time ago
as you can see it was waxed on all sides, and i thought it
was dry.
time is always a problem for me and i don, t always get
to finish a project in one session, so is it best to leave a project
on the lathe or take off and try get it centred again?
Laser pointer ! might have to look into that one!
Speed and measuring?? Not too sure on either
maybe 1200 /1500 rpm,,, and no I did not measure
with anything..but i will be next time............
No catch...i used my hollower
Thanks again for your comments and advice
much appreciatedCheers smiife
-
9th October 2014, 03:23 AM #12GOLD MEMBER
- Join Date
- Sep 2008
- Location
- North Carolina, USA
- Posts
- 2,327
Smiife,
My jaundiced opinion of waxed blanks is the seller hopes they won't split until they are sold.
I assume that anything I turn, mostly bowls, is going to move if left overnight, a week, or a month. If I'm going to be back to a bowl within a week, I leave it on the lathe. If the timber is fresh cut, it may rust the chuck, so I take those off.
I got busy with my smaller lathe and left a roughed out bowl of semi dry palm trunk on the big lathe for over 6 months. It twisted all over the place. I had left plenty of thickness so it will be OK.
The "dry" blanks I rough turn leaving the thickness about 5 to 10 % of the diameter, leave it over night and if not too warped take some more off and set it aside for a week or more, then finish.
The found-on-ground or fresh cut pieces I rough out with a thickness of 10 to 20% of the diameter and boil, or soak in dish washing liquid and water for two weeks, or not treat. Then I wrap in several layers of newspaper and let dry for 6 months or longer. They move all over the place and become oval shaped. Then I treat as above for "dry" blanks.
I assume that all timber moves when roughed out, some more than others.
Straight grained kiln dried cherry, maple, or walnut moves the least. Straight grained timber is the least interesting to me. Crotches, stumps, and burls are the most interesting to me and the least stable.So much timber, so little time.
Paul
-
9th October 2014, 03:18 PM #13
A steady rest could cure a lot of those ills.
Cheers,
JoeOf course truth is stranger than fiction.
Fiction has to make sense. - Mark Twain
-
9th October 2014, 07:55 PM #14GOLD MEMBER
- Join Date
- Aug 2012
- Location
- Imbil
- Posts
- 1,167
Hi Smiife and all,
Movement is not only from moisture content perfectly dry timber can move considerably simply by the process of removing material from the piece and the resulting release of stresses in the timber can cause serious deflection in the circumference and vertical plane. (as for speed $13.00 digital taco is pretty simple)
Regards Rod.
-
9th October 2014, 08:38 PM #15
Hi paul
Thanks for your thoughts, very much appreciated
Hi joe,
Not too sure where you are going with that ?
Hi rod,
I think that is what has happened,
as for the speed I just turn It up to what i think is safe!Cheers smiife
Similar Threads
-
Hollow Form
By Tangoman in forum WOODTURNING - GENERALReplies: 7Last Post: 18th September 2014, 11:08 AM -
Yew hollow form
By Dalboy in forum WOODTURNING - GENERALReplies: 8Last Post: 5th November 2013, 04:00 PM -
First hollow form
By Chrome in forum WOODTURNING - GENERALReplies: 4Last Post: 25th July 2012, 07:53 PM -
yew hollow form
By cornucopia in forum WOODTURNING - GENERALReplies: 10Last Post: 3rd March 2011, 08:16 AM -
Another Hollow Form
By Gil Jones in forum WOODTURNING - GENERALReplies: 8Last Post: 21st September 2006, 07:00 AM