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Grumpy John
14th October 2007, 05:40 PM
Finally started on the burl I took to Ern's last turn-fest (trying to find out what timber it is). Finished the top no worries, made up a jam chuck to suit inside of bowl , tapped bowl onto chuck and proceeded to start cutting. Maybe this would be a good time to mention that I had oiled the top with a 50-50 mix of boiled linseed oil and turps, this obviously had a detrimental effect on the gripping power of the jam chuck. Upon commencing the second cut the bowl parted company with the jam chuck, don't worry my face stopped the bowl hitting the floor :doh:, I now have a very fat lower lip. As far as I can see I have two alternatives, 1/ continue using the jam chuck chuck but put a live centre in the tail stock and use that to support the bowl, or 2/ mount some scrap soft timber onto my cole jaws and turn them to the inside diameter of the bowl so as not to mark the finished surface. Any other ideas from forum members would be greatly appreciated.

Cheers
GJ

TePe
14th October 2007, 06:45 PM
Hi GJ, I would use your first option. I always use the tail stock when reverse turning, then remove for the last little nub that's left.

Also if I'm going to use a oil finish I either leave the oil to dry, or if you want to continue leave the oiling to last once the piece is off the lathe. In my experience Linseed oil takes too long to dry for me, so I use Danish or Finishing oil they have driers in them so will dry hard overnight.


Beautiful piece of burr, I'm very envious of you guys over there with some of the timbers you can get.

Sorry about the lip, but at least the platter is safe :wink:

Grumpy John
14th October 2007, 07:59 PM
Also if I'm going to use a oil finish I either leave the oil to dry, or if you want to continue leave the oiling to last once the piece is off the lathe.


Hi Tam,
I don't usually oil 'till the job is finished, however I was too impatient this time and I paid the price.

Cheers
GJ

Skew ChiDAMN!!
14th October 2007, 09:50 PM
'Tis looking better now than I remember it at the Ernfest. Could be just the finish and my bad memory, but still... :2tsup:

Another option for a bit of tailstock pressure is to mount a bit of dowel in a jacob's chuck. This'll avoid the "ding" from the tailspur and gives you a bit more elbow room between the tailstock and bottom of the piece, but does still leave a small mark. 'Tis usually nothing that can't be sanded out though.

scooter
14th October 2007, 10:34 PM
Looking good, John :2tsup:

Where's the pic of the fat lip? ;) :D

TTIT
14th October 2007, 11:47 PM
Thats one very nice looking bit of wood John - and a nice looking shape you've given it :2tsup: Go with the tailstock option - always the surest method to finish off with.

GC
15th October 2007, 12:05 AM
Hi Grumpy,

I usually use the wall of the garage to stop things that leave the lathe, once I used the roof even. I'll have to think about the face method.

I would use the tail stock method, it seems to work for me.

GC

mick61
15th October 2007, 12:16 AM
G`day the best way is to turn a cone out of pine about 50mm long or longer if you like. The cone needs a recess that fits the revolveing part of your live centre.
Mick:D

Little Festo
15th October 2007, 09:17 AM
Hello John,

Have you thought of using some hot melt glue?? If you can get some "industrial" hot melt not the cheap clear plastic stuff from Bunnings. The Bostic yellowish stuff is much better. You might need to rub the linseed back a bit or try sealing it off with a couple of coats of clear shellac - I use ubeauts (de-waxed white) shellac sanding sealer quite a lot, that would be ideal. You could also wipe on a bit of diluted varnish to were the jamming/hot melt gluing occurs as this will make getting the hot melt off a bit easier, makes it come off the lathe a bit easier too. It's important to true it up too, when remounting, if it's trued up there will be less force wanting to throw it off. You will still need to use fine cuts too and tail stock support when possibly too. A vacuum chuck would be ideal:D

Hope this helps - Peter

Calm
15th October 2007, 02:54 PM
John

I had a similar type of problem with the first Burl bowl i did. 2 weeks ago

Having just discovered the donut chuck to clean up the bottom of bowls.

I mounted the burl on a faceplate and finished the outside sanded and all and made a tenion on the bottom to do the inside with the intention of removing it with the donut chuck later.

Two cuts with the gouge and the tenion crumbled and the burl hit the shed wall & floor (missed me). What to do??

I remembered at Erns turn fest talk of hot glue guns so off to Home hardware - one block down the street - bought a $16 hot glue gun.

Mounted the burl back on the faceplate, removed the crumbled tenion, made an off cut of redgum the same curve as the botton of the bowl, hot glued it on made a tenion on it and had the burl mounted in the chuck and turning by the redgum within 5 minutes after the glue was applied.

Finished the inside and mounted the bowl in the donut chuck and turned the redgum off it and sanded and oiled the bottom.

Probably wont help you as you have done the inside first but my first experience of hot glue guns was great. Would use again.

Sorry if i have side tracked your thread.

Good luck with yuors

rsser
15th October 2007, 06:51 PM
Another tip for tailstock support with minimal marring: put a garden hose fitting over the live centre cone. .... the adaptor used to attach a click fitting to a 3/4 BSP garden tap.

But the piece looks good GJ.

Grumpy John
15th October 2007, 07:55 PM
Thank you one and all for the helpful suggestions and compliments on the bowl. I think I'll go with Mick61's method of making an extension with an internal cone (using a #5 centre drill to do this).

Unfortunately the hot melt glue method is out because of the curved bottom of the bowl and the burl is so holey that a vacuum chuck would never work.

Once thanks again for the response.

Cheers
GJ

hughie
15th October 2007, 09:59 PM
GJ,
A Longworth wood be handy. :U

BernieP
15th October 2007, 10:12 PM
G'Day GJ

Just a thought could you somehow adapt this idea? http://www.johnsturn.com/shopnotes.cfm?subj=flatjaws

Cheers
Bernie

Tony Morton
15th October 2007, 10:58 PM
Hi John

For platters I find the white glue and a sheet of good quality computer paper works well. I know it wont work in your situation as you have turned the face first. What I usualy do is turn the bace held with either screwed to ply face plate or on a forsner bit recess with larger diameters tailstock for safety except when working the central area. When sanding is finished I have a foot of about 15 mm wide and depending on size of platter 150 -200mm in diameter thenapply pva glue to the foot area then apply the sheet of paper then on the un glued side of paper apply glue to area relevent to the foot bring up a ply face plate and centre it with the tailstock and cramp up for an hour or so but have done them on occasions in a few minutes. before removing from chuck or faceplate and with the tail stock still in place true up the rebate in ply faceplate a bit awkward but essential to run true when you re chuck to turn the face of platter. Mount the piece on the chuck and bring up the tail stock for security as glue has only frictional hold at this stage. turn the outer face of the platter in to aninch or so of the centre then carefully with light cuts finish the centre. re aply tailstock and sand the outer area when this is finished finish centre and blend in no heavy preasure on outer edge when you ate satisfied with finish turn of lathe and with one hand cradling the platter with one hand give the back of the top edge a bump with ball of the other hand the paper splits and a quick cleanup with some warm water and all finished.

Cheers Tony

Grumpy John
15th October 2007, 11:21 PM
G'Day GJ

Just a thought could you somehow adapt this idea? http://www.johnsturn.com/shopnotes.cfm?subj=flatjaws

Cheers
Bernie

Bernie
I was thinking of something similar using my cole jaws.

Cheers
GJ