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smidsy
19th Jul 2004, 08:41 PM
Hei Guys,
I have just laminated some 290mm pine which I plan to use for a bowl - the bowl will be a nut bowl with one of those ships wheel style nut crackers in the middle.

Since the bowl will have a hole drilled all the way through anyway, would it be feasible to mount it on a peice of threaded rod and then mount the rod in a drill chuck for turning with the other end of the rod supported by the tail stock.

Thinking of doing it this way instead of just using the screw on the scroll chuck so I can turn the bowl more than once for finishing and polishing.

If I can do this, what size threaded rod would I need - the block I've laminated is 290mm square and 114 mm thick.

Cheers
Smidsy

RETIRED
19th Jul 2004, 09:06 PM
The short answer is "not advisable".

The rod can flex unless you use a fairlly heavy one.

The jaws of the drill chuck offer no "flat spot" to bear against like a screw mounted in a scroll chuck.

If the hole is not drilled square the wheel at the top will be off centre and that looks rank.

A drill chuck will not drive the piece of timber.

Do it in the screw chuck but only drill far enough for the screw and drill the mounting hole for the wheel when you turn it.

Have fun. :D

Christopha
19th Jul 2004, 09:38 PM
The short answer is "not advisable".

The rod can flex unless you use a fairlly heavy one.

The jaws of the drill chuck offer no "flat spot" to bear against like a screw mounted in a scroll chuck.

If the hole is not drilled square the wheel at the top will be off centre and that looks rank.

A drill chuck will not drive the piece of timber.

Do it in the screw chuck but only drill far enough for the screw and drill the mounting hole for the wheel when you turn it.

Have fun. :D


All of what said!!!! Not a good idea at all really and be very careful turning laminated blanks at all, dangerous damned things!

smidsy
19th Jul 2004, 09:58 PM
So what do I need to watch when turning laminated blanks - this is a big one, 290mm square and 6 layers of lamination for a total thickness of 114mm.
Cheers
Smidsy

RETIRED
19th Jul 2004, 10:09 PM
I have turned a lot of laminated blanks and only had a few problems generally while day dreaming.

Watch when you go up against the grain. It can split if you get heavy handed or the tools blunt.

Start from the "round" face and work towards the square edge, backing off as less timber is under the chisel.

Hope you understand this.

Alastair
20th Jul 2004, 01:16 PM
Provided the jointing surfaces were properly prepared and mated (as for any jointing) and a good glue used, (I use the aliphatic resin glues), and you take the care that suggests, you should be OK. I have done numbers of segmented turnings wirhout problem, and laminated blanks up to a max of 600 mm diameter. It is also a good idea to keep the lathe speed down.

If the glue-up is shonky, however.........?

Alastair

RETIRED
20th Jul 2004, 02:18 PM
wear hard hat and sharpen the reflexes.:D

smidsy
20th Jul 2004, 02:37 PM
The laminating should be pretty good as I used Saligna cross link PVA glue and applied it with a roller - aferwards I set the timber in sash clamps to get the edges even and left a 10kg wieght on top.
As for the hard hat, I'll just make sure I'm not standing in the launch trajectory when I turn it.

Cheers
Smidsy

Bob Willson
20th Jul 2004, 05:07 PM
sharpen the reflexes Up to what grit ? Is 600 enough or do you need to able to see your reflection?

RETIRED
20th Jul 2004, 10:28 PM
I would personally go up to flour paper, then jewellers rouge and lastly toothpaste because they have to be razor sharp. :D

Toggy
20th Jul 2004, 10:47 PM
,

Would that make it scared sharp???


Ken