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Old 11-08-2008, 08:33 PM   #1
Maryak
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Default Turning Between Centres

Hi Guys,

I've noticed in a couple of posts that when turning between centres, the soft centre is held in a 3 jaw chuck.

I've not seen it done that way before.

Please, why is it done this way

Thanks
Bob



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Old 11-08-2008, 09:14 PM   #2
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Default Re: Turning Between Centres

I think you saw my posts.

The shop doesn't have the slotted dog plates handy AFAIK. The jaws work just fine given that the leg of the dog is long enough for contact.



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Old 11-08-2008, 09:40 PM   #3
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Default Re: Turning Between Centres

Maryak--The biggest reason is that it saves me the agravation of having to remove the chuck and install the faceplate.

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Old 11-08-2008, 09:54 PM   #4
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Default Re: Turning Between Centres

kvom, Brian.

Thanks for helping me out, I understand much better now

Regards
Bob

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Old 11-08-2008, 09:58 PM   #5
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Default Re: Turning Between Centres

that's the way machinists do it, because its quick and accurate. skim any piece of steel to put a 60 degree cone on it and there's zero run out

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Old 11-08-2008, 10:07 PM   #6
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Default Re: Turning Between Centres

Mcgyver,

Makes a lot of sense, funny how you can't see the wood for the trees sometimes

Regards
Bob

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Old 11-08-2008, 10:30 PM   #7
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Default Re: Turning Between Centres

on our little lathes it might not matter that much, but i can see why you'd want to avoid changing tool on a larger lathe......but I like to pretend I'm a machinist so that's how i do it

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Old 11-08-2008, 10:38 PM   #8
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Default Re: Turning Between Centres

Because if you mount the centre in the headstock as is standard on some gap bed lathe you finish up with the saddle over the gap and unsupported.
Also you often have run out of bed length to get a bed stop on and still reach the end of the work.

Using a quickly trued up centre in the chuck will have the effect of moving the job down the bed a bit.

As others have mentioned it's also for the inherently idle

.

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Old 11-09-2008, 01:08 AM   #9
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Default Re: Turning Between Centres

Thanks Guys, for all the good reasons for the 3 jaw chuck approach.

Filed away in my "I must remember that" box.

Best Regards
Bob

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Old 11-09-2008, 11:58 AM   #10
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Default Re: Turning Between Centres

Maryak, I've taken a similar approach myself.
Chuck up a bit of steel and put a point on it, then weld a "dog" on the end of the workpiece which will engage one of the chuck jaws. This allows you to turn all the way down the piece.
The dog is, of course cut/ground off after turning.

I may be a lazy bastard, but I'm good at it



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