Cheap chucks from ebay.

[MWParticipant @mw27036]

 

Posted by Martin Kyte on 20/02/2017 15:43:12:

So my conclusion is if you want a cheap chuck go for an economy standard precision new one rather than a high end old one. You are unlikely to get the low run out that the high end one once had and the jaws will have seen some use to boot. With then new one at least the jaws should close parallel. I know you can always regrind but that will not put the wear back on the tenons and new jaws are expensive.

That said I pensioned off my old griptru by buying it a set of soft jaws. In addition I have a 2 independent four jaws, a self centering four jaw an a Super Precision Pratt Burnerd for Sundays.

regards Martin

Unless you know for certainty that it's good then yes, I can say I have experience of prestigious large chucks that well and truly had it at 0.2mm runout, and gave me a difference in 0.05mm in diameter every 5mm or so. Try making gauges out of that!

Luckily it wasn't my machine but it was an extremely good make of industrial lathe that had seen a thrashing over it's lifetime.

My own home lathe can certainly do better than that, but anyways, standard 3 jaw chuck for my £800 machine gives 0.03 runout on nominal bar stock.

May have not been all the old chucks fault but I can't imagine it helped matters.

C'est Incroyable!

Michael W

Edited By Michael-w on 20/02/2017 16:49:25

[Nick Taylor 2Participant @nicktaylor2]

Out of interest, everyone is always talking about old Pratt chucks or new import chucks – is no one interested in new Pratt chucks?

I have an old 125mm 3 jaw super accuracy which is very worn, the outside jaws are not so bad but the bar gripping on the inside jaws is terrible and very badly bell mouthed.

I'm temped to buy a 125mm standard accuracy Pratt chuck, seeing as they can be had brand new for less than £200 online. Any reason not to? Other than price compared to the other offerings.

Cheers,

Nick

[Martin KyteParticipant @martinkyte99762]

Sound like a plan to me Nick although new Pratt chucks would be outside the topic of the tread.

Martin

[John Stevenson 1Participant @johnstevenson1]

Pratt chucks EXCEPT the grip-true are now made by TOS in Poland and have been for quite a few years.

Made on the same line they make their own chucks.

[Nick Taylor 2Participant @nicktaylor2]

Posted by John Stevenson on 21/02/2017 10:07:12:

Pratt chucks EXCEPT the grip-true are now made by TOS in Poland and have been for quite a few years.

Made on the same line they make their own chucks.

Ahh ha, thanks John – didn't know that!

cheers

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