Pratt Burnerd 6 jaw self centering 3 1/4″ Chuck

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Pratt Burnerd 6 jaw self centering 3 1/4″ Chuck

This topic has 14 replies, 5 voices, and was last updated 30 August 2014 at 00:43 by Chris Trice.

Viewing 15 posts - 1 through 15 (of 15 total)

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28 August 2014 at 20:26 #162055
Adam Harris
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@adamharris13683
I have one of these which is not a grip-tru version like the ones Pratt Burnerd currently sell and I wonder how rare or desirable or valuable they are compared to the usual 3 jaw self centering chucks. Since I have never seen another like it I imagine they were not particularly popular or useful. The face of each jaw is rather narrow and it looks somewhat like a claw out of an Alien film – very peculiar! Any comments? A photo is in my library.
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28 August 2014 at 20:26 #17489
Adam Harris
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@adamharris13683
28 August 2014 at 20:27 #162056
Adam Harris
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@adamharris13683
3 1/4" diameter (not 3 1/3&quot
28 August 2014 at 20:37 #162057
Michael Gilligan
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@michaelgilligan61133
Adam,

It looks interesting, but the [grinding] marks on the sloping surface of those jaws don't look up to Burnerd's traditional quality; so I am more than a little puzzled.

Your photo doesn't fully show what I presme to be he model number … do please tell.

MichaelG.
28 August 2014 at 20:46 #162058
Adam Harris
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@adamharris13683
BP79/2803
28 August 2014 at 20:48 #162059
Adam Harris
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@adamharris13683
I suppose 6 jaws would give a better grip than 3 but these jaw faces are almost like knives so i wonder what one would choose to grip with them….
28 August 2014 at 20:50 #162060
Adam Harris
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@adamharris13683
The grinding marks are identical on each jaw and each groove line has a slight curve to it so I can only presume they are original – certainly could not be accidental
28 August 2014 at 20:52 #162061
Adam Harris
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@adamharris13683
Looking more closely I would say these "grinding" marks are more like an engraved pattern possibly to offer finger grip?
28 August 2014 at 20:56 #162062
Max Tolerance
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@maxtolerance69251
Probably been used on a drill grinding machine the Brierly company type. I have two of these chucks both made by Pratt Burnerd one is on my brierly and the other is threaded for the J&S 310 T&C grinder.
28 August 2014 at 21:02 #162063
Adam Harris
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@adamharris13683
Hi Max. thanks for that – I see on google the chucks holding the drill bit for grinding on the Brierly type machines do indeed look very similar!
28 August 2014 at 21:06 #162064
Michael Gilligan
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@michaelgilligan61133
Nice one Max !!

… I had just found this Bison one for comparison.

MichaelG.

.

P.S. Drill Grinding

That might explain those marks on the Jaws.

Edited By Michael Gilligan on 28/08/2014 21:33:50
28 August 2014 at 21:50 #162071
Chris Trice
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@christrice43267
I’ve got a Japanese Hama 4″ version which I use for small bore brass tube. My one is spot on for cocentricity. The down side is no reverse/reversible jaws. I can’t help feeling there is a market for a proper 4″ six jaw chuck. There is one made by an Indian company but I’m not convinced that the quality is there enough for me to pull out the cash.
29 August 2014 at 01:49 #162081
Muzzer
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@muzzer
Here's a page from the local tool emporium (in Canada) which shows 2 models. The bottom one has reversible jaws. They are generally for thin wall pipes etc and seem to be more popular in North Merca.

These own brand chucks are generally Chinese or Indian. I was quite temped to get a 6-jaw or possibly a 4-jaw self-centring chuck at one point but a different kind of sense prevailed in the end.

Murray
29 August 2014 at 21:37 #162147
Adam Harris
Participant
@adamharris13683
Michael, I am certain the grooved/engraving marks on the sloping surfaces are there for grip when you reassemble after cleaning – one needs to push all six in when engaging the scroll. I have just done this and can see how it helps. Adam
30 August 2014 at 00:43 #162159
Chris Trice
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@christrice43267
This was the conventional 4" six jaw I found.

http://littlemachineshop.com/products/product_view.php?ProductID=2276
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