60 forum posts
I purchased a “new old stock” Pratt Burnerd 200mm 3 jaw chuck a few months ago, it came with both external and internal jaws. Unfortunately when I put it on the machine I found that the internal jaws were wrong.
Just to be clear here, the internal jaws are what I consider the “normal” chuck jaws.
The jaws look right and are the right “scale” for the chuck, but somehow they are not quite right being very stiff....I think the scroll form is different, the jaws perhaps being for a slightly larger or smaller chuck.
I set off to find replacement jaws, and to cut a long story short...eventually sourced a new old stock set from the US that are perfect - this leaves the jaws that came with the chuck redundant.
The jaws are unused as far as I can tell and look a quality job...if they would suit you, then let me know and they are yours for the cost of the postage or just come to Cheshire and pick them up. They are marked R148.
|Mike Poole||11/11/2018 21:20:09|
2045 forum posts
The number on the jaws should match the number on the chuck, if they don’t then you have a mismatch. It must be a tribute to PBs tolerances that a random set of jaws are a satifactory fit.
1215 forum posts
Funny old life.
|Chris Trice||12/11/2018 11:05:58|
1362 forum posts
With the change from imperial to metric chuck sizing (4" to 100mm for example), I found the tooth spacing on the jaws also changed. That could be the source of the confusion. Newer sets of replacement jaw won't fit old chucks.
|Pete Rimmer||12/11/2018 17:44:44|
|398 forum posts|
Maybe they are not originals, but replacements. Replacement jaws from PB come with a note that they might need work to ease the fit as they are machined 'tight' to allow for wear in the chuck.
60 forum posts
Good news! A new home has been found for the jaws.
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