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Posted by Bob Minchin on August 17, 2008, 12:48 pm
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Geoffrey Johnson wrote:
> Andrew Mawson wrote:
>
>
>>> Our club workshop pillar drill really needs a new chuck. We've got
>> a
>>> keyless jobby in mind but need to get the existing chuck off the
>> spindle.
>>> The Progress 1S spindle has a neat slot, right through the spindle,
>> and
>>> just above the chuck. Below that is a round knurled nut that can be
>>> screwed down, presumably to help with chuck removal. We just can't
>>> understand what the slot is for. It's about ¼" wide and ¾" high,
>> and
>>> there's what looks like a block of steel full-width across the
>> bottom.
>>> Can anybody clarify please?
>>> I'm anticipating that the mount is probably going to be JT6. It's
>> evident
>>> that considerable BF&BI is going to be needed to free the taper.
>> I'd
>>> guess that it's been on there for 50+ years. From the state of the
>> round
>>> nut it's evident that others have been there before us! The
>> existing ½"
>>> chuck simply says it's a Jacobs 34. Current-day Jacobs numbers have
>> a
>>> suffix which identifies the mounting taper e.g. 34-06 for JT6.
>> We've got
>>> a pair of wedges but initial trials indicated that a force greater
>> than we
>>> could apply from a big toolmakers' clamp would be needed. Any
>> thoughts?
>>> Geoff Johnson
>>>
>>>
>
>> Sounds like a slot for an ejector drift (wedge) to knock out Morse
>> Taper drills (or chucks)
>
>> AWEM
>
> It might sound like it Andrew, but it ain't!
> The slot's only an inch or so above the chuck. This model definitely
> doesn't have the modern, technological advancement of a MT drill hole.
> G
>
I think we need a picture. All the progress drills I've seen have an
ejector slot. The advent of a JT extension on the end of the spindle is
(to me) a modern embuggerance seen on cheap chaiwanese drills.
Intruiging though!
Bob
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