Author Topic: D1-4 to D1-3  (Read 468 times)

Offline pycoed

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D1-4 to D1-3
« on: April 06, 2021, 05:23:13 AM »
Several years back a couple of mates & I bought 3 Harrison M250ís out of a school auction, the other two sold theirsí on, but I stored mine ( code for stuck it in the garage behind an old Drummond, piles of dismantled Merc engines, Mini bits, tractor rams & general useful stuff).
Bringing it into operation this year, I found that, while the 3-jaw chuck & catchplate were both D1-3 & were fine, the 200mm Elliot 4-Jaw in the lathe cabinet was a D1-4 Blast! Double Blast!
Hence my question:- Since I can find a 125mm D1-3 backplate for £50-60, would it be feasible to bore out the Elliot chuck to fit a suitably reduced D1-3 backplate & bolt the two together? I have a Kerry lathe plus a Marlow mill available for the job. Has anyone accomplished such a task &/or what are the flaws in this proposal? Is there an easier way of converting D1-4 down to D1-3?

Offline John Rudd

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Re: D1-4 to D1-3
« Reply #1 on: April 06, 2021, 08:12:58 AM »
Sell the chuck and buy a D1-3 chuck to replace it...
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Offline pycoed

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Re: D1-4 to D1-3
« Reply #2 on: April 06, 2021, 12:34:19 PM »
Yeah, but where's the fun in that? :)

Offline awemawson

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Re: D1-4 to D1-3
« Reply #3 on: April 06, 2021, 01:58:57 PM »
But you might keep your sanity - says he who keeps dithering on his A2-6 to A2-5 special hydraulic adaptor !
Andrew Mawson
East Sussex

Offline Spurry

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Re: D1-4 to D1-3
« Reply #4 on: April 06, 2021, 02:01:14 PM »
There are two types of chuck for my Harrison M250, ones with separate backplates and others with integrated. If your 200mm chuck is the former, Chronos sell a D1-3 x 200 backplate for just a couple of quid more than you were quoting for the 125mm.

Offline pycoed

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Re: D1-4 to D1-3
« Reply #5 on: April 07, 2021, 04:53:44 AM »
Sadly my 200mm chuck is an integral one, so I think the overhang may be a bit much with another inch of backplate, hence the idea of boring out. Perhaps a bit more measuring & thought is called for ... I wonder if thinning a D1-3 200mm backplate & turning a D1-4 taper locating nose on it may work? Would thus leave the original  chuck un-hacked, apart from threaded holes.

Incidentally, I don't reckon the M250 is as nice a lathe to use as my aged Kerry AG3, I just wish it was in better nick & I would have invested in some metric changewheels for it

Offline Spurry

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Re: D1-4 to D1-3
« Reply #6 on: April 07, 2021, 12:42:21 PM »
As I was using my 160mm ō  4 jaw today, I suspect that a 200mm one would be almost unusable with the jaws poking out of the sides.
Perhaps you are much braver than me.
I bought the M250 in 1988, so it feels quite familiar. The only other lathe I've ever used was a 140 Harrison at evening classes.