Lathe chuck

[Peter Simpson 1Participant @petersimpson1]

I have Boxford ME lathe and would like to fit a 6" independent four jaw chuck. I have seen several 160 mm chucks, Arc Euro have a slim body version that looks ok. The problem nobody seems to supply a back plate to suite. Is there anyway round this problem ?

[Peter Simpson 1Participant @petersimpson1]

[davebParticipant @daveb17630]

I believe Chronos stock suitable backplates.

[OldironParticipant @oldiron]

I got a 5" backplate from Chronos which was plenty big enough to cut the register and drill threaded holes for my 6" independent 4 jaw chuck. It has the correct spindle thread ready cut. The back plate was 127.5mm OD so just check that your register is a little less than that. m Not sure if they do a 6" version but check with them.

regards

Edited By Oldiron on 02/01/2018 19:46:56

[JasonBModerator @jasonb]

My Bison 160mm slim body is on a 5" backplate, works fine for me. ARC do 5" backplates threaded for Boxfords

[davebParticipant @daveb17630]

Most 4 jaw independent chuck backplates are smaller than the body diameter. With 3 jaw chucks, the backplate is (usually) the same size as the diameter. Check the specs of the chuck you intend to buy, will tell you what size you need.

[Peter Simpson 1Participant @petersimpson1]

Sorry school boy error. I misread the chuck dimensions. The register is 82.5 mm and the bolting PCD is 69.8 mm. It's an age thing.

[Howard LewisParticipant @howardlewis46836]

Not a Boxford owner, but dare I suggest that the Register is actually 3.25 inches (82.5mm = 3.2480315&quot and 69.8mm (2.7480315&quot was probably was designed and made as 3.750 inches?

Assuming that a British lathe, of some vintage, was more likely to be made to Imperial dimensions?

If so, a couple of thou clearance would not improve precision

Howard

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