3jaw lathe chuck

[migman]

Hello everyone,
i have a Harrison L5 lathe in my garage.it has a 4jaw chuck on it and i would like
to put a 3jaw chuck on it,where would be the best place to purchase one.
picture of 4jaw included.numbers stamped on it are 4304-160

 

[addjunkie]

You can buy pre machined cast back plates. You then machine up to fit the chuck of your choice. They range from about 90 quid to about 500, depending where you buy, rdg and chronos cheaper, or any of the tool dealers may have a used british one.

Once the chuck is fitted to its back plate leave it there dont keep taking it off.

 

[Pete.]

I have a TOS chuck for my Monarch and I like it a lot. It holds good concentricity, seems well built and has steel sliders in the cast iron jaw slots so should wear very slowly.

 

[migman]

have a back plate already fitted to the lathe.
just need the 3 jaw chuck to match it

 

[steve_s]

have a back plate already fitted to the lathe.
just need the 3 jaw chuck to match it

You need a back plate for each chuck you change the chucks back plate and all.

 

[brightspark]

I have a TOS chuck for my Monarch and I like it a lot. It holds good concentricity, seems well built and has steel sliders in the cast iron jaw slots so should wear very slowly.

ive got a tos 3 jaw on my harrison and its good quality

 

[brightspark]

have a back plate already fitted to the lathe.
just need the 3 jaw chuck to match it

u machine the backplate to suit the chuck

 

[migman]

thank you everyone for the information.

 

[dobbslc]

You need a back plate for each chuck you change the chucks back plate and all.

Is that why I can't get my 4 jaw to fit the 3 jaw backplate then?

 

[MrFluffy]

The register on the chucks will all be different, as said above you machine the register o/d in place on the actual machine to suit the chuck's recess or registration feature as near as possible then its right for that chuck on that machine spindle.
http://lathes.co.uk/latheparts/page7.html

migman what fitting is your harrison? they came with 3 that I know of, the 1.5 inch of the early small ones, the 2.25" large bore screwed fitting and a L00 fitting.

 

[MrFluffy]

And as a extra, you really want a 4 jaw AND a 3 jaw. The 4 jaw will always be more concentric and repeatable once you get the hang of bumping things in using a clock. 3 jaws are just for general chuck something in and have it spin roughly where it should be jobs when concentricity isnt extremely important.

 

[brightspark]

And as a extra, you really want a 4 jaw AND a 3 jaw. The 4 jaw will always be more concentric and repeatable once you get the hang of bumping things in using a clock. 3 jaws are just for general chuck something in and have it spin roughly where it should be jobs when concentricity isnt extremely important.

and once u take a cut it will be 100 percent accurate 4 jaw only needed if original diameter wont need cutting

 

[Pete.]

I don't actually turn a register. I clean and deburr the backplate register, mount it, turn and face it then drill the holes and bolt the chuck up using a dial gauge on the OD to get it running true.

 

[migman]

This is a photo of the thread fitting on my lathe.i am a beginner
and finding it difficulty to get workpiece true in the 4 jaw chuck.

 

[brightspark]

use a dti gauge. dial test indicator on a magnetic stand

 

[migman]

I have got those,but takes me ages getting the
work piece to run true

 

[galooph]

Follow @doubleboost's method on getting work centred in a 4 jaw, it works really well

 

[wookie]

Another great video from @doubleboost, his explanation on how to center a 4 jaw chuck so easy to understand, I especially like the last few seconds where he calls himself for getting it wrong.

 

[MrFluffy]

This is a photo of the thread fitting on my lathe.i am a beginner
and finding it difficulty to get workpiece true in the 4 jaw chuck.

what is the diameter of the plain bit before the thread starts proper in inches? it should be either 2.25" or 1.75.