New three jaw chuck suggestions

[lfoggyParticipant @lfoggy]

I am going to treat my lathe to a new high quality three jaw chuck. Looking for a 125mm chuck with a D1-3 Camlock fitting. I want new chuck rather than second hand. Would be grateful for some advice.

I’m thinking a Pratt-Burnerd ‘super precision’ or maybe a ‘Grip-Tru’. How consistent are the ‘super precision’ chucks? PB website says max runout 25µ. What about the Grip-Tru – is that worth the extra complication compared to a good standard scroll chuck? Bison do a premium scroll chuck that claims a maximum runout of 15µ which seems unrealistic for a scroll chuck but then it is very expensive. That would be a three-jaw chuck with the concentricity of a collet system though.

Also considering two-piece jaws to allow aluminium soft jaws to be fitted more easily but have never used these so wondering how practical they are.

[lfoggyParticipant @lfoggy]

[Clive Brown 1Participant @clivebrown1]

I have a PB 4" Grip-Tru, purchased new, on my Boxford. It's not a bad chuck but I don't think I'd buy again. It's fairly awkward to adjust and if set accurately for a particular diameter it's not spot-on for a different diameter.

I find a 4-jaw independant quicker to adjust, but obviously needs to be set every time.

Basically I just use it as an ordinary 3-jaw, no better or worse than my PB 5".

[EmgeeParticipant @emgee]

I bought a D1-3 TOS 125mm 3j SC chuck from Rotargrip many years ago and it is still going well, not super precision but as good as you get with a SC 3 jaw.

Emgee

[thaiguzziParticipant @thaiguzzi]

Posted by Emgee on 12/11/2019 22:16:00:

I bought a D1-3 TOS 125mm 3j SC chuck from Rotargrip many years ago and it is still going well, not super precision but as good as you get with a SC 3 jaw.

Emgee

+1 for TOS, great quality for the price.

Still made in Poland or the Czech Republic?

[Thor 🇳🇴Participant @thor]

Another +1 for TOS, it is the best chuck I have.

Thor

[David George 1Participant @davidgeorge1]

I bought a Pratt Bernard chuck from Rotagrip repeatability is great.

David

[Nigel McBurney 1Participant @nigelmcburney1]

I have bought 8 inch Bison chucks in the past from Rotagrip ,and they have proved very good ,one is 30 years old and had a lot of commercial use, so I bought another for regular precise jobs and kept the old one for rough jobs,plus i have a 6 inch TOS from another source and that has proved ok, I buy my back plates and soft jaws from Rotagrip,though looking at current new prices,the eastern european chucks are a lot more expensive than they were,though I have found Rotagrip to be a good supplier, I have been told that Pratt Burnerd chucks also come from eastern europe though they still use their own dimensions for the jaw sizes etc. Never did see the point of the expensive grip true chuck, the ordinary Burnerd chuck was very good if looked after ,its overtightening and straining that ruins a 3 jaw chuck, I also have a 5 inch Burnerd chuck for my Myford ,i aquired it second hand,it required a backplate,so I machined the register with a couple of thou slop, put an inch dia precision roller in the chuck and trued it up on the back plate with bolts a little more than finger tight then really tightened it when was running true, you might ask why have a 5 inch chuck on a Myford when you also have a Colchester,well some times with tricky jobs which easily fit in the jaws of a 5 inch chuck do not fit so conveniently in 4 or 6 inch chuck jaws,and the 5 inch is for only occasional use,I dont go silly and spin it up to top speed.

[JasonBModerator @jasonb]

Unless you have money to get rid of or feel happier with a chuck that has a high spec I would say save your money. I have a standard Bison 3274 series and that will clock 0.015mm  (0.0006" )so just as good as the one you quote above. What's more it is also mounted straight onto the original Chinese backplate that came with my lathe.

I have steel softjaws for it from Rotagrip and you could always get a second set and machine them to take homemade aluminium jaws if you have a need for very soft or custom shape holding. Or the similar spec 3275 has screw on jaws if you want to use the ready made ali ones

Also picked it up for just over £100 new and boxed which is approx 1/3 list price

Edited By JasonB on 13/11/2019 12:05:05

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