decent 4 jaw chuck to fit myford speed 10?

[jon hill 3Participant @jonhill3]

[jon hill 3Participant @jonhill3]

I currently have a 4" Pratt Bernard independant chuck that its jaws are looking worn out, either that or the sloop in the jaws suggest it is a chinese fake.

Any suggestions for a good quality replacement, perhaps with bigger jaws as the current one isnt up to holding very much?

[Robert ButlerParticipant @robertbutler92161]

A good Pratt Bernard would be an excellent alternative. Robert Butler

[jon hill 3Participant @jonhill3]

Incidently could I fit a larger diameter chuck eg 5" as the centre hight is 4.5"?

[Mike Henderson 1Participant @mikehenderson1]

My Spped 10 came with a 5 inch Pratt Bernard 4-jaw, which I understand was original equipment. Certainly, I wouldn't want to go to anything smaller.

However 4 1/2 inch centre height it isn't.

Mike

[HopperParticipant @hopper]

I'll give you 10 quid for that worn out counterfeit chuck you have in the pic.

[not done it yetParticipant @notdoneityet]

I’ll give you 11 quid for it!🙂 Apart from ‘looking’ worn out, what is actually wrong with the chuck?

I often use a 100mm chuck on a larger lathe than yours. Likely half the weight of the usual chucks in general use.

It’s definitely a fake if it is really marked as “Pratt Bernard”.

[JasonBModerator @jasonb]

Going by the marks on the tape the front of the jaws are not making contact assuming it was used on something parallel.

Bison would be another option for a replacement.

[JohnFParticipant @johnf59703]

Jon, see your messages

[HopperParticipant @hopper]

Seriously, there have been posts on here before of as new PB chuck with mis-manufactured jaws that did not grip parallel. Easiest fix is take the jaws to a machine shop with a surface grinder and get the gripping faces ground square to the surface that slides in the chuck body. Or you can grind them in situ in your lathe with s toolpost mounted Dremel tool. Search this forum for past threads on Pratt Burnerd jaws or similar for further info.

[Mick B1Participant @mickb1]

Posted by jon hill 3 on 15/08/2020 22:33:28:

Incidently could I fit a larger diameter chuck eg 5" as the centre hight is 4.5"?

4.5" c/h? You must have risers under head and tailstock if that's true. Mine was 3 1/4" standard.

[SillyOldDufferModerator @sillyoldduffer]

A few more photos would help. It's not clear to me what the problem is. Jon says the jaws look worn, and then covers them with tape! Could be the jaw faces have been abused, or screws & teeth mangled by excessive tightening, or perhaps the wrong jaws have been fitted. (Not all pre-loved lathe owners are geniuses!)

Reassuringly expensive products are not immune to mistakes or being thrashed. Assuming the chuck body and screws are OK, possible to buy replacement jaws for Pratt Bernerd chucks, though unfortunately the company is a Price on Application operation. Whether or not spare jaws can be found for an old chuck is another question.

Assuming the worst and a replacement is necessary, ask if buying a 'decent' chuck is worth the money. 'Decent' is deeply suspect as an engineering specification. Professionals look for 'value for money' and 'fit for purpose' rather than 'decent,' 'good' or 'quality'. Those words waste money galore because best is the enemy of good enough.

Expensive tools tend to save time rather than provide marvellous extra capabilities. And they usually resist wear and tear longer in busy workshops. Being smooth in operation makes centring work in a 4-jaw that much faster – but not more accurate, or with a stronger grip! Down to the operator to decide if smooth operation and long-life are worth spending money on. Time wasted by second-class tooling is irrelevant to the experimental moderate precision work I do. Same tools would be a major problem if I machined for a living: time is money.

Psychology plays a major part in amateur workshops. Pays to consider your mindset. My outlook is utilitarian: tools need only be good enough to get the job done. Others see it different, because not only is pleasure to be had from owning and handling 'good' tools, but some find imperfect tools downright frustrating. As hobbies are to be enjoyed, strong feelings may be a must scratch itch, even if absolutely unnecessary to the job. Another manifestation: clean tidy workshops versus stuff everywhere. A shortcoming of the clean tidy approach is keeping workshops neat often become more important than making anything! As opposed to untidy workshops were nothing is made because the lathe is under a boat.

Buying tools, I advise being honest about why it's wanted. Don't buy a mini-lathe if the goal is to put the club's boastful Myford Connoisseur owner in his place. Best way to deal with swankers is to install a Dean Grace & Smith in a purpose built air-conditioned workshop, with a long story about the cost of running 3-phase across your land. But bear in mind a mini-lathe is a better choice than a big DSG for most hobby purposes.

Point is, a new Far Eastern 4-jaw bought from a reputable source will do the job. Order today, delivery next week. Don't do it if your gut rejects the idea!

Dave

[jon hill 3Participant @jonhill3]

Interesting points, firstly I am fairly new to using 4 jaw independent chucks. I have don a fare bit more on my 4" PB self centering chuck, which I think is the grip tru version. As most will appreciate the jaws of the former are more robust being larger and give me confidence they can grip much larger work.

The PB 4 jaw 4" PB chuck is the light duty version. the jaws in there current state rock back and forth and side to side! I don't think the scroll is seriously damaged so I think replacement jaws could be ordered.

However I am looking to hold the same same scale of work that I can with the 3 jaw, plus odd shaped stuff eg rectangular. I suspect that the light duty 4 jaw has been used beyond its normal load capacity leading to slackness in the jaws.

Regarding the centre height as some more experienced users pointed out it is not 4.5" as I mentioned but 3.25", rooky mistake.

I am still interested if I could use a larger 4 jaw any ideas?

[HopperParticipant @hopper]

Any 5" from any of the reputable suppliers plus a Myford threaded backing plate should do it. You could go to a 6" maybe. But with no gap in the bed you cant let the jaws or the job stick out past the body so could be limited.

You will need to machine the backplate to fit the chuck in situ.

Edited By Hopper on 16/08/2020 13:13:55

[BazyleParticipant @bazyle]

Posted by jon hill 3 on 16/08/2020 13:01:37:

! I don't think the scroll is seriously damaged so I think replacement jaws could be ordered.

That 4 jaw doesn't have a scroll. If it is a fake you won't be able to get new jaws and ones from PB won't fit any better if at all.

You can use a bigger chick. It sounds like even a 6 in would fit but the extra weight puts a strain on the lathe and is probably mostly not required.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 16/08/2020 12:02:28:

.

[…] As opposed to untidy workshops were nothing is made because the lathe is under a boat.

.

What a lovely succinct way of expressing my situation !

… I don’t actually have the boat, but that’s irrelevant.

MichaelG.

[Douglas JohnstonParticipant @douglasjohnston98463]

A 5" independent chuck was what I got with my Speed 10 lathe and that would seem to be the best size for the lathe. I also have a light weight 6" one which I have often also used on the lathe to hold larger work although one has to be careful since the outside diameter just clears the lathe bed.

Doug

[Ron LadenParticipant @ronladen17547]

If I was looking for a 5 inch 4 jaw independent chuck I would go with the one from ARC at £55 plus they stock Myford backplates.

Yes it's Chinese but going by the 3 and 4 jaw chucks I had from them for my mini lathe I wouldn't hesitate, quality was very good indeed and the 3 jaw had next to nothing in terms of runout.

I have a 6 inch PB 4 jaw which came with my 918 lathe it's very good but at 8X the price of the ARC one it needs to be. Will it be 8X better of course not and assuming the ARC one is as good as the 2 chucks I had from them I doubt that there would be any difference in use apart from having a PB badge to keep looking at..

Ron

[Peter G. ShawParticipant @peterg-shaw75338]

My twopenorth (spelling doesn't look right, wonder what I've done wrong!).

I have a Bison 6.5 inch 4 jaw independant chuck, (actually 160mm) which came with the lathe. Good chuck, apart from where my grandson managed to damage it although it's still usable, but it's heavy and advancing years aren't helping. As it is, right from new 25 years ago I had to use a piece of scrap wood to rest it on whilst lining up the fixing screws. The point about watching clearances is well made – my saddle bears witness to contact with one or more jaws, fortunately the part that catches is an aluminium piece holding the bed wiper in place.

I also have an 80mm 4 jaw independant chuck which gets used quite frequently and was bought from Arc at one of the shows. I had to make my own backplate, from aluminium as it happens as a temporary device pending purchase of a suitable piece of cast iron but still in use(!). I do find it most useful being of a lighter weight.

I am mulling over buying a 5 inch 4 jaw independant, (Vertex?) to fill the gap betwen the large Bison and the small Arc.

Peter G. Shaw

[Andrew TinsleyParticipant @andrewtinsley63637]

I have exactly the same PB chuck on my ML10. It is in the same state as yours (which isn't a copy but the real McCoy)

It was knackered when I purchased the lathe, but everything else was fine. I suspect it is far too lightweight for any serious work apart from very small objects.

I took the Bull by the horns and enlarged the slots and loctited in some spacers to bring it back to nominal. The jaws were OK. It isn't perfect but infinitely better than it was.

Andrew.

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