I have been reading this forum for a while, and registered her yesterday to post this.
I want to buy a four-jaw chuck for my Myford ML7, and have bee wondering getting a nice used original Pratt and/or Burnerd of the typ specially made to fit the gap in the Myford. But I have also considered getting a new chuck (not from Myford as it' way too expensive for me), as they are quite cheap nowadays. I reckon that high precision is not very important with a four-ja chuck, as you always centre it manually.
I have browsed several online shops, like RDG and Chronos etc. But when I saw one at Arc Euro Trade with a slim body and front mount I thought it would be ideal for me. I doubt that the jaws of the 6 model will fit in the gap when extended, so I guess the 5" model i suitable for me. It's also nice that it is screwed on the backplate from the front.
Hunt around for a used Myford 4 jaw. On average, they get used somewhere between little and not at all.
No point talking to Burnerd, they are too costly for even Myford to buy these days.
Buy used!:-)
The originals for the ML/S7 are pretty decent and can be had for pretty reasonable. You are getting pretty far down in the scheme of things, if you are payin less than used prices for new goods of comparable size.
As to registering here. This is usenet. Pretty close to the electric version of the wild west. If you registered, you registered with someone else that is porting you through to the usenet through a website. No biggie, but often posts get garbled, and there is often a timelag, sometimes of days, between posting and being able to see your new posts. If your ISP has usenet access, it is worth exploring, as is a decent newsreader. FreeAgent gets mentioned a lot, though I have been satisfied with the capabilities of the Netscape mail program. Learn how to set up your settings so that malware is not automaticly run , in the event that some is posted on a group that you are reading. This is one of the failings of Outlook Express, as installed with Windows, that the default settings are to pretty much leave the lights on and the doors wide open, security wise.
Hello Thomas if you live near Nottingham shire give premier machinetools a ring some= times has the secondhand ones in stock I picked a 6" Pratt burnerd front mount onto a ba= ckplate for =C2=A350.00 Cash a bit mucky but underneath like new worth a try Cheers Co= lin
Hello Thomas if you live near Nottingham shire give premier machinetools a ring sometimes has the secondhand ones in stock I picked a 6" Pratt burnerd front mount onto a backplate for a very reasonable price Cash a bit mucky but underneath like new worth a try Cheers Colin
A couple of things for you to think about when deciding which 4 jaw chuck to buy. The only chuck that I know of that will fully fit into the Myford gap is the Pratt/Bernerd "screwed body" type. This is because with the spindle thread and register cut directly into the slim body the chuck is mounted right against the headstock and the chuck jaws extend into the gap allowing full use of a 6" diameter chuck. The total width of the chuck with jaws is 65mm. Although the ArcEuro chuck you mention is the same width it requires mounting on a backplate that will push it forward in the gap and the jaws may foul the bed if extended beyond the body much. Don't forget though that the jaws are reversible and with them reversed the 6" chuck will hold something approaching 5" diameter without the jaw extending beyond the body enough to strike the bed. None of the new cheaper chucks I know of are slim enough; even the RDG 4 jaw offering which is called "threaded body" appears from the picture to be wider and may suffer the same limitation. I haven't seen one of these fitted so you would need to check. So if you need the full capacity of the Myford gap I don't think you have any choice and that is why the Pratt/Bernerd of this design is so expensive secondhand.
If this is not an issue for you then modern "import" chucks are improving all the time. I have seen the ArcEuro one you mention and it looks a well made and capable chuck that I personally wouldn't hesitate in buying if I needed one. The other "names" to look for in reasonably priced chucks would be Toolmex and TOS, they make excellent chucks in the mid-price range; I have owned and regularly used a number of these chucks and not had a problem with any of them.
In looking at secondhand 4 jaws then you are correct that they are less critical than self centering 3 jaws but there are still some things to be wary of. For some unknown reason 4 jaw chucks are one of the most often abused things on a lathe, they are drastically over tightened regularly and the jaws and their operating screws suffer greatly, make sure they operate freely and smoothly. Check that the jaw slots are not too loose and the key operating holes are not cracked at the corners, a regular problem caused by putting the key in and hitting it to release a tight chuck from the spindle. As always with any chuck ensure that the mounting thread and spindle register are undamaged.
I have no idea where you are located but as always E-bay will have some on offer although the prices seem to be fairly high particularly for the Pratt/Bernerd type. Second hand dealers will have them (at a price), there is one here:
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I don't know anything about them and just post it as an example.
While I agree that a 4 jaw might not get used all the time it is absolutely essential for some tasks and when you have cracked setting it up properly is quick to use and more accurate than a 3 jaw. My own personal opinion is that if you do not need the full capacity of the
6" in the gap then buy new.
Apologies if this is "teaching granny" but it is difficult to know from a first post where you are on the constant learning curve that metal working provides, hope this helps a little
Buy a good one and cry once when you pay and not whenever you use it. Along with my lathe came a 4 jaw chuck. I had to return it *two* times to get one that was within the mfg's specs. When the jaws were reversed, they stood out (axial) different. Difference of 0.2mm. Chinese Crap, inspected by "#2" with quality-assurance supervisor "#1".
I am aware that the 6" model from Arc won't fit in the gap with
backplate, that's why I would choose a 5" model. I thought it would be a good idea to choose this model as it's lighter and would reduce the load on the front spindle bearing.
I have also considered buying a nice used one, but haven't found on until recently. This seems like a nice one with integral threads o eBay here
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If I can win this auction with a reasonable price, I will go for it! Lets cross our fingers :) . What do you guys think this is worth?
I live in Norway, and there is not easy to get such a chuck here, so am prepared that I probably have to pay up to about £50 shipping fro UK to get one :eek: .
*UPDATE: "The seller ended this listing early because the item is n longer available for sale. F**K, F**K! :censored:
The 6" model _will_ fit in the gap with a back plate... Burnerd made 6" 4 jaw chucks with and without back plates. I have one of each. With the back plate, the jaws will foul on the bed if opened to the widest extent, but if you held the same sized work in the 5" chuck the jaws would be dangerously extended.
However...
The 6" chuck has almost exactly the same dimensions as the Burnerd (possibly it's a copy?) This includes the centre hole. You can make a back plate that has a 3-6mm flange at the back for the mounting screws and the main part of the back plate inside the chuck. With a 6mm flange that would give 3mm more overhang than the screwed body Burnerd if you left the back flat. If you turned a 3mm deep counterbore for the lathe spindle register, then the chuck would have exactly the same overhang as the Burnerd.
In the ASCII are, " and = are the back plate and w is the thread on the back plate. | and - are the chuck :-
Yes, thanks, I had read the spec of the centre hole as 25.4mm (the 5" chuck figure) instead of the 40mm that it actually is. I didn't pick it up as being incorrect as on my screwed body Bernerd the hole is of course the spindle thread diameter so it didn't seem too far out. As you say by turning the backplate round as it were and allowing the backplate "boss" to go down the centre hole it will certainly fit with an adequate thread length and flange. Tempting as I do like the lightweight 6" on the Myford but I suppose you can only use one at a time!
I didn't read your post thorough until today, when I noticed the lin you pointed me to. Unfortunately the chuck was already sold :( . They said that they get them in fairly regularly, so I will watch thei website (and eBay of course). Does anyone know of other places they sell these used chucks?
At £95 it's not much more expensive than the one sold by Arc. Is £95 a bargain? what do these used ones sell for usually?
Pity you missed those two but don't worry they do come up often. The few I've seen sold on E-bay in the last 3 months varied in price between =A345 and =A370 ish although last year they were making a lot more. Try a wanted add on this website:
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Very active and is read by lots of "engineering" types so you might be lucky. There is also a link page that has links to a few used tool dealers in the UK.
Have a word with these people it is the type of thing they get in although their prices seem variable:
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I don't really know what prices are fair at the moment but I have seen them recently at dealers who were asking =A3125. Personally, I don't think I would pay more than =A375 for an average one and for =A395 I would want it to be virtually unused. As Mark said in his post if you are able to make a backplate for it yourself then the ArcEuro 6" slim body could be made to fit in the gap and as that is =A385 I would be tempted to make that my benchmark.
Sorry I can't be more help and it may just be a case of waiting patiently for the right one to come up, good luck.
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