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Why I like two-piece chuck jaws (pics)

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  • oldtiffie
    replied
    "Chucking"

    Originally Posted by oldtiffie
    The chuck I bought had the normal inside/outside 3-jaws. The 2-piece jaws are an accessory/extra.
    Originally posted by lazlo
    But have you purchased the optional 2-piece soft jaws for them? Those optional jaws will only work on the same brand/model chuck.
    In a word, and to "dot the "i"'s and "cross the "t"'s, yes.

    That was a the reason I bought the chuck - and the "2-piece" jaw accessories/"extras" for the convenience of the "2-piece" jaws and the soft jaws. It was not cheap but I was more than satisfied.

    I often see here where people have C5 or R8 collets (which have a limited range over which they will grip) and/or a "missing" ER collet (which has a gripping range of 1.00mm (~0.040") for your lathe, then "soft jaws" may rescue you. If you have limited normal use for say ER or metric collets and you have a "2-piece" (soft) jaw sat, it may just do the job for you.

    I am surprised that "time" is such an issue for so many HSM-ers as it suggests that, at least in part, that "time = money" which suggests a commercial component. If that is the case, then perhaps the question is not so much as to whether you can afford to buy them, but whether you can afford not to.

    I am not suggesting that "soft jaws" are the panacea for all the ills, ailments and problems with "chucking" on the lathe (or mill) but they are a very handy tool or accessory to have.

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  • oldtiffie
    replied
    Deleted - duplicated post

    Deleted - duplicated post
    Last edited by oldtiffie; 02-08-2009, 05:31 PM. Reason: Deleted - duplicated post

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  • lazlo
    replied
    Ian, to hold really thin parts, like for making washers, in a normal 3-jaw chuck, see the neat jig that Peter Neill made recently.

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  • Teenage_Machinist
    replied
    I would have a few for the 3 jaw just for those odd thin parts that are nigh impossible to hold.

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  • lazlo
    replied
    Originally posted by oldtiffie
    The chuck I bought had the normal inside/outside 3-jaws. The 2-piece jaws are an accessory/extra.
    But have you purchased the optional 2-piece soft jaws for them? Those optional jaws will only work on the same brand/model chuck.

    Leave a comment:


  • lazlo
    replied
    Originally posted by JCHannum
    In the home shop, most jobs are one off, and a four jaw chuck is usually much faster to set up and run the part that to fit and machine a set of soft jaws. In a production or job shop where multiple parts are usually the case, the soft jaws will quickly pay off.

    A well equipped lathe should have a face plate, four jaw chuck and three jaw chuck, pretty much in that order.
    Agree Jim. The 3-jaw chucks for my big lathe have 2-piece jaws, but my "go-to" chuck is a superb Burnerd heavy-duty 4-jaw.

    I've made soft-jaws for the 3-jaw a couple of times, including Forrest's recommendation of turning an acme thread into them to hold a leadscrew while I was turning down the ends, but in general they're not worth the time/effort for 1-off jobs, especially if you have a collet setup.

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  • JCHannum
    replied
    There is no best way of doing something other than the one that is at hand and works.

    Every job has a cost and time is only one part of that. In the home shop, most jobs are one off, and a four jaw chuck is usually much faster to set up and run the part that to fit and machine a set of soft jaws. In a production or job shop where multiple parts are usually the case, the soft jaws will quickly pay off.

    The other difference with the commercial shop is that the soft jaws are usually figured into the cost the customer pays as either tooling or amortized as overhead. You might not find an over used four jaw in a commercial shop, but you may well find a large pile of equally dusty soft jaws under a bench. I have seen both in many instances.

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  • Spin Doctor
    replied
    Yes Soft Jaws work quite well. The problem I hve with them is measuring the diameter . In a perfecrt world we'd use the pie shaped sections

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  • wierdscience
    replied
    Originally posted by mochinist
    For a homeshop you guys always say time isn't an issue. For a pro shop, face it we all have slow times occasionally, thats when you make up stuff like soft jaws for the lathe and your mill vice, if you have a cnc mill even better as you can pump them out pretty quick. Say you never have any slow times, then you can afford the expensive ones out of the tool porn catalog, good for you.


    Once again, I go in a lot of shops, the four jaws are usually covered in dust because of lack of use.
    Yup the four jaw is sitting on the floor infront of the lathe,last time it moved was last week when somebody swept under it,before then????

    As for making the jaws it took longer to bandsaw out the stock than it did to mill,drill and counterbore.If I had some 2x2 stock it would have took 45 minutes tops.

    Leave a comment:


  • mochinist
    replied
    Originally posted by JCHannum
    I don't think anybody has denied the advantages of a three jaw chuck fitted with soft jaws that are machined to fit the workpiece. It is a very accurate way to go.

    The soft jaws are also expensive to purchase and time consuming to make. They are usually only used when no other means is available or when repeat parts are to be made. The soft jaw is just another tool in the box to be used when it's advantages outweigh it's shortcomings.

    A well equipped lathe should have a face plate, four jaw chuck and three jaw chuck, pretty much in that order.
    For a homeshop you guys always say time isn't an issue. For a pro shop, face it we all have slow times occasionally, thats when you make up stuff like soft jaws for the lathe and your mill vice, if you have a cnc mill even better as you can pump them out pretty quick. Say you never have any slow times, then you can afford the expensive ones out of the tool porn catalog, good for you.


    Once again, I go in a lot of shops, the four jaws are usually covered in dust because of lack of use.

    Leave a comment:


  • JCHannum
    replied
    I don't think anybody has denied the advantages of a three jaw chuck fitted with soft jaws that are machined to fit the workpiece. It is a very accurate way to go.

    The soft jaws are also expensive to purchase and time consuming to make. They are usually only used when no other means is available or when repeat parts are to be made. The soft jaw is just another tool in the box to be used when it's advantages outweigh it's shortcomings.

    A well equipped lathe should have a face plate, four jaw chuck and three jaw chuck, pretty much in that order.

    Leave a comment:


  • oldtiffie
    replied
    Jawing

    Sorry lazlo.

    I went to a lot of trouble to make sure that the specific soft-jaws or "2-piece" jaws fitted the specific chucks.

    The chuck I bought had the normal inside/outside 3-jaws. The 2-piece jaws are an accessory/extra.

    I've seen chucks modified by then arc/stick now MIG welding a "U" to each jaw ("open" end inward) with a tightening radial bolt on the "outer" part of the "U" with the sides of the "U" drilled for bolts that pass through the "U" and the "soft-jaw". The soft jaws were made to suit.

    Sure, it was a "jury rigged" job, but it worked.

    I've seen HR mild steel "soft jaws" "stitch"-welded (not too much!!) to the chuck jaws and just ground off and replaced when necessary. Didn't do the chuck a lot of good, but it was pretty well buggered before the welding anyway. The machining of the soft jaws "corrected" (m)any of the "faults" in the chuck.

    There are a lot of misconceptions about the accuracy of 4-jaw chuck and collets. Both may be reading "spot on" near the chuck jaw face but can also "throw" and be "off-centre" say 2", 3", or what-ever out from the jaw faces so that the job describes a cone instead of a cylinder. And they will be with the manufacturers specs or industry bench-marks.

    If you have a short length of a job protruding from a 4-jaw chuck or collets and it is "spot on" as regards TIR and most of the job is inside the lathe spindle bore, you will have no real idea - just a lot of trust and hope - that the job TIR is just as accurate "in there". Maybe so - but bore the soft jaws and you can have a LOT more, perhaps pretty well total confidence in the concentricity and TIR of the part of the job inside the lathe spindle bore.

    Next, any "throw" in any holder (chuck or collet) is not a real problem at all if the finished job is within the work-piece envelope inside the "throw". In short if the TIR is 0.100" and there is 0.105" to be removed, the throw will not affect the accuracy of the finished job.

    A passable set of soft-jaws on a three jaw chuck can not only "correct" these "errors" but can operate to the full extent - and beyond - the limits of the 3-jaw basic jaws - just as the OP showed in fine fashion.

    There is far too much made of collets and 4-jaw chucks to the detriment of 3-jaw chucks with soft jaws.

    I suggest that anyone who is pushed for money and has a need should seriously consider getting a 3-jaw chuck with "2-piece" jaws for use with soft jaws.

    Leave a comment:


  • lazlo
    replied
    Originally posted by oldtiffie
    Well TM,

    As your lathe will take a 4" chuck, I doubt that a 5" chuck would kill your lathe so try these:
    A selection:
    https://www.machineryhouse.com.au/Lathe-Chuck-Soft-Jaws
    Tiff, most chuck jaws from different manufacturers aren't interchangeable.
    Heck, many machinists will tell you that replacement jaws from the same manufacturer never fit as well as the original jaws.

    If you want soft jaws, you really need to buy a chuck with 2-piece jaws.

    Nice job Darrin!

    Leave a comment:


  • oldtiffie
    replied
    Jaws.

    Thanks Steve.

    You won't regret it.

    If you can bore the hole you are there!! Further, as the OP had pretty well done, you can incorporate an internal "stop" as well (counter-bore etc.). Just about every soft-jaw you see only shows them gripping on external surfaces - they work just as well as "internal" jaws gripping tubes, bores etc. The "trick", generally, is to clamp the jaws onto something while they are being machined for the part. The more accurate it is, the closer you will be to having the same points of the scroll and jaws in contact when the part is being clamped.

    Using soft-jaws all but wipes out the case for 6-jaw chucks (expensive) for "thin round" material as well. I have two 6-jawed chucks on specialist grinding tools and I've never even had to consider let alone use them on my lathe.

    There is no reason why soft-jaws cannot be prepared on the lathe and then transferred to the mill table or rotary table.

    They can be very versatile.

    They can beat the snot out of collets and 4-jawed chucks for accuracy and repetition.

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  • S_J_H
    replied
    Wierd-
    That's a great example of what can be done! I have never used soft jaws before. I can certainly see how useful they can be.

    Tiffie,
    I'm going to have to try soft jaws soon. I have an old 3 jaw I think I'll modify the jaws on to accept them.


    Steve

    Leave a comment:

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