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Tell me about collets please

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  • Tell me about collets please

    What is the scoop on collets for my lathe? I have never used them, and don't know an awful lot about them. I believe that the chuck must be removed and the shank of the collet fits into a corresponding taper in the end of the headstock spindle .As I understand it, they come in 1/32" increments and will hold a shaft more securely than a 3 jaw chuck.They are supposedly more accurate (My lathe chuck has about 0.003 TIR). Some have a threaded i.d. and need a threaded rod that passes all the way thru the lathe spindle to a threaded handwheel at the far end of the spindle tube to draw the collets closed. Some have a threaded o.d. on the front of the collet which takes a threaded nut which is tightened by a special tool to close the collet and securely grasp whatever is held in the collet. Some others have a large handwheel that sets where the chuck normally goes to tighten and loosen the collets. I have seen adds for collet blocks, both square and hex shaped on the o.d. into which the collets, gripping a part can be inserted. People have been suggesting that I should have a collet with a square center hole to grip a series of 3/16" square rods on which I wanted to turn a diameter on one end for my current Stephenson's Rocket axle spokes. I have both a 3 jaw chuck and an independent jaw 4 jaw chuck, and they have worked well for me for twelve years. The diameters of material I work on run the gamut from 1/8" up to and including 5 1/2' diameter. Very little work that I do is repetitious. Would it benefit me in any way to buy collets?---Brian
    Brian Rupnow

  • #2
    thats a question with a long answer and will have a confusing array of answers depending on ones paradigm. imo the three jaw doesn't much enter into it, you usually need better concentricity than it offers when considering a collet so its more collets vs 4 jaw. They are obviously a real time saver vs the 4 jaw chuck for accurate work and with a quality set they are capable of very accurate work. Clearly their greatest benefit is that clamp to work surface is very close to perfectly concentric with the lathes axis, so you can multiple operations and keep things concentric.

    with small lathes (instrument makers/watchmakers) they are pretty much a requirement. You'd see probably dozens of lathes with full sets of collets before you came across one with a 3 jaw. On larger lathes, its arguably more a convenience, although I couldn't hold for example 1/8 in my big lathes 4 jaw. Regardless, I wouldn't be without them and they probably see more service than any other tooling
    Last edited by Mcgyver; 07-11-2020, 01:35 PM.
    in Toronto Ontario - where are you?

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    • #3
      If I had to make more than 4 pcs of the same part or the same cut, I would be wanting collets. They can give you 4-jaw accuracy without the hassle of having to indicate it in every time -- with collets you only have to do the setup once. A huge time and aggravation saver when multiple parts require accuracy.

      My lathe came with 3C collets which work in the spindle but the size range is quite limited simply because the spindle itself is limited (3/4" or 20mm ID). ER collets with a collet block to fit your spindle can give the full range of sizes that your spindle has, and even go beyond it. Bonus, ER collets are very common and popular.

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      • #4
        Lot of variables in collet selection for a lathe. The most important consideration is the bore dia through the spindle and what the taper of the spindle bore is. The most common / desirable lathe collets are 5C BUT they are probably too large to use with your lathe (spindle bore). Another option is a 5C collet chuck, that gets by the spindle bore problem, it mounts like a regular chuck and opens/closes with a chuck key. There are countless other types of collets also, if your lathe bore is MT3 or MT2 those collets are also common.

        So.... need a bit of data about your lathe spindle to narrow down your choices.

        Oh yea, don't limit your thinking to the lathe, a collet setup often is also used on the mill a lot, there are blocks etc to hold the collets.

        Lathe manufacturers very often offer collets systems made for their lathes, you might check into that.
        Last edited by Sparky_NY; 07-11-2020, 02:04 PM.

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        • #5
          Not all collets are created equal. Some of the imports are not exactly centered. I wish there were a way to know which were reliable. My experience is with 5C collets in this case.
          Vitَria, Brazil

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          • #6
            My lathe is 1.5" inside spindle diameter. It comes with a 5/3 reducing sleeve to allow use of a MT 3 center in the end of the spindle.
            Brian Rupnow

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            • #7
              Click image for larger version

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ID:	1886235 Maybe a 4 Jaw scroll Chuck might fit your needs I have a 8"&4" that I grip with my 12" 3 jaw.Shars has them as small as 3" the 4" will grip down to 7/64" and 5/8" square shaft slides through.You could make a Press in plug to go in back of Chuck for a stop for doing repetitive jobs like your wheel spokes. Click image for larger version

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              • #8
                Originally posted by brian Rupnow View Post
                My lathe is 1.5" inside spindle diameter. It comes with a 5/3 reducing sleeve to allow use of a MT 3 center in the end of the spindle.
                Wow, didn't think it was that large ! You can use 5C on that lathe then. Check to see if the manufacturer offers a collet setup for your lathe. If not, you will need a MT5 to 5C nose piece (bushing) and a drawbar the proper length.

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                • #9
                  I just priced 4 jaw scroll chucks. They seem to start at about $700 and range from there up to $1700.--bit to rich for my blood. I couldn't find a 5" size.
                  Brian Rupnow

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                  • #10
                    For small parts in low quantities <100, it is often faster to hold a collet chuck in a 3 jaw rather then change chucks, Kalamazoo makes these nice small 5C chucks.

                    Less then $500.00 https://www.ajaxtoolsupply.com/ka5cc...SABEgLgDPD_BwE

                    If you switch between chuck work and collet work often it is well worth the money.
                    Say from this

                    To this

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                    • #11
                      CDCO Tools.com has 5C collet chucks on sale for $133.00 and $139.00 depending on your lathe.
                      Vitَria, Brazil

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                      • #12
                        Brian, I would recommend that you look at an MT5 to 5C adapter and a drawbar for your situation. 5C is a great way to go, the collets are still commercially available (from many suppliers) and used quality brands are easy to come by. They are very nice for both repetitive jobs and small diameter jobs. Say you had a batch of stay bolts to make, #10-32 thread diameter on both ends of a rod. Take some drill rod and the right sized collet with a stop, set up your cross slide with a cut-off tool and put a die in your tailstock and go to town. You can now make stay bolts as fast as you can load / unload the collet (which doesn't take much time). Another bonus that has not been mentioned is that for the small diameter work you can get nice and close to the collet to keep flex and chatter to a minimum without worrying about hitting chuck jaws. It just feels like you can get in nice and close while keeping things safe and controlled.

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                        • #13
                          Zero-Set style chuck backing plate is another option. Adapt your current chuck with one, get it dialed in to .0005 repeatability on the same diameter of work. Might be the cheapest option of all.

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                          • #14
                            Originally posted by brian Rupnow View Post
                            My lathe is 1.5" inside spindle diameter. It comes with a 5/3 reducing sleeve to allow use of a MT 3 center in the end of the spindle.
                            Thats a good generous size. You could use the full capacity of the ER40 collet range and have room to spare -- ER collet tooling is so popular nowadays (for good reason, IMHO) thats what I'd be looking at. Plus as others have mentioned, they are useful in mill setups too.

                            EDIT Sparky has an even better idea with using 5C collets directly in the spindle.

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                            • #15
                              Originally posted by brian Rupnow View Post
                              I just priced 4 jaw scroll chucks. They seem to start at about $700 and range from there up to $1700.--bit to rich for my blood. I couldn't find a 5" size.
                              Shars 3"$146,4" $155 ,6" $167 US I would think you could grip any of these in your 3 jaw with external jaw,I use mine lot's.

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