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straight shank vs. dedicated shank milling tools

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  • straight shank vs. dedicated shank milling tools

    So I've got a bridgeport and almost all of my tooling is R8 integral shank.. chucks,
    indexables, saws, etc.

    I'll admit getting the drawbar in and out is getting a bit tiresome and I'm considering
    moving to maybe 3/4" straight shank everything and just leaving the 3/4" R8 collet
    in the spindle.

    I've always prefered integral shank but I'd be hard pressed to give you a good
    reason why. Just seemed better?

    Not too worried about losing Z space as I don't work on much of anything that is
    very large.

    Any downsides to moving away from integral shank other than some lost headroom?

    I'm in the market for 2-3" 45* indexable face mill.

    Option B is a power drawbar.

  • #2
    I'd go with option B, saves time on tool changes. Why replace tooling you already have?

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    • #3
      Option B. You'll lose a lot of rigidity with larger cutters and they can walk out of single angle collets.

      1/2" is often the recommended maximum for collets and heavy cuts.

      Could be that your drawbar's too long. An inch or so of engagement is plenty.
      Last edited by Jono; 12-06-2013, 09:38 AM.

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      • #4
        Unless youre less than 5'8" or have a riser on the mill I see no problem with a manual draw bar.
        Now there are 3 or 4 of the kids in shop classes that do have a real problem on our Bridgeports. :-)
        But a one step "stool" does fix that. :-)
        ...lew...

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        • #5
          You always want to maintain the shortest distance from the spindle bearings to the load (cutting forces.) Your integral shank holders are always going to be the strongest, with less chatter and better tool performance overall.

          Get a power drawbar or look at a quick change system. Here's one I have seen and the users have raved about it. I have not been able to justify the expense of even a power draw bar, but I could see it happening with a few years more of aging.

          http://www.mach-1tooling.com/

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          • #6
            Hard to argue against a power drawbar For manual drawbar, though, definitely use a ratchet. I wonder if your "getting a bit tiresome" is due to having to continually reposition a solid wrench?

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            • #7
              I have a mix of dedicated R8, straight shank and set screw endmill holders and collets. For cutters that will see a heavy load I prefer the set screw holders. For boring heads I prefer the dedicated R8. For milling heads I prefer dedicated R8. For drill chucks I have dedicated R8 and straight shank. For everything else I prefer the convenience of the collets.
              It's only ink and paper

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              • #8
                wow, that mechanical quick change system is something else. I watched the youtube "installation" video -- now I see why
                its so expensive.

                Arthur -- ratchet.. thats an interesting idea, I'll have to try it. Right now I've got a double ended hammer, socket on one
                face, brass on the other.

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                • #9
                  I used a ratchet/socket for quite a while. Then I got an air ratchet. It was a bit unhandy with the air hose. Finally went to an air drawbar. Such a big difference! Have one on both mills now.
                  I also have the Tormach tool system on the mill with SWI retro fit CNC. So far it has been a good set-up for that mill. But for manual milling the Tormach tooling can pull out of the collet with too heavy a feed/cut.
                  R-8 shank tooling is much more ridged. And for some operations is preferred. You have to judge which is better for each job. That's why I keep both on hand.
                  Krutch


                  Mentally confused and prone to wandering!

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                  • #10
                    Originally posted by krutch View Post
                    I used a ratchet/socket for quite a while. Then I got an air ratchet. It was a bit unhandy with the air hose. Finally went to an air drawbar. Such a big difference! Have one on both mills now.
                    I also have the Tormach tool system on the mill with SWI retro fit CNC. So far it has been a good set-up for that mill. But for manual milling the Tormach tooling can pull out of the collet with too heavy a feed/cut.
                    R-8 shank tooling is much more ridged. And for some operations is preferred. You have to judge which is better for each job. That's why I keep both on hand.
                    The cheap little butterfly-impact at HF, $14.99-$29.99 depending on sales and coupons, is one of the best bang-for-the-buck things you can buy for yourself. Drawbar is no longer drudgery, just a quick second to engage or disengage a collet. Try it, you will not only like it, I guarantee that you will love it. The butterfly-impact is well suited to holding in the palm of your hand while working. The one I got at HF also had a builtin swivel for the air hose connection, making it even easier to deal with.
                    Cheers,
                    Gary

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                    • #11
                      I am using a dewalt 1/4" hexchuck battery impact driver. . . an adapters and a socket, works great altho I still have to smack it most of the time with a soft hammer. maybe a 1/4" plate affixed to the bottom of the battery would work instead of the hammer.. .. anyone else try that ?

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                      • #12
                        yes I always need to smack my tooling out.
                        loosen with hammer-wrench, flip to brass side, one tap and its out.

                        Though I think its time for a new drawbar, I've shortened a few times, I think I only have 3/8" engagement so those
                        little taps add up, deforming the first few threads over time.

                        I'd be interested to hear how the air/electric impact driver guys get the bar out -- is the just action of using
                        an impact driver enough to simply get the works loose? No tap required?

                        Comment


                        • #13
                          My power draw bar is a butterfly impact afixed atop the drawbar with a spring to lift it when not in use.
                          I have never had to tap the drawbar since I installed the impact!!!

                          THANX RICH
                          People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

                          Comment


                          • #14
                            Originally posted by v860rich View Post
                            I have never had to tap the drawbar since I installed the impact!!!

                            Interesting. I just recently built a power drawbar unit, and a few tools still get stuck in the spindle. A real pain since there's no room to tap! Maybe I'll try polishing the spindle taper and the offending tools. Any other ideas?

                            Comment


                            • #15
                              I had the same problem with the DIY butterfly impact wrench based power draw bar.

                              But whatever power unit you're going to install, keep in mind that you'll need to uninstall it every time you use a right angle or some other BP attachment.
                              Mike
                              WI/IL border, USA

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