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5C collets for mill spindle?

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  • 5C collets for mill spindle?

    I would like to make a vertical head for my horizontal mill. I don't need to make a quill, as the mill head has vertical movement on dovetail ways with a hand lever, that gives about 6" travel. All I need to build is an adapter to attach to the overarm, a bearing housing and a spindle.

    My question is; Are 5C collets suitable for use in a vertical mill spindle?
    The reason I'm considering them is that I already have them in a greater range of sizes than the B&S #9 (9B) that the horizontal spindle takes, and they can take up to 1.125" versus .750" for the 9B.
    Also the 5C takes a hollow drawbar, which may come in handy someday, versus a solid .5" for the 9B.

    Are there any mills out there that use the 5C in the spindle?
    I know that 5C is used extensively in lathes, but have never heard of it being used in mills.
    I would appreciate hearing the pro and con of such an application. If someone out there is useing it, I would like to hear about it.

    BTW the mill is a very old "Garragus" #0
    it has rack and pinion feed for the X feed and the head vertical motion (horizontal spindle)and screw feed for the knee (Z) and Y feed. It was an old lineshaft driven machine. I mounted a 1400 RPM 3/4 HP reversible motor on it and replaced the flat belts and pulleys with V belts and pulleys with the final drive to the spindle #40 roller chain. (about 22-1 reduction) Very slow and powerful
    I don't use keys on the arbors, to provide something to give if there is a major jam up.

    Thanks in advance for any advice.

  • #2
    I have a small old vertical mill that has a spindle that takes #2Morse taper collets, but I see no reason that the design couldn't be modified to use 5C collets. In fact I have an acient horizontal mill that I was thinking of building a head for, and the 5C collet would be a good option, as I have a set for my SB lathe. My old vertical mill is belt driven and a very simple design. I purchased a mill drill and don't use it much any more, I could dust it off and send digital pics if you are interested.


    • #3
      Did the old Hardinge horizontal mills use 5c's
      Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


      • #4
        5C is a poor choice because it has short bearing pads and only a minor keyway preventing turning. Best to stick to full length collets such as the double angle ER or single angle (8*) TG series for maximum versatility. 5C collets can be purchased for use in tool grinders that have a 1.25" collet length, but they are for sharpening, not endmills.

        Another good choice would be a Osborn Autolock Chuck - these use the threaded endmills which are screwed into the collet which is then clamped in the chuck - preventing pullout of the endmill.


        • #5
          I would think an R 8 would be the best choice.


          • #6
            Another reason not to use 5c collets. When you are milling on the side of an end mill there can get to be considerable screw effect trying to pull the end mill out of the collet. I used to use B&S #7 and #9 collets for holding end mills. Not any more! Don't even ask why! But I found out the hard way that end mills will pull out of collets.


            • #7
              I don't know for sure...but realize that for a milling machine you can get by with only about 3 collets, anyway, (3/16, 3/8, 1/2), so buying new ones, even good ones, is not a huge expense.

              I think I'd go with R-8. Of course, Thrud has I think the best idea -- get one of those Erikson ER double-angle collet sets.
              Try to make a living, not a killing. -- Utah Phillips
              Don't believe everything you know. -- Bumper sticker
              Everybody is ignorant, only on different subjects. -- Will Rogers
              There are lots of people who mistake their imagination for their memory. - Josh Billings
              Law of Logical Argument - Anything is possible if you don't know what you are talking about.
              Don't own anything you have to feed or paint. - Hood River Blackie


              • #8
                Thanks everyone for your replies

                Dave, I actually have a few ER type collets,
                I was considering 5C because I have a much larger assortment of them. With ER type I would need to machine a relatively longer taper seat and also make a closer. I have a B&S #9 reamer so I am leaning towards making the spindle B&S #9, but making it oversize so in the future I can retrofit it with ER collets. Unless I find a vertical head cheap.....
                Then whatever it comes with, is what I'll have to use, unless it is easily modified to ER.

                I guess 5C is OK for lathe use because there is no force pulling out of the collet, and if long bars are held, they would usually be stabilized at the outboard end of the spindle by a cathead or such. With endmills there is more side load, and pulling out force unless useing right hand cutting left hand spiralend mills.

                Thanks for your advice, someday when I get to actually build it I'll let everyone know what I did.


                • #9
                  Just a thought but I once made a small mill spindle out of a TG-100 collet chuck with a 8" long shank.I simply shrank on a collar on the chuck end and annealed the opposite end keywayed and threaded it.Then made a housing to accept some tappered roller bearings and walla!one milling machine head!Hot fast and cheap.

                  [This message has been edited by wierdscience (edited 01-20-2003).]
                  I just need one more tool,just one!


                  • #10
                    This discussion kinda touches on a question that's been festering in the back of my mind for some time. What is the main purpose of those R8 endmill holders? Is it to get a tighter grip? .. or for convenience in changing endmills? ...or what? I can't see much convenience gain, since changing size endmills you still have to change the holder.
                    Plus, it seems you will have introduced one more potential source of runout.
                    Lynn (Huntsville, AL)


                    • #11

                      The R-8 mill holders are the po'-boy solution to endmill retention. Pretty clunky, but close enough for most everyone.

                      Collets are required for safe carbide use (Less chance of the carbide pulling out while cutting) and are second only to the shrink systems in accuracy. They are also used for accurate drilling, tapping, and reaming. Much more useful than normal endmill holders.

                      Hot & cold shrink systems are currently top dogs for accuracy. The Cold shrink system is used on 3/8" and smaller mills at 30K+ rpm - developed in Minnesota...

                      [This message has been edited by Thrud (edited 01-22-2003).]


                      • #12
                        so I see some people say r8 over c5 why?


                        • #13
                          For the mill, the most common spindle in home machines will be MT#2 or R-8. R-8 is the best milling spindle. but to hold endmills better, collet chucks are prefered over just an R-8 enmill holder for the reasons discussed above. That does not make an R-8 Endmill holder bad, it is just not as accurate, but it is cheaper to start out with. A full range R-8 Endmill holders would set you back about $300 for a really good set. A ER-40 Shank and collet set would cost about $900 for a really good set. But the collet set is far more versatile, and eliminates the need for a drill chuck.

                          Good points to each side. In a perfect world we could have all of it...