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R8 endmil holders

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  • R8 endmil holders

    I have a set of R8 collets x 32nds, and a set of ER40 collets and R8 collet chuck. Do I REALLY need to invest in setscrew endmill holders? If so, whycome?

    Son of the silver stream ..... Bullet caster.

  • #2
    Wouldn't have thought so.
    I have just the standard R8 collets in metic and imperial and a R8 to ER32 chuck and collets and that does me for all my work.

    In fact I don't own any end mill holders only a couple on INT 40 for the big mill but they never get used.

    Personally I have never liked the idea of just one screw on a flat holding a cutter.


    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


    • #3
      Do some searching, the answer to what you ask is akin to a religious argument and has played out many times.

      I also see no reason for EM holders, and generally use only collets. I've even had screw ups so bad that it visibly (dramatically!) lifted a 9x42 Bridgeport table and knee, breaking a carbide EM, and it never moved in the collet. I know it didn't move because it was a TiN coated 1/2" bit and the coating was just at the edge of the collet both before and after the event.

      For me, the only time I look for an EM holder is when I need clearance from the quill/spindle. Sometimes you need that EM out from the spindle just to get where it needs to be. Far from ideal in many ways, but there are EM holders that will give you more range.

      Others will swear that disaster looms for any so foolish as to put an EM within 5" of a collet. Me, I haven't seen it. I say keep your collets clean and properly tightened, save the EM Holder money for other tools...
      Master Floor Sweeper


      • #4
        Same here.

        I second John Stevenson's answer.

        I have never had anything shift in an ER collet. I have an MT3/ER-32 and a MT3/ER-16 set.

        If the end mill cutter "walks down" the/its spiral from the collet, there is something drastically wrong.

        In my opinion a set/grub-screw is a poor excuse for a driver/key.


        • #5
          I third Sir Johns answer.

          The Mazak FJV-20 machining centre in my business partners toolroom uses ER32 collets, and with 20Hp on the spindle it tends to cut a bit more agressively then most home shop machines



          • #6
            And I concur as well. I use R-8 collets for all my work, including for drill bits that will fit properly.
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            • #7
              I've never had a problem with holding an end mill in an R8 collet. I've got top-quality Hardinge collets. If I had collets that cost $3.99 for a complete set by 64ths, its might be a different story.

              I have a couple of end mill holders that I use occasionally only to get more clearance. Depending on its design, your ER collet holder may achieve that same purpose for you.

              In your situation, I think I'd wait until I ran into a situation where I said, "Self, for this job I NEED an end mill holder" before I went out and bought one.
              Last edited by SGW; 08-05-2008, 07:31 AM.
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              • #8
                As stated by SGW, they give you alittle more reach


                • #9
                  The choice is personal, or job dependant, the EM holder providing extended reach when that is needed.

                  I will contest John's statement regarding the holding power of an EM holder. The setscrew holder is intended to be used with endmills having Weldon flats, and when those end mills are installed properly in a properly designed holder, holding power is superior to an R8 collet and accuracy is comparable.

                  The Weldon flats may not be as prevalent across the ocean as the Clarkson system is not often encountered here, but it is a very secure method of end mill retention.
                  Jim H.


                  • #10
                    Originally posted by John Stevenson
                    I have just the standard R8 collets in metic and imperial and a R8 to ER32 chuck and collets and that does me for all my work.
                    Same here, I use an R8 collet set and an ER40 chuck and that covers all my needs. I just nabbed a 1" APKT insert facemill that will be an interesting test of the holding power of the "25 - 26mm" ER40 collet.

                    If that doesn't work, I've got 3/4", 7/8", 1" ETM R8 endmill holders that I occasionally use for my big corncob roughers.
                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


                    • #11
                      And, in the other corner.....

                      This discussion is pretty lop sided so far, so let me try to balance it a little

                      I use the em holders quite a bit. As stated, they give the extra reach sometimes needed to clear clamps, etc. They also come in large sizes (1, 1 1/4, 1 1/2) which I use to hold carbide face mills with straight shanks and screw machine drills over 1 inch. In general, the em holders have a smaller dia head than collet holders and give a little more clearance in some applications. I also use the face mill holders for large carbide face mills.

                      OTOH, since getting a er-16 collet extension, I have the extra reach for small size em's, etc so I don't use the smaller ones as much. Plus the er collets can be used for drills when needed.


                      • #12
                        I use end mill holders for some of the same reasons stated by others: to get the tool in the position I want it for certain jobs. However, since I have recently purchased an ER 32 holder and collets, that may change. I have also used R8 collets for holding primarily end mills. I have a modest collection in 1/8" increments, but I have rarely ever used anything other than the 3/8', 1/2", 5/8" and 3/4" sizes. Which gets me to the question of why buy a set of R8 collets in 1/32" increments? The ER collets should be much superior in holding tools that require any variation in size.


                        • #13
                          I can pull an endmill out of the best R8 collets made and have done so in our ER collets at work also.
                          The main thing here is useage. When using a hog mill (like pictured) and taking a very heavy cut (.375 DOC or deeper) I do use an endmill holder. Only because prolonged useage and heavy cuts will pull them slowly out of the collet no matter what. A Weldon style tool holder with a set screw will not do this if the endmill is installed correctly.

                          Collets will do probably 75% of the work but an endmill holder is very, very useful in 1", 3/4" and 1/2" diameter sizes. I have a 1/2" and 3/4" I use in my garage shop, at work we have several other sizes that get used alot.

                          If someone has never pulled an endmill from a collet they are obviously not pushing the cutter to its limits or trying to make money with it. Collets simply won't consistently hold a large endmill 5/8" or larger in diameter when worked hard. Light cuts they work great and will hold fine.


                          • #14
                            Mcruff-- I think the issue is the particular mill you have pictured...

                            If I am seeing it correctly, the helix angle and cutting resistance wants to pull the mill out of the collet.

                            Paul Carpenter
                            Mapleton, IL


                            • #15
                              Originally posted by sidneyt
                              Which gets me to the question of why buy a set of R8 collets in 1/32" increments?
                              Well for one thing, like Evan, I use my R8 collets for drill bits also. I can get way more clearance that way. Especially when I have work clamped to my 10" rotab and taking into account that I loose about 3 inches of vertical travel in my head because it hits the ceiling before toping out. ( I need a new shop!!!)
                              Last edited by dockrat; 08-05-2008, 11:40 AM.
                              Ernie (VE7ERN)

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