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  • Too close to the spindle.

    I was inspired to share this by someone posting about modifying an R8 collet to take a drill bit.

    This is my solution to not wanting to, or not being able to, lower the table and put in a drill chuck.

    It fits in my largest R8 collet. Maybe most of you have already done something like this, or it's nothing new.

    But.... here it is. It seems I can hold almost any smaller drill bit with this set of collets which came from who knows where.
    Attached Files
    Vitَria, Brazil

  • #2
    Those are ER series collets of some sort. You can GO HERE to look up the OD size and length of the collets to see which series. I'm thinking that they are ER25 or possibly ER20.

    That same thread has me recalling the times I needed to extend drills or end mills by some amount. I'm thinking of possibly an ER25 collet chuck with a 20mm shank. So essentially what you have already.

    And for that I'd also need to buy a set of metric R8 collets. But I've been thinking of that anyway since most of the lower cost solid carbide end mills I can get easily tend to have metric shanks.

    What an ER25 chuck with the 100mm long 20 mm shank would provide is an adjustable stick out to work in closer to some tight edges or as a drill chuck alternative to give me back a couple of more inches of vertical room. That would be a handy thing.

    The other option is the shop made alternative of a great number of shop made spuds that are turned to some OD to fit my inch collets with a short or long as required extension to fit end mill shanks or specific drill sizes. This would use time and round bar up. It would be cheap though. But perhaps more annoying is that the need to stop and make such items would always occur right in the middle of something else. Granted it won't use up MUCH time. Probably 15 to 20 minutes each time. But still..... we're talking right in the middle of something else. But it only costs a little time and about a buck's worth of steel bar stock.... but still we're talking right in the middle of something else.... and round and round we go.....

    The message though is that there are options out there. Either buy and put away until needed or make up as the need arises.
    Chilliwack BC, Canada

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    • #3
      Originally posted by BCRider View Post
      Either buy and put away until needed or make up as the need arises.
      Better to have tools you don't need, than to need tools you don't have.

      Comment


      • #4


        "What an ER25 chuck with the 100mm long 20 mm shank would provide is an adjustable stick out to work in closer to some tight edges or as a drill chuck alternative to give me back a couple of more inches of vertical room. That would be a handy thing."

        That is an advantage I forgot about. There are times when a drill chuck is too close to the work piece.

        Also, if you are tapping, sometimes although a drill bit will fit, the tap won't. I do have a few long "pulley taps" but

        nowhere near enough for every situation.



        Vitَria, Brazil

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        • #5
          The reach thing is more about having something with a smaller diameter than the chuck or nose of the mill. But yeah, you've certainly got the reasoning behind the idea of an extendable small diameter holder with wide range of grip sizes courtesy of the collet choice.

          Your idea for drill vs tap is an idea that didn't occur to me. Might be worth having TWO ER25 long shank chucks. I know I've often ran into issues with the drill bit being long enough to avoid the proximity to a side feature only to realize that the tap won't reach. In most cases I was able to tap from the other side. With one I actually did make up an extension. So yeah, that is a great additional reason for something with some degree of extension adjustment.
          Chilliwack BC, Canada

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          • #6
            Those look more like ER16 to me. You can also get ER11 and ER8 to go really small. I have ER16 through ER40 and use them all on a regular basis.
            Kansas City area

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            • #7
              Maybe it's not worth making anything yourself. Look what I just found on Amazon. Click image for larger version

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              Vitَria, Brazil

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              • #8
                Back when I still had a mill-drill, I'd spent what was then a small fortune on an ER-25 holder with a 3/4" shank. I cut down the shank to only about an inch and a half long.

                That way, I could mill and if needed, drill with the holder in a collet, without having to readjust the head height, and thus lose my 'zero'.

                I still have it today, along with R8 shank holders in ER-16 and ER-20, and straight-shank holders in ER-11 and ER-16. They're quite handy, and I use them frequently.

                Given the fairly decent quality and comparative low cost of an imported ER holder, I wouldn't even consider trying to make one.

                Doc.
                Doc's Machine. (Probably not what you expect.)

                Comment


                • #9
                  ER16 only goes to 3/8 or 10mm's. I'd like to keep the option of up to 1/2" shank.... which apparently I can. I found an ER20 chuck with 3/4 x 2.5" long shank. Scaling off the side view I find that the chuck portion is roughly 1 5/8" long. So roughly half the length of the drill chuck.

                  The 2.5 inch long shank seems a touch short. But when I checked my 3/4 inch R8 collet will only take just a whisker more than 2.5". If I were to find a 100mm or 4 inch long shank option for later I could use it for lighter duty use. But the stickout would prevent anything larger or more than the lightest of cuts anyway.

                  With 1" of shank in the collet I'd be looking at 1.5 + 1.63 = 3.13" of extension. And for extended milling with smaller sizes I'd consider that just fine for that sort of shank diameter. The nut is roughly 1.38" in diameter. So not super ideal. But I think it will cover a lot of uses. It's on order and should arrive this Thursday. I'll hopefully have time for a quick report on the quality level

                  Chilliwack BC, Canada

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                  • #10
                    With R8, the best size straight shank for er series collet holders is 19mm or 3/4". They can then pass deep into the R8 collet. This allows a good choice of lengths. The biggest properly usable R8 collet is 20mm which only allows a relatively short depth, as the middle of the collet is not large enough diameter on the od to be bored more than 19mm.

                    Comment


                    • #11
                      Originally posted by old mart View Post
                      With R8, the best size straight shank for er series collet holders is 19mm or 3/4". They can then pass deep into the R8 collet. This allows a good choice of lengths. The biggest properly usable R8 collet is 20mm which only allows a relatively short depth, as the middle of the collet is not large enough diameter on the od to be bored more than 19mm.
                      Yep. I made mine 3/4".
                      Vitَria, Brazil

                      Comment


                      • #12
                        Yep, the 3/4 shows this clearly when looking inside. The clearance portion above the ground 3/4" section (which is 1" long BTW) is a mere few thousandths bigger than the 3/4". I could just feel it with my pinky.

                        Which means that the next more sturdy and rigid option would be an extended ER chuck with an actual R8 arbor. But it doesn't appear that anyone makes such a beast. So it would be up to some intrepid machinist.

                        I checked and the big end of the nose taper on my collets is roughly 1.25". So I think I'd go with 1.5" bar. It would clean up to around 1.4 so the actual tail of the R8 arbor area is the only real flexible part of the whole thing. The nose would be reduced and fitted to the new ER20 size which I'm apparently adding to my shop collection this coming Thursday. And the nut for the ER20 seems to be roughly 1 3/8" diameter. So the bar used for the extension might as well be a little bigger than the nose of the R8. Sooooo... I think given that I'd finish the bar to the same diameter as the ER collet nut for the optimum advantage for the new extended collet chuck. I'm thinking something like 3" from end of the R8 taper to the nose of the collet nut? So for something like a 1/4 end mill which has a roughly 1" stickout I'd have a 4" total extension to the cutting action?

                        I sure wouldn't want to go much more than that or I think chatter would rear it's very ugly head. In fact it might still do so and quite possibly this would be a bust of an idea from the beginning.
                        Last edited by BCRider; 08-09-2022, 10:50 PM.
                        Chilliwack BC, Canada

                        Comment


                        • #13
                          Originally posted by BCRider View Post
                          Which means that the next more sturdy and rigid option would be an extended ER chuck with an actual R8 arbor. But it doesn't appear that anyone makes such a beast.
                          Are these what you are looking for?





                          SE MI, USA

                          Comment


                          • #14
                            I noticed you used a die to cut the threads on your holder for the cap.
                            Die cut threads are not accurate axially or radially. Not enough precision
                            for a spindle chuck. Consider lathe cut threads are really the process
                            that gives you the accuracy best for an application like this.

                            -Doozer
                            DZER

                            Comment


                            • #15
                              The middle one is close to what I'm thinking. But if I'm scaling the picture correctly the nose is a touch under 2" long. I can get that much and more with the 3/4 straight shank that is arriving tomorrow.

                              I've got this angle plate project I want to do which needs, as we see, a rather long extension to face off surfaces for the clamping washers at the blue tape positions before milling the slots from the other side.
                              Click image for larger version

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                              So I went on a description of why I need something with a long extension. Then just before I hit "Post" I thought.... "What about a small 1.5" boring head?". That seemed like a great idea for a good extension. And then I had another sudden thought about a piece of long forgotten tooling in the back of the lower drawer.... And found this R8 3/4" end mill holder. It was bought and used for some long forgotten project early after I got the new mill about 8 years back. Perhaps as a reach extension?.... which would be quite embarrassing if that was the case....

                              Click image for larger version

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                              And I've got a 3/4" straight shank collet chuck coming. So now I've got a nice sturdy way to hold that new ER20 chuck a further 2.5" lower than with just a collet. And the OD of the holder is the same 1.74 as the nose of my spindle. I'll just need to grind a flat along some of the new ER20 chuck's shank to give the locking screw a flat to ride against. Or possibly mill it with one of the new carbide end mills I got recently. And perhaps at some point I'll have a go at turning the OD of this extension down to match the OD of the ER collet nut. We'll see if the need arises...

                              So I'm good for extending things it seems.......
                              Chilliwack BC, Canada

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