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  • Terminology neded

    I'd like to get more of this type of stubby drill in a few sizes. This particular one is 3/8. They don't have side cutting flutes and on the lathe they do an excellent job of self centering and drilling very straight.
    I searched a while under various names, stub, screw machine, spot, to no avail so I'm sure I'm not using the right terminology. What I find has side flutes as on a standard drill bit.

    Click image for larger version

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  • #2
    How about spot drill or spotting drill. I have tried it on Ebay and got many hits.
    I do have several of them and no longer use a center drill on a lathe unless I need a center on a part.

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    • #3
      agreed, looks like a spotting drill to me

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      • #4
        Yep, spot drill.
        Kansas City area

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        • #5
          Thanks guys. I'll try additional terms on ebay. I used spot and came up with spot weld removing drills.

          edit: Got it, thanks again.

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          • #6
            Yeah, spotting drills. Mine are all 90 degree point. They're fairly expensive, must be because they don't sell many.

            I had guys out of the community college machining program who had to be trained to use spotting drills and never center drills to spot holes. You still see supposedly experienced machinists using center drills to spot. It's a very bad habit that's hard to break.

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            • #7
              Originally posted by DR View Post
              You still see supposedly experienced machinists using center drills to spot. It's a very bad habit that's hard to break.
              I'm a supposedly experienced machinist (22 years) and I use center drills because that's what I was taught and what I have. They seem to do the job. Send me some spotting drills and I'll be happy to use them.

              It's all mind over matter.
              If you don't mind, it don't matter.

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              • #8
                Originally posted by MrWhoopee View Post

                I'm a supposedly experienced machinist (22 years) and I use center drills because that's what I was taught and what I have. They seem to do the job. Send me some spotting drills and I'll be happy to use them.
                Have you ever read books on machinists hints, tips, tricks, etc? If you have you know they will usually have a method to remove the broken tip of a center drill. Removing the broken tip can be an expensive proposition and might ruin a valuable workpiece. So, why take the risk?

                The rule I had with employees, you get one warning for spotting with a center drill, do it again and you're fired. I'm kind of a soft touch though, one guy did it twice and I gave him 5 days off without pay.

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                • #9
                  I use spotting drills most of the time and they seem to do a better job than a center drill. Sometimes I follow up with a center drill especially if I have to turn a part on centers.

                  JL.....

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                  • #10
                    Originally posted by JoeLee View Post
                    I use spotting drills most of the time and they seem to do a better job than a center drill. Sometimes I follow up with a center drill especially if I have to turn a part on centers.

                    JL.....
                    Hmm? Well, I am limited in my years of machining, and with that?

                    I have only really used my center drills with the lathe, to in actual make a drilled hole with a angle my center likes. Center drill. Other than that, Ill spot drill everything. JR

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                    • #11
                      Agree. A spotting drill shouldn't be used to create a centre for turning because it lacks the little pilot which accomodates the point of the centre and means the centre seats nicely against the taoer sides of the hole.
                      'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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                      • #12
                        Mr slocombe would be spinning in his centre, it’s true but like most I use a drill that’s for making a hole for a dead or live centre as a drill to make drills centre, a stub drill is a better drill to start but most use centre drills as they’re thick and stiff hence don’t deflect, it’s quite normal to use a lathe tool to centre by surfing a little divet, dent or hole, I have a few centre drills with the pin ground off as well
                        mark

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                        • #13
                          Originally posted by Richard P Wilson View Post
                          Agree. A spotting drill shouldn't be used to create a centre for turning because it lacks the little pilot which accomodates the point of the centre and means the centre seats nicely against the taoer sides of the hole.
                          Are you agreeing with me ?? I should have worded my post a little more clearly but It was late.

                          What your saying is what I meant to say, the angle and the clearance for the point of the center. Besides the angle isn't correct.

                          JL..............
                          Last edited by JoeLee; 02-24-2022, 09:01 AM.

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                          • #14
                            Originally posted by JRouche View Post

                            Hmm? Well, I am limited in my years of machining, and with that?

                            I have only really used my center drills with the lathe, to in actual make a drilled hole with a angle my center likes. Center drill. Other than that, Ill spot drill everything. JR
                            I've used them for spotting when drilling on the mill.

                            JL.............

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                            • #15
                              What I like the spotting drill for is not actually what they were intended for. I made a drilling spindle for the tool post on my little 9" south bend for perpendicular drilling into whatever is been whittled.There is not much room on this machine and full length jobber bits often are too long and won't fit. These stubby little drills will fit and being rigid poke a nice accurate hole. Of course their limited diameter range is a factor. At that point yeah I'll use them to spot for the right size drill.

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