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Hammer & punch or press to remove tight pin?

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  • Hammer & punch or press to remove tight pin?

    I have a, let's say, "hobbiest" quality pinch style knurling tool. Being a hobbiest tool, there is a bit of play in the knurls. I'd like to drive out the "axles" (?) make larger ones & ream their bores.

    I tried removing one with a punch and hammer, but it's way tighter than I'm used to. Before I start using ever bigger hammers, I thought maybe I should get your advice. Bigger hammer or hydraulic press? Or are these things made to not come apart without breaking?

    While we're at it - is there a good rule as to when a press is better than a hammer & punch?

    Thanks, Bob

  • #2
    Originally posted by Bob Engelhardt View Post
    While we're at it - is there a good rule as to when a press is better than a hammer & punch?

    Thanks, Bob
    Just my uneducated self talking here.

    I would say press them. I am not a fan of "shock" loads to move things that were pressed in originally.

    That being said I have a dewalt jack hammer that I converted some tips to use as a BFH!!

    I have a press so real easy for me to say always press. Some folks just dont have the option. If you do, press away. It will stiil be exciting. Eyewear.. JR

    My old yahoo group. Bridgeport Mill Group

    https://groups.yahoo.com/neo/groups/...port_mill/info

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    • #3
      Just my opinion. For something that is very lightly in but a bit more than can be pressed in or out by hand, a few gentle taps with a hammer can be appropriate. In general, continual even pressure from a press is less likely to damage anything. Unless of course it wasn't meant to come apart anyway, in which case the hammer would have broken it also, just differently.
      "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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      • #4
        Bang them out with a hammer and punch, common knurling tooling is very simple and cheap compared to other tools.

        This is a simple knurl wheel, 3/4" OD with a 1/4" ID straight bore that runs on a pin, no bearings involved. Older tooling tends to have a straight bore on one side and a tapered bore on the other to fix the pin in place, make sure that you are driving or pressing the pins out from the correct side.

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        • #5
          Use a vise, or lathe tailstock for light pressing... lots of control..
          Last edited by 754; 09-19-2020, 09:44 PM.

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          • #6
            What Bented says. I have a pinch style tool (scissors?) and just knocked them through with a 32-oz hammer. (2 lbs, 1 kilo) A few good solid shots.

            My RULE is: as long as the head of the pin is flush or below the surface, you can hit it good and hard without worrying. Make sure your punch is a good size and you hold things steady.

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            • #7
              The hammer and punch will move things that a press will not. Surprisingly high "pressure" equivalent in that hammer.

              Yeah, sometimes it is an OK thing and others not. You have to use some judgement.
              1601

              Keep eye on ball.
              Hashim Khan

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              • #8
                Originally posted by J Tiers View Post
                Yeah, sometimes it is an OK thing and others not. You have to use some judgement.
                X2 on using judgement -- I have got in trouble with taper pins before, if the end mushrooms or you hit the wrong end.... gonna be a long day

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                • #9
                  Originally posted by Bented View Post
                  Bang them out with a hammer and punch, common knurling tooling is very simple and cheap compared to other tools.
                  I say you just go ahead and bang the fricktion right out of it, that dang pin owes me money type of banging.

                  Im with Bented. Hmm, mmm. Bented? Diff meaning? hmmm. HuH Bented need hammer Bang that pin.. JR

                  My old yahoo group. Bridgeport Mill Group

                  https://groups.yahoo.com/neo/groups/...port_mill/info

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                  • #10
                    When thinking about drilling and reaming the knurls, I have never tried it but would think the knurls very hard.
                    Sarge41

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                    • #11
                      The knurls are gonna be VERY hard . And you do, or should, know that they need to float a bit .. THAT is why the diameter is NOT important in knurling . It's been proven/shown here that the old tale of having to have the diameter some exact relationship to the knurl is just so much BS. The float of the knurls on the axles is what aligns with the previous track. For those that don't believe it just forget you read this..
                      ...lew...

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                      • #12
                        Having a custom made anvil with the right sized hole is an important factor in punching pins.
                        I have two British made ones which use countersunk head screws with a plain part for the bearings, so much more sophisticated.
                        Last edited by old mart; 09-20-2020, 09:41 AM.

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                        • #13
                          Originally posted by Lew Hartswick View Post
                          The knurls are gonna be VERY hard . And you do, or should, know that they need to float a bit .. THAT is why the diameter is NOT important in knurling . It's been proven/shown here that the old tale of having to have the diameter some exact relationship to the knurl is just so much BS. The float of the knurls on the axles is what aligns with the previous track. For those that don't believe it just forget you read this..
                          ...lew...
                          yes, THANK YOU for saying this... i don't even bother to argue about it any more, some people need to have a definite number for everything for some reason. I gave up trying to convince others that sometimes there isn't a definite answer and it isn't needed.

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                          • #14
                            Originally posted by Lew Hartswick View Post
                            The knurls are gonna be VERY hard . And you do, or should, know that they need to float a bit .. THAT is why the diameter is NOT important in knurling . It's been proven/shown here that the old tale of having to have the diameter some exact relationship to the knurl is just so much BS. The float of the knurls on the axles is what aligns with the previous track. For those that don't believe it just forget you read this..
                            ...lew...
                            You talking endwise float? Or sloppy axle?

                            Don't see endwise float doing jack with a straight knurl
                            1601

                            Keep eye on ball.
                            Hashim Khan

                            Comment


                            • #15
                              Originally posted by J Tiers View Post

                              You talking endwise float? Or sloppy axle?

                              Don't see endwise float doing jack with a straight knurl
                              It doesn't do anything with any other kind of knurl either.

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