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Re: [GrizHFMinimill] Re: More Newbie Questions

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  • JZ
    Whoa! No whapping on any machines here! :-) Pardon me for jumping in, but these guys are talking about removing the drill chuck and arbor (which are usually
    Message 1 of 33 , Dec 31, 2012
       Whoa! No whapping on any machines here! :-)

       Pardon me for jumping in, but these guys are talking about removing the drill chuck and arbor (which are usually together as one piece) from the machine, and then separating the drill chuck from the arbor...

       For example, here is an R8 to JT33 drill chuck arbor. I.E. - the JT33 chuck is not shown. Notice how short the Jacobs Taper #33 is on the left end of the R8 arbor shown in this picture.
      R8 / JT33 arbor

       And here is an inexpensive drill chuck with a JT33 taper mount that would fit on the above R8 arbor. (I chose R8 because that is what my mini-mill's spindle  uses; there are MT2 and MT3 to JT33 arbors and etc. as well. MT2 - Morse Taper #2 - arbors are very common for the tailstocks on the 7x mini-lathes, for example. Drill presses use various kinds that you'd have to check out for yourself to see what you have.)
      1/2" drill chuck - Jacobs Taper # 33

       What the other good people are describing is basically separating and finagling the chuck to arbor mounting back together as needed, so as to end up with least runout possible. The point here is there is no whapping and tapping being done on a mini-mill, drill press, or mini-lathe tail stock.

       What gets more fun is measured run out on, say, a 1/8" or 1/4 inch diameter bar held in the chuck, is liable to be a little bit different from the measured runout on a 3/8" or 1/2" test bar, and so forth. In the 10 billion conversations you will see about drills tending to drill holes a bit oversize from their stated sizes, this is one of the culprits details not always mentioned. Most every mini-mill and mini-lathe comes with a very inexpensive drill chuck on an appropriate taper mount, so we all get to play around with trying to get more accuracy out of our cheap drill chucks, sooner or later. Mileage varies widely. :-)

       John Z. York, Pa. USA.

      On 12/31/2012 6:56 PM, temmach2 wrote:

      thanks, I did not whacking my drill press all day to get it closer to true, but I am feeling pretty paranoid about what any tapping would do to the spindle bearings, is that definately ok?
      --- In GrizHFMinimill@yahoogroups.com , BrianK <briankenyn2@...> wrote:
      > As an afterthought, separate the drill chuck from the arbor and using a DI, find the 'sweet spot' and lightly tap it home. Remove the chuck and arbor from the machine and use a piece or two of wood to insure that the chuck and arbor are tightly joined. Reinstall and pray.

    • John Lindo
      Barry I agree with your reply. Guards can also help protect other surrounding people not associated with working machines. I worked many years in a piecework
      Message 33 of 33 , Jan 4, 2013
        I agree with your reply.
        Guards can also help protect other surrounding people not associated with working machines.
        I worked many years in a piecework tool room. IE Paid for what you produced per hour.
        So dollars versus adequately guarded machines and safety seemed the norm and came in second place.
        Milling machines are particularly hard to effectively guard.The coolant seems to go everywhere,but some eventually falls on the floor,where
        One day a storeman walked past a milling machine in operation ,slipped on the coolant on the floor and broke his ankle.
        It's always worth considering yours and other people's welfare and safety,whatever you or they are doing in life.
        I am sure you teach this philosophy to your students in class.
        John L

        From: Barry Young <barryjyoung@...>
        To: "GrizHFMinimill@yahoogroups.com" <GrizHFMinimill@yahoogroups.com>
        Sent: Saturday, January 5, 2013 2:48 AM
        Subject: Re: [GrizHFMinimill] Re: More Newbie Questions



        I teach Apprentice and also Career Training Machinists. I also have witnessed several major "accidents" including loss of a shoulder. All these accidents were witnessed in industry, not where I teach. I do not take this lightly at all. Not in any way. But no blanket statement will apply to all situations. Not all guards make machines safer. Knowledge does. You cannot make a guard that works to keep stupid from happening. But, understanding of the machine and safe work habits will keep you safe on unguarded machines. Do you suggest that a person will be safe only depending on the guarding available? What happens when that person goes to an older machine which was made before the current ridiculous or even dangerous guard was invented? Is that person who relies on guarding the safety problem? Yes! It is far better to rely on knowledge and training than it is to rely on guards which may be in place to satisfy a government or insurance company requirement rather than a real safety hazard. What if the guard fails Ian? If you work as though there is no guard, you will work safer than relying on guards to be alert for you.

        You are absolutely right, a great deal of bad advice gets disseminated on forums. Think that one over.

        If you truly have a professional commitment to safe operation of machinery, then you should be suggesting that people learn to work safely rather than depend on any guard which may or may not be beneficial to safe running of a machine. You should also be thoughtful of the statement that the original poster made that his vision was obscured indicating that this is indeed a poorly designed guard. 

        People need to know what they are doing with guards in place or removed. People get hurt on guarded machines too if they don't know what they are doing.

        Every situation is different. You simply cannot say that any process is right. Ian, some guards are bad. If they make it impossible to see, as indicated in the OP, they make it unsafe to operate the machine and they need to go. 

        Barry Young
        CNC Machinist Instructor

        From: Ian Newman <ian_new@...>
        To: "GrizHFMinimill@yahoogroups.com" <GrizHFMinimill@yahoogroups.com>
        Sent: Friday, January 4, 2013 11:13 AM
        Subject: Re: [GrizHFMinimill] Re: More Newbie Questions

        Hi Chuck,

        We appear to have different attitudes to this issue of safety.  My position is somewhat bias - I teach engineering apprentices and a great deal of emphasis is placed on safety.

        As you correctly point out, a large number of inexperienced operators get hold of machine tools and use them without any training.  My advice to any new user is to sign up to a machining or workshop course at your local college - get expert tuition and do not rely on random advice (which may be good or bad) from a forum.

        To give advice to an inexperienced user that indicates that it is safe or sensible to remove guards it grossly irresponsible and could result in group members being blinded or maimed.  The fact that you try to justify giving such advice on the grounds that accidents should never happen simply astounds me!

        Of course there are some people who do stupid things, but it is also true that accidents do happen.  I stand by my statement that you should never try and by pass safety systems (as I stated earlier I have a professional commitment to this).

        In your last but one paragraph you make the comment that "if a guard is removed, you had better know what you are doing" I agree with you wholeheartedly, the issue is that people reading these threads may not know what they are doing.

        I first used a lathe in 1969.  I have never seen a major accident.  From your post I guess that you too have not witnessed a major mishap.  Long may our good fortune continue.

        All the best,

        On 4 Jan 2013, at 15:54, <ckinzer@...> wrote:

        First, you aren't supposed to have your fingers in a place where they can be cut by sharp swarf.  You aren't supposed to have loose sleeves (or anything else like loose hair) that can get tangled.  These are basic safety tenets in any machine shop.
        I think the guard has been added to these small machines for largely "lawyerly" reasons.  In the business (and I am involved in machine safety working at a company that manufactures machines) it is called "liability proofing".  But it is not a black and white business.  And the low cost of these machines means many get into the hands of neophytes that may have poor safety training or attitude.
        Also, the vast number of manually operated lathes and mills that have ever been made and are that are still being made have no such guard.  That alone doesn't mean that a guard should be dismissed because safety standards and trends do change over time.  But that does not mean that some safety device is there for safety as much as it is for defense in litigation.
        In some cases, the presence of ladled on safety devices actually lead to higher risk.  (Tilt switch engine disables on lawnmowers for instance when people learn to depend on the switch to turn the motor off instead of turning the motor off properly before servicing under the motor deck.)
        A somewhat similar tale is the blade guards on table saws.  A great many people remove them.  I think you will find that in most cabinet making shops do not use the guard (there might be exceptions).  Many wood hobbyists remove them (or never install in the first place) for same reasons that it gets in the way so much.  But they seem to know how to safely operate with an unguarded blade.
        As another example, how about existing things built to older safety standards.  I have an old Sears air compressor with belt drive made before they were putting belt guards on them.  But I am rather inclined to stay clear of it when it is operating.  So I am still safe.  Some careless or just plain stupid individual might not be and that is probably why they have belt guards now.  Of course, it is possible to trip and fall or do something careless so in that case if it had a guard I would leave it.  Because the presence of the guard does not hamper the utility of the device.
        There is more than one way to be safe.  So I don't say "never".  But if a guard is removed, you had better know what you are doing in order maintain safety.
        My first machine shop teacher's first words were:  "Metal is stronger than flesh.  Never forget it."
        Chuck K.
        ----- Original Message -----
        Sent: Friday, January 04, 2013 3:45 AM
        Subject: Re: [GrizHFMinimill] Re: More Newbie Questions

        Spell checker destroyed some of my previous post:

        Eye protection will not protect your fingers from sharp swarf or prevent a loose sleeve getting caught

        All the best,

        On 4 Jan 2013, at 11:42, Ian Newman <ian_new@...> wrote:


        A further comment on safety:

        Shields are there for a reason.  Eye protection will not stop your fingers getting caught by sharp scarf of prevent a loose sleeve getting trapped.

        There are three rules of safety devices:

        Rule 1) Never bypass the safety device.

        Rule 2) Never bypass the safety device.

        Rule 3) Never bypass the safety device.

        If you break the first rule, and the second rule, and the third rule, you deserve everything that may happen to you........

        All the best,

        On 4 Jan 2013, at 01:06, "John Herrmann" <guessed@...> wrote:


        1. is it crazy to ditch the protective shield if I am already wearing protective eyewear?, or do most people cheat, cant see a damn thing with that hazy scratched up shield.

        You might want to check out:
        (Look for "hman's stuff" in the Photos section if the URL doesn't work)

        I didn't like the hard shield that came with my Mini - got in the way too often. So I got a piece of thick flexible vinyl and screwed it to a piece of aluminum bar. Attached it to the original mounting hole using a piece of 6mm threaded rod and a wing nut. The vinyl is easily cleaned, cheap to replace, and easy to swing out of the way if I need to get a close view of the setup.

        Safety is always worthwhile, and this shield gives some added "ballistic" protection and is flexible enough not to interfere with the mill table, workpiece, and fixturing.

        Best wishes,

        - John Herrmann

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