Dead blow hammers and parts in vises - Page 5
Close
Login to Your Account
Page 5 of 5 FirstFirst ... 345
Results 81 to 92 of 92
  1. #81
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    14,240
    Post Thanks / Like
    Likes (Given)
    4853
    Likes (Received)
    5133

    Default

    We used to set two .o10 (or so) precision shims under a part and feel if they were both tight, so knowing our part was down on the floor of the vise. the sure beast finding a to-size part is out of square.

    I almost never use a vise on a surface grinder because vises are rarely good enough for precision work.
    One can make a surface grinder vise by setting a part between two 123 blocks and then adding a C clamp to tighten the blocks on that part. (two C clamps even better).

    Yes with knowing first that your123 blocks are square/right angle.

  2. Likes Trueturning liked this post
  3. #82
    Join Date
    Jul 2012
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    3,499
    Post Thanks / Like
    Likes (Given)
    1427
    Likes (Received)
    1558

    Default

    Quote Originally Posted by Corn View Post
    Sorry to bring this old thread up. I was wondering is there any chance that with smaller mills like robodrill or speedio which uses linear ways to actually balls (linear way guide internal balls) denting the ways when hammering down the stock? Of course with box way machine it's not a thing but linear ways where the surface area for contact is very small, is there a chance to do harm. I'm not talking about sledge and crazy beating..

    Not when done right. The trick to using a dead blow hammer to seat a part in a vise or fixture is to tap on it just hard enough to seat it, too hard and the part will bounce back up. With the right hammer it doesn't take much force. If a machine can survive crashing the Z axis into a part then tapping parts down is a non-issue.

    Keep in mind how many balls are supporting the table in each block, and that those balls are compressed/deformed so they are preloaded so the contact area is larger. There is a lot of spring in those balls, just try measuring one with a micrometer.

  4. Likes Corn liked this post
  5. #83
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    6,067
    Post Thanks / Like
    Likes (Given)
    219
    Likes (Received)
    2094

    Default

    Just to amplify this a bit further, the technique is to start lightly tapping on a part while vise is just starting to tighten on a part. If it rises with that first bit of tightening of the jaws, it is still loose enough to easily tap it down. This continues as the vise handle is turned to further tighten the the grip on the part. You do not get the vise 80% or 90% tight and then start tapping: start at 5% or 10% tight.

    Another point is that with the use of a proper milling vise or what is called a screwless machinist vise, the movable jaw is pulled down as you tighten. If the part sits on the bed of the vise or at least more than half way down the vise jaws, then it will not rise very much, if at all and tapping is really not needed. The tapping is only really needed when a thin part is held by the top half of the movable jaw. Such a part usually sits on parallels.

  6. #84
    Join Date
    Jan 2015
    Country
    UNITED STATES
    State/Province
    Missouri
    Posts
    1,552
    Post Thanks / Like
    Likes (Given)
    233
    Likes (Received)
    978

    Default

    If a block is truly square it will set down on the parallels with the lightest tap. If the sides are are true to the bottom it will lift up it has to. That’s why people beat on parts they are not flat and parallel. Try clamping something that is truly square it will amaze you how nice it will clamp up
    Don


    Sent from my iPhone using Tapatalk Pro

  7. Likes SIP6A liked this post
  8. #85
    Join Date
    Feb 2010
    Location
    ch
    Posts
    3,381
    Post Thanks / Like
    Likes (Given)
    279
    Likes (Received)
    471

    Default

    Quote Originally Posted by EPAIII View Post
    Just to amplify this a bit further, the technique is to start lightly tapping on a part while vise is just starting to tighten on a part. If it rises with that first bit of tightening of the jaws, it is still loose enough to easily tap it down. This continues as the vise handle is turned to further tighten the the grip on the part. You do not get the vise 80% or 90% tight and then start tapping: start at 5% or 10% tight.

    Another point is that with the use of a proper milling vise or what is called a screwless machinist vise, the movable jaw is pulled down as you tighten. If the part sits on the bed of the vise or at least more than half way down the vise jaws, then it will not rise very much, if at all and tapping is really not needed. The tapping is only really needed when a thin part is held by the top half of the movable jaw. Such a part usually sits on parallels.
    well, the more you tighten the vice the more it deforms. thats why you have to tap with full tightening force. however, having the part down on the parallels does not ensure it sits "flat". you have to know your vice. e.g. with my hydraulic vice if clamping a precision block i give it one turn, tap it down and give it two additional turns. then the top surface is parallel to the y-ways.

    considering the mass of vice, table and part, no way a dead-blow hammer will brinnel the ball-ways.

  9. #86
    Join Date
    Sep 2014
    Country
    UNITED STATES
    State/Province
    Georgia
    Posts
    573
    Post Thanks / Like
    Likes (Given)
    405
    Likes (Received)
    242

    Default

    When I worked at Grumman in the tool and die department (before Kurts), the vices had two or three holes drilled and tapped in the moveable jaws. You would tighten your part and then use strap clamps to push the piece down and pull the moveable jaw up.

  10. #87
    Join Date
    Jul 2021
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    264
    Post Thanks / Like
    Likes (Given)
    128
    Likes (Received)
    114

    Default

    I've used many vices over the years and have always tapped my parts down till either the parallels don't move or if not using parallels I'll use paper.
    no matter how good the vice is.
    I've never seen anyone beat on a part, but tapping it down till the parallels or papers are tight on both sides is a common practice in every shop I have ever worked in. Not that I have studied all of my co-workers set up habits, but you're actually the first person I've heard of in 30 years that doesn't do it...and if you are accurate by that much every time...then Kudos to you

  11. #88
    Join Date
    Mar 2019
    Country
    UNITED KINGDOM
    Posts
    295
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    75

    Default

    Didn’t anyone get taught how to block up properly?

    Not tapping on the first side, skim to clean up.

    Fresh cut face on the fixed jaw, no tapping. Cut second face.

    Flip 180 with first face against fixed jaw, then tap job down to parallels, if both parallels tighten up, you are good on squareness, if not, re cut either face.

    Cut third face down to size.

    Put 1st side down and tap down square. Cut face 4 to size.

    Then square one end for face 5. Then face 5,tap down and cut to size.

    The rule is tap down if you want to be flat and parallel against the bottom face, don’t tap if you want preferential squareness to the face against the fixed jaw.

  12. Likes Tom Lg liked this post
  13. #89
    Join Date
    Feb 2010
    Location
    ch
    Posts
    3,381
    Post Thanks / Like
    Likes (Given)
    279
    Likes (Received)
    471

    Default

    you forget the vice is bending. if this matters depends on the accuracy your after.

  14. #90
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    14,240
    Post Thanks / Like
    Likes (Given)
    4853
    Likes (Received)
    5133

    Default

    Duplicating or making machine parts often one does not have a square side to put in the vise as the part may be a casting or forging with the top and bottom need be precise and all the other all over the map. That is a good place to use two shims or parallels and a hammer whack. The old lead hammers were good for this.

    Sometimes the reasonable whack does not work and the part may need re-setting in the vise a time or two.

    QT dian: [the vice is bending] why a vise is a poor hold on a surface grinder with a magnetic chuck.

  15. Likes dian liked this post
  16. #91
    Join Date
    Jul 2001
    Country
    UNITED STATES
    State/Province
    North Carolina
    Posts
    2,227
    Post Thanks / Like
    Likes (Given)
    261
    Likes (Received)
    558

    Default

    I am surprised that some machinists do not form an intuitive nature when
    doing things repeatedly like seating a part in a vise. Then tapping
    a part down, you listen, you feel, you see. You get an idea about how
    hard is not enough, and how hard is too hard, and the part bounces back.
    I have used of course Kurts, Chicks, old Bridgeport vises, cheap no name
    vises, never had a problem seating my part. You just figure out your technique
    as you do it. But if you are a person who just exists on this planet, and
    does not take in any sensory feedback, and does not try to figure things out
    and do them better each time, then maybe you will never get it.

    -Doozer

  17. #92
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    14,240
    Post Thanks / Like
    Likes (Given)
    4853
    Likes (Received)
    5133

    Default

    I would often give perhaps up to 3 reasonable taps with feeling my shims or parallels and if one was still not tight then I would re-vise the part and try again.

    Not much sense in checking the part after milling because then it may be to size and one side it of square.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •