Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    Nov 2006
    Location
    Heidelberg, Victoria
    Age
    79
    Posts
    2,074

    Default The hole is too big

    Dear members,

    I have just bored a 10mm hole in a piece of brass, and plow me, it turned out to be 10.2 in dia. Is there any way I can reduce the dia?

    Is there an internal 1-piece knurling tool that I can introduce into the bore to shrink the dia?

    Yeh, I know, I can always bore it out, and fit a bush, or simply start again. Prefer not to.

    Any clever answers, would be appreciated.

    Regards,

    Ken

  2. #2
    Join Date
    Dec 2004
    Location
    Montgomery,alabama U.S.A.
    Posts
    1

    Default Re internal Knurling tool

    I saw pics of one made from the striker wheel off a disposable butane lighter. Just turn a shoulder on a piece of keystock and drill and tap for a socket head capscrew. Use just like a small boring bar.
    I will look for picture.
    alabamaed36046

  3. #3
    Andy Mac Guest

    Default

    Hi nekmerj,
    Butchery I know, but you could hammer the brass with a ball pein around the margin of the hole and it will push out, squeezing the hole smaller.
    Now where's my striped apron...?

    Cheers,

  4. #4
    Join Date
    Jul 2003
    Location
    The Fabulous Gold-plated Coast.
    Age
    69
    Posts
    2,251

    Default

    Further to what Andy said, if you have any big bearing balls lying around, you can use one on each side of the hole, hammering briskly to swage the hole smaller. Butchery might be too kind of a word for this, however.

    Would a 0.004 shim stock strip do you? That would take your dia to 10 mm and be no more inelegant than the knurl.

    Greg

  5. #5
    Join Date
    Feb 2006
    Location
    Melbourne
    Age
    65
    Posts
    316

    Default

    Quote Originally Posted by neksmerj View Post
    Dear members,

    I have just bored a 10mm hole in a piece of brass, and plow me, it turned out to be 10.2 in dia. Is there any way I can reduce the dia?

    Is there an internal 1-piece knurling tool that I can introduce into the bore to shrink the dia?

    Yeh, I know, I can always bore it out, and fit a bush, or simply start again. Prefer not to.

    Any clever answers, would be appreciated.

    Regards,

    Ken
    Hi Ken,

    Not having mentioned what the hole is for this might not be as good an idea as those mentioned above. But would braizing or silver soldering the hole up be OK? If it was I would bore the hole larger first so there is more than a 0.1 wall.

    Regards
    MH

  6. #6
    Join Date
    Jun 2007
    Location
    sydney ( st marys )
    Age
    64
    Posts
    4,887

    Default

    first thing to work out why is your bored hole oversize,correct that problem before trying any solution,and if your making that optical aligning tool why not just make your lens and punch to suit your oversized bore.

  7. #7
    Join Date
    Oct 2006
    Location
    Tallahassee FL USA
    Age
    82
    Posts
    372

    Default

    Machinery's Handbook devotes a paragraph to "Accuracy of Drilled Holes." Factors cited include: accuracy of the drill point; size of the drill; length and shape of the chisel edge; whether or not a bushing is used to guide the drill; length of the drill; runout of the spindle and the chuck; rigidity of the machine tool, workpiece, and the setup; also the cutting fluid used, if any. "The diameter of the drilled holes will be oversize in most materials."

    Joe
    Of course truth is stranger than fiction.
    Fiction has to make sense. - Mark Twain

  8. #8
    Join Date
    Nov 2006
    Location
    Croydon, VIC
    Posts
    136

    Default

    If you're really desperate to save pitching the brass, a sleeve would be the most elegant solution.
    'What the mind of man can conceive, the hand of a toolmaker can achieve.'
    Owning a GPX250 and wanting a ZX10 is the single worst experience possible. -Aside from riding a BMW, I guess.

  9. #9
    Join Date
    Feb 2006
    Location
    Melbourne
    Age
    65
    Posts
    316

    Default

    Quote Originally Posted by Article99 View Post
    If you're really desperate to save pitching the brass, a sleeve would be the most elegant solution.
    Hi Article,

    I think that is what Ken meant when he said fit a bush?

    Cheers
    MH

    Dear members,

    Yeh, I know, I can always bore it out, and fit a bush, or simply start again. Prefer not to.

    Regards,
    Ken

  10. #10
    Join Date
    Feb 2003
    Location
    Garvoc VIC AUSTRALIA
    Posts
    1,656

    Default

    You may be able to run a couple of rows of centre punch pricks around the insides of the hole. So if its only to locate something that should do but if its to run a shaft in you need to bush it
    Regards, Bob Thomas

    www.wombatsawmill.com

  11. #11
    Join Date
    Nov 2006
    Location
    Croydon, VIC
    Posts
    136

    Default

    Yeah, I know, MH. But you'd have to admit, knurling a bore just so it's not oversize... uggh.
    Might suck doing the extra work, Ken, but it'd be worth it over knurling.
    'What the mind of man can conceive, the hand of a toolmaker can achieve.'
    Owning a GPX250 and wanting a ZX10 is the single worst experience possible. -Aside from riding a BMW, I guess.

  12. #12
    Join Date
    Feb 2006
    Location
    Melbourne
    Age
    65
    Posts
    316

    Default

    Quote Originally Posted by Article99 View Post
    Yeah, I know, MH. But you'd have to admit, knurling a bore just so it's not oversize... uggh.
    Might suck doing the extra work, Ken, but it'd be worth it over knurling.
    Hi Article,

    I have never seen knurling done on a internal diameter. Is it possible?.

    Ta
    MH

  13. #13
    Join Date
    Nov 2006
    Location
    Croydon, VIC
    Posts
    136

    Default

    Anything's possible. -You should know that.

    Time and inclination, however, are another story. -Something I'm sure you'd also already know.

    Can't say I've ever heard or seen it done either, so it may just be a delusional myth.

    One of the lads I work with once bored an oversized hole in a piece of expensive high-tensile for a foreigner. Poor bugger was shattered when he first measured the bore. He did manage to save it, however. Ended up running a 2mm parting wheel down the length to split one side, heated it up in the furnace, gave it a squeeze in the press and then brazed the small gap up. Bore didn't exactly resemble round any more, but it was small enough to re-bore true and to the correct size.

    OD did end up smaller as a result, but he still had enough meat left on to clean it up to size.

    Quite the save, I thought.
    'What the mind of man can conceive, the hand of a toolmaker can achieve.'
    Owning a GPX250 and wanting a ZX10 is the single worst experience possible. -Aside from riding a BMW, I guess.

  14. #14
    Join Date
    Oct 2006
    Location
    Tallahassee FL USA
    Age
    82
    Posts
    372

    Default

    You haven't mentioned the thickness of the brass stock, I think, nor its function. If the diameter is critical, you could possibly braze to restore most of the metal, then drill a smaller pilot hole and ream to the exact diameter. (Assuming you have a suitable reamer, of course. Grizzly #G9418 is 25/64" (9.9219mm) at US$7.95 plus shipping etc.; Oz engineering shops may have metric sizes.)

    Joe
    Of course truth is stranger than fiction.
    Fiction has to make sense. - Mark Twain

  15. #15
    Join Date
    Jul 2007
    Location
    Thailand
    Posts
    1

    Default

    Internal knurling is not only possible , but widely used in engine rebuilding to re-condition valve guides. The tool is pretty simple and resembles a reamer that has wood screw threads on it. I would suggest a quick visit to an automotive machine shop in your area to see if they can help you either repair your part or direct you to a supplier of the tools.

    I am a thirty year tool maker so if I can offer any help just let me know.

    BTW when trying to bore a hole to size it is good practice to "sneak" up on it once you are within about .010".

    Reamers are also pretty cost effective and much more forgiving.

Page 1 of 2 12 LastLast

Similar Threads

  1. 20mm hole in 5.5mm thick Titanium.. any takers?
    By dyrodium in forum METALWORK GENERAL
    Replies: 19
    Last Post: 22nd Jul 2006, 04:15 PM

Tags for this Thread

Posting Permissions

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