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  1. #1
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    Default put a hard point on a small bolt ?

    G,day fellers , I need to put a hard point on a small bolt . Thought of hard facing the end and grinding it to a point but cant seem to find any hard facing rods smaller than 3.2 which is a bit big . Anyone got any ideas --- thanks ---Mat--

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  3. #2
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    What is the intended use? I've case hardened the heads previously, but the case hardening is thin and I don't know if it would be thick enough, depending on what you mean by a "point". Why does it need to be hardened, and how much wear are you expecting?

    Pete

  4. #3
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    Quote Originally Posted by Mathuranatha View Post
    G,day fellers , I need to put a hard point on a small bolt . Thought of hard facing the end and grinding it to a point but cant seem to find any hard facing rods smaller than 3.2 which is a bit big . Anyone got any ideas --- thanks ---Mat--
    Need to know the diameter of the bolt to really offer a suggestion.

    If it was suitable size you could drill out the centre and bronze in a HSS drill shank and taper that.

    Hard face welding rod will eat away anything small.

    So give us more info.

    Rob

  5. #4
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    Quote Originally Posted by Mathuranatha View Post
    G,day fellers , I need to put a hard point on a small bolt . Thought of hard facing the end and grinding it to a point but cant seem to find any hard facing rods smaller than 3.2 which is a bit big . Anyone got any ideas --- thanks ---Mat--

    What about cherry red? case hardening compound...



    You can get it from these guys Case Hardening Powder 250gram NON Toxic Made IN THE USA Suit MILD Steel | eBay

    Regards
    Ray

  6. #5
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    What Rob said.
    Drill a hole and insert a bit of drill shank.

    SWK

  7. #6
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    I believe drill shanks are soft. That's why they score when they spin and why you can file the knobs off. Couple of suggestions: Buy a high tensile bolt the right size and grind the end to a point. They are more tough than hard, but may do the job. Otherwise, make the bolt from a hardenable material and heat treat to taste, eg point hard, threads not so much.

  8. #7
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    Default thanks fellas

    thanks fellas that gives me a few things to try till somthing works . Guess I,ll start with the easiest option [high tensile bolt] and work my way through the other options if it doest work .

    The bolts screw into nuts welded onto brackets on a small electric SkillMill and stops the rails dropping from the required height . So the point screws in against gal mild steel square tube and stops the collar sliding down under probably 30k of weight on each side .
    good night all

  9. #8
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    Quote Originally Posted by RayG View Post
    What about cherry red? case hardening compound...

    You can get it from these guys Case Hardening Powder 250gram NON Toxic Made IN THE USA Suit MILD Steel | eBay

    Regards
    Ray

    Or you can buy it from me. You get more Cherry Red (400gm v 250gm) at a cheaper price ($42.50 posted v $54.90 posted).


  10. #9
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    Quote Originally Posted by bob ward View Post
    Or you can buy it from me. You get more Cherry Red (400gm v 250gm) at a cheaper price ($42.50 posted v $54.90 posted).

    Definitely going to keep that in mind Bob, I am going to need some soonish.

    Phil

  11. #10
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    Consider using cone point set screws.

    Gene

  12. #11
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    Quote Originally Posted by easymike29 View Post
    Consider using cone point set screws.

    Gene
    Another option I believe is Dog Point.

    http://www.fasten.it/immagini_utenti/2969_19658.jpg

    ALBERT PASVAHL GMBH & CO: Albert Pasvahl offers you their experience...

    Nev.

  13. #12
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    Default put a hard point on a small bolt ?

    Hi Mat

    You asked the wrong question, you should have asked how to stop a slipping collar.

    What you need is something to increase the friction between the collar and the frame maybe a rubber block under the bolt, and a piece of flat steel to apply the force from the screw to the rubber pad.... which gives a larger surface area and more friction.

    The pointed bolt will just dig in and cut into the Galvanized surface and eventually it will get chewed up and probably rust, since the gal will be scratched through..

    A picture of the current set up will help, I'm sure there will be a better solution than a hardened pointed bolt...

    Regards
    Ray

  14. #13
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  15. #14
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    Quote Originally Posted by RayG View Post
    Hi Mat

    You asked the wrong question, you should have asked how to stop a slipping collar.

    What you need is something to increase the friction between the collar and the frame maybe a rubber block under the bolt, and a piece of flat steel to apply the force from the screw to the rubber pad.... which gives a larger surface area and more friction.

    The pointed bolt will just dig in and cut into the Galvanized surface and eventually it will get chewed up and probably rust, since the gal will be scratched through..

    A picture of the current set up will help, I'm sure there will be a better solution than a hardened pointed bolt...

    Regards
    Ray
    I agree on the OP question bit - and that a pointed bolt is not the way to go.

    But I have to disagree on the more surface area, the greater the friction - not so for a given force. Stays the same.

    This is probably the only experiment I remember from skool days Oh, and burning out the see through OHM meters we had.

    Look it up and you will see what I mean.

    Rob

  16. #15
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    Default pointy bolts el-cheepo design

    Yes I agree , pointed wing-bolts is one of a number of cheap and crappy design faults and probably why Peterson discontinued the SkillMill . The pointed wingnut bolts that screw in to stop the rail slipping get blunt and slip . Bought some grub screws 2day that are very hard - if they dont work I,ll have to consider changing the design as kindly suggested .

    Not a big problem compared to the rest of the world - riots and wars etc . have a good night blokes ----mat--

    oh and the missus is serching for our camera
    Last edited by Mathuranatha; 28th June 2013 at 08:22 PM. Reason: forgot to add onr point

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