Burke Bar

  1. Yamhon Member

    Messages:
    925
    Location:
    Earth
    Guards on grinders... I recently did the "American thing" removed the guard; although I didn't have the side handle fitted either; YouTube gave me the impression it was the done thing for flap discs; ~4 weeks later my finger still isn't fully healed and that's with 2 trips to A&E and 2 nurse visits. Both guard and side handle are back on my grinder.
     
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  2. Yamhon Member

    Messages:
    925
    Location:
    Earth
    I watched a video on YouTube last night about flame straightening, given what you're trying to achieve here, I think it might be a useful technique for you.

     
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  3. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    Dunno how useful that info will be for this application but it was damned interesting to watch!
     
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  4. Screwdriver

    Screwdriver Member

    Messages:
    5,261
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    Tweaked the forge to make it run a bit hotter. Dropped the burner lower into the chamber, upped the pressure and opened the air a little. Also stuffed it full of soft firebrick to reduce the cavernous volume. I know it's a bit "too big" but easier to deal with than too small.

    [​IMG]

    And it worked. Here it is after it cooled from the first heat. I also needed to lift the jig to put the handle in a better position because as seen here, it's too low and the handle is behind the press!

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    Not unhappy with the angle. It could go a bit more but I'll let it cool slowly over a cuppatea then maybe cut in the nail puller and see if I like the ~35 degree or I need the full 45.

    [​IMG]

    I like the jig but at the extreme angle, it fired the pin out the other end of the retaining bar. I just need to make up a clamp for each end and jobs a goodun.

    [​IMG]
     
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  5. 123hotchef Member

    Messages:
    8,422
    Location:
    Kent
    are you going to heat treat it when it is done?
     
  6. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    Yes. Harden then spring temper. I think the forge is generating enough heat now. Just need to leave it in there for a while. It has 2 inches of kaowool wrapped around the inside so once it gets hot, it stays hot.

    Need to tidy it up a bit, maybe sharpen it (!) then cut the nail puller while it's relatively soft. I measured the angle at ~33 degrees so I will need to bend it a tad more. Better sort out the jig first.
     
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  7. bigegg

    bigegg I drink and I know things. Its what I do.

    Messages:
    6,609
    Location:
    Leeds, West Yorkshire
    i used to spend a couple hours every month turning housecoal into beans for my first forge.
    one of the first uses for my flypress.
    that, and squashing apples to make cider.
     
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  8. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    Five minute job turned into an hour long nightmare (seemed longer).

    [​IMG]

    Looks easy enough. Mark out a little V, make an angled cut, bobs yer uncle. But the angle of the cut is a compound angle on a wedge. Getting the hacksaw to move is one thing, getting it to move and keeping the correct lateral angle AND the correct long angle is a headbender. Plus you need to orient it so you're not hitting your knuckles, the vice and/or the other end of the bent up section. Turn it in the vice to the right angle and you need to stand on the ceiling to get the right position. Then you have to keep swapping sides to do the mirror image cut.

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    I got it very wrong, just once. That was enough to have me chasing the flaws in the hacked out cut to try and file it down to a good finish.

    [​IMG]

    I was happy with it at the size above but had to file it out and make it really, bigger than I wanted. Hey ho. Live and learn.

    [​IMG]
     
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  9. Screwdriver

    Screwdriver Member

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    5,261
    UK London
    Actually, looking at it now I can see my mistake and how I could have fixed it. The angle of the sides is too shallow. A steeper side angle would deepen the lower V. I might do that after it's hardened. Need to fix the bender jig first and I managed to snap a drill bit off in one of the case hardened pins.

    Getting into case hardening is ok, coming out the other side seems to upset the bits. Plus I have to thread it for a set screw...
     
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  10. Parm

    Parm I have fun doing stuff

    Messages:
    10,058
    Location:
    Towcester
    That’s come out good
     
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  11. Screwdriver

    Screwdriver Member

    Messages:
    5,261
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    The makeshift bending jig is working well. I mean, come on, a half inch thick bar of truck spring. Doesn't come much harder. Drilled and tapped the tractor pins for some grub screws.

    [​IMG]

    Set up on the flypress...

    [​IMG]

    Bonk!

    [​IMG]

    It's not 45 degrees of course but 135 but you know what I mean. Sorry you missed the exciting part. Got it as hot as I dared with everything in the tiny cramped forge getting red hot, definitely red hot but not quite the bright red/orange you'd really want for full hardening. My guess is it got up to 850/900 and more at the tip where it's thinner. I didn't want to burn that end.

    Dunked into chip oil with clouds of smoke (which I had forgotten) then as I jiggle it about and take it in/out for a thorough quench - massive ball of fire! I really need to be videoing this but am "saving up" for a Mac Pro that can run the required editing software. Be great if someone had a spare one kicking about I could have :D Until then, I am kinda stuck.

    Here's an interesting picture of the temper...

    [​IMG]

    Left it in there until it soaked up enough heat to get to a blue spring temper.

    Which it did!

    [​IMG]

    Now just got to cut up the 2x1 box, insert the blade and weld it up. Do that tomorrow before the first snap test...
     
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  12. 123hotchef Member

    Messages:
    8,422
    Location:
    Kent
    nice job it is looking great
     
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  13. Parm

    Parm I have fun doing stuff

    Messages:
    10,058
    Location:
    Towcester

    Is square tube strong enough? Would it not be better with solid bar?
     
  14. 123hotchef Member

    Messages:
    8,422
    Location:
    Kent
    it would be very heavy with solid bar!
     
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  15. cheb Forum Supporter

    Messages:
    499
    Location:
    Outer Hebrides
    It's not square, it's rectangular. Pedantic maybe, but it's a crucial difference.

    I've an ex military bar about 6' long and 40mm diameter. It's stupidly heavy which limits it usability. Skipped by the air force for some unknown reason.
     
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  16. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    It is a rectangular box section which does a fair bit more than meets the eye compared to a square or cylindrical bar.

    It's comfortable in the hand
    Is light
    Has all it's strength in the one direction required (doesn't need so much strength sideways)
    The open end is a cheater for bending rebar for example.

    I went for 3.5mm wall thickness so it's plenty strong anyway.

    It is quite cleverly attached to the blade as described in the first post. Can't wait to get it welded up. The blade is quite pretty with the peacock blue temper colours (I'm sitting here now playing with it!). Since I am not 100% convinced I got it hot enough to properly harden it, I stuck it in the vice and hit the tip with my big sledgehammer. It's still in one piece!

    I will clean it up with a light sanding maybe to 80 grit and sharpen the blade a bit too. Not too much but it's about 50 thou so maybe a secondary bevel just to keep the danger element. Even this disconnected 3.5 kg lump of spring steel is certainly not something you'd want to drop on your foot.
     
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  17. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    Notched out the handle.

    [​IMG]

    Heated and bent to wrap around the blade.

    [​IMG]

    Badly welded.

    [​IMG]

    Made up a support strap and welded that on too.

    [​IMG]

    It's too long at 69 inches but I was saving the length in case I needed to remake the blade end. Next to it is my current "comealong" which is fantastically useful for shifting lathes, lifting panels and even in the garden. that's 55" so I guess I'll chop the Burke bar down to about 56".

    [​IMG]

    Needs paint then a quick test...
     
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  18. Screwdriver

    Screwdriver Member

    Messages:
    5,261
    UK London
    All done. Couple of coats of Hammerite black from a rattle can.

    [​IMG]

    Course, now it's tricky to photograph and I need to wait for the paint to really go off before testing.

    [​IMG]

    But now I have a flavour for it and a spare couple of metres of 2x1, I might make another one. @123hotchef went out of his way to donate these to the cause:

    [​IMG]

    Couple of the larger truck springs for reference but there's some interesting shapes there just waiting to be sharpened!

    [​IMG]

    The difference in thickness will help tremendously, especially for the heat treat which I'm still not sure went to plan.

    [​IMG]

    These lumps of steel will take a battering though and I am already thinking a dead straight blade like a super strong sharpened spade would also come in handy.
     
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  19. Memmeddu

    Memmeddu Member

    Messages:
    1,510
    Location:
    Italia Sardegna
    Also metabo makes excellent guards , same system you pull a lever and you can move and lock the guard how you prefer
     
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  20. Parm

    Parm I have fun doing stuff

    Messages:
    10,058
    Location:
    Towcester

    What are those leaf spring off ?

    I’ve got some here from an articulated lorry, not sure if from the trailer or tractor unit.

    They are about 20mm thick and nearly 1.5 m long
     
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