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Thread: Scavengers new furnace build!!!

  1. #21
    Quote Originally Posted by Petee716 View Post
    Wow Justin, very impressive. All this skill and motivation AND a sensitive side too? You are over the top,man.
    Seriously, nice work.

    Pete
    Pete, I am very sensitive.... to my shop time being interrupted....

    The knock-out round was last night and one more failed marriage may have been prevented.

    But at the cost of no shop time yesterday and no updates or pictures today.

  2. #22
    Senior Member 4cylndrfury's Avatar
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    Shop time > therapy time. Marriages come and go, but furnaces last forever...or at least until flux happens

    just kidding man - good on you for helping out where youre able. But dont put off shop time for too long. We are starting to get the shakes from picture withdraw

  3. #23
    Quote Originally Posted by 4cylndrfury View Post
    Shop time > therapy time. Marriages come and go, but furnaces last forever...or at least until flux happens

    just kidding man - good on you for helping out where youre able. But dont put off shop time for too long. We are starting to get the shakes from picture withdraw
    Flux happens.... Sounds like a bumpersticker for casters!

    Things seem to be going well, which means things are going well for the shop. I got in 4 solid hours without interruption! And it was a fridgid 64 degrees with a slight breeze. It was like a reward for the previous days deeds. You picture feinds will have something to look at today.

    I elected to start the lifting tongs. Again my design with inspiration drawn from the many different designs of lifting tongs I have seen on the net.

    I started as I always do with large diameter bearing races. They are tapered to the shape of the crucible.





    I cut them with the torch into thirds and set them aside to cool. See how the shape of the bearing matches the shape of the crucible?



    Then I started on the piviot... Two pieces of flat plate with a 1/2" hole drilled into it. It is then bolted and a lock nut is added to prevent the nut from backing off.



    Then I cut some 1" square stock for the jaws and mocked it up.





    More coming.

  4. #24
    I bent the square stock to match the crucible contour. This required the torch and some leverage.



    The first one is easy. Getting aother one that looks the same is where the challenge lay. THe second one took a little longer to bend, but I gotta say... Nailed. It...



    Mocked up and tacked. The bearing races were heated and bent to better form to the crucible.



    All welded up.



    Now it was time for handles.

    I got into a zone and forgot to take some pictures, but here is the finished product. The crucible is suspended with no clampping force. The weight of the crucible allows the tongs to pinch down on the crucible. More weight, more clamping force.



    Here are the tongs opend up.




    There are three handles. Some tongs only have 2. I added the third one so one person could have control of the the jaws without cantilevering the handle to open the jaws. The other man is just there for lift.

    The design has worked well on my a-12 tongs as shown below. I built the a-12 tongs to get us used to a 2 man operation. Having control of both jaws from one side makes crucible extraction very easy. I do not even use the second handle to exert more clamping force onto the crucible. I could if I wanted to, but to date with 10 or so pours, not one bit of slippage from these tongs. Even a mis-clamp does not allow the crucible to slip. It feels rock solid.





    So I have to finish up the pouring shank and get a hole bored into the furnace for the burner. I also have to mount my lid into my lifint mechanism, and make sure everything is well adjusted. If I can work like I did last night the rest of the week, finishing up by Saturday will be a breeze.

    Justin

  5. #25
    This is looking great!

    Interesting shank design. Gonna put stop bolts on it right?
    Knowing how to make something is far more valuable than knowing where to buy it...

  6. #26
    Senior Member Essej's Avatar
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    Very, very nice work Justin... You may just beat me to becoming a millionaire foundry owner

    I do have to second GT's thoughts on a stop bolt... that thing's gonna be heavy, too much clamping force and you could be wading in molten iron... not cool! (<- pun intended )
    Last edited by Essej; 01-23-2013 at 04:55 PM.

  7. #27
    I really have not thought of putting on limiters.

    I have never had any stoppers to limit the amount of squeeze on any of my lifting tongs. I have built 4 and used 3. I have never been able to squeeze a crucible to deform or break it. I see lots of people talking about over squeezing a crucible, but has anybody actually over clamped one?

    I have a place on top of the handles that would be very easy to add an adjustable stopper. I will add it. It would be interesting to see if the crucible does deform or not.

    Justin

  8. #28
    Senior Member Essej's Avatar
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    I have never had any stoppers to limit the amount of squeeze on any of my lifting tongs. I have built 4 and used 3. I have never been able to squeeze a crucible to deform or break it. I see lots of people talking about over squeezing a crucible, but has anybody actually over clamped one?
    I think it's probably one of those things that will not be a problem 999 times out of 1000 ... but it only takes that one time for the problem to become very serious, very quickly. I have very limited foundry experience, but in my 19 years of working in the building trades with a lot of potentially dangerous tools and equipment in potentially dangerous situations, I learned that when s**t hits the fan, it does so rather quickly and usually with little or no warning. I've seen many people get injured and have had my fair share of injuries... careful as you may be, it only takes one little oversight, misstep, or equipment failure and a split second for things to go very wrong. Doing what we're doing here, I don't think there's such a thing as too many precautions, definitely better safe than sorry

  9. #29
    I will add a stopper to be safe. It is easy and will be a good way to monitor if the crucible actually bends.

    I think that with my clamps gripping the bottom of the crucible is best. It is squeezing a circle, one of the strongest structures in nature. Much the same way it is nearly impossible to break an egg by squeezing it.

    I have never liked tongs that grip the middle of the crucible. That seems dangerous.

    But I would like to know; has anybody actually broken a crucible by over squeezing it? They are way tougher than most people realize.

    Justin

  10. #30
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    I put stop bolts on everything that handles crucibles, any crucibles. At up around 3000 degrees I don't know how soft they get, and I don't want to find out.

    Richard
    When I die, Heaven can wait—I want to go to McMaster-Carr.

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