Thursday, August 23, 2012

Rod Bender

This was one of the easiest little tools I have ever made lately. Like a lot of the things I do there is a behind the scenes story to tell. This one starts maybe 30 years ago when I made a cheesy little bender for forming 1/4 inch diameter steel rod. The shop were I was working in used the steel rod as wiring looms to route bundles of wire inside high voltage switch gear. These wiring looms were kind of fun to build a little like road building for wires. When I first started making the looms I just bent the rod in my bench vise with a mallet and welded them to the interior of the switch enclosure. When I switched to copper jaws on my bench vise this rod bending operation just shredded the jaws for any other work. Right then I decided to build a dedicated rod bender. Don't laugh but I still have it. I'm pretty sure that is the original dowel pin in the center. I cannot ever remember breaking one.
Like I said don't laugh. I made it from junk I had lying around the method of all good scrounges. The frame is a chunk of angle iron that I bushed to hold a hardened dowel pin as the forming pin. The back fence is cold rolled steel that I milled the slots in using a drill press of all things. I have used the crap out of this bender making hundreds of bends in the quarter inch cold rolled loom rod.

It got borrowed all the time by the other guys that had to do looms in the equipment they were building. Well all things end eventually so when I left that shop Trayer Engineering my little rod bender went with me. Sure enough I started using it for other things since it worked so well on the rod. After a few years I had quite a little collection of bushings and blocks for doing all kinds of weird little forming jobs that came up.
So this little rod bender just moved around with me from shop to shop. We used it quite a bit at CVM and that's were the story gets  a little more interesting. It was only after I left the company and the little rod bender went with me that it gets funny. One of the guys from CVM came by my new shop for a  shop tour and social visit. We were walking around the shop shooting the breeze when he spotted the little bender and said, "Jeez you just about crippled us when you took your bender" I asked Marty why they didn't just build another one and quit whining about it. He then told me he had tried to get one of the other guys to draw it up for him without success. He even sweetened the pot with this guy trying to entice him by telling him he would build two of them one for him if he would just make a drawing for him. Well I'm part deaf but I know an invitation when I hear one. I kept my mouth shut and started thinking about it. The cool part was I already had it in mind to make a better one but it was a low priority because I already had one that worked.
 It always starts with a sketch around here. I have no business jumping on the computer until I can put something down on paper. It helps to stay in practice hand sketching. You never know when you might have to communicate with an alien species.
Part of the appeal of this bender is its simplicity. I didn't want to lose that in the new design. So I spent a few hours on Solidworks and made a nice little drawing package for Marty. I never told him I was working on it. I sent the drawings in a package through the mail with some other stuff  to him at the shop. Not wanting to miss a chance for a joke I labeled the outside of the box in big letters with "Erectile dysfunction home test kit" and addressed it to him. I'm sure there were a few laughs from the mailman over that.
A few weeks later I still haven't heard anything from him so I'm starting to wonder if he got the package. Finally he emails me with a question so I know he's working on them. True to his word Marty walks in one Saturday at the shop and he has the metal version of the new design bender in his hand. He did just like he said and build two of them at the same time.
They work great and behave like the original but smoother and tighter. The new bender has a much larger bearing surface on the pivot and the bending pin is removable so you can change pin sizes and add other types of dies (like tubing) to it easily. To make repeatable angle bends you just make a witness mark with a sharpie on the rotating part of the pivot. You could put a graduated scale but then you would have to remember the number. For each diameter of rod or tube the barrel will have a different position. So a witness mark in this case is less confusing. I suppose I could make an adjustable reference mark. Hmmm, might be a good upgrade. I also added a measuring scale along the front to make gaging the bend lengths easier. Its just one of those adhesive scales which happened to be numbered in the right to left direction. Where did I find that? I'll give you one guess, McMaster Carr.
The rod I just bent in the picture is 3/8 diameter steel. I haven't tried it yet, but I think this one will do up to 1/2 inch in steel. You can slip a tube or pipe over the spud on the right side for more leverage. So all in all it was a really fun project because of the collaboration. Marty had the time and willingness to do the machine work and I had fun designing it and seeing something useful come to life. Hope you will like it also.



48 comments:

  1. Hi Tom

    Really amazing work.

    I am trying to make this same bend on a 3/16 square rod. Would a bender like this work on a square rod?

    Also, do you sell this bender?

    Thank you

    Jason

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  2. Hi Jason,

    This bender would easily bend 3/16 square. It would probably bend 1/2 square if I put a long handle on it. I don't sell them but you can make one from the drawings in this article.

    Regards,

    Tom

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    Replies
    1. Hello Tom,
      Can you indicate the different grade of metals used for each piece.
      I do not understand why this detail is always put aside, whereas in my mind, this is very important. People can not familiarize themselves with nuances if the Youtubeurs never speak of them.

      Delete
  3. Hey Tom, just found this after watching the latest YouTube video. I now have a new shop project. Keep up the great work and put me on whatever list for the shirts. I like the K&T shirt as well as the Oxtool shirts. Any others in the works?
    -Kyle

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  4. Hi Kyle,

    Thanks for the comment. Yes I have quite a few shirts in mind. What is your size? Stay tuned for the roll out of the Ox tools tool crib. All kinds of swag will be available to keep the wheels of industry turning.

    Best,

    Tom

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  5. Any possibility of getting the drawings in PDF? My old eyes don't see nearly as well as they used to.

    ReplyDelete
    Replies
    1. Hi Roladska,

      I don't have them in PDF sorry. Thanks for the comment.

      Best,

      Tom

      Delete
  6. I really like the metal bender, is there any way you could repost the drawings on a larger scale or is there a way I can enlarge then.

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  7. Hi 19441978,

    You do know that if you click on the pictures they expand to a larger size. See if that enlarges them enough for you. Thanks for the comment.

    Best,

    Tom

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  8. how do i get in touch with you? i have 4 bends on half inch cold roll rod. all different angles

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  9. Hi Michael,

    You just did. What is it you are looking for?

    Cheers,

    Tom

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  10. Tom,

    I've made your two sided, facing and profiling lathe bit (it's now my go to tool), am drawing up a mini-pallet plan, and just finished a bender after hours of looking at a previous video and stopping and rewinding etc. I just saw in a comment today that you had plans in the blog and that Donald had built one with a build video, oh well next time I'll do it right, mine works so far, but is much less elegant. Thanks for all the great sharing of your talents.

    Pete

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  11. Hey Pete,

    Thanks for the comment. Glad you are finding some useful stuff on here. The rod bender is a great little project and really useful as well.

    Cheers,

    Tom

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  12. where can i buy one, or have one made?

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  13. Hi Michael,

    The plans are free. You can make one yourself or have somebody near you make one. I don't sell them.

    Cheers,

    Tom

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  14. Hello there TOM, from DURBAN, SOUTH AFRICA
    Already have Your fantastic book. As rookies Learned stacks therefrom.
    Been watching "Meat Loafs" and Your other videos.
    Some superb coverage there.
    Keep 'em rolling.
    Would love to build this ROD BENDER. We think we are ready for such a project.
    One question though - would any of these PINS or parts need be HEAT TREATED, or will heavy Duty virgin stock suffice ???
    Do kindly confirm.
    Thanks in advance and
    All the best.
    aRM

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  15. Hey aRM,

    Thanks for the comment and support. The pin is made of un-treated tool steel. I think you can use it for quite a while before you will need a heat treated pin.

    Cheers,

    Tom

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  16. Hello there Tom
    Will try that
    Thanks again and
    Take care
    aRM

    ReplyDelete
  17. This comment has been removed by a blog administrator.

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  18. What does the bottom pc with 3 holes bolt to? Im confused. Seems Likke it wouldnt turn if it were bolted to any thing above that. Im sure im wrong. But what are u bolting that bottom pc to? It looks as act to prevent bender/ handle from fall8ng down.

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  19. Hi Brandon,

    The plate with the three holes in it mounts to the main pivot boss. It prevents the moving arm from sliding down off the boss. It does not rotate. There is a matching bolt pattern in the pivot boss. Hope this helps.

    All the best,

    Tom

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  20. Hello Tom,
    Could you describe how did you make the pivot arm? thanks

    ReplyDelete
    Replies
    1. Hi Manny,

      It will depend on your shop capability. My friend Marty did the pivot arms out of one piece on a CNC mill. Some guys have made the arm in two or three pieces and welded them together to make the final part. Hope this helps.

      Best,

      Tom

      Delete
  21. I have problem figuring the welding part, need help!!
    Thank's
    Danny

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    Replies
    1. Hey Danny,

      What is the problem you are having?

      Regards,

      Tom

      Delete
    2. wondering where the weld will go.. should a make a groove around the pivot boss or on the table to let the weld stick correctly?

      Danny

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    3. Hey Danny,

      You would prep around the pivot boss so the weld can penetrate deeply into the angle. The weld on the top surface gets removed so you have a smooth table top/ Leave the weld buildup on the underside. Plan on welding the boss all the way around. Needs to be a pretty strong weld.

      Hope this helps,

      Tom

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    4. wich type of weld would you recommend? (rode, mig, flux core)?

      Thanks for your time

      Danny

      Delete
    5. Hi Danny,

      For a small weld like this I would most likely TIG weld it.

      Best,

      Tom

      Delete
  22. Hi Tom,

    Thank you for making the drawings available! The fine text is too small for the resolution of the posted JPEGs. Could you re-generate at the JPEGs at a higher resolution and/or export them as a PDF and/or post the solidworks CAD file?

    Thanks again,

    -Josh

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    Replies
    1. Hi Josh,

      If you click on the images they get bigger and the text is readable. Thanks for the comment.

      Cheers,

      Tom

      Delete
    2. Hi Tom,

      I suspect that blogspot is resizing or recompressing the original JPEG uploads. When I download the image files, the legend text is illegible. Eg. https://1.bp.blogspot.com/-SG7Zg8lOLpw/UDgZadzpxyI/AAAAAAAAAbU/kn-Nwekxfio/s1600/clamp+plate.jpg

      I apologize if this is covered in the drawings, do you have a recommendation for the type of bronze bushing to use? I have not worked with them before. McMaster-Carr carries oil embedded, graphite embedded, and leaded options.

      Thanks,

      -Josh

      Delete
  23. Hi Josh,

    I would choose the 660 bronze bush for this. Its harder and tougher than the oil impregnated stuff.

    Best,

    Tom

    ReplyDelete
  24. Hi Tom,
    Any chance you could tell us about the original pivot? Perhaps a picture of the underside?

    Thanks,
    Chris

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    Replies
    1. Hi Chris,

      Not much to tell. Its a bushing that is welded into the angle. The underside has a 3/8-16 female thread in it and the top has a reamed hole for the 3/8 dowel pin pivot. The bending handle is bored to fit the projection on the underside and is free to rotate. The thread underneath keeps it from falling off. Hope this helps.

      best,

      Tom

      Delete
  25. It's just amazing post,
    I really like it,
    metal bending

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  26. Tom,

    Again, thanks for the info. I'm building a bender based on your design. I have a number of bending projects in the queue already, and building the bender to support those. I do have a question.

    When I use this tool, I put a rod in the bender and yank on the handle. I see that. But won't the rod slip at some point during the travel, if for example, I bend beyond 90 degrees? Would the bending action move from the fence to the bending pin? More specifically, should provisions be made to promote the workpiece sliding over the forming pin, or fixing the workpiece to the forming pin and sliding along the fence? I can see it working either way, but don't know which way is desirable.

    ReplyDelete
  27. hello. i work for a small company in grand haven michigan. i was approached my the owner to redesign our display racks for a product. i really like the design of the bender. would you be interested in building me one and i will pay for material and your time. thank you in advance for your response. you can e mail me if you would like at shipping@americanpanelhearth.com. thanks.

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  28. Awasome ! it's fantastic blog. really very good article for pets... Thanks
    midwest crate replacement metal pans

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  30. Thanks for the post. I am nearly finished with my build of your bender. I am about ready to do the welding part.
    Mel

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  31. Hello Tom, I am a huge fan, and really appreciate you taking all the time to teach us. I have been watching your videos for years, but this is the first time on the blog. Thank you for making the drawings available, and answering everyone's questions. Please keep at it! By the way, what model band saw did you use for your lapping plates?

    ReplyDelete
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