Make a hinge - how to cut a narrow slot?

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dansawyer

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I am trying to make a two part hinge on a 14 inch diameter round clamp. The clamp is made from 3/16 x 1 steel bar rolled in a circle. My thought for the hinge was to weld 3/8 nuts and cut horizontal half way in above on one side and below on the other; and then cut a vertical between them. What is the best way to cut the vertical?
I had thought of grinding the center and then step drilling toward the ends.
Any thoughts on improving the plan or cutting the vertical appreciated.
Thanks, Dan
 
Any photos? I'm trying to picture how this is so difficult to cut vertical.
If your goal is to have two "C" shapes come together with a hinge on one end and a bolt or screw on the other. It may well be easier to make a double hinge and bolt connection on both ends.

Make two "C" with the ends terminating in little "P" shape on the ends. Run four bolts vertically through the holes, traveling trough 4 roler chain master links to bridge to two together.
 
I’d cut straight across. Then get/make two barrels 1/2” long, bolted together to make a 1” long barrel. Set that combined barrel above (outside) the cut with the band ends lined up as if they weren’t cut, and weld one small barrel to one side of the cut, and the other barrel to the other side.

Or, weld a one inch barrel across the outside of each end, and mill out alternating pieces to make a more complex hinge.
 
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Maybe there's a better/simpler way. Since the clamp is only 1 inch wide, it appears to be needed for something like supporting a pipe or something else that's 14 inches in diameter (HVAC stuff???). What about metal strap used for restraining tanks? It has lots of holes in it to present lots of options for mounting/hanging. 3/16 thick material suggests you need some strength but only YOU know the particulars, not us.

On the other hand, maybe you need something that can be put up and taken down easily. But....we dunno what the actual requirements are.

Presenting a question with just your notion of what's necessary is limiting the possible solution space. More background would help us (and perhaps you, to better define the problem). Just a friendly suggestion :).
 
Photos needed.


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You are correct. Below is a picture of the current joint. The curennt part is made from cast aluminum and broken just out of the pictue. I am creating a replacement part from rolled steel. The picture shows the hinge made of thickened casting with threads. A bolt is used to create the mechanism.
My plan to make the hinge is ot cut a Z. The top of the Z is 1/2 way through perpendicular to the band, the vertical is 1 inch along the band, and the bottom of the Z is perpendicular to finish the cut. My plan is to weld a nut to the each of the tangs. These will correspond to the thinkened parts of the castings.
 

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Have you determined why the original part failed? Steel will be stronger but may also fail if the design isn't up to the task. More details/pictures needed....

John
 
Yes. The clamp is used to mount a 50 lb telescope. A mounting block is used to attach the clamp to the telescope base. The mounting block is about 4 inches end to end; this creates a short fulcrum. I have extended the block from 4 inches to just over 9 inches. Thsi will decrease the torque by over 3:1.
 
Hopefully nothing else was damaged when the clamp broke. That sounds like a fairly large/expensive telescope.

Judging from your photo, it looks like the original design has a continuous curve around the hinge point, perhaps to avoid crushing the telescope tube there. Is your fabrication approach meant to achieve that? I'd been wondering why you weren't going to just shape the ends of two pieces and then weld the nuts to them, but that would likely cause problems when bending the straps.
 
There was small damage to the tube, It is made from carbon fiber and when the clamp broke the ends dug into the tube. It looks like a partial puncture.
Yes, the clamp is a continous arc about 14 1/2 inches in diameter. I have created a round continous band of 3/16 x 1 steel into the correct diameter with about 2 inches of overlap on the ends. I will bend the ends back. 90 degrees, by about an inch or so and drill holes to allow a bolt to squeze the ends and create a firm fit.
I am proceeding with welded nuts idea. I will post a picture.
 
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