Little job for fabricator?

  1. DTS Forum Supporter

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    Not sure if this is the right section but a mate of mine needs about 50 off little metal parts for motorbikes making. Pictures below. I have an original but it’s a rare thing so looking for small fab shop? They’re only about 48mm long, 1mm mild by the look of it. Anyone like to quote? Bend looks a bit tricky.

    C0031165-8DC9-4359-AEE3-0CCFD2723BC2.jpeg C0031165-8DC9-4359-AEE3-0CCFD2723BC2.jpeg 3B51FF4C-98F6-44FF-99BC-7FC3D11210C7.jpeg 8C0A2164-EE11-465D-BF44-B6F77ABABC40.jpeg
     
  2. pedrobedro

    pedrobedro Man at Matalan

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    Sort of thing we used to make on a fly press at the boiler factory when I was working.
     
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  3. tom2207 Member

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    laser cut and fly press fold . or small folder .
     
  4. Agroshield Member

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    You will need to give a lot more information before you can get a sensible quote.

    You also have to decide how true to original you want them. The originals have been stamped out of sheet (so the edges are smooth). Then they have probably been stamped again to bend them into shape (and the oval hole likely formed at this second stage). You are unlikely to be able to go this route for the reproductions as the tooling to stamp them will be expensive and its cost is only amortised over 50 pieces.

    You need to obtain a flatpack version of the object and might have to give up some precision with the hole*. As tom2207 says, laser cutting will be the way to do this, for which you will need an electronic drawing. A fabricator will charge you for making this drawing. The laser cut parts will not have the same edge finish as the originals. The flat parts then need to be bent into shape, for which a tool will need to be made (for 50 pieces, nothing too fancy is needed).

    How will you communicate to the fabricator what you want? Will you give them an original and say, 'I want 50 copies of this please'? Will you expect the original back unmolested at the end? If the answer to both questions is yes, that is your most expensive route.

    If I were doing this and starting there, you would need to give me two originals and you can expect one of them back. One of them would be pounded flat and then drawn up for laser cutting. The other would be used as a template to make sure the bending jig is correct. There would be some trial and error involved as it is by no means guaranteed that the first laser-cut-from-drawing-from-pounded-one will turn into a correctly bent one.

    You also have to consider the finish on the final item. Pickling or tumbling before plating is probably easiest.

    Picking a number out of my ass, I reckon if you can get them done for less than £15 each, you will be doing well.

    *It is not round, so laser cutting is the easiest way to form it, but when the flat piece is bent, the position may not be quite right. Forming an oval hole after bending is expensive.
     
  5. tom2207 Member

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    That sums it up perfectly .
     
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  6. DTS Forum Supporter

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    197
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    Thought it was not going to be easy. Tried a couple of local guys but they said as above, it’s the drawing without flattening the original and they don’t have lasers to cut anyway.
    Sold my CNC plasma. Original is off someone’s “pride & joy” so can’t wreck it.
    Thanks for the replies though.
     
  7. Brad93

    Brad93 M J B Engineering

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    I can make that but it would have to be plasma rather than Laser.

    Flattening it wouldn’t be a problem, I’m sure I could work out the bend allowance.
     
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  8. Matchless

    Matchless I started with nothing, still have most of it left

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    make two copies by hand, hammer, grinder, anvil, file, when you have a pair, flatten one out, give both to a fab shop......
     
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  9. Brad93

    Brad93 M J B Engineering

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    I’ve got some 5mm coming tomorrow Pat I’ll finish those engine brackets.
     
  10. Matchless

    Matchless I started with nothing, still have most of it left

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    Thanks, I hope to get over sometime next week, sparky coming later this week to finish my 3 phase, bike ride tomorrow,
     
  11. Mr Roo

    Mr Roo Member

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    Edinburgh
    I’m glad someone else said it! My first thought was “measure it, figure out the bends, draw it out, job’s a good ‘un” but wondered if i was missing something when everyone else said it needed flattened first!
     
  12. Agroshield Member

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    1,027
    It is a time and money thing. Anything is possible if the customer is willing to pay.

    The difficulty with this particular part is the angled bend. If it was like a Z but with a vertical shaft, it would be easy to work out the flat shape. See this excellent post: https://www.mig-welding.co.uk/forum...ences-for-rolling-cylinders-rings-etc.103304/ , same principle. With the angled bend, the tab with the hole will end up at an angle to the main bit when it is flat. That is quite tricky to determine just by measurement of the finished part. Also, because of the proximity of the two bends at the bottom of the slope, the bend allowance is not trivial to determine as one bend will influence the other.

    I am coming at this from the point of view of being very fussy. It is easy to make reproduction parts that nearly look like the originals - the car panel market is full of them - but to make facsimile copies takes a lot of effort.

    I know I would get it wrong the first time, and probably the second time as well. So you have to pay for my initial measurement, my initial drawing, the first flat laser cut test piece, the first test bend, the thinking and swearing when it does not fit (cursing is always best done on other people's time), more drawing, a second laser cut, a second bend, more thinking, final drawing, final test laser cut, final test bend and then you are ready for production.

    Alternatively, flatten it, scribe round it and hand cut the salient bits (the lower curve and the hole are not needed here) and test what you have made in your bending jig to see if it goes back to original*. Then, based on that knowledge, make your first drawing. With good luck on your side, the first laser cut part might work. If not, the second surely will. It is a shorter and hence cheaper route to the finished part.

    Mr Matchless' suggestion is very good. If you make a hand crafted one first, you can separate getting the bends right from getting the shape right. Bend up something that is way too big but where the angles come out right. Then file and sand the bent bit to the correct shape before flattening and sending off to the fabricator. That is a long day's work of your free hobby time that will pay great dividends.

    *And you will probably have to modify the bending jig as well at this stage.
     
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