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How to stamp/press a flat spot in stainless steel wire

KP114

Plastic
Joined
Oct 7, 2021
Hi Everyone,

Long time visitor, first time poster here. My question is as follows:

Most welding filler rods come with a flat spot/tab pressed into them at the ends (see attached photo). I'd like to be able to consistently create such flat spots in the wire at various places, but without the lettering.

Filing is not an option, because I need the material to expand, so it can act as a stop for a spring that fits around the metal rod.

The material I'm using is 316L stainless steel wire in 3.2 and 2 mm diameter.

I'd like to be able to do this at home without having to heat the material. Do any of you have a suggestion on how to achieve this? My vise is obviously not strong enough, but I wondered if a manually operated arbor press would be able to do the job. Are HSS blanks safe to use as stamps in a press like that or will those shatter?

Thanks a lot!

IMG_7068.jpg
 
Small benchmaster punch press, a small die set, a polished flat anvil (bottom) and a punch that is radiused and polished.

Appropriate back and side stops to locate part in press.
 
We do random low volume pressing operations in the press brake. Nice controllable depth makes the tooling easier to accomplish. I try to find premade tooling for a similar application and then make an adapter to fit into the press brake. One source of nice hard and polished tools are the rivet setters used on air hammers.
 
Hi KP114:
What kind of resources do you have to do this?
Do you have a shop.
Is it decently equipped?

If you have a milling machine, you can probably generate enough force with the milling vise.

If you don't, then a hammer is probably your best option.
I'm serious, the force you can generate by striking is high...you just need to make or commission a punching system that can hold your rods between an anvil and a punch, with limit stops so you can't overstrike it.

You could also buy a cheapo hydraulic press from someone like Princess Auto, or Harbour Freight, and build the tooling you need
I don't think you're going to be able to generate enough force from a lever type arbor press, a fly press maybe...but you'd have to find one and then still have to build the tooling for it.


If you're hitting the punch with a hammer I don't recommend HSS for the tooling unless you cushion it somehow.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 

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Question is, how much wire do you want to process and is the flattening for a given batch i.e. a spool, or is it variable within a given length? What is a typical length between flats?

Tom
 
Hi All,

Thanks for the suggestions so far!

To answer a few questions:

- I don't have a lot of equipment. Basic tools and a drill press, so I'd prefer a low tech/simple solution.
- I'm not working in batches, it's just an idea I'd like to explore for making a sort of jewellery items.
- The hammer and punch system sounds the most like what I had in mind so far.
 
Hi All,

Thanks for the suggestions so far!

To answer a few questions:

- I don't have a lot of equipment. Basic tools and a drill press, so I'd prefer a low tech/simple solution.
- I'm not working in batches, it's just an idea I'd like to explore for making a sort of jewellery items.
- The hammer and punch system sounds the most like what I had in mind so far.

That's what I would suggest. Simple enough to fabricate a jig even with just a drill press and hand tools. I would suggest buying a Starrett flat-faced punch of the desired size and make a simple jig to hold the wire and guide the punch.

PS: Another way would be to buy small bolt cutters and grind/file notches in the jaws that would make the desired crimp depth when fully closed. For repetitive work clamp one handle to the bench so you can use one hand to hold the wire and the other to press down on the loose handle.
 
That's what I would suggest. Simple enough to fabricate a jig even with just a drill press and hand tools. I would suggest buying a Starrett flat-faced punch of the desired size and make a simple jig to hold the wire and guide the punch.

PS: Another way would be to buy small bolt cutters and grind/file notches in the jaws that would make the desired crimp depth when fully closed. For repetitive work clamp one handle to the bench so you can use one hand to hold the wire and the other to press down on the loose handle.

+1 for modified bolt cutters. That was my immediate thought as well.
 
I am going to offer an opinion not based on personal experience with this very process. But, we are talking 1/8” diameter stainless wire compressed enough to deform its cross section about 50% and do it in a controlled fashion. And we need to do that with minimal tooling at our disposal.

I like the simplicity of the bolt cutters, but I don’t see an easy way to make a jaw die 1” long to fit in them and I doubt they’d generate the force to do the op in a single press. If multiple presses and the resulting irregularity is OK, then pressing a 1/4” segment at a time would work. Read no further.

My suggestion will require the assistance of a friend with a welder and a horizontal saw.
To make a single-press flat like the one shown requires huge forces. The simplest way to accomplish that I would guess would be to first grind a matching set of HSS dies each one inch in length and made from at least 1/2” square HSS and let them into some 1” by 4” bar stock 18 to 24” long each. (If milling a slot for the dies is not an option, I think the dies could be silver soldered onto the bar surface, but the pocket would support it better.) I’d silver solder them in place using a rosebud on an O/A torch. Locate the dies 1” from one end weld a flexure on that end of the bars of 1/2 x 1” bar stock. Once welded, open up the far end enough to put a slight open bend on the flexure so the jaws want to spring open enough to get stock in between the dies. Weld a couple 1.5” cubes one to each open end of the bar. The cubes should be bored to accept a 3/4 bolt that will span the open end.

Now slip the stock between the jaws, get out your wrenches and smile as you smush the bar like a piece of taffy. And the HSS will not shatter. It takes enormous compression forces and is even fairly tolerant of shock. Many years ago I made some nice center punches with O1 striking ends and HSS steel pointed ends. They have served me well surviving countless blows and have not required sharpening.

Denis
 
This is related to a question I've had for a while. It's common to see a shaft with two protrusions, pretty much like what you could get with ground-away bolt cutters. The feature is so common there has to be some standard die that does it. It's so common I can't find a single example or even what term to search on, but you'd recognize it instantly if you saw it.
 
This is related to a question I've had for a while. It's common to see a shaft with two protrusions, pretty much like what you could get with ground-away bolt cutters. The feature is so common there has to be some standard die that does it. It's so common I can't find a single example or even what term to search on, but you'd recognize it instantly if you saw it.

Ya, I have seen this “crimp” (not the correct term) hundreds of times. But, nope, don’t know its name.

4D799027-8178-4B4A-97D3-05952544E3FF.jpg

I suspect that’s what you are referring to. Someone here, working in wire fabrication, will know.

Denis
 
If you have a sturdy vise with removable jaws you could try this if you only need a spring "stop" and not a long flat spot:

Make a set of jaws to fit the vise out of say 1 inch steel.

Drill a hole in the top of each jaw across from each other.

Mill away enough of the jaw face to expose maybe a third of the hole.

Drop a dowel pin in each hole.

That will give two point contact and you might be able to generate enough force in a good vise to crimp the rod.

If you only relieve the middle section of the jaws when the uncut jaw surfaces close on each other you'll have a consistent crimp.
 
Yes, the "wing like" crimps might be even easier to produce by hand. Found a video on youtube on how they're made industrially. I have some time the coming week to try stuff, so I'll keep you all posted! With the proper tools it looks so easy, but I like the challenge of doing it at home with basic equipment.

Screenshot 2021-10-09 at 23.11.08.jpg

Crimping a Round Bar - YouTube
 
Very cool. I assume the top and bottom dies are identical. Seems doable at home with any good vise, but getting the really pretty results requires machining the radius feature on the dies; not easy without CNC. OTOH, not everything I do is pretty!
 
Yes, the "wing like" crimps might be even easier to produce by hand. Found a video on youtube on how they're made industrially. I have some time the coming week to try stuff, so I'll keep you all posted! With the proper tools it looks so easy, but I like the challenge of doing it at home with basic equipment.

View attachment 331744

Crimping a Round Bar - YouTube

That little crimp shown in the video could easily be done with a set of dies placed in a medium-sized bolt cutter. I repurposed a 36” bolt cutter with a chipped cutter by making new tool steel dies to crimp fittings onto 1/4” cable. They make such a crimp with ease. The wire crimp shown would not require very much power.

Denis
 
Finally got around to trying the bolt cutter modification, and some progress has definitely been made! The force the cutters generate is indeed more than enough to deform the metal, so that's awesome. They leave a nice, symmetrical flat spot. The only thing I would like is the material to "bulge out" more to the sides, so it can stop a washer or a spring from slipping off the rod. At the moment the sides remain pretty flat. For this test I just filed a 1mm flat spot on either side of the bolt cutter jaws. Maybe it would work better with a rounded notch? Already very pleased with where this is going, so a big thanks to everyone for thinking along with me!

Screenshot 2021-10-16 at 13.14.17.jpg

bigger image: Dropbox - Screenshot 2021-10-16 at 13.14.17.png - Simplify your life
 
Your bolt cutter die makes the rod longer rather than wider because that is the path of least resistance. To widen the rod, I think you will need a mechanism that produces a notch in the rod that is parallel to the length of the rod. You can experiment with a small cold chisel held parallel and see your results.
 








 
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