Drilling holes in steel?

[Ryan Mcdermott]

Of I wanted to drill a 3" diameter hole in some 12 gauge steel...how
would I do this with things at the lab? Or can I?

Maybe a hole saw? Is there any special precautions to take with the
still press if I did that? Or is that even a good idea?

-Notrix

[Will Bradley]

You mean 0.1094 inch thick steel plate? Yeah, hole saw with proper lubrication. Just buy a hole saw at the hardware store with the appropriate sized drill bit in the center and drill adapters. Use the drill press... buy us a new drill vice while you're at it? :)

Clamping and wearing out the hole saw is the main issue. I practically melted my way thru the top of an Antec steel computer case in high school with a hole saw, double check the saw material and like I said set up lubrication and clamping. Google the appropriate speeds.

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[Ryan Mcdermott]

Thanks Will!

What do I use for lube?  I asked around a bit when I was drilling holes in the dome struts but nobody knew.

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[Will Bradley]

Anything, WD40 is cheap. https://www.google.com/search?oq=drilling+lubricant

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[afmanufacturing]

Use a knockout hole punch any electrician will have a set for popping holes and electrical panels to run Conduit you just drill a small pilot hole put one half on each side and put the bolt through the center, tight up the bolt and Bam a perfect cut hole with no distortion, they make them from .5 to 6 in I think even Harbor freight has a cheap set for occasional use.

[Will Bradley]

Since we're on the topic of steel, anyone know how to cut 0.035" soft tempered black oxide steel springs? Our snips and pliers shudder. Best luck I have so far is using the diamond-coated hacksaw thing. Anyone got a beefy brake? I need to cut 3/4 inch strips.

On Wed, Oct 24, 2012 at 12:47 AM, afmanufacturing <afmanuf...@aol.com> wrote:

Use a knockout hole punch any electrician will have a set for popping holes and electrical panels to run Conduit you just drill a small pilot hole put one half on each side and put the bolt through the center, tight up the bolt and Bam a perfect cut hole with no distortion, they make them from .5 to 6 in  I think even Harbor freight has a cheap set for occasional use.

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[Mike Bushroe]

Spring steel sounds like a case for abrasive cutting, either a dremel tool with a cut off disk, or a chop saw with a metal cutting abrasive disk. Depends on how accurate the cuts need to be, and if losing heat treatment is a problem. EDM would be the best if precision and/or minimal lose of heat treatment were an issue, but we don't have one.

Mike

[Nate Plamondon]

Dremel also makes circle-cutting guides for their rotary tools. I
think I have one you'd be welcome to borrow.
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Nate Plamondon

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[Jasper Nance]

How do you know its spring steel? just out of curiosity? I don't even really know what spring steel is to be honest!

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Jasper Nance - KE7PHI
Creative and Scientific Imagery
http://www.nebarnix.com/

[Aaron Hicks]

Coping saw with a metal blade might work well, too.

-AJ

[Will Bradley]

Cuz I'm cutting a spring :) also I'm going to McMaster to buy stuff called spring steel which I plan to cut :)

Thanks for the advice! I'll go with abrasive.

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[Jasper Nance]

Derp. Sorry Will, I missed that. Thought we were still talking about Ryan's hole...

[Will Bradley]

Oh sorry :) As far as how to tell, generally if you can bend metal it'll stay pretty bent. Spring steel tends to snap back to its original shape unless it's bent too much. I think its tempering has to do with its toughness too.

On Oct 24, 2012 1:44 PM, "Jasper Nance" <nebar...@gmail.com> wrote:

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[Ryan Mcdermott]

Jasper, am I taking crazy pills or did I hear somewhere that a tig welder can be used in the same fashion as a plasma cutter?

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[Jasper Nance]

It can but we need a special torch head that hooks to an air compressor and holds carbon rods. Look up carbon arc cutting or gouging

[Austin Appel]

On 10/24/2012 4:23 PM, Will Bradley wrote:
>
> Oh sorry :) As far as how to tell, generally if you can bend metal
> it'll stay pretty bent. Spring steel tends to snap back to its
> original shape unless it's bent too much. I think its tempering has to
> do with its toughness too.
>

In the metallurgy/engineering world, this is the difference between
elastic deformation and plastic deformation. Spring steel has a larger
range of elastic deformation.

[Will Bradley]

Speaking of metallurgy, does anyone do tempering?

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[Corey Renner]

Yes.

c

[Will Bradley]

How much of a pain is it to do? Trying to gauge how many hours to spend hunting for the perfect spring online versus taking this soft temper music wire and making it a hard temper.

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[Corey Renner]

Music wire arrives properly tempered for spring use, all you need to do is wind it on a mandrel, no heat treat is necessary.

cheers,

c

[Will Bradley]

Yeah but it loses its shape by ~10% when I stretch it to fit in the part. Not nearly as stiff as other springs of similar measure.

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[Corey Renner]

In small sizes, a very small change in wire diameter makes a big difference in spring stiffness.  You can also make a stiffer spring by making less coils (coarser pitch).  Another option is to make a double spring with one set of coils inside another.  Assuming that you have the correct type of wire, I don't think that it's likely that you'd be able to improve upon the factory heat-treatment, probably best to just buy the right stuff from McMaster.

http://www.mcmaster.com/#music-wire/=jvkaje

cheers,

c

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[Will Bradley]

It's a single 270° bend with a kink in it, only name I've found for this type is "G spring" because that's what it's shaped like.

It's effectively a single-ended, single-coil torsion spring. A cam shape is put in the center and rotated, expanding the spring's overall diameter slightly.  See the bright stainless steel "G" shaped thing in this photo: http://www.flickr.com/photos/hslphotosync/8117988979/in/photostream

The most effective way of making these so far seems to be cutting up existing springs. Existing springs of the same wire and outer diameter get much better performance than the ones I made from music wire. The main downside to cutting existing springs is that it's been hard finding the exact right dimensions, but I'm sure I can find if I keep looking.

By comparison, I'm sure if I tried bending the spring in a real punchdown tool, it'd just snap. Hence my thinking towards tempering :)

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[Corey Renner]

Aaaaaaah!  I see, it's more of a clip.

That could definitely be a different alloy or heat-treat than a normal spring.  Springs are expected to flex millions of times without failure, most clips (like for wrist pins etc) would expect to see many fewer cycles.

cheers,

c

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