How would I cut a hole for this - round w/ flat side

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charles_steiner
 
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How would I cut a hole for this - round w/ flat side

Post by charles_steiner »

Image
https://www.adafruit.com/products/827

I'm attaching this to sheet metal.

Is there a trick or a tool to cut a hole with a flattened side? Is it even necessary?

THANKS!

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adafruit_support_mike
 
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Re: How would I cut a hole for this - round w/ flat side

Post by adafruit_support_mike »

There are punches that will cut the right shape, but for one-off applications it's easiest to do it by hand.

Draw the shape on the metal, drill a few holes inside it about 1/16" inside the line, then use a rat-tail file to remove material to the line.

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bluefirepony
 
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Re: How would I cut a hole for this - round w/ flat side

Post by bluefirepony »

I've used those IP glands on many projects - aluminum, sheet metal and plastic.
If you are new to drilling sheet metal just use a good titanium bit, slow RPM (or the bit will just spin on the sheet metal and heat up), use a good 3-1 lubricating oil.
Start with a smallish bit to drill a pilot at the center and then on the next pass a bit 1/2 the diameter. If that goes well then the next pass use a bit that matches your target size. If you struggle with prior passes, reduce the jump in size and just be patient. You can do it with a single pass once you get the hang of it....drilling sheet metal is a challenge to patience...just when you think you can speed up, the bit bounces and snags and you are onto another bit .

Mike's suggestion of filing is a good practice.
.

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charles_steiner
 
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Re: How would I cut a hole for this - round w/ flat side

Post by charles_steiner »

Thanks for the quick response, guys!

That's good food for thought

I did buy a step drill bit a few weeks ago that's itching to be used but for this, to get the flat side, I can imagine outlining and drilling the small holes then file the flat portion. It's an ammo box; the metal is not super thin but it's not hard. TBD

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adafruit_support_bill
 
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Re: How would I cut a hole for this - round w/ flat side

Post by adafruit_support_bill »

Step-drills are definitely the way to go for round holes in sheet metal. For flat-sided holes without the appropriate punch, Mike's technique - possibly aided by a nibbler tool - is the most practical approach.

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charles_steiner
 
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Re: How would I cut a hole for this - round w/ flat side

Post by charles_steiner »

Ok. So the flat side isn't necessary. Makes sense, the seal covers it.

I'm sure I'll some silicone on it, anyways

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adafruit_support_bill
 
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Re: How would I cut a hole for this - round w/ flat side

Post by adafruit_support_bill »

The flat does make it easier to install without a second wrench. But you are correct. The seal will cover it.

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