Enlarge a hole in steel chassis

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glenlivet

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Hi All,

I'm guessing someone here has "been there done that", so I figured I'd ask before I jump in...

amp2.png


Some of the holes in this steel chassis need to be larger.....for jacks, and a lamp....
Is there a "best" way to do it ? ( without messing up / bending / mauling the chassis)

No drill press available ... but I do have a Dremel, and a good DeWalt (non var. speed) drill.



tep Drill Bit Set.png

Drill ????



grindingbit.png



grind ????




file2.png






Go old school ????


Or am I off base.....and there is a better way.... ???

Thanks for and advise.

-S
 

mrmousey

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One option would be the good old fashioned reamer
It's a hand tool with a T-handle
Very easy to enlarge holes in small increments with
out messing anything up
Very affordable, and no muss-no fuss
Kind like a manual version of the step drill you had pictured
Step drill also good, but it's possible to mess things up if you're not careful
After posting I noted that winged words just posted the same idea with a picture
 

teleteej

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I work with low-voltage electrical enclosures that often need the holes to be enlarged. I have always used the Versa-bit with a drill. Just go slow and keep checking the size and it should go fine.
 

tvas22

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Sheet metal hole punch? Saw that recommended on an Uncle Doug video recently.
 

radiocaster

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The size difference is not that much, could be done with a hand drill if you have a good clamp for the chassis. Only use bits for metal though, the ones for wood are no good.
 

JuneauMike

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If you are doing a one off thing then sheet metal punches would be overkill. Reamers, drill bits and step drill bits would be the solution here. As was mentioned earlier, you have to be careful with step drill bits, things tend to happen fast with them. If you are just enlarging the hole a bit then you could use a drill bit, but have a backing plate clamped in place so the drill bit doesn't catch. The backing plate could be pre-drilled sheet metal (make that hole diameter smaller then the hole you are drilling and don't go all the way through) or just a block of wood. If you are doing this with a hand drill, make sure everything is clamped solid and keep your speed down.
 

zipseattle

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A step drill will work well - go slow. Also, I've used Irwin brand and Harbor Freight step drills - I found Irwin to work well, and Harbor Freight not so much. That was several years ago, perhaps the HF quality has improved (?).
 

glenlivet

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"Sheet metal hole punch?"
-- don't know if that would work.....this stuff is already kind of bent where I want it......and it's thicker that you think...surprised me the first time I tried to manhandle it...

I like the taper reamer Idea....but how fast are they ?? Like I said...the steel isn't exactly thin.
(Sorry I don'y have exact measurements...)

I think the bigger hole on the left is 1/2 inch (??) and that's the biggest I'd need to make.
The smaller holes are (obviously) about 1/2 of that (so maybe 1/4 inch..)

then 2 more of the smaller holes reamed out to guitar jack size....



123.png


So it looks like the HF reamer might do it ??

https://www.harborfreight.com/t-handle-reamer-66936.html



12345.png



Guess i could always start with the reamer.....and go from there.....

Thanks all !!
 

Recce

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A step drill will work well - go slow. Also, I've used Irwin brand and Harbor Freight step drills - I found Irwin to work well, and Harbor Freight not so much. That was several years ago, perhaps the HF quality has improved (?).
HF Quality improved. Now that’s funny. You go to HF if you need a tool to use once and quality isn’t of the utmost importance. I think he wants a little better quality. Sounds like he would prefer Zipseattle’s Irwin step drill from the recommendations so far.
 

King Fan

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To go up by actual fractions, a quality step drill (eg Irwin/Unibit) is easier and more precise, although a reamer is handy to have and fine to go up a few hundredths.

As noted go slow. It's easy to go too far. It helps to mark the 'step too far.'

A6EC4550-D206-468E-86A6-795A4E7CF710.jpeg


Finally, *clamp the work* -- ie, the chassis. If the step drill binds, you'll turn that chassis into a propeller. If that happens, keep your, um, junk out of the way.
 
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glenlivet

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OK...ordered reamer kit and a 3 bit step drill bit kit.....both were pretty cheap.

(besides... I don't mind spending a few bucks on tools....If I need them once, there is a good chance I'll need them again.)
 

The Ballzz

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Please note that the OP @glenlivet mentioned that for a drill he has "a good DeWalt (non var. speed) drill" so that is a factor!
I Agree With The Unibit/Step Drill Idea,
Gene
 

WingedWords

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It's true that enlarging 1/4" to 1/2" isn't really a job for a taper reamer. I'd go with King Fan, drill slightly undersize and then ream to size which will clean up any burrs too. And note all the precautions mentioned in previous posts. Drilling sheet metal isn't fun.
 
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muchxs

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Step drill works fine up to about 1/2", maybe 5/8". They're virtually self- centering if you have a clean and properly located pilot hole.

I inherited a whole herd of Milwaukee 14.4v drills when a cabinet shop upgraded. A cordless drill and a stepped bit chews like a beast...

Over 1/2", use Greenlee punches and carefully eyeball your centers.

A nice sharp U.S. made file is great it you need a "D" shaped knockout or a knockout with flat sides for your power cord.
 

schmee

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Get yourself a hole punch set from Harbor Freight for next time. You need a 3/8 hole to use it any way. Works great without a bunch of chips and dust etc. ~$40 Used it many times by now and still works fine.
 
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