Drilling Holes in Holey Metal

[Necro]

Minor issue popped up when drilling my CP.  I'm using a previously used Omega Race panel and it has a few holes in it already.  Of course, a few line up EXACTLY with where I want to put button holes. This presents a problem in drilling out the 1-1/8" holes for the buttons as I have nothing to drill the 'centering' drill into OR the centering drillbit is going to wander because it's right on the edge of the existing hole.

Thoughts, ideas?  I'm debating tightly clamping everything in place and then 'free drilling' the 1-1/8" holes with just the hole saw (no guide bit) or having the guide bit go into a piece of wood below the metal.

Any other suggestions?

[jimmy2x2x]

Sandwich the metal between 2 pieces of wood, clamp it all together then drill.

[mgb]

I'm currently in the middle of building a metal control panel that has existing button holes but I want a different layout.
I first contemplated having the holes filled with metal slugs welded in.
I instead went the somewhat cheesy but cheaper way of using the knock out slugs from an electrical box (3/4" fitting).
I took the knock outs and roughed them up real good with a dremel tool cut off wheel. I removed the galvanizing from both sides of the knock out.
I also roughed up the metal of the control panel too. I placed the panel on a flat surface and placed the the knock outs in the unwanted holes and went over them with a skim coat of JB Weld. after those cured overnight, I did the same thing to the other side. you can then build them up as needed and skim coat the whole thing in bondo.

[Necro]

Will JB Weld hold when you drill though?  And I thought bondo would just shatter if I were to use a hole or step drill on it. 

From a 'visuals' perspective, there's going to be art over it so I'm comfortable filling it/fixing the holes 'post' drill - it's more the getting it stable to drill. 

Also, 'sandwiching' with wood won't work - hole saws won't cut wood properly and if it did, I couldn't get the drill oil on it properly to actually cut the metal.   I'm thinking the 'half a sandwich (i.e., wood under' approach may be the best for the initial drilling, then 'repair/fill' where needed, and dremel out touch ups if necessary to ensure controls fit.  I guess... :/

It's never easy...

[brad808]

Hopefully this makes sense to you....

What I have done before is cut a piece of wood the same size as the control panel. I then cut out the inside of the control panel so there was only an inch boarder around the outside. Then take the wood and route a one inch boarder in the wood the same thickness as the metal. This allows the wood and metal to sit flush.


This does require something to hold the wood in place, I used 4 carriage bolts in the corners, but the control panel I did this on was otherwise beyond repair. Pus it looks like the bolts are simply holding the plexiglass

[leapinlew]

Also, 'sandwiching' with wood won't work - hole saws won't cut wood properly and if it did, I couldn't get the drill oil on it properly to actually cut the metal.   I'm thinking the 'half a sandwich (i.e., wood under' approach may be the best for the initial drilling, then 'repair/fill' where needed, and dremel out touch ups if necessary to ensure controls fit.  I guess... :/

It's never easy...

pre-cut the holes in the wood...

[Necro]

Hopefully this makes sense to you....

What I have done before is cut a piece of wood the same size as the control panel. I then cut out the inside of the control panel so there was only an inch boarder around the outside. Then take the wood and route a one inch boarder in the wood the same thickness as the metal. This allows the wood and metal to sit flush.

Oh - it's nowhere near this bad.  It's, quite literally, 6 holes.  Two regular button size and 4 small ones.  It's just making the new holes that's an issue. 

Leapinlew: That defeats the purpose of the top piece of wood giving stability to the drill bit and would be equivalent to just a piece of wood underneath.

[leapinlew]

wouldn't the holes give your drill bit stability?

[mgb]

If you're using a hole saw and a drill press, anything firm under the panel like wood should give you stability as long as its clamped well. personally I would not use a step bit as I find them to not be very stable.

[nox771]

Maybe not the cleanest method, but couldn't you just mark it with a pen and use a dremel with a grinding bit to enlarge the hole?

[DeLuSioNal29]

wouldn't the holes give your drill bit stability?

I think Lew's onto something here.  Here's what I would do:

• Pre-cut the holes on wood to the layout of your choice using a wood bit.
• Clamp the wood to the metal with the wood on TOP.
• Switch to the metal bit and then using the holes as a guide, make the rest of the holes in the metal.

Note:  You may need to drill out a small hole in the center of each on the metal one once you make once the wood template and clamp it to the metal.  This should be done with a slightly bigger bit than the bit you will be using to make the button hole; with a normal drill.  Then, when you drill through the metal using the metal bit, the wood holes themselves will stabilize the outside portion of the drill bit; since the metal center of the bit will not be touching anything.

DeLuSioNaL29

[Necro]

Delusional - I think I get it now.  I'm still a bit iffy though because I won't be able to use the cutting oil easily.  I actually had a blank art 'template' and pre-drilled the pilot holes for everything (hence finding out the issue as kind of a surprise when I went to drill and the bit wandered/shifted unexpectedly).  Based on that, I actually can make a single hole 'jig' I can clamp to the panel and to underlying wood and then use that in my drill press repeatedly as I can center it on the hole as necessary.  Nice...very nice!


I have a feeling I'm going to try 2-3 of the above options until I get it done.  Luckily, my artwork/overlay will cover any mistakes and I should be able to 'fix' things with glued on metal backing or wood if necessary based on where the holes are.  

Thanks everyone.  If work goes well tomorrow, I may take friday off to get this thing done. 

[gryhnd]

pre-cut the holes in the wood...

Agreed. Works well. I did the same thing when I needed to widen the holes in an old TV cabinet:

[mgb]

I like that idea, I may take Friday off too in order to show my support.
.... but wait we're cooking out at the office that day, hmmm maybe I'll take monday off instead.

[Necro]

Agreed. Works well. I did the same thing when I needed to widen the holes in an old TV cabinet:

The problem is 'm cutting through steel and it requires cutting oil...if it was wood, it would be fine. (see what I did there)

[leapinlew]

Agreed. Works well. I did the same thing when I needed to widen the holes in an old TV cabinet:

The problem is 'm cutting through steel and it requires cutting oil...if it was wood, it would be fine. (see what I did there)

Cutting oil? How thick is the metal on this control panel? I think you are making much more work out of this than you have to. I've cut through plenty of metal CP's with predrilled. here is the process I took:

1. I clamped a piece of wood on the bottom and I used bondo to repair the holes.
2. I cut the control panel I wanted out of 3/4 MDF or Plywood. The control panel was cut to size.
3. I clamped the finished wood control panel top to the metal CP that has been repaired with bondo and still has the bottom piece of wood forming a sandwich.
4. I used a sharp hole saw to cut out the button holes/joystick holes. Once it cut the metal, I moved on to the next hole.

Honestly, after the bondo repair, you probably don't even need to have the wood jig. I've done it both ways with success.

Screw the oil. You'll be fine.

[Nephasth]

Screw the oil. You'll be fine.

+1 I've only had to use cutting oil when drilling through THICK metal (3/4"+). I have also found that using paint thinner for a drilling lubricant kept the bits cooler and allowed them to cut easier than when using oil (I only use lubricant when drilling a lot holes in one session).

[Necro]

2" Plate Steel.  Why...that's not normal? 

And just kidding - it's about 1-2mm thick steel.  A metal drill bit goes through it decently, but I'm more worried about the hole saw as I need to cut...a LOT of holes as I'm doing 3 swappable panels.  Also, I thought the bondo wouldn't hold the pilot bit in place.  Never used it before.

I'll know rather quickly after drilling the first hole whats needed I guess.

[Necro]

Well - I drilled one panel.  Did all 1-1/8" holes with the hole saw and the 5/8" holes (for cone buttons) with a step bit.  Overall, I actually like the holes the step bit makes much more.  MUCH cleaner, less 'chatter', etc.  But, I can't see the bits I got lasting for 3 panels so I went with the hole saw.  The holes are not 'perfect' - i.e., the alignment is 100% perfect - but for something I did by hand myself on a drill press I think it's good.  Only one hole/button may have an issue and need some 'structural support' added so the button doesn't slide.  Oh, and two empty button holes are going to get the washer/JB weld treatment just for structure/ensuring the art doesn't get ripped.

In case anyone's wondering, I used an 1/4 inch hard board overlay to align the holes, get things setup, and get the hole saw aligned (from the top).  I used wood supports under the panel and drilled into it when necesary, but having it behind the metal didn't actually do much aside from provide support.  Also, cutting oil 100% helped the cutting.  I even put it into the 1/4" hard board holes to assist there.  Should keep the blade sharp longer and usuable for all the cutting I need to do.

Thanks again all for the help/advice!