Hole Drilling Tips

[jacobyjd]

Well, just for clarity, I didn't mean any accusatory or hostile tone with that question. I suddenly started thinking, "Have I been sending out stuff with bad holes and not realizing it?" I just wanted to make sure there wasn't something I was missing.

No problem, no offense taken - it didn't sound hostile at all. I probably hit the "precision" more than was needed.

As a somewhat interesting aside, there is a trick for drilling a square or triangular hole with a space bit in a hand-held drill. Neat trick but it's such a special purpose thing I didn't bother to put it in long term storage.

I use a hand drill for everything, and it does have its quirks. I'd agree that most people can't use a hand drill as well as a drill press. I grew up making custom furniture with my grandpa, so I developed a steady hand with mine.

To all the hand-drillers out there, use oil and go slowly with a sharp bit. Then deburr with a larger bit if you like, or finish it with files. Always use a pilot hole. i drill everything with a 1/16 bit, then the bit for the actual hole size I need. Patience is a virtue, to be sure

[John Lyons]

No kidding Jacob! Those boxes you sent were very nicely drilled.
Usually when I drill something with a hand drill I put it on the ground
and hold the object with my feet of knees depending on the size.
This way I can position and hold the drill with two hands kind of
like a human drill press. 

[jacobyjd]

No kidding Jacob! Those boxes you sent were very nicely drilled.
Usually when I drill something with a hand drill I put it on the ground
and hold the object with my feet of knees depending on the size.
This way I can position and hold the drill with two hands kind of
like a human drill press. 

Why thanks, John--that's high praise coming from you.

I just use a craftsman corded drill--mine has an extra handle...not sure why--it gets heavy...

Sneaky tip for drilling footswitch, 1/4" jack, and round DC jack holes: For all these I use a 1/2 inch flat wood bit. Drill 1/16" pilot hole, keep steady pressure while the finer point digs in, then hold on for the ride at medium speed while the main bit shaves away the aluminum. I let off pressure right at the end to keep from breaking my thumb when the last bit of burr catches. It leaves a rough little washer when you're done.

I don't recommend the above if you're not rather experienced, have weak hands, or want to keep from bleeding.

[Toney]

I just use a hand drill, but I am careful and I have not had a single one turn out bad yet. The rule I follow is measure, measure again, and then again as you go.
I doubt that it's in the rules of good practice, but what I do is start with care fully measured punched-out marks, then do a pilot hole, then get stuck in with the Unibit. I measure at each clunk and quite often strain the bearings as I "aim" it more this way or that.
Care factor is not too high as my hand drill was only $20 on special, but the results (so far) have been excellent.
Measure, measure again.... keep measuring.
Oh, and patience , Grasshopper.

[John Lyons]

Well, since this thread is shaping up and people posting tips....
Here is a box drilling template I made.
This one isn't complete but shows the basics.
This is my working prototype.







Just place the template over the box and drill pilot holes.
Works perfectly every time. I mark the jack holes with
the transparency template. It's a lot less crucial...

Thanks to R.G. for the template(s) on his site. I modified them
a bit for my needs.

John

[juse]

I got  a new Harbor Freight paper in the mail yesterday & they have the small Central Machinery brand 5-speed benchtop drill press for $39.99. Sale lasts until Sept 7, 2009.

[R.G.]

A drill press for the price of a hand drill is very tempting y'all. 

My first non-handheld power tool was a drill press. I bought that in 1978. I still have the same drill press. Properly cared for, power tools are very durable.

[jacobyjd]

Wish I had a place to put it...apartments suck sometimes

[Ice-9]

One big mistake when drilling holes that people make is to drill out in stages , it is always good to drill a piolt hole but its not neccessary to drill the hole bigger in stages. A drill bit self centre's l. So if you have a hole that is say 8mm and you use a 10mm drill to make it bigger then the drill will shake in the hole and not correctly centre itself. This will cause vibration while drilling and make a hole which has a ripped shape. It is far more accurate to drill a 1or 2 mm pilot hole then use the final drill size at the correct speed to open up the hole correctly. We only need holes about 10mm in our boxes there really is no need after a pilot hole to drill in stages. pilot hole  then full size.

[juse]

Wish I had a place to put it...apartments suck sometimes

These are smaller than they appear. This is the Northern Tool version, but they are the same size.

Basketball & a 5-year old's handprint for size comparison

[Ibanezfoo]

Wish I had a place to put it...apartments suck sometimes

Huh?  I have that same Harbor Freight drill posted up there ^^^^^ and right now its sitting in front of my fireplace.  Wife's not too thrilled but its too hot outside.  Its small enough you can carry it and plop it wherever you need.  Not noisy at all either.  Some of these PCBs take so long to drill its nice to have in front of the TV for background noise.

[tempus]

Why do you drill slowly? Is this to avoid the bit from travelling or to reduce the chance that you'll dull the bit? I'm working on drilling into stainless steel at the moment and it's not going well. I have a couple smaller size cobalt bits and they're awesome - they cut right through and after several holes are still sharp. However, for the bigger holes (for footswitches - about 1/2") I used a 5/32" cobalt bit for the pilot holes, then a 15/32" titanium bit for the main hole. The titanium bit is dull and won't go through the steel at all after only 1 hole.

So I'm wondering if I should go with a 15/32" cobalt bit (which could be pretty pricey). Has anyone tried a spade bit on stainless steel? Any other suggestions?

[jacobyjd]

Why do you drill slowly? Is this to avoid the bit from travelling or to reduce the chance that you'll dull the bit? I'm working on drilling into stainless steel at the moment and it's not going well. I have a couple smaller size cobalt bits and they're awesome - they cut right through and after several holes are still sharp. However, for the bigger holes (for footswitches - about 1/2") I used a 5/32" cobalt bit for the pilot holes, then a 15/32" titanium bit for the main hole. The titanium bit is dull and won't go through the steel at all after only 1 hole.

So I'm wondering if I should go with a 15/32" cobalt bit (which could be pretty pricey). Has anyone tried a spade bit on stainless steel? Any other suggestions?

Drilling slowly was in reference to aluminum and plastic. You're going to want to crank up the speed a bit on steel. It would be a good idea to use oil as well.

[newfish]

Hand Drill, Uni (stepped) bit and a work-mate does it for me.  Work-mate holds the box firmly, so it's much safer to drill.

Thanks for the tips on Vegetable Oil.  Will remember to use that next time.

+1 on the Tapered reamer.  It does make things neater.

If I can pass a tip on it is this...  Wrap your box up in construction paper as though it were a gift (leaving the bottom open).

Cover this with a layer or two of Duct / Gaffer Tape, then with another layer of Masking Tape (the white stuff you can write on).

Mark out where your holes should be on this cover, then drill small (5mm or so) pilot holes.

Remove the cover, then continue to drill your larger holes as normal.

If you keep your cover, you now have a template for the next few dozen boxes (assuming you make everything in the same size case).

I've written the 'steps' near the holes on mine, so I know that 3 steps is a Pot shaft, 2 steps is an SPST switch, and 5 steps is a DPDT / 1/4" Jack socket.

Using this cover, I know that my DPDT hole is in the correct place for the body of the switch to hold a PP3 9V battery in place.

[Paul Marossy]

Clean, sharply cut holes, edges, surfaces, etc. requires rigidity in the clamping of the part being cut, the cutting tool, and the cutting tool holder. Accordingly, it is incredibly difficult to drill clean holes in metal or plastic (and wood, for that matter, if not using a pilot bit) by hand. I would say impossible, but then someone might have the skills. I can't, and I've tried for decades. Holes drilled with a hand-held drill will always be out of round and rough.

I have always put the object being drilled into a vise, using a variable speed hand drill. I use a Uni-Bit for 95% of the holes I drill and don't have a problem with the holes not being round, clean or perpendicular. Even if they aren't perfectly round, it doesn't matter a whole lot because a pot, switch or jack in inserted thru the hole and you can't tell anyways. I have drilled dozens and dozens of Hammond enclosures over the years and the same Uni-Bit I bought eight years ago is still going strong.

I even use my Uni-Bit for drilling plastic enclosures. As mentioned, the trick is to keep the drill speed down so it doesn't melt the plastic as it's drilling and causing the rough edges. It's also a lot easier to get out of round holes with plastic, so I am extra steady with my hands while drilling. Drilling steel is the most challenging actually, it's just tougher to drill. I have even used those spade wood drill bits to drill good round holes for tube sockets in an aluminum and a steel tube amp chassis.

If I had to do large quantities of drilling enclosures, I would be looking at having a CNC machine do it.

[bbmonster]

Anyone know what that blue cutting liquid is as see on Myth Busters when they machine their own metal parts? It like dribbles down drill bit on their press before they drill something. I've been using WD40 as a lubricant but don't like the smell and will give that veggie oil a try on the next enclosure.

[jacobyjd]

I'm guessing that's some sort of industry standard cutting oil.

Re: vegetable oil--I use it because it's cheap and I have to use things that don't give off nasty fumes in my carpeted apartment. No guarantees that it's the best thing out there.

Also, I just found out yesterday that i'm getting  a bench-mount drill press whether I like it or not--my father in law is moving and needs to get rid of his. Lol...I guess I'll have to MAKE it fit darn!

[Talon5051]

I got  a new Harbor Freight paper in the mail yesterday & they have the small Central Machinery brand 5-speed benchtop drill press for $39.99. Sale lasts until Sept 7, 2009.

I bought one today at my local store not  for 39.99 but at 59.99.  Still seems to be a good deal.  I needed one because the ex wife took the hand drill (it was her dad's so it would have been hard for me to keep).

[tempus]

Those step bits look promising - it's nice that you can drill so many sizes with one bit, even if they are on the pricey side. So, has anyone tried to drill stainless steel with them?

[juse]

I bought one today at my local store not  for 39.99 but at 59.99.  Still seems to be a good deal.  I needed one because the ex wife took the hand drill (it was her dad's so it would have been hard for me to keep).

Bummer... I looked a little closer - l guess it's a coupon deal:



Maybe referencing the numbers would still get you the same price...

LOT NO. 38119/44506

85196780