I was curious with what bits you guys have been using to drill holes in your frames. I'm not pleased with what I see at Lowes and Home Depot, but maybe thats me. What have you guys relied on for most of your metal hole drilling.

 

Sancocho....Thanks for this thread, it reminded me that Santa brought me a new "Drill Doctor" last christmas, I wonder where it is. I wonder how long it will take to sharpen about about a thousand old dull bits. Anyway I just buy the gold colored super duper bits at the local hardware store. When you start drillin' you'll find out what "Ford Tough" means.
________________________
XFM
'53 F100

 

Joe -

The best drill material for carbon steel drilling is High Speed Steel. Very common and available from Sears. Cobalt is also excellent and tends to hold a sharp point a little longer. Cobalt drills will be found at a machine shop supply house (where machinists go to buy stuff). The gold colored drills are a coating that helps hold the edge, but not for long. Don'y buy cheap drills from Harbor Freight or anyone else who gets them from China. The steel there isn't very good. A dull drill just "worries" the hole open, wears the drill edge down real fast and creats a lot of heat. A waste of time.

Every new drill has a good point. The difference is in how long they hold it. A tip: center-punch the start to keep the drill from walking, put a drop of motor oil on the punch mark and be sure to use a low rpm (300-600). You will cut through the steel much quicker and the oil helps the drill cut the steel and holds the edge longer.

 

I prefer to use titanium nitride coated bits, they are easily recognized by their gold color. The biggest mistake people make when drilling metal is trying to drill a large hole in one shot. I always start with centerpunching the spot with a sharp centerpunch then drill a pilot hole with an 1/8" bit. I then enlarge the hole in 1/8" increments to the final size. If the metal is thinner than 10 ga. I drill the 1/8" pilot hole then finish drilling the hole larger using a stepped unibit rather than a twist drill, a large twist drill will tend to grab and tear thin sheet leaving a less than round hole. Another problem I see a lot is people trying to increase the drilling speed by running the drill at a high speed. The mantra for drilling steel is SLOW speed, HEAVY feed! Use a variable speed drill motor and set the stop to allow a max of 1/2 speed only. Push hard enough to produce a steady stream of course chips or better with a good sharp bit continuous curls of metal. Speeding up the drill will only help dull your bits faster. If you are not getting course chips or curls stop and resharpen your drill bit. If the bit has turned blue at the tip throw it away. If drilling 1/4" or thicker, give the spot and bit a shot of WD40 or cutting oil. You'll be amazed how much faster a lubed bit will cut.
If you don't know how or have the right grinder to sharpen bits, invest in a quality sharpening machine, it will shortly pay for itself.

 

I have to plead ignorance on the tech part of this but I bought a self starting 10 bit DeWalt set from Lowes that I have been very pleased with. A dab of cutting oil is a definite help. Thanks for that tip about the step bit on sheet metal, that's what I love about this forum.

 

My post seems to have disappeared. FF56 you'd like it if you team up the step bit with an appropiate size Whitney punch for filling misc holes. Just punch out a bunch of discs the same size out of similar thickness metal to the repair area, and use the step bit to drill out all the smaller or out of round holes to the same size as the discs (the step bit will round out misshapened holes too) and plug away! No stopping to cut out a bunch of different size and shaped plugs. The fit will be so good that you can put the plug in place with a dolly behind, give it a couple taps with a body hammer and the plug will swell enough to lock in place while you weld it!

 

AXracer,

Thanks for the tips. A little common sense and patience goes a long way. My father taught me your way of drilling with 1/8" steps years ago. His thought was that it took longer, but did a more precise job and save your bits. The step bit is a great idea as well to eliminate the problem of wandering larger bits. Your tip for filling holes is very creative and I can see that it would work well.

It's always nice to add a couple of "work smart, not hard" tips to the list. Thanks...

 

I must give credit for the filling holes tip to Ron Covell in his "Basic Metalworking Techniques" video. HIGHLY recommended, full of tricks of the trade.
A major problem with using a large bit to drill a hole in one shot is the center of the bit is broad and moving very slowly and you are trying to cut a lot of metal at once so it doesn't drill very effeciently, often overheating the metal and bit before you actually start drilling the hole. It will also invariably catch and bind as it starts to break through distorting the hole and risking injury to the "driller" and damage to the bit.

Another quick tip I was taught as a youngster: to remove the burrs around the hole pick a sharp bit quite a bit larger than the hole, and using it in your hand rather than in a drill motor put the point in the hole and give it a couple twists to cut away the burrs.

 

That's a great tip on filling holes (no matter who said it first) I don't care how long you do this stuff you can always learn some neat little trick that some one else has known for years. I also learned the burr removing trick as a little kid. Of course there wasn't any electricity then so we had to drill all holes that way.

 

Actually I did first learn to drill holes with a hand drill! My father didn't own an electric drill motor at the time. We had a small crank drill and a large one with a saddlehandle that I would lay across for weight (I was a skinny little 6 year old!) That's why I learned to drill out a hole in increments (and watch out for pinched fingers in the gears ).

 

Chuck, you must be almost as old as I am!

 

I'm so old my father was on a first name basis with the Allmighty! (59)

 

58..............

 

Any steel drill bit will do it. It's best to use a 1/2 drill instead of a 3/8 drill. AXRACER I've reused drill bits that have turned blue. I just lately resharpened on my bench grinder have have so far drilled over 40 holes through rivets and sheetmetal. It just keeps on going. Grinding drill bits on the grinder is trial and error. The more you do it the better you get at it. It's best to just clean up the point.

 

We do a lot of stuff on hardened and high-toughness alloys at work. The aircraft industry standard (if you can afford it ) is a 135 degree split point, jobbers length, heavy-duty cobalt steel, standard flute, bright finish (uncoated). A 1/8" to 1/2" by 1/32" (15 drill bit) set is about $75 from McMaster-Carr. A 1/8" to 1/2" by 1/64" (29 drill bit) set is about $125 from McMaster-Carr.

These bits will last practically forever if you follow Chuck's and others advice about keeping the temperature down while drilling. Pretty pricey - but I bit the bullet some 10 years ago and bought the big set. I think I've only broken one of them over the years and my Drill Doctor keeps the rest pretty sharp.

The 135 degree split point really keeps the bit from wandering and makes a cleaner hole in most alloys. We don't use the Nitride coating at work since it isn't recommended for titanium and some wrought aluminum alloys. For steel it should be an advantage as the guys have said.

When I drilled out the rivets on my frame, I bought five or ten 1/8" and 1/4" cobalt bits from McMaster cuz I knew I'd break off at least a couple during the process. Those smaller sizes are actually fairly cheap.