Question about drilling 1/4" steel plates.......

[Stanley Steamer]

I am going to mount a small winch on the tongue of my landscape trailer in case I ever need to pull something up on it.......

I cut a small 1/4" piece of steel plate to weld to an adjustable riser......I marked my holes with the plate on the bottom of the winch.....and scored them with an awl.....

I have a tabletop Craftsman drill press on a stand and used a 11/32 drill bit(two sizes bigger than the actual bolts with the winch) and got the first hole drilled about 3/4's of the way through the plate before the shoulder of the bit wore out and wouldn't go any farther..... ......I didn't have any cutting oil, but I did put a drop of air tool oil in the hole when I tried again with another bit....still a no go....the tip of the bit went all the way through, but won't finish the job.....I even tried to go at it from the other side.....

I guess I need a real good set of drill bits or a sharpener..... ....

[tank_post142]

always drill through with a much smaller drill first, use lots of oil and use a low speed on mild steel.

[ArmyValker]

always drill through with a much smaller drill first, use lots of oil and use a low speed on mild steel.

Yeah, that. Oh, and a Drill Doctor.

[the inspector]

Stan.....you can't drill that size hole in 1/4" plate!

"the inspector"

[Stanley Steamer]

Stan.....you can't drill that size hole in 1/4" plate!

"the inspector"

Dohhhhhhhhh........... ........

[the inspector]

Good to see your keeping busy my friend!

"the inspector"

actually I was thinking about the same project....just in case!

[da prez]

 Depending on the type of steel, I have drilled up to a 1 in hole in steel plate with my bench top drill press with no problems. Good drill bits, properly sharpened ,lubed and extreme care. If possible, fasten or clamp the work down. I sharpen my own drill bits on a bench grinder by hand. I learned about 45 years ago while working in a machine shop. Most quality drill bits will do the job right out of the box and give you long life. If you drill to slow, or to fast you will have problems. It's a learning process. A sharp drill will give you a string or curl type chip. In most cases a pilot hole is not necessary. Knowing what type of steel and a little practice is all it takes. I have been fabricating for about 40 years and am still learning. If I can be of any more help ,please let me know.
                          da prez

[Stanley Steamer]

Depending on the type of steel, I have drilled up to a 1 in hole in steel plate with my bench top drill press with no problems. Good drill bits, properly sharpened ,lubed and extreme care. If possible, fasten or clamp the work down. I sharpen my own drill bits on a bench grinder by hand. I learned about 45 years ago while working in a machine shop. Most quality drill bits will do the job right out of the box and give you long life. If you drill to slow, or to fast you will have problems. It's a learning process. A sharp drill will give you a string or curl type chip. In most cases a pilot hole is not necessary. Knowing what type of steel and a little practice is all it takes. I have been fabricating for about 40 years and am still learning. If I can be of any more help ,please let me know.
                          da prez

I bought the plate at Lowes a while back....mild steel probably?....I started with a new bit...and I did have it firmly clamped down to the table.......it went gangbusters for most of the way and then capoot....it was throwing out nice long curls of metal at first.......granted, most of my experience has been in woodworking, but I think I'll check the top of the drill press to see if it's on the slowest setting...I think it depends on where the belts are set?...been a LONG time since I've even used the drill press.....

[BigM]

I,ve been around welding,machining,etc. also. Worked in the zinc mines several years. At 21.  One trick a old mine foreman showed me. You can put two hex nuts together and get the angle to sharpen a drill bit to. Side by side holes facing you. Put the bit up to the btm. of the two nuts and the tip should be same pitch as the nuts.

[Rio Wil]

Hmmmmmmmm....a picture would be greatly appreciated.

[Red Diamond]

Stan.....you can't drill that size hole in 1/4" plate!

always drill through with a much smaller drill first, use lots of oil and use a low speed on mild steel.

With a 1/4" drill bit, you do not need to pre-drill with a smaller bit. Set you drill press speed at about 1800 RPM's and you are good to go. As was mentioned use some type of fluid to dissapate the heat and don't apply a lot of pressure. Watch the chip size and stay consistant  with your pressure. Let off every now and then, if you have a continious chip, you  are doing fine. Remember, any type of fluid is better than no fluid, water, oil, transmission fluid, regular oil, cutting oil. No WD-40 or spray lubricants other than cutting oil from a spray can. WD-40 is highly Ka-Boom. When you near the bottom of the hole, only very light pressure, the bit may snap or bind. The smaller the bit, the higher the speed. 1/16" bit, as fast as the drill press can turn. The larger the drill bit, the slower the drill press will turn.

Some may think that the smallest drill bit need to be turned slow, but quite the contrary.

 

[tank_post142]

http://store.curiousinventor.com/guides/drill_speed/

[FryeVRCCDS0067]

Just as the bit starts to break through the other side you need to lighten up on the pressure. It will usually sound a little different and feel a little different on the handle of your drill press when it reaches this point. If you don't let up in time it can cause the bit to "push" through enough to wedge the cutting edges into the work and stop the bit or break the bit.

Once it's happened it's more prone to do it again on the same hole so feed a new sharp bit into the hole really slowly from the original side you were drilling from.

Many steels (mostly cold rolled steels) will work harden on their surfaces as they are made which amplifies the problem.

[Jess Tolbirt]

i got a hold of some chineese steel once and couldnt drill it at different places,, it was determined that the cheap process of amking the steel had some old hardened bearing races melted in with it and no way possible to drill it,, we wound up using a torch,,,

[Rams]

Drilling is all about the tool (the bit) and the technique.  I should know, I've ruined hundreds of drill bits.   ???

[FryeVRCCDS0067]

http://store.curiousinventor.com/guides/drill_speed/

Thanks for posting that. I printed out the chart to hang next to my lathe.

[BigAl]

Cobalt High Speed Bit, or Titanium Oxide(GOLD OR YELLOW) are the ones for those that cannot sharpen a drill bit by hand.

Start with half of the size you want to end up with when you get over 1/4 inch in diameter is a good rule of thumb.

Don't give up , you just need a sharp bit.

Turning in the right direction of course.

AL

[Walküre]

Didn't see it mentioned - what possibly has happened, with the first hole, is as the bit dulled, you "burned" the hole, letting it get very hot, before stopping - basically, "work-hardened" the metal around and under the bit. This makes the steel quite a bit harder, than it was when you started, so another bit, even a good one, very well might have trouble going through. You DO need to get a smaller bit - 1/8" or so, and drill with it, first. It might still be somewhat difficult. Usually mild steel doesn't work-harden as much as high carbon, but it can be enough to stop standard drill bits.

Been there, done that...have the bits to prove it!

Roger

[Stanley Steamer]

Okay......I lowered my drilling speed to the slowest setting and got one hole finished.....and part of another one drilled....I'm going to have to buy some new bits and a sharpener before I can finish this "simple" project.....






It was throwing some pretty good chips on the first hole when I first started....




And my small drill bit assortment.......the gold ones are Titanium