Drilling holes in Tposts problem

[BrightBay]

My son needs to drill holes in some Tposts. He's used DeWalt Pilot point cobalt drill bits, Hitachi black gold 135 split point and Bosch titanium drill bits. All are 5/16ths. Some worked better than others, but none have been able to drill more than 3 holes before they can no longer penetrate the Tpost. My father suggested he go slow, try putting some oil on them and let them cool between drilling to prevent them from getting dull. Still, no luck. What is he doing wrong?

[blooba]

is he working in the field or in a shop? Sounds like it is overheating, if its a cordless drill lower the gearing (they run too fast for metal in high gear) but if he's in a shop drill in a cooling oil bath(whether submerged or someone almost constantly squirting) Let the drill do the work and don't push too hard.

I'm thinking you could also heat them up to soften the metal.

[Harry Chickpea]

Might go faster using an acetylene torch w/cutter head?

[watcher]

I've never had any trouble drilling holes in T post. It sounds like he's trying to go too fast and putting too much pressure on the bit as well as not using any type of coolant/oil/lube.

Slow down, use less pressure (let the tool do the work) and plenty of coolant. Spraying WD40 will work but gets a bit expensive if you are drilling lots of holes. Used motor oil in a squirt can works.

[wally]

you might try a mig cutter to blow the holes thru

[Ross]

Masonary bit, hardened steel is just ugly to drill

[Old Vet]

Going slow is the key along with using oil to cool it. I use a 1/8 inch first and drill the 5/16 last and I also use cutting oil. It works and not as expensive like the WD40. Cutting oil will cool and make the drill go faster. Look at the curls you make and do not get them too thick.

[artificer]

Adding to everyone elses information...

If your chips are blue, you're going too fast. I like to use emulsion oil for cooling. Mostly water so great cooling, with 1/40 oil for lubrication. Not going to find it in the back yard shop, so used motor oil is the second choice. Let the drill do the work.

Good drill bits are a must, but the Dewalts should be at least decent.

What brand are the t-posts? Could the metal be hardened? If its hard metal, you can take a torch and heat the area you want to drill until its a dull cherry red. Let it cool slowly, and try again. This should anneal the post. One test of hardness is to try and file the post. Does the file skim over the post, or does it bite in. If it doesn't bite well, its hardened, and thats the problem. They shouldn't be, but you never know. We received a batch of posts that broke, rather than bent, which means the metal was really bad, or hardened, or both.

Michael

[plowjockey]

Never heard of a "T" fence post made from hardend steel. What would be the reason that it would need to be hardened?

[HermitJohn]

I've never heard of hardened T post, but drilling old bed frame angle iron will dull bit fast and they are hardened. Depending on need, many times I find it easier to just cut slot with cutoff saw if needing to make bolt holes in hard metal. Those cutoff wheels dont care if hardened metal or not.

[Ed Norman]

The T posts I've drilled were tough, stringy steel, but not hardened.

I also guess he is using too high a speed. Slow down the speed but increase the feed. Chips take the heat away from a cutting project, if you give a real slow feed and let the bit ride on the work, there are not enough chips made to remove the heat and the bit gets hot. Put the bit against a piece of beeswax to keep the chips from sticking, if needed, then turn slow and push hard.

[Allen W]

T posts are made out of recycled junk steel. He might have better luck with a different batch of posts.

[Harry Chickpea]

More specifically, a LOT, if not most, of T posts are made from old railroad rails. Mixed scrap would require a lot more processing, and the plants that make them are set up to use rails that can't be recycled back into rails. This has been going on for years. (My mind is filled with silly trivia like this) I get a kick out of thinking that a neighbor's fence posts may have actually carried pioneers west on the early transcontinental lines.

[Ed Norman]

Originally Posted by Harry Chickpea

More specifically, a LOT, if not most, of T posts are made from old railroad rails. Mixed scrap would require a lot more processing, and the plants that make them are set up to use rails that can't be recycled back into rails. This has been going on for years. (My mind is filled with silly trivia like this) I get a kick out of thinking that a neighbor's fence posts may have actually carried pioneers west on the early transcontinental lines.

Well now, that's amazing. Thanks.

[rambler]

Yup, saw an hour show on the process of turning rail iron into Tee posts. Just roll them through dies or rollers & press them into shape, come out thinner & a lot lot longer.

Was very interesting.

--->Paul

[artificer]

I didn't mean the T-posts were intentionally hardened. Like others have said, junk metal posts can have varying properties. If you take a higher carbon steel, forge it, and dump it in water, its probably going to be fairly hard.

Thats why I suggested hitting it with a torch to anneal it, and see if it makes a difference.

Michael

[Curtis B]

It is also possible if he is drilling too clost to the T part of the tee post that the cutting edge on the bit catches as it is breaking through thinner metal and chiping.