Drilling Hacksaw Blades

[Blink]

Well, the title says it all. I'm trying to drill some holes in my carbon steel blades. Any tips? I've tried heating the metal, and cooling it slowly, and fast, to try and weaken it. Neither of those worked, one drill bit down. I tried just center punching it and drilling, no luck. I've tried regular bits, and I'm tried coated titanium bits.

Anyone got any tips?

Thanks

Blink

P.S. I've tried searching, ran 5 or so strings, and nothing about how to drill carbon steel.

[SFGOON]

You might need a drill press for that. Also, are you sure you're using the proper type of drill bit? From what I understand, machinists use a different, much more expensive type that you don't generally find at the local hardware store.

[undeadspacehippie]

I've used a punch to pop holes in the ends of the blades. Try bimetal hacksaw blades - they may be a bit more expensive, but the metal is nice to work with.

I would start with a smaller bit and then increase the diameter after that, use cutting oil/lubricant.

[Octillion]

A pointed aluminum oxide bit for a Dremel rotary type tool might work. Just spin it at a high speed and insert it slowly and carefully, periodically cooling the metal with water.

[devildog]

Yeah, you could use a small dremel bit at 35k rpm to open it up. Also, it just seems that, as this is just normal steel, a regular HSS bit should be fine, but I've never tried it before, so...

[Shrub]

Heat the blade up so it is as bright as you can get it then let it cool in air.

Get a centre punch or nail and mark where the hole is to go by hitting the punch or nail.

Use a normal HSS drill bit and run it on a medium speed of around 3-400 revs.

The drill bit needs to be as it comes and not resharpened.

If it doesnt cut squirt some water on the blade where your drilling.

Keep a steady and constant pressure on the drill until all the way through, drill it on top of some wood.

If you let off pressure or kep going into the work you will blunt the drill.

leave these coated drill bits etc alone they are all crap, we dont use special drill bits or anything they are just used correctly.

When driled re-heat the blade to as bright as possable and quench it, then polish it up, then heat it up SLOWLY and GENTALLY until the metal turns a straw colour (yellowish) and then quench it again, finished.

If you go past the yellow stage continue to a bright red again and quench and polish and try again, the straw colour comes on very fast and soon.

[Blink]

Great post shrub, thanks a lot for the details. I do have some normal HSS bits, so I shall give those a try later on.

Should I used an oil instead of water as a cutting fluid/lubrication?

Also, what do you use to SLOWLY and GENTLY heat up the blade to a yellow straw color? I have a propane torch that I used to heat it to bright red, but it can achieve that color in 15-20 seconds (approximately).

Thanks for all the replies guys, greatly appreciated.

Blink

[HeadHunterCEO]

get a couple of 1/8 (or whatever size)masonary bits for hammer drills

push real hard and turn the bit as slow as possible

as mentioned a press will help if you don't have the weight to generate decent force

[Shrub]

Use your blow torch but dont hold it to close for too long, you maybe only need to wave it over the blade to get it to temp, you should then quench it after that.

Masonary drill bits are ok but to make sure you dont simply work harden the material tryinmg to drill it you need to grind some clearances on the tips and that can only properly be done with a green wheel.