Drilling Through Normalized(?) O1 Tool Steel

D

duurza

Joined
Jul 4, 2015
Messages
107
Hi Everyone,

I am currently working on a sword. About 2 months ago, I went to the blacksmith and forged out the tang. It is about 3/16 inch thick O1 tool steel. I made sure that after I finished forging, I reheated the blade to yellow and then wrapped the tang with kaowool. I think it took roughly 25 minutes to cool to room temperature.

The tang is about 10 inches long and I know that part of it hardened because the kaowool only covered 9 inches of it (pommel to the crossguard). When I tried to further flatten out the tang with my file, it easily worked on the 8 inches that were covered but the 2 inches nearest the crossguard seemed to have hardened significantly. I can scratch it but not really remove much material.

Yesterday, I tried to drill a hole through it but after about 1/32 deep, I can no longer continue. The drill bit isn't getting dull or anything and I'm not sure what is going on. I'm not drilling into the area that I know is hardened but rather at the pommel end. That area was very soft when I filed it.

I only have titanium drill bits and a few carbide drill bits and a portable drill at 600 RPM. Am I using the wrong tools? I didn't bother tempering it since the residual heat from forging would have done more than what my oven could do.

Any help/tips/other drilling methods would be great!
 
Properly Spheriozed Annealed O1 works like absolute butter

Try again with a proper - (others will chim in I'm sure)




Your drill bits are not titanium

They are probably HSS
High Speed Steel with a gold coloured Titanium Nitride coating
 
12345678910 said:
Properly Spheriozed Annealed O1 works like absolute butter

Try again with a proper - (others will chim in I'm sure)




Your drill bits are not titanium

They are probably HSS
High Speed Steel with a gold coloured Titanium Nitride coating
Click to expand...

That's what I thought. The package labeling just said Titanium.

A while back, I drilled through quarter inch O1. I didn't put it through any heat treatments and it worked well. I assume that was spheroidize annealed.

Unfortunately, I have no chance to do any further heat treating on this other than tempering as I do not have the equipment at home. There is an artisan blacksmith near where I live and I just pay to use his equipment and space. But if I am there, I could probably just hot punch the holes I need.

Is there anyway to drill through hardened steel? I don't plan on going back to the blacksmith for at least 2 months as I am waiting for him to purchase a heat treat furnace and I'm still working on the math for the final heat treat. In the mean time, I want to get the holes drilled so I can continue on with getting the handle and pommel done.
 
Drilling hardened steel is a bear, if you can get ahold of some carbide drill bits you might have a chance but even then it will be difficult. Someone with more info will chime In soon I'm sure but I wonder if you could anneal it with a blowtorch maybe like the guys who do the hidden tang knives.
 
duurza said:
That's what I thought. The package labeling just said Titanium.

A while back, I drilled through quarter inch O1. I didn't put it through any heat treatments and it worked well. I assume that was spheroidize annealed.

Unfortunately, I have no chance to do any further heat treating on this other than tempering as I do not have the equipment at home. There is an artisan blacksmith near where I live and I just pay to use his equipment and space. But if I am there, I could probably just hot punch the holes I need.

Is there anyway to drill through hardened steel? I don't plan on going back to the blacksmith for at least 2 months as I am waiting for him to purchase a heat treat furnace and I'm still working on the math for the final heat treat. In the mean time, I want to get the holes drilled so I can continue on with getting the handle and pommel done.
Click to expand...


Cobalt bits, low speed, and a lot of rapidtap work for me. Still that's only in at max 58ish rhc
 
Pancake House said:
Cobalt bits, low speed, and a lot of rapidtap work for me. Still that's only in at max 58ish rhc
Click to expand...

What counts as low speed? I only have a portable 600 RPM drill. I don't think the steel hardened to anything above 40 RHC. With a file, I can still easily remove material.
 
Carbide drill bits are your best best for getting through the hard stuff, but unless you have a rigid drill press, there's a good chance you'll break bit right out of the gate. Carbide is very brittle and doesn't like run out or wobble. You MIGHT get through it with cobalt if you're careful.

You can also try a carbide tipped masonry bit as they're a little more durable/forgiving, but can still cut the hard stuff.
 
I'll be the first to say I'm a newbie and take what I've got to say with a grain of salt. Couldn't the original poster spot heat with a torch the area needing drilling to temper it so he could drill with normal bits?
 
LCoop, yep but that runs the risk of having too much heat move into the blade.

I have done this myself a couple of times before I learned to drill BEFORE heat treat. What I found works the best is a cheap masonry bit. Get mine from Home Depot for like five bucks. Goes through tempered O1 like a champ.
 
Yeap I agree drill BEFORE also. But could the OP not use a heat sink goop or a wet rag etc and spot heat with a torch. I've tired the cheap masonry bits before on hardened steel and it sure didn't work out for me. But what it did was taught me a good lesson, drill before HT! lol
 
Metalhead0483 said:
LCoop, yep but that runs the risk of having too much heat move into the blade.

I have done this myself a couple of times before I learned to drill BEFORE heat treat. What I found works the best is a cheap masonry bit. Get mine from Home Depot for like five bucks. Goes through tempered O1 like a champ.
Click to expand...
Just put the blade in a bucket of water with the tang sticking out while you heat it.
 
Thank you for all of your responses. I don't have access to a drill press right now so if I absolutely need one, I might need to put this on hold. I will look for some carbide/cobalt drill bits and honestly, if they cost less than $10 each, I'll give it a shot.

As for putting heat into the blade, I'm not worried, I just don't have a blow torch. The sword blade is 28 inches and the tang is around 9 inches total and I would be drilling a hole literally within the first quarter inch of the pommel end of the tang.

Although I don't think tempering it would soften it by much, I'll give it a try tonight and see how it goes.
 
I highly doubt you're gonna find carbide bits for 10 bucks! They're pricey! Do you have a plumbers torch? That works for softening tangs. If not they're pretty cheap at the big box stores.
 
NickBoyle said:
I highly doubt you're gonna find carbide bits for 10 bucks! They're pricey! Do you have a plumbers torch? That works for softening tangs. If not they're pretty cheap at the big box stores.
Click to expand...

In that case, I will ask my friends and see if they have the equipment I need.

I have a plumber's torch but not at my place. I don't have a large space where I live so I store all of my non essential things elsewhere.

I ideally would like to drill 3 holes; 2 to secure the wooden handle to the tang and 1 at the very end to secure the pommel. I really only need the one hole to hold the pommel because I'm not interested in hot peening it. I might want to change the pommel design later on.
 
duurza said:
Hi Everyone,

I am currently working on a sword. About 2 months ago, I went to the blacksmith and forged out the tang. It is about 3/16 inch thick O1 tool steel. I made sure that after I finished forging, I reheated the blade to yellow and then wrapped the tang with kaowool. I think it took roughly 25 minutes to cool to room temperature.

The tang is about 10 inches long and I know that part of it hardened because the kaowool only covered 9 inches of it (pommel to the crossguard). When I tried to further flatten out the tang with my file, it easily worked on the 8 inches that were covered but the 2 inches nearest the crossguard seemed to have hardened significantly. I can scratch it but not really remove much material.

Yesterday, I tried to drill a hole through it but after about 1/32 deep, I can no longer continue. The drill bit isn't getting dull or anything and I'm not sure what is going on. I'm not drilling into the area that I know is hardened but rather at the pommel end. That area was very soft when I filed it.

I only have titanium drill bits and a few carbide drill bits and a portable drill at 600 RPM. Am I using the wrong tools? I didn't bother tempering it since the residual heat from forging would have done more than what my oven could do.

Any help/tips/other drilling methods would be great!
Click to expand...
The part in bold is Not Normalizing. 01 is very temperature sensitive.
 
Don Hanson III said:
The part in bold is Not Normalizing. 01 is very temperature sensitive.
Click to expand...

I took that information from http://www.cashenblades.com/steel/o1.html

Normalizing: Heat to 1600 °F (870 °C). cool from temperature in still air.
Click to expand...

I wrote a program to repeatedly calculate the temperature change of the blade due to still air heat transfer and using the values for PURE IRON (good enough estimate for most lower alloy steels), it shows that it would technically produce martensite with the above instructions. It takes roughly 200 seconds from 870 C to reach around 200 C and according to the TTT, it would be a mix of ferrite/cementite/martensite.

http://s7.postimg.org/j24t86j7v/image.png

Also, one thing I noticed while doing the math is that at heat treating temperatures, heat loss to still air is virtually negligible as radiation is 10x more effective at the start. Still air only begins to play a significant role when temperature differences are less than 400 C (see the last two columns for heat transfer coefficient of radiation and natural convection).
 
The "yellow" heat could be a problem. Could be a lot hotter than 1600f.

The wrap it in kaowool is not something I do when normalizing.

3 times works best, reducing heat each time.

Like I said, 01 is very temperature sensitive. 1084 or similar would be a better steel to learn with.
 
Don Hanson III said:
The "yellow" heat could be a problem. Could be a lot hotter than 1600f.

The wrap it in kaowool is not something I do when normalizing.

3 times works best, reducing heat each time.

Like I said, 01 is very temperature sensitive. 1084 or similar would be a better steel to learn with.
Click to expand...

I was hoping to anneal the blade as I was still intending on working it to get it to a nice shape after forging which is what the kaowool was for. Without the kaowool, wouldn't it be considered hardening due to the formation of martensite?

I live in Toronto, Canada and I can't find any local sources of 1084. I asked around for 1045 and it seems that that isn't even available anymore. I figured that it would be better to use what is widely available and focus on that. O1 was my choice and I will probably stick to only using that. In the future though, I'm going to plan out all rough profiling processes before any heat treatment is applied.
 
duurza said:
I was hoping to anneal the blade as I was still intending on working it to get it to a nice shape after forging which is what the kaowool was for. Without the kaowool, wouldn't it be considered hardening due to the formation of martensite?

I live in Toronto, Canada and I can't find any local sources of 1084. I asked around for 1045 and it seems that that isn't even available anymore. I figured that it would be better to use what is widely available and focus on that. O1 was my choice and I will probably stick to only using that. In the future though, I'm going to plan out all rough profiling processes before any heat treatment is applied.
Click to expand...
No, heating and cooling in still air is normalizing and should be done after forging and before annealing. But going by color is very tricky, is the shop dark, bright, or in-between? A yellow heat is usually too hot for a normalizing heat.

1050, 1060/5, 1070/5, 1080/5 is all good sword steel and less problematic. But 01 is good steel and if that's your choice, learn all you can about it. Learn to anneal it for drilling holes ect. and how to best set it up for hardening.

I no longer use 01, as W2 id my choice for all non-damascus blades.
 
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