Thread: Drill bits for knife making

Originally Posted by SixtyTen

O1 Tool Steel!
Can be bought in very knifemaker friendly sizes (4x40x500, 3x30x500, 3x50x500 etc)
It is sold as gauge plate (fully annealed and precision ground) from a few different companies. I mostly dealt with Special Steels in Auckland. Email them for a price list of all their sizes. I was buying 4x40x500 for around $23 a piece a few years ago.
I started knifemaking using old sawblades but once I started using gauge plate I never looked back.
O1 is very easy to heat treat in the home workshop using nothing more than a map gas torch ($100 from Mitre 10) a few fire bricks, a few liters of canola oil and the kitchen oven for tempering.
Many of my early knives were heat treated with very basic equipment until I build a PID controlled electric furnace.
https://www.facebook.com/Guildford-K...6427120825057/

The only negative with O1 is that it is a hypereutectoid steel (carbon >0.8%), which means that to get the most out of it, you need to be able to soak it at a stable temperature of 800-820 deg C for 10-30 minutes to get all the carbon into solution before quenching. For a beginner, this can prove to be difficult, and you run the risk of de-carbing the steel, which will result in a poor hardness.

This is why for beginners, 1084 is ideal as it is a eutectoid steel (carbon ~0.8%), so you heat it up until it becomes non-magnetic and then quench. Because 1084 is so simple to heat treat well, its performance will exceed that of O1 with an average heat treat achieved without a temperature controlled furnace and de-carb paste. Plus, 1084 or 1075 are way cheaper to purchase than O1.

It's all about the speeds and feeds. I can use one 6mm hss drill bits for about 40 holes through 12mm 316SS at the cutting sweetspot, or 1 hole if I'm going too fast.
I use G-Wizard CNC for determining the correct settings. Saved me a fortune in broken or stuffed cutting tools.

Ssm metals in Auckland is a good place to get O1, which will also do your heat treatment in a vacuum furnace for you once you have made the blade.
O1, due to its formation of small compact carbides and the fact that it’s a tool steel, designed to be made for cutting, will outperform any 10xx steel out there, so that if you do make a blade you like you will have a blade good enough to pass on to your kids...just don’t let it rust.

If you need a chemical analysis on some steel let me know and I will test it for you. I will need a piece about the size of an old 50 cent coin which it flat. From there it will be easy to google a heat treatment process for it. Open offer to forum members.

Originally Posted by hotbarrels

The only negative with O1 is that it is a hypereutectoid steel (carbon >0.8%), which means that to get the most out of it, you need to be able to soak it at a stable temperature of 800-820 deg C for 10-30 minutes to get all the carbon into solution before quenching. For a beginner, this can prove to be difficult, and you run the risk of de-carbing the steel, which will result in a poor hardness.

This is why for beginners, 1084 is ideal as it is a eutectoid steel (carbon ~0.8%), so you heat it up until it becomes non-magnetic and then quench. Because 1084 is so simple to heat treat well, its performance will exceed that of O1 with an average heat treat achieved without a temperature controlled furnace and de-carb paste. Plus, 1084 or 1075 are way cheaper to purchase than O1.

Technically you are completely correct. However, I still have most of my early knives that were heat treated with a short dwell time and they are perfectly serviceable blades. Not as good as my later work with scale protection and a proper furnace, but far better than any knife cut from an old sawblade or made from a file, I never managed to find a good source of 1084 or 1075 in NZ. Availability was the main reason for me choosing to work with O1.