D-bits

lampy · 04-07-2012, 11:53 AM

I found a few threads about how to make D-bits and would like to try my hand at it, I have a newbee question about the making of D-bits. Will a HSS cut drill rod? If not what do I need? I don't foresee a surface grinder being added to my shop in the near future so I am limited to using my HF mini mill and Craftsman lathe. Should I get oil hardening or water hardening drill rod?

chucketn · 04-07-2012, 12:01 PM

HSS will cut drill rod nicely. I have made several tools from it on my X2 mill and 7x14 lathe, d bits, threading tools, and countersinks.
As to oil hardening or water or even air, it's up to you. I think either type would work for you. I use oil hardening because I change the oil in my vehicles and lawn mower, so I always have old oil on hand.

Chuck

lampy · 04-07-2012, 12:10 PM

Thanks for the quick reply Chuck. I am going to order some drill rod from Enco and they offer two different types of drill rod, water hardening or oil hardening. I am unsure if one is better than the other for making d-bits or other tooling.

chucketn · 04-07-2012, 12:19 PM

Before you buy, do some more research on the differences between them. I did, and chose oil, but I honestly can't remember why. Maybe because I had old oil on hand. I don't think there is much difference in how hard they get. You also must temper the tool bit to draw back the hardness. If you just harden the tool is glass brittle, and can break/shatter. Tempering is a way of putting back a Little flexibility but not softening back to the machinable state.
If you need to adjust the shape after hardening/tempering, you can anneal the metal back to machinability by heating again and letting it cool slowly. Yes, it is an art, but no more than machining the bit in the first place. Goggle is your friend, search for hardening and tempering drill rod (or silver steel as it's called in Europe). It's a common topic on lots of forums.

Chuck

lampy · 04-07-2012, 12:41 PM

I just got done with a google search and found people who swear by oil hardening rod and just as many who swear by water hardening rod..... My guess is either will work. I could be wrong but from the description in the enco catalog water hardening rod could be used without heat treating, but does that mean it's going to be harder to machine? Oil hardening is going to be easier to machine but will require hardening.... Please correct me if I'm wrong.

Tin Falcon · 04-07-2012, 12:43 PM

Lampy just buy a couple pieces mark it so you know what it is and make some bits learn what works for you.

water hardens faster than oil oil you need to do outside. you can buy w-1 rod and quench in oil and not have to temper. there are lots of ways to manipulate results.
Tin

lampy · 04-07-2012, 01:02 PM

Thanks Tin. Kind of funny I didn't of trying both

Tin Falcon · 04-07-2012, 01:15 PM

No problem I think when we start out we want to do everything right. It is ok to try different things within reason and use what is on hand sometimes relax and enjoy the journey. It makes getting to the destination more enjoyable and rewarding.
Tin

chucketn · 04-07-2012, 01:18 PM

Lampy,
What are you going to use the D bit for? I have lots of notes on making/using them.

Chuck

lampy · 04-07-2012, 01:49 PM

I don't have a specific job that I need one for yet. I just got done building an air motor and could have used a reamer to make a better fitting hole. I started looking at reamers but don't want to spend the money on a set of reamers yet, my research on reamers led to a thread about d-bits and how they can be used to bore a clean, close fitting hole along with making custom profile end mills and lathe bits. I think this would be a useful skill/tool so I want to get set up to be able to make what I need when the need arises

I thought I'd start with 1/4", 3/8" and 1/2" to match my collets.