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davidwdyer
12-28-2009, 03:22 PM
I'm planning to try to make some gear cutters and I need to know what kind of tool steel. What is a good combination of good and simple? Should I get oil hardening, air hardening or water?
I do have a temp. controlled furnace to play with.
Will I need stainless foil to wrap the pieces?

Oldbrock
12-28-2009, 04:07 PM
The question is how much is your time worth. If it is more than $30 an hour you will be ahead just to look around on ebay and see if you can find the cutters you are needing. High speed steel is the tool steel of choice but I think the hardening process is beyond the usual HSM . I have made hardened and tempered cutters which performed quite well from 4340. Needed sharpening more frequently than hss but worked for me. Peter

SGW
12-28-2009, 05:02 PM
For "good and simple" I'd use O-1.

The stainless steel wrap wouldn't hurt, if you think you can open the packet and quench the part quickly enough. I've had pretty good luck with "KeepBryte Anti-Scale Compound," which is sold by the usual suspects (MSC, Travers, etc.)

deltaenterprizes
12-28-2009, 05:51 PM
Is this a repair?
For one or two gears you can grind tool steel to form the tooth profile and use it in a fly cutter.

Glenn Wegman
12-28-2009, 06:34 PM
The stainless steel wrap wouldn't hurt, if you think you can open the packet and quench the part quickly enough.

What's the time frame there?

davidwdyer
12-28-2009, 06:53 PM
I have been thinking about O-1 which I can get from McMaster.

The time frame is that I will be in the U.S. in Jan. and I want to order something to bring back to Brazil.

Cutters here are rare to non-existent and so I would like the capability of making my own when and if I need them.

There is no pressing need right now, but the idea of making my own is intriguing.

I do have a surface grinder to remove scale should that be necessary. The stainless foil seems absurdly expensive.

Mcgyver
12-28-2009, 07:11 PM
I have been thinking about O-1 which I can get from McMaster.
.

that's the stuff to use...but there must be industrial supply locally...cripes, every one of them around here has a stand of drill rod (usually o1) growing somewhere on the premises



Cutters here are rare to non-existent and so I would like the capability of making my own when and if I need them.


I keep a stock of drill rod handy so i can always make a cutter when needed. are you familiar with the facetted type of gear cutter...sort of approximates an involute form and is great for low speed, low duty cycle applications...another advantage is only one cutter is needed for any number of teeth....here's an excellent account of it:

http://www.helicron.net/workshop/gearcutting/gear_cutter/


I do have a surface grinder to remove scale should that be necessary. The stainless foil seems absurdly expensive

not needed, nor is the SS foil. just stone the cutting face. I usually do this prior to tempering - serves as a place to see the colours.

philbur
12-28-2009, 07:49 PM
Get this book, it's almost free.

http://www.amazon.co.uk/Gears-Gear-Cutting-Workshop-Practice/dp/0852429118

Phil:)


I'm planning to try to make some gear cutters and I need to know what kind of tool steel. What is a good combination of good and simple? Should I get oil hardening, air hardening or water?
I do have a temp. controlled furnace to play with.
Will I need stainless foil to wrap the pieces?

philbur
12-28-2009, 07:51 PM
And this one:

http://www.amazon.co.uk/Hardening-Tempering-Treatment-Workshop-Practice/dp/0852428375/ref=sr_1_1?ie=UTF8&s=books&qid=1262047834&sr=1-1

Phil:)


I'm planning to try to make some gear cutters and I need to know what kind of tool steel. What is a good combination of good and simple? Should I get oil hardening, air hardening or water?
I do have a temp. controlled furnace to play with.
Will I need stainless foil to wrap the pieces?

JoeCB
12-28-2009, 07:55 PM
I too usually use O1 for most cutting tools , taps etc. However I reciently had to make a threading die for a very unusual thread form 1 " in diam. I had a lot of time invested and was concerned with cracking upon quenching. I invested in some air hardining A1 steel (not cheap!) heated in foil and air quenched with the help of a small fan to keep air moving... 63 RC and no cracks or scale. You might want to consider A1 for your mill cutter.
Joe B

davidwdyer
12-29-2009, 06:16 AM
Hey Philbur,

Thanks so much for the recommendations.

I already have Law's book and another bood one by Bryson about heat treating.

Mcgyver,

I did find thin drill rod, but nothing like I would like to make my cutters.

No doubt, I could find them in São Paulo, but a trip there would take up a day or two and be expensive. I think I'll go ahead and try the O-1. At least I will learn a lot through the experience.