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alsinaj
09-26-2012, 02:52 PM
I just "modified" a bead roller die from my Harbor Freight bead roller. That thing ate my HSS cutting tool as if it were made of wax! One cut of about .015" and the tool looked as if it had been fed into a grinding wheel. Carbide eventually did the job, but it was still tough going. What on earth are those things made of? I might want to modify some more dies. Is there a better way? Or should I forget about it and just make new ones from a known material?

Grind Hard
09-26-2012, 03:11 PM
Harbor Freight uses a rare alloy that does the exact opposite of what the end user expects.

If it's supposed to be hard and impact resistant it will shatter. If it is supposed to be wear-resistant it will crumble. If you are intended to machine it, it will either explode, turn to dust or destroy your tools by achieving impossible levels of hardness.

ogre
09-26-2012, 03:20 PM
Be interesting to know what got mixed into that die!

flylo
09-26-2012, 03:44 PM
Probably don't want to know!

Forestgnome
09-26-2012, 03:53 PM
Most likely case hardened. I doubt they would bother making anything out of good steel.

alsinaj
09-26-2012, 05:08 PM
Yes, there was a hard skin, which I ground off. But the inside was damn hard, too!

MotorradMike
09-26-2012, 05:23 PM
You might want to check it with a Geiger counter.

lazlo
09-26-2012, 05:51 PM
I just "modified" a bead roller die from my Harbor Freight bead roller. That thing ate my HSS cutting tool as if it were made of wax!

Were you using Harbor Freight HSS? :)

CCWKen
09-26-2012, 07:33 PM
The dies are hardened. I'd say in the 55-60 range. It's the best part of the "kit" and the only thing that makes the HF bead roller worth the price. I relieved the edges on mine with a TP grinder and polished them. I wouldn't modify them past that. If you need different dies, make them. I've made various dies from cast iron, steel (known and unknown), wood and HDPE.

Spin Doctor
09-26-2012, 08:34 PM
Harbour Freight uses it's own propriatory alloy known as HarborFreightium

darryl
09-26-2012, 09:26 PM
HF puts the label HSS on some cutting tools because the particular batch of steel was air-lifted to the factory. At one point it got up to about 650 mph.

There is a difference in what's called HSS- some of it is not very good at all, while other stuff is actually what you might expect. I have some of both here, and it's quite an education to compare the cutting action between them.

But, that doesn't answer your question, which has already been answered. Dies are pretty hard. The ones you have may actually be harder than they should be if they skipped a step or two in the heat treatment. That's probably good until or unless something snaps while in use.

dp
09-26-2012, 10:14 PM
Except that it is the world's most expensive potato chip it is a pretty decent foundation for creating a good bead roller. The rest of the kit is bloody expensive, too. Stick welder not included.

Evan
09-26-2012, 11:21 PM
They are usually made of white cast iron. White iron is formed by fast cooling while grey iron forms from slow cooling. That's perfect for a rolling die since the outside cools first. The same principle is used for nearly all metal rolling equipment including very large steel rolling mills. White cast iron is so hard that even carbide has a difficult time touching it. The excess carbon turns to iron carbide because it doesn't have time to come out of solution in the iron as it cools. Grinding is the best way to work it. White iron doesn't look like cast iron when it has been ground since there is no free excess carbon to make it look dark.

Forestgnome
09-27-2012, 10:34 AM
Never heard of white iron. Learned something new. I had just learned about putting a "chill" on cast iron by chilling part of the mold to make that surface harder. Looks like the same process.

Evan
09-27-2012, 01:52 PM
White iron and chilled iron are the same thing. Various additives can be used to promote or delay the formation of white iron but the rate of cooling is all it takes even without pot additives.

Here is an example in the form of an iron barbell weight. The outside cools fastest and forms white iron. Closer to the centre is mottled iron and near the centre is mainly grey iron.

http://ixian.ca/pics9/bbiron.jpg

I turned this with type 1 carbide which is the toughest grade available. It is used for things like rock grinders, stump grinders and chipping knives for trees that may have rocks in them.