How can I soften silver-steel?

[geoff p]

I want to soften a broken end-mill so I can turn its shank to a combo pilot+countersink form, then re-harden it. The new tool will be used on/in wood for only about sixty holes so I guess it won't have to be fantastically hard.

I've tried heating to (fairly bright) red-heat and letting it cool but it is still far too hard.

Any suggestions, please?

Geoff
Thailand (where they don't seem to even have a word for silver-steel.)
www.purpletiger.com

 

[Jasonb]

Its far more likely to be High Speed Steel (HSS) than silver steel (drill rod) which is not so easy to soften in the home shop.

J

 

[Swifty]

What Jason said. For the home engineer, HSS is virtually impossible to anneal and re harden.

Paul.

 

[geoff p]

Bother or words to that effect.
Thanks, chaps.

 

[gbritnell]

Actually the shanks on most end mills is a little bit softer than the cutting portion but I wouldn't want to try and make any type of tool from the shank. If the tool you need can't be made from the cutting part of the end mill then why not make your own tool from silver steel/drill rod?
gbritnell

 

[bazmak]

You cant really do anything with HSS it still retains its hardness
even under red heat.High carbon steel (silver Steel)can be softened and retempered.Cheaper cutting tools taps and dies etc can be softened
by taking to red heat and cooling slowly.Back to red heat and quench
to reharden.

 

[geoff p]

George, I guess my by-line was too subtle - my nearest source of silver steel is probably USA, about a gazillion miles away from Thailand, from where the postage-costs start at an Arm before our import duties/customs charge a Leg.

I'm sure some companies in Thailand actually stock metals, but getting the b******rs to deal with a bloody foreigner like me is quite beyond my ken. I've tried, frequently!

Meanwhile, where I live, Hot-rolled steel is about all that's available.
Sorry, folks. Rant over.

Perhaps I'll try Bazmak's route and let-down a drill (much cheaper than taps etc.)
Thanks, all.

 

[enfieldbullet]

you can get a fairly good hardenable steel from roller element bearings, they're usually 52100 steel (IIRC) it's hardness is almost that of HSS when hardened. and can be softened by the traditional methods.

also automotive leaf springs (6150 steel IIRC) will make great cutting tools. those you can get at any auto suspension shop , specially volkswagen shops, they always have something in stock.

bearings can be sourced from local scrapyards. the best way to 'extract' the metal is to cut the outer race in two with an angle grinder, remove the balls/rollers (you can also use these) , then cut the inner race in two with the angle grinder as well. after that you can head the 'bananas' in a charcoal fire to soften and cut/hammer to shape.

i've made great knives with both steels.

tool steel is everywhere

 

[Mechanicboy]

my nearest source of silver steel is probably USA, about a gazillion miles away from Thailand,

Possible you can order the silver steel/drill rod (same steel with 2 difference word) from China or Japan who is nearest Thailand?

 

[Wizard69]

I want to soften a broken end-mill so I can turn its shank to a combo pilot+countersink form, then re-harden it. The new tool will be used on/in wood for only about sixty holes so I guess it won't have to be fantastically hard.

If it is only 60' holes you might be able to get buy with plain steel, maybe case hardened. Unless of course it is one o those very hard and abrasive tropical,woods. Assuming you want to do better than that consider automobile salvage yards and the like for better grades of steel. Someone already mentioned leaf springs but other car parts can be considered.

As for Thailand, I've never been there so take this with a grain of salt but there has to be at least one supplier in the country. More so there must be a machine shop or two around someplace that might be able to give you pointers.

I've tried heating to (fairly bright) red-heat and letting it cool but it is still far too hard. Any suggestions, please?

Most high speed steels will be difficult to deal with. You might have some luck forging to a rough shape and then grinding.

Geoff Thailand (where they don't seem to even have a word for silver-steel.) www.purpletiger.com

I have a friend at work that just got back from that area. Nice and warm there, right now it is freezing (literally) here.

By the way some of the cheap Chinese brad point drills appear to be carbon steel. They might be easier to work with. Also don't forget things like printers as possible donor machines.

 

[gus]

Hi Jeff,
HongKong is nearby. Budget Airfare is cheap.
Bought my Silver Steels from Kam Yuen Hong Machinery Store,443 Reclaimation Street,Mongkok, Hongkong while on holiday. The owner----Mr. Fok speaks some English.Try wandering around same street and Canton Road. Bought cutting tools too. Spotting drills,HSS tool bits etc.Prices cheaper than UK/US vendors. Found shop that sells mini lathes,mills and accessories. Shop name---Wing Hung Machinery,974 Canton Road.
Here is their my silver steel and tool vendor's e-mail address [email protected].

The HongKong Machineshops prefer non-China made cutting tools and tool steels.

Good Luck.

 

[gus]

Hi Geoff,
Also found a shop in Singapore that sells a good range of cutting tools for lathes and mills.Drill bits,reamers and micrometers etc.
The owner speaks good English. Found it. website: trustechtools.com.sg.

Good Luck.

 

[geoff p]

Many Thanks to all of you.
I used Bazmak's idea: "cooked" a 6mm drill to as bright-red as my humble kitchen cooker would go, letting it stew for a while before cooling at a natural rate.
I stuffed the flutes into the lathe-chuck so the shank stuck out. It machined very easily with HSS tooling.
Then ground it to a "D"-bit and a couple of notches so I could snap the flutes off, et voila! It works well enough for now.

Again, thanks for all of your ideas,
Geoff
www.purpletiger.com

 

[gus]

Hi Geoff,

Glad to hear you succeeded making DIY D Reamer.
The HMEM members are very helpful.