Thread: Playing with some HSS

I always thought the Australian Stanley HSS blades looked like a Bronze because all the joins Ive seen on old blades had a Yellow look to it .
Last night I buffed the top of this join. I see it is Silver and not Yellow when cleaned.
Perhaps Silver solder oxidizes to a yellow.
I have a rod here of unknown silver content that I scrubbed back between the Red arrows . You can see the silver bright colour compared to the rest sort of Yellow colour of the oxidized rod .
That rod would be of a low to mid silver content because Ive never bought the expensive high Silver content rods . Never needed them .


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The buffed top of join below and the slightly dis coloured look below it .
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Pic of another blade
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Rob

Originally Posted by Bushmiller

I have wondered how this process was done commercially. It occurred to me that HSS planer blades are made in a similar fashion.
Regards
Paul

I reckon its a silver solder join as well Paul and if I go heat one of those up the Tungsten is just going to float off.

Some sort of weld and the two become one so I don't think separation could occur with just heat.

Ill go get my roughest blade and see .

Rob

Originally Posted by auscab

I reckon its a silver solder join as well Paul and if I go heat one of those up the Tungsten is just going to float off.



Ill go get my roughest blade and see .

Rob

Rob

Only a small percentage of tungsten. The more expensive blades have 18% tungsten.

I await your results.

Regards
Paul

Originally Posted by Bushmiller

Rob

Only a small percentage of tungsten. The more expensive blades have 18% tungsten.

I await your results.

Regards
Paul

Is it . Always learning something here ! I thought they were 100 % . Is that the same for router cutters too ?

I had a go . The tip and gas wasn't giving me enough heat and it turned out it needed a lot more heat than I thought . It wasn't just going to float off. I just did a section at a time and ended up grabbing a screwdriver , stuffed the temper in that for sure but Ill fix it later.

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I had to get it up around this colour for it to let go . The braze melted out before this but because I didn't have the whole thing that hot I had to bend the Tungsten off as I moved along. It needed to be that bright for the Tungsten to bend.
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I could see this pooling out from the join while heating . With a bit of sand paper to brighten it it looks like its a light copper colour.
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Originally Posted by auscab

Is it . Always learning something here ! I thought they were 100 % . Is that the same for router cutters too ?

Router bits and saw tips are tungsten carbide.

Originally Posted by elanjacobs

Router bits and saw tips are tungsten carbide.

Yeah but is it a % like Paul is saying or are they pure Tungsten ?

And
The stuff on saw tips is the same as the TCT router cutters isnt it ?

I think we are getting our metals a bit crossed up. A friend made exactly the same mistake and it is easy to do.

So we have the pure Tungsten Carbide, which is seen on router cutters mostly as a "tip", but sometimes solid. Router cutters used to be made in HSS as well but have not seen these for quite a while now. It is a similar material to the tungsten carbide tips on circular saws. This same tungsten carbide can be found on the throwaway planer blades too. There are many different grades.

HSS blades have a small proportion of tungsten up to 18% as mentioned before and, if that is the case, it is usually stated on the blade "HSS 18% tungsten." HSS is an alloy so several metals are combined in varying proportions to give the result we want.

Regards
Paul

Originally Posted by auscab

Yeah but is it a % like Paul is saying or are they pure Tungsten ?

Technically, neither.

Tungsten carbide is a compound of tungsten and carbon, much like silicon carbide or aluminium oxide or regular table salt (sodium chloride), and it's sintered with a cobalt binder to make the tips. It's not like alloying, where alloying elements are added to a base metal; the tungsten carbide powder is made first, then it's stuck together with the binder.

You could say it's 10% cobalt, 45% tungsten and 45% carbon, but it's really 10% cobalt and 90% tungsten carbide because once the tungsten and carbon are bonded they become a new thing

The wikipedia page has quite a good analogy: "Cemented carbides are metal matrix composites where carbide particles act as the aggregate and a metallic binder serves as the matrix (like gravel aggregate in a matrix of cement makes concrete)."

Originally Posted by auscab

I had a go . The tip and gas wasn't giving me enough heat and it turned out it needed a lot more heat than I thought . It wasn't just going to float off. I just did a section at a time and ended up grabbing a screwdriver , stuffed the temper in that for sure but Ill fix it later.

IMG_3668.JPG

I had to get it up around this colour for it to let go . The braze melted out before this but because I didn't have the whole thing that hot I had to bend the Tungsten off as I moved along. It needed to be that bright for the Tungsten to bend.
IMG_3677.JPG

IMG_3678.JPGIMG_3679.JPGIMG_3680.JPG

I could see this pooling out from the join while heating . With a bit of sand paper to brighten it it looks like its a light copper colour.
IMG_3683.JPG

Thanks Rob for destroying one of your blades.

That full width blade is HSS. I have no way of telling how much tungsten would have been in it. I am not in fact at all surprised you had difficulty separating the insert. It has to withstand high forces in the electric tool spinning at around 10,000 to 16,000rpm.

Some links for HSS:

This one little bit Chinese:

About The High Speed Steel (HSS) You Must To Know - Songshun Steel

and from Wikipedia:

High-speed steel - Wikipedia

What I would like to suggest, and have seriously considered doing myself, is utilising these blades in shoulder and rebate planes. My idea is that you make use of a blade such as the now defunct one above by cutting them to suit various widths of plane. Weld a suitable strip of mild steel to the back edge of the blade as a tang to extend the length and you now have a shoulder /rebate plane blade. The weld should be relatively easy as the bond is to the ordinary steel (could be high carbon) and there would be comparatively little stress on the joint anyway.

If you have a planer blade that is deep enough you might even be able to make a spokeshave blade, but usually by the time there is enough depth in those blades the thickness will have increased to an unacceptable level. Cutting the planer blade is easy with those thin cutting discs in an angle grinder.

I should also point out that my description of HSS is very broad. The mind boggles at the variations possible and their relative advantages/disadvantages.

The HSS/Steel join could be done by vacuum, high-pressure, High-temperature, furnace which requires no intermediate material.
Some TC cutters are bonded direct to steel this way.

Back in 2007 I made a spokeshave blade out of a piece of HSS from McJing.
Bugger to flatten and sharpen but it stays sharp for a looooooong time.
I used a thin kerf abrasive wheel in an old 8" table saw and a grinder to shape the blade.

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Originally Posted by Bushmiller

Thanks Rob for destroying one of your blades.

No probs.
I have some spares. Some need re grinding and some nice new ones as well . To sacrifice one for a bit of knowledge is well worth it .

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Originally Posted by Bushmiller

That full width blade is HSS.

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Now that's interesting .
Ive always thought they were Tungsten . Id never even thought of trying to re grind and sharpen them myself!
And before I read what you said I picked this up and went to my linisher and sanded it clean . I was thinking being Tungsten the belt is just going to skid off it and wear down the grit . But it didn't ! It cleaned it up .
I then though Id test the strength of this slither of metal and being Tungsten and so thin it would snap . But no way is that thing snapping . I cant bend or break it with my hands.
So yeah they are HSS and they are a good little source of a small blade for some future project maybe .

Originally Posted by Bushmiller

What I would like to suggest, and have seriously considered doing myself, is utilising these blades in shoulder and rebate planes.

Yes that's what I'm thinking too . I made some dowel cutters a while back . Posted them here somewhere . I'm dreaming of doing larger ones and drive the wood in the lathe . HSS ended blades would be great .
Possibly like the blade in this.

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Rob