Thread: Cuting High speed steel??

I find a 1 mm cut off wheel in the angle grinder works great just don't do it all in one cut if you do just spray it with a water bottle don't let the blue zone get to big Bruce

EDM would be the go but it would probably be cheaper to just buy some HSS

Why not just use a zip disc, do it bit by bit and cool it as you go ?

I have cut quite a few lengths in half that way and they have always held the edge ok after sharpening,
but I'm not to sure about this, you would have to be careful not to grind to much heat into it as cut.

Depending on the HSS I believe some of them are pretty much "untemperable" by normal means.(though I wouldnt bet on it)

What I'm wondering is how well the diamond tool holder will grip if the HSS blank isnt square?

Stuart

This is sort of cutting my old baby (8") table saw fitted with a thin cut off wheel, conventional fence, and a water drip does a really nice job at.

I use a dremel with a cutoff wheel works for 1/4 inch stuff ok
Pete

Originally Posted by BobL

This is sort of cutting my old baby (8") table saw fitted with a thin cut off wheel, conventional fence, and a water drip does a really nice job at.

This was a favourite trick my grandfather used often. He always made a temporary blade guard from 4"x2"'s and clamped them over the blade leaving a small opening for the cut. One day he was in a hurry and didn't bother setting up the temp guard and the cutoff wheel exploded in his face. Nearly killed him. It split his face in half right down the middle and left a 2" hole in his forehead. At 75 years old he was very lucky he lived. He spent more than 6 months in hospital.

Friction blades in table saws can kill. Please be careful if anyone tries this.

Steve

Originally Posted by maggs

This was a favourite trick my grandfather used often. He always made a temporary blade guard from 4"x2"'s and clamped them over the blade leaving a small opening for the cut. One day he was in a hurry and didn't bother setting up the temp guard and the cutoff wheel exploded in his face. Nearly killed him. It split his face in half right down the middle and left a 2" hole in his forehead. At 75 years old he was very lucky he lived. He spent more than 6 months in hospital.

Friction blades in table saws can kill. Please be careful if anyone tries this.

Steve

Even on 10,000 rpm angle grinders thin (1 mm thick) 125 mm cut off wheels do not "explode", they either break off at the arbor whereby they do nothing, or if fragments of the wheel break off they have so little mass but such a large surface area that air resistance quickly slows them down within cm of leaving the wheel. I have broken dozens of these wheels and there has never been an explosion. On a table saw the revs are less than 1/3rd of an angle so the energy is <1/9th of that on a an angle grinder so they are even less dangerous. Nevertheless I still wear a full PC face shield while doing this.

Wheels thicker and larger than this I pay a bit more attention to.

Originally Posted by BobL

Even on 10,000 rpm angle grinders thin (1 mm thick) 125 mm cut off wheels do not "explode", they either break off at the arbor whereby they do nothing, or if fragments of the wheel break off they have so little mass but such a large surface area that air resistance quickly slows them down within cm of leaving the wheel. I have broken dozens of these wheels and there has never been an explosion. On a table saw the revs are less than 1/3rd of an angle so the energy is <1/9th of that on a an angle grinder so they are even less dangerous. Nevertheless I still wear a full PC face shield while doing this.

Wheels thicker and larger than this I pay a bit more attention to.

Agree completely and I too have broken a lot of these disks.

On the original question, HSS is air hardening tool steel. You are NOT going to anneal it by cutting it with an angle grinder and this is an old wives' tale. It dates from the days of high carbon steels which would be annealed by the heat.

I have ARC WELDED sticks of HSS to arbours to make custom cutters then used a T&C grinder to clean up the cutting edges. The whole assembly got glowing red hot and was cooled slowly to minimise cracking in the HAZ.

Still cut fine.

So use a 1mm cutoff disk in an angle grinder and get it done.

PDW

Originally Posted by BobL

Even on 10,000 rpm angle grinders thin (1 mm thick) 125 mm cut off wheels do not "explode", they either break off at the arbor whereby they do nothing, or if fragments of the wheel break off they have so little mass but such a large surface area that air resistance quickly slows them down within cm of leaving the wheel. I have broken dozens of these wheels and there has never been an explosion. On a table saw the revs are less than 1/3rd of an angle so the energy is <1/9th of that on a an angle grinder so they are even less dangerous. Nevertheless I still wear a full PC face shield while doing this.

Wheels thicker and larger than this I pay a bit more attention to.

It was a 10" or 12" blade about 3/16" thick if I remember correctly. Nobody knows for sure what he was cutting as there was nothing much left to provide an insight except a small part of the blade still on the arbor and he remembered nothing. I've been using smaller cutoff blades for over 40 years and have never seen anything like it either but, I can assure you it happened. I went and cleaned up the mess afterwards in his workshop. This happened in the mid 70's so my memory of it isn't perfect but I'll never forget the image of him in hospital. He was so badly damaged that I couldn't recognise him in the intensive care ward and had to read the name on the meds chart to make sure it was him. One theory we had was that he used to buy lots of stuff from a disposal yard in Sydney and it's possible the blades were factory seconds or rejects that somehow made it to sale. This was a common practise back then.

Originally Posted by PDW

Agree completely and I too have broken a lot of these disks.

On the original question, HSS is air hardening tool steel. You are NOT going to anneal it by cutting it with an angle grinder and this is an old wives' tale. It dates from the days of high carbon steels which would be annealed by the heat.

I have ARC WELDED sticks of HSS to arbours to make custom cutters then used a T&C grinder to clean up the cutting edges. The whole assembly got glowing red hot and was cooled slowly to minimise cracking in the HAZ.

Still cut fine.

The main reason I have water cooling on the table saw with the, thin cut off wheel is for carbon steel but it comes in handy for cutting any steel because it means I can just keep cutting without having to stop and cool it off. For rod and bars etc I use my metal cutting bandsaw but the table saw is good for steel plate up to about 6 mm although I have cut thicker just very slowly.

Originally Posted by BobL

The main reason I have water cooling on the table saw with the, thin cut off wheel is for carbon steel but it comes in handy for cutting any steel because it means I can just keep cutting without having to stop and cool it off. For rod and bars etc I use my metal cutting bandsaw but the table saw is good for steel plate up to about 6 mm although I have cut thicker just very slowly.

Straying away from the original question but - for cutting steel up to 10mm thick the cheap 50A Chinese plasma cutters do fine. For stainless, probably 8mm for a reasonably clean cut. I've cut a lot of 6mm stainless with mine and there's no way I'd use a bandsaw if I had a choice. The ability to make a template from MDF or thin ply then literally run the plasma torch around it makes odd shapes and blind holes etc simple.

My h/v bandsaw mostly gets used for docking off rounds, angle iron, RHS and the like. The 18" vertical one is set on wood cutting speeds, cutting steel on it is a slow PITA really.

I cut a whole boatload of 4mm A36 plate with the plasma cutter....

PDW

Originally Posted by maggs

It was a 10" or 12" blade about 3/16" thick if I remember correctly. Nobody knows for sure what he was cutting as there was nothing much left to provide an insight except a small part of the blade still on the arbor and he remembered nothing. I've been using smaller cutoff blades for over 40 years and have never seen anything like it either but, I can assure you it happened. I went and cleaned up the mess afterwards in his workshop. This happened in the mid 70's so my memory of it isn't perfect but I'll never forget the image of him in hospital

Was it a fibre reinforced wheel?

Back in the 70's there were slightly thicker thin cutting discs around which were NOT reinforced and were only meant for low speed use.

Maybe he used the wrong disc - spun it too fast.

My bro in law had a large rubber angle grinder sanding disc mount break up on his widow maker angle grinder and it was lucky it didn't take the family jewels with it.

Just missed em by inches and he had a massive huge bruise on the inside of his leg just a bit lower. Only wearing shorts when it happened. Silly mug as it was obviously out of balance and old and he used it like that.

Bang, cop that. Yow.

Never take chances with this stuff. It can do you no good.

Rob.

Angle grinder with a cutoff wheel.
narrow ones are good if you have one.

is there a reason they need to be 1.5 inch long ?
when first using the diamond tool holder i cut them short enough so the post can be turned 360 degrees, and sharpened both ends of the tool.
the drawback is the waste once the HSS gets too short.
now use HSS in the diamond holder at 2"/3" long, "basically cut the long hss in 1/ 2 and only sharpen the end furthermost from the grinder cut".
found that the post can still be turned to the positions needed, even with 2 tools in the post, when using the longer HSS bits.