Thread: Homemade Plane Blades from M2 HSS for Wooden Planes

Groggy thank you for your efforts.

Originally Posted by Groggy

These blades are incredibly tough (I own a few Academy Saw works blades - these are harder).

I concur with you on this, from my experience with these blades and the Academy Saw blades that I own. However this raises a question, Why are these D2 blades so much harder then the Academy Saw M2 18% Tungsten HSS blades? Both are treated to Rc 60 - 62, and the M2 18% Tungsten HSS should be harder/tuffer than plain Jane D2 high carbon tool steel. BobL and sumu, any comments and ideas as to why?

I am surprised at the tuffness of these blades, I am however happy with as positive indication. I feel confidant that Bohler-Uddeholm sold us what they promised, and that Rippon Grinding did what they were paid to do and that the heat treatment was performed correctly. I also see this as a good indication to the edge retention of these blades.

I think that Batch 02 will by default have a 30º/25º bevel ground on them by Rippon Grinding, with the option for those who wish to do it themselves at a reduced cost per blade.

Luckily I have staked my claim to some DMT Diamond Plates in the new year, looks like they will come in handy.

Ahh the joy of modern metallurgy

Originally Posted by thumbsucker

I concur with you on this, from my experience with these blades and the Academy Saw blades that I own. However this raises a question, Why are these D2 blades so much harder then the Academy Saw M2 18% Tungsten HSS blades? Both are treated to Rc 60 - 62, and the M2 18% Tungsten HSS should be harder/tuffer than plain Jane D2 high carbon tool steel. BobL and sumu, any comments and ideas as to why?

I guess it is probable the ASW blades are harder, I just haven't spent two days trying to get a bevel on them.

TS

Reading all of this discussion, I was wondering whether every second cut for Batch 02 could be at 45 degrees? That should put a 45 degree bevel on to start with on each blade without any significant extra cost. Any it should be easier to grind a 25 degree bevel from 45 than from 90.

Originally Posted by jmk89

it should be easier to grind a 25 degree bevel from 45 than from 90.

Good idea

This way we would avoid the problem of cooking the edge during heat treatment. A 45º bevel we can then remove as we grind down to 30º. Maybe a 40º or 35º bevel milled in by Rippon would be sufficient to give us enough waste that we can grind away to get a good evenly tempered edge.


Who thinks it is a good idea?

Hello,

Originally Posted by thumbsucker

Why are these D2 blades so much harder then the Academy Saw M2 18% Tungsten HSS blades? Both are treated to Rc 60 - 62, and the M2 18% Tungsten HSS should be harder/tuffer than plain Jane D2 high carbon tool steel.

Well, first of all, 18% tungsten in a HSS implies to type T-1, not M2. T-1 is the classic HSS, still common in Europe, and provides higher heat resistance and generally about 20% better wear resistance than M2. The problem with it is that 18% of W makes it expensive, and requires a bit different and a bit more accurate heat treatment parameters than M2.

Then, D2 is high carbon high chromium steel. It IS tough, and maybe you are a now a bit stunned by the sheer "size effect" of the block of steel .

But it is not (at the same hardness level) tougher than M2, at least it should not be is everything is gone as promised. Okay, there may happen some anomalies considering how the grinding media works, but I would still say you are just stunned. I'm not patronizing you at all .

Ahh the joy of modern metallurgy

Yes . Next time, get them prepared out of T-1 or M42 and grind the bevels yourselves. (Noo...ooot )

About bevel grinding, it really should at that point occur all the time under water or cutting oil, at slow speed. Minimizes the danger of heat shock at the very edge region.

kippis,

sumu

Originally Posted by sumu

It IS tough, and maybe you are a now a bit stunned by the sheer "size effect" of the block of steel .

Sumu - thanks for that, what you say makes sense and it is most likely just a little shock on our part. All good.

Better hard then soft I always say.

Originally Posted by thumbsucker

Sumu - thanks for that, what you say makes sense and it is most likely just a little shock on our part. All good.

I must say, my comment was just a reflection from a very similar kind of situation I have been in. With those chunks of steel, 25 deg bevel for a 8mm thick iron makes over 18 mm of bevel depth.

( BTW, go and tell to some Texan guy that he is stunned because something is too big for him, well... Ouch . Done that, too .)

Better hard then soft I always say.

Can't put it any better .

kippis,

sumu

TS, about the 45 degree pre-grind - I don't favour the idea. This stuff is so hard that if any pre-grind is to be done, I'd ask that the finished angle be ground (hollow ground). It seems a waste to take it to a grinder and not finish the angle.

I'd also suggest, as Derek did too, that people consider just a standard 25 degree angle be put on the blade, then, if they want 30 degrees, they can simply grind the 30 degree onto the tip.

PS - Derek, I tried the Scangrinder - forget it, though once hollow ground it is good for final tidying up if you want presentation quality. It takes about 30 minutes to smooth out a pre-ground hollow on the water wheel.

wow, this stuff sounds hard! Should be fun grinding it on my little 5" 1/3hp black & decker bench grinder. ....

Originally Posted by Groggy

TS, about the 45 degree pre-grind - I don't favour the idea. This stuff is so hard that if any pre-grind is to be done, I'd ask that the finished angle be ground (hollow ground). It seems a waste to take it to a grinder and not finish the angle.

I would agree very much here on my behalf. It is a waste not to finish the bevel there, because I just guess it would cost the same or close the same than 45 deg angle.

The other thing I would be worried about is that if you use for grinding for example a bench grinder and to cool the piece between grinding you dip it in the water repeatedly, the steel surface undergoes kinda minor tempering for let's say 20-100 times (depends on the guy) before bevel is finished. It is absolutely and completely possible to be successful in this reshaping at home, but it is a drag. You should be more careful than you'd like to be.

I'd also suggest, as Derek did too, that people consider just a standard 25 degree angle be put on the blade, then, if they want 30 degrees, they can simply grind the 30 degree onto the tip.

I would agree here too. It is a huge chunk of steel, and with just it's enormous massive bulk, it makes one of the greatest hand plane irons ever seen the daylight. It's specific resonance is somewhere up high, and it's vibration amplitude is small. It indeed will make some serious quality cut print on the planed wood.

For 25 deg, the blade (bevel down) will touch the plane bed first time at about 17mm from the plane sole. With 30 deg, the distance is about 14mm. The 3mm difference is insignificant, but 25 deg is much more effective for further microbevel (or no microbevel) adjustments, making the blade just more versatile.

kippis,

sumu

Have been following this thread with interest, although it is not of immediate interest (yet).

Was trawling through the FWW site for info on sharpening, now that I have bought a Triton Wetstone Sharpener, and found this article on steel for tools.

Thought it might be of interest to some of you.

Originally Posted by sumu

The other thing I would be worried about is that if you use for grinding for example a bench grinder and to cool the piece between grinding you dip it in the water repeatedly, the steel surface undergoes kinda minor tempering for let's say 20-100 times (depends on the guy) before bevel is finished. It is absolutely and completely possible to be successful in this reshaping at home, but it is a drag. You should be more careful than you'd like to be.

Sorry but I disagree. If you hold the blade with your bare hands and put your fingers near the bevel and as soon as you feel the heat, dip it in water the temperature, if it does not hiss it will not have gotten much or at all above about 100 hundred degrees.
If you look at this graph you will see that you need to get it above 350 F (175oC) to get close to starting a small retemper. Even more significant, tempering of D2 requires holding at that temperature for an hour and half per inch of thickness. And even if you manage to get it up to 800F that is only going to drop it to Rc 58 anyway - that in fact might be nice! In contrast O1 drops to Rc 52 at 800F and does so very quickly.



If one follows the cooling method, the few seconds that the temperature gets anywhere near a retemper is also only going to affect the first few 1/10ths of mm which are all going to be be ground away anyway. This is why some folks are considering an angle grinder to cut most of the bevel as it cuts so quickly maybe it can be used to grind all, bar the last mm or so away. I have never done this so I can't comment on how effective this would be.

The slow grinding of the bevel people are experiencing is not unexpected - It's not just hard - It's tough stuff - slight difference there. Tough stuff glazes abrasives as some folk are experiencing. I suspect the heat treatment has not changed the hardness of the steel significantly and it is around Rc 62. I won't be able to run an RC test on it until mid Jan when I get my blades back from melb. I will also test the bevel as well as the rest of the blade.

Originally Posted by Groggy

TS, about the 45 degree pre-grind - I don't favour the idea. This stuff is so hard that if any pre-grind is to be done, I'd ask that the finished angle be ground (hollow ground). It seems a waste to take it to a grinder and not finish the angle.

Groggy

I agree, if there is going to be a pre-grind, let's get it done to 25 deg.

However, my thought was that when the blanks are cut from the strip, they could be cut at an angle. Originally I thought in terms of 45 degrees (probably because I havve been cutting mitres all day!!!), but of course, if you cut at 25 degrees/155 degrees, both blades will be bevelled at 25 deg. Before we take this aspect any further, TS could contact the people who do the cutting to see if they can do it at an angle, and if so what the most acute angle that they can do may be.

Originally Posted by jmk89

the most acute angle that they can do may be.

The answer is regrettable no to angles, Bohler can only or are only willing to cut at 90º. The bevel must be milled by Rippon Grinding. An angled cut by Bohler would have been ideal however.