Thread: Homemade Plane Blades from M2 HSS for Wooden Planes

I agree with Toolin Around, it is best to get a uniform temper across and through the whole blade, before establishing the primary bevel. The skin effect were the outer casing of the steel will be softer then the inner only extends 1+/- mm of the surface of the blade. This skin affect is resolved when the blade is ground flat after tempering by removing that outer skin of steel.

However if the primary bevel is ground before tempering, then we will lose more the 1+/- because the thin bevel edge will become overheated during tempering which will force us to significantly regrind the whole primary bevel twice, wasting time doing two grinds of the primary bevel, costing us money because grinding the primary bevel is the most costly part of the process even in the steel's annealed state, and having to grind away 5 mm - 10 mm of a now overcooked and worthless steel from the primary bevel that was established for no reason in the first place. Regardless of what approach you will take you will have to grind the primary, and if it is such a difficult and thankless job why would one ever seek to do it needlessly twice.

It is therefore only reasonable to conclude that the best approach is to establish the primary bevel only once after the tempering process is complete.

There is a bit of info on D2 steel and its use here.

Originally Posted by Groggy

There is a bit of info on D2 steel and its use here.

Groogy that is an interesting read. I find it interesting that industry has been using theses steels for 40 plus years with great success, and in fact they have moved on to harder and even more durable steel then D2/M2. Yet in woodworking we languish with A2 as the gold standard, personaly I think A2 is to soft for Australian hardwoods. As the article talks about D3/D6 and M4 amongst others. I remember when making my calls a lady refereed to D2 as very soft steel and wondered why I did not get a harder more durable and better steel for my purposes.

I was reading through this nice chart I got from Bohler Uddeholm they had some steels on that chart I would be itching to try.

Originally Posted by derekcohen

You would need a grinder preferable a slow speed grinder to do it yourself, it would take a little time however it could be done.

That is one's of the worlds understatements! D2 is bloody hard. Did you know?

I would rather aim to get them ground, then heat treated - and if necessary, we can regrind them ourselves later. What often happens when you heat treat a bevelled blade is that the hardness is not even owing to the thin bevel edge being overheated. Frequently, even with quality blades, one has to grind back a bit to get to the "good steel".

I would grind with a high speed grinder using a 46 grit white wheel. Does anyone know what the limit of the heat these blades can take before losing temper? I assume that it is similar to HSS. If so, a high speed grinder will not harm them. A slow, wet grinder will be at it until Christmas 2008.

The hardness is one of the reasons I want a 25 degree bevel. It is easier to add a microbevel of your choice to this than hone (eg a camber) on a bevel of 30 degrees.

Regards from Perth

Derek

I have a grinder that will go from 1rpm up to 6000 so I should be able to find a good speed somewhere in there. I'll use a real course gray wheel. If I'm not mistaken I don't think D2 is classed HSS it's tool steel with a tempering temp similar to A2.

I've ground hardened tool steel with little problems and that's well over RC 64. Even gound carbide with a green wheel and had little problem with that. So I don't think tempered back D2 which will be around RC 60-62 will be a problem in any case, it's all about getting the right wheel for the job.

Today I finished up getting some more quotes I had cast my net wider and called as many companies I could and followed a couple of recommendations given.

Our grinding, stress reliving, heat treatment, and milling budget is $400.

In order of least to most expensive:

Quote from Wayne at Pure Edge Saw & Knife phone: (03) 9739 8444 - $10 per blade $200 total
Quote from John at Rippon Grinding phone: 9791 8522 - $22 per blade $420 total
Quote from M D K Toolmakers phone: (03) 9720 3637 - $200 Jeff - $25 per blade $500 total
Quote from Hans at Jalor Tools phone: 9763 1377 - $44 per blade $880 total
Quote from Steve at POLAN PRECISION phone: 0438 233 011 - $52 per blade $1,040 total
Quote from Ivan at Alcol Precision Engineering phone: (03) 9720 4860 - $70 per blade $1,400 total
Quote from Jeff at Marand Precision Engineering phone: 8552 0600. - $220 per blade $4,400 total

Pure Edge Saw & Knife after all my calls was still the cheapest however I am uncertain what kind of job he would do. Also his $10 per blade is not a final figure however more a guesstimate for how long he expects it to take it could take much more time.

Rippon Grinding was recommended to me by Bohler Uddeholm and at $22 a blade they are with in our budget. Since we have the money and they were recommended as reliable, I think it would best to go with them. They can also have the job completed in two weeks.

In all fairness the quotes span a huge range of prices but I think the target demographic and the tolerance each work to are very different. Marand Precision Engineering would produce a blade that would exceed the standard of Lie-Nielsen or Veritas as they are targeting the aeronautical industry, however for our purpose I do not think it is worth paying the $4,400.

Hi TS,

Yes, I am inclined to agree with the recommendation for Rippon Grinding, but will go with what you think is best. Thanks for the update.

Cheers
Pops

TS, I'll trust your judgement on this as you are the guy with the details, Rippon sounds ok. Thanks for doing all the tedious legwork for us.

Here is an interesting graph showing the Temperature and Hardnesses for a range of steels. M2 is clearly the hardest of these over the widest temp range. D2 and A2 are pretty similar, while O1 (ie typical of regular carbon tool steel) drops off significantly above 800F which is why you can't hold these too long on a grinder without softening them. Grinding bevels on D2 should be similar to A2 - easier than M2 but more difficult than O1.



My experience with forming bevels/blades has been primarily with M2, O1 and old files. I have only ever sharpened A2 blades.

On M2, forming a 30o primary bevel on a 3/4" chisel takes me about 30" to grind with a white wheel on high speed and dipping into water about every 4-5 passes. This also includes a minute or so break every ~5 minutes otherwise I go barmy. The time could be reduced significantly with some more practice and being less conservative by taking more metal off between cooling since M2 can be taken to red heat without destroying the temper but for good control I like to hold the blade with bare fingers quite close to the bevel and it gets too hot to hold after more than 4-5 passes. On the same size blade in O1 it depends on the temper but generally it takes about 15 - 20" to form the bevel mainly because it is really important not to get it too hot.

With a 1" chisel blade in either M2 or O1 it only takes a few minutes longer in each case because the time for making the extra length passes is minimal and the time for cooling is about the same.

The only plane blades I have made are from re-tempered files (similar to O1) and are between 1 and 1/2" wide. I have also made some chisels from old files in sizes ranging from 3/4", to 3/16" wide. Most retempering ended up deliberately @ ~Rc61 which is about as hard as M2 while others were slightly softer. Just reducing the hardness by a couple of Rc Units makes a big difference.

The only 2" M2 blade I have ground a bevel on was a 20o spokeshave blade. This took about two hours () to grind the bevel - main reason being the blade is small and hard to hold and I had to rest regularly to stop my fingers from bleeding from the indentations from the sharpish square edges. Next time I would do this I would make a blade holding jig.

However, the bevel forming is only half the job, getting the backs flat varies from piece to piece and the area of flat you want to generate first up and how you do it. The chisels were relatively easy but the spokeshave blade was a pig because it was so small and difficult to hold. Depending on how flat it is to start with probably you made need to allow the same time as the bevel forming.

A2 blades seem to fit nicely between M2 and O1. It takes me a bit longer to sharpen A2 than O1 but not as long as M2. I don't see sharpening as an issue because the M2 and A2 blade edges last comparably longer.

To summarize. D2 is going to be somewhere between M2 and O1 in bevel forming and sharpening times. You should be able to grind the bevel on a 2" plane blade using a high speed grinder and keep it at hand holding temp in under an hour and much less if you are prepared to heat it further than hand holding temperatures. Flattening the back depends on how flat it is to begin with and how you do it.

I would rather the bevel on the D2 blades is preground by someone else and then tempered, simply because I have no idea how careful they will be in the bevel forming stage. If this is not possible I would prefer to grind the bevels myself.

I hope this is useful.

Originally Posted by Toolin Around

I have a grinder that will go from 1rpm up to 6000 so I should be able to find a good speed somewhere in there. I'll use a real course gray wheel. If I'm not mistaken I don't think D2 is classed HSS it's tool steel with a tempering temp similar to A2.

Correct, above 1000 F it interacts with the atmosphere which is why it needs an atmosphere controlled furnace for tempering. If you make it glow in air it will change the nature of the steel significantly and mess with the hardness.

Originally Posted by Toolin Around

I've ground hardened tool steel with little problems and that's well over RC 64. Even gound carbide with a green wheel and had little problem with that. So I don't think tempered back D2 which will be around RC 60-62 will be a problem in any case, it's all about getting the right wheel for the job.

I know that various people like their pink, grey, green, white or blue wheels but just about any coarse wheel at more or less any speed will be ok provided the blade is prevented from too hot. Slow speed is the easiest way to keep it cool but it will take longer. Faster requires monitoring the temp. I do the Jake thing of nude finger tip monitoring and regular water dips and using a coarse white wheel. I recently got a blue-max wheel but haven't had a chance to try it out.

Cheers

I'd prefer hardening/tempering only - then just send it to me... I'll bevel it myself.

4" angle grinder works a lot faster than a grind wheel. Rough it out this way before fine tuning on the grinder.

Originally Posted by rsser

4" angle grinder works a lot faster than a grind wheel. Rough it out this way before fine tuning on the grinder.

Yeah - but it grinds way too hot and can destroy the temper. But as long as you do it carefully it should be OK - maybe use a water spray bottle?

Haven't found it a problem Bob when I was shaping a hook scraper out of 3/8 x 1 1/2" M2. Just did a few passes before leaving it to cool (or better, resting it on another piece of steel to transfer the heat).

Also did most of the shaping by cutting with an Inox wheel. Now that did produce some bluing. Some folk say this isn't an issue. Any case, I found that the bluing didn't go very deep at all. A few passes with a diamond hone and it was gone.

Originally Posted by rsser

4" angle grinder works a lot faster than a grind wheel. Rough it out this way before fine tuning on the grinder.

I've got a few thin cutting wheels for the 5" grinder, I might have a go at cutting the primary bevel if it comes to that