Thread: Stanley Bench Planes Replacement Blade Bulk Order

Originally Posted by SilverSniper

So if our blades are going to be the same thickness as a Hock blade, then the Hock chipbreaker should be used as the reference template

This maybe a fortuitous solution. Sine the hock blades are 0.238125 mm thick and we can get M2 in 2.5 mm sheets, which with grinding after heat treating would bring our blade to almost exactly 0.238125 mm.

800 mm x 2.5 mm x 1500 mm sheet is only $828 plus GST

Originally Posted by SilverSniper

two further thoughts - I see from your drawing that the measurement for the 'yoke slot' in the chipbreaker is taken from the top of the chipbreaker. IAW the posts above, this measurement should be taken from the bottom of the chipbreaker, as this is the reference edge (this probably doesn't matter if its laser cut, but better to be safe than sorry)

You're correct, it doesn't matter. I unwrapped a brand new blade and chipbreaker today, so the measurements are accurate and laser cutters have more accuracy than is required for this task.

Looking at the list, there appear to be a lot of variations in blade specs. I assume this is due to different measuring tools and interpretation by their users.

I think where examples exist, it's safer to stick to a blade similar to the ones being produced by Helmut (i.e. the Hock blades) because we know they fit and work and there's no potential for discrepancies due to non-original blade swaps, etc.

Maybe at the moment we should use the m2 as it is cheaper and available atm.
If it is possible, we can also start ordering small amount of s390 from europe now and get it in 6months. So we get a bit of both. This is my opinion

Originally Posted by thumbsucker

This maybe a fortuitous solution. Sine the hock blades are 0.238125 mm thick and we can get M2 in 2.5 mm sheets, which with grinding after heat treating would bring our blade to almost exactly 0.238125 mm.

800 mm x 2.5 mm x 1500 mm sheet is only $828 plus GST

0.238. . . . mm ???? what do you mean 1/4 mm?

With respect to the heat treatment of M2 - I suspect all they will do is temper (hopefully, double temper) to change the final hardness. Maximum hardness (Rc ~65) will be abrasion resistant, Maximize toughness (Rc 62), or somewhere in between.

Impressive work woodwould!!! it even has the brandname

Hi Bob

What Bohler was telling me that the tempering is not the important part, but what temperature they take it to initially when it is getting heat treated. The temperature range for heat treating M2 is 1190 to 1230°C (2174 to 2246°F) going by the data sheet. It states that for cold working tools (like plane blades) lower temperatures are of importance for higher toughness. So the decision that needs to be made is abrasion resistance or is toughness more important for plane blades?

My two cents is that toughness is more important because what I quoted earlier - "Since fatigue damage is usually what limits the life of tools and fractured carbides apparently play an important role in the damage process of crack initiation and propagation."

*EDIT* However none of the regiments outlined below gives the stated Rc that Academy Saw's have at 63 -64. :confused: - need to do more research.

++++++++++++++++++++++++
This is what Bohler sent me regarding Maximum Toughness
++++++++++++++++++++++++

Heat Treatment of M2 for Maximum Toughness

Harden 1190°C
Temper Twice - 600 °C
Resultant hardness 60 – 62 RC

Harden 1170°C
Temper Twice - 560 °C
Resultant hardness 61 – 63 RC

Harden 1120°C
Temper Twice - 560 °C
Resultant hardness 58 – 60 RC

Harden 1190°C
Temper Twice - 560 °C
Resultant hardness 56 – 58 RC

The above treatment gives toughness, not red hardness.

I recall reading recently, it might have been from Derek Cohen or the Hock website, that you could make a plane blade that was impossibly hard, but it would then be very difficult to sharpen. I would recommend going for a 'standard' hardness, whatever that may be.

I have another question about the level of finish on the blade. Paul hand flattens his blades, you can see the pick marks on his irons and he polishes the backs I think. If every one of his M2 blades requires this work, won't your blades also require flattening? and polishing. I'm not sure I want to have to flatten the back and polish it myself.
(tell yourself that dark smudge is not rust, I'm telling myself that)
Cheers
Michael

SilverSniper if it only that simple. Their is no such thing 'standard' or in truth hardness more correctly called RC. Their is 'applications' and depending on what characteristics your application need will define the RC that you blade should be given as well as the relative balance of abrasion resistance and toughness. That is why their are many formulas to bring forth characteristics needed from the steel.

standard hardness for tool steel is 58-62 RC, with plane blades at the higher end (according to Tom LN)

seems pretty simple.

Originally Posted by mic-d

I have another question about the level of finish on the blade. Paul hand flattens his blades, you can see the pick marks on his irons and he polishes the backs I think. If every one of his M2 blades requires this work, won't your blades also require flattening? and polishing. I'm not sure I want to have to flatten the back and polish it myself.

Cheers
Michael

Michael these blades will be very flat, modern tools steel are very dimensionally stable and the vacuum furnace helps to keep it that way. These blades will need very little work to get them polished. Just work through your various stone grits and in 5 minutes at the most your blade back will be flat. Also for $15 what do you want, if you want to pay some one and extra $115 per blade just to do 5 minutes work, that is your choice.

Originally Posted by SilverSniper

standard hardness for tool steel is 58-62 RC, with plane blades at the higher end (according to Tom LN)

seems pretty simple.

58-62 RC may only be 4 digits, but in terms of metallurgy, it's a very broad scale.

Originally Posted by Woodwould

58-62 RC may only be 4 digits, but in terms of metallurgy, it's a very broad scale.

acknowledged, my thinking is, lets go for something that everybody will agree on, ie a standard measurement, rather than something different. Don't forget, some people want to order quite a few blades and they won't want to end up with something impractical.

Originally Posted by SilverSniper

standard hardness for tool steel is 58-62 RC, with plane blades at the higher end (according to Tom LN)

seems pretty simple.

That is complete untrue as a general statement. It could apply to some extent to A2 which LN uses and if the tool is a plane blade. However tools steels can be as low as RC 50-52 as LN uses for its Floats, were hand saw's can have an RC of 52 - 60, LN uses 52 for their saw's. Then it also depends on the steel some steels can go up to 75 RC, things like wrasps and filers are commonly hardened that high.

All these steels are types of tools steel, all have different 'applications' and therefore have different RC's.

Secondly 58-62 RC is a large space RC range by itself a single Rc can change the characteristics of how tool works.

Ever had a cheap chisel or plane blade and the bloody thing just cannot keep an edge. Why? Because the steel was tempered two far back and it simple does not have an RC high enough for the task.