# Cryogenically Treat Carbide Router Bits?



## NavyCharles24 (Feb 23, 2011)

So thanks for all the advice over the years. I am still a bit wary of the Router but I am not as intimidated as I was in the past. I think that is in LARGE part to you all.

Dewalt Router with Bosch Cabinet and a bunch of other tools! 

The thing is, Router Bits are friggin' expensive! Admittedly I go shopping, a lot, and buy cheap and sometimes real good.

So I am thinking of doing this Cryogenic treatment for Router Bits?
It's supposed to extend the life of my tool. So that it lasts longer.
So I think I want to send them my Router Bits, Saw Blades (another expensive item) and my cutting blades on the Porter Cable Joiner/Planer.

What do you all think? Anybody here ever use Cryo treatment?
The company is 300 Below in Decatur, Illinois.

Yes? No? Thoughts?


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## DaninVan (Jan 1, 2012)

And they do this treatment for free, shipping included? 
The first thought that comes to mind is that in a very very competitive market, if this process was all that effective, why wouldn't the top end manufacturers use it on their products? If they already do, then you're just be duplicating their process.
Just a suggestion, but how about directing that question _directly_ to a couple of the highly regarded (and user friendly) domestic manufacturers...maybe Whiteside and one other? Be interesting to hear what their Engineering staff have to say.


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## MAFoElffen (Jun 8, 2012)

Good question...

Read about it, but have never used personally. ...and there are costs involved.

Seems a gamble. On Carbides, their out is saying that some do not react or change. If it did, then gains might be up to twice the tool life for each sharpening and more sharpenings... but for more sharpenings, you would have to have a sharpening program and they would have to be aware to take off just what was required. But those claims were averaged for production manufacturing's toolings... for those that could afford to gamble on those savings.

This is extra cost that I would assume that I would want to do to a new tool bit before it is used. Since I am not a "go by claims" and more a "show me the data" kind of guy that is real self-conscious about where my money is going... Instead of rushing out and doing everything I had on something that I'm not sure about, I would probably get a few things done at a time, so I could see for myself.

Just me...


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## Semipro (Mar 22, 2013)

I do not see the point unless your doing commercial work
Only trouble I've every had was me dropping them and chipping a tooth you can cut a lot of lumber with a good bit, I think my t/s blade good for 40000 ft lumber do not think that going to happen anytime soon


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## neville9999 (Jul 22, 2010)

Charles buy good quality router cutters and get them sharpened when they need to be sharpened, keep your beer in the fridge as beer needs to be cold and cutters need to be sharp. NGM


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## rwbaker (Feb 25, 2010)

First, you might look around for another brand of carbide bits if you think the ones you are using are expensive; expensive is a matter of opinion and circumstance. If you are wearing out bits then evaluate why they are wearing out, it probably is not the bit as most quality carbide bits (Whiteside, etc) work and work and work.

Yes, I have used cryogenics on the angle of attack detectors for ultra high speed recon aircraft and everyone involved knew that this was done at the point of manufacture and not as a after-market solution. Do you see this being done for hand chisels, table saw blades, drill bits? If there was a competitive advantage it would be available and advertised as part of the manufacturing process.

Seriously, evaluate the brands, where purchased and how they are used as a first step toward longer bit life and less expensive life of bit cost before investing in third party solutions to non-existent problems.

Good luck - Baker


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## neville9999 (Jul 22, 2010)

rwbaker said:


> First, you might look around for another brand of carbide bits if you think the ones you are using are expensive; expensive is a matter of opinion and circumstance. If you are wearing out bits then evaluate why they are wearing out, it probably is not the bit as most quality carbide bits (Whiteside, etc) work and work and work.
> 
> Yes, I have used cryogenics on the angle of attack detectors for ultra high speed recon aircraft and everyone involved knew that this was done at the point of manufacture and not as a after-market solution. Do you see this being done for hand chisels, table saw blades, drill bits? If there was a competitive advantage it would be available and advertised as part of the manufacturing process.
> 
> ...


Richard I agree, I understand that when any metal gets very cold then a sharp edge would get a very small amount tighter and that would mean a very small amount sharper but all that would go away when it came back to room temperature, I would need to see very serious proof before I treated this seriously as this sounds like a way to separate a man from his money and I can do that without any help. N


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## tvman44 (Jun 25, 2013)

Sounds like the kind of thing you sell to someone who wants to buy a bridge.


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## NavyCharles24 (Feb 23, 2011)

lot's of thoughts out there. I think one of the reasons I asked that question was I read an article in Popular Woodworking? Magazine. It mentioned the Cryo process and that led to me more research. It talked about Forstner bits, Hock Tools, Lie-Nielsen? about those tools benefitting from Cryogenic Processing.

I think I am going to send 300 Below Inc. a couple of tools and see what I can benefit from them. The pricing seems really low.

Neville9999-thanks for the beer advice. You're funny!

You guys are always helpful, :haha:


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## harrysin (Jan 15, 2007)

The only experience that I've had with cryogenics was many years ago when, for instance an apple was dipped into liquid Nitrogen and then dropped onto the floor it shattered into thousands of pieces but I'm sure that if the apple had been allowed to come back to room temperature it would have been as before. In any case I agree with all of the above, just no point in considering it.


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## neville9999 (Jul 22, 2010)

harrysin said:


> The only experience that I've had with cryogenics was many years ago when, for instance an apple was dipped into liquid Nitrogen and then dropped onto the floor it shattered into thousands of pieces but I'm sure that if the apple had been allowed to come back to room temperature it would have been as before. In any case I agree with all of the above, just no point in considering it.


I agree Harry, that apple would be effected by being frozen, the freezing would break down some of the tissue and it would likely be a bit spongey when thawed, the more I think about it then freezing steel would not change it at all and when it came back to room temperature then it would be exactly the same as it was before hand, last post for me as this is a waste of time. Neville


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## jw2170 (Jan 24, 2008)

Eggs and other "stuff" is frozen for later use.....

The horse industry would find it difficult to survive without Cryogenics. There does not seem to be any after affects, but hey, that maybe why all the horses i back run slow......


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## harrysin (Jan 15, 2007)

Another demonstration that I witnessed was a coil of 1.5mm resin cored 60/40 solder dipped into liquid Nitrogen and a heavy weight hooked on the end, it bounced up and down like a spring, but as it's temperature increased the coil grew longer and longer until it became a straight length of solder with the weight sitting on the floor.


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## 2manytools (Nov 11, 2008)

I have been in the tool business since 1981 and have been interested in cryogenics for decades. 

As I see it there are several problems with cryogenics they keep it from becoming widely used.

1. It is not a predictable process. I’ve talked to 300 below several times over the years and they cannot promise definite results. Their answer is always that I don’t have to pay for it if it doesn’t work. I don’t want to get involved in selling tools that work sometimes and don’t work other times.

2. The only scientific papers I can find show that it can work. I have copies of those someplace and I can probably find them for you if you want them. I can’t find anything that convincingly explains the mechanism. I’m not much of a steel guy but I do know something about carbide and the explanations I read about carbide just don’t make any sense.

3. Long tool life really isn’t that big a deal for most tool users. We sell long life saw blades that can deliver up to 10 times the life of ordinary carbide but they’re really not a popular retail item. We do sell both the blades and the teeth into sawmills and commercial shops successfully.

I think cryogenics is a really cool technology and it definitely works sometimes but is just not ready for mass market. 

Tom Walz
Carbide Processors


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## Cherryville Chuck (Sep 28, 2010)

This is the first I've heard of it. Normally hardening is the process of heating steel to around 1500F/800C and then cooling it quickly to around 200F/100C or less. This would be sudden cooling from 70F/20C to -321F/-196C. There isn't the same differential between the two methods but that doesn't mean the metal won't react the same at the different temperature ranges. Then there is the issue that carbide is a metal ceramic. We already know it can get a lot hotter with no effect on hardness. I would be inclined to agree with several others that the process seems dubious but we could all be wrong.


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## NavyCharles24 (Feb 23, 2011)

I read a decent article published in Cabinet Maker FDM Magazine about Cryogenics and it was really insightful.
The other day I read a White Paper on Cryogenics, it's long and boring but it did verify Cryogenics processing. Int'l Journal of Eng. & Sciences Scientific Study of Cryogenics.

Folks swear by this process. So for me, it's worth the few extra dollars to Cryo treat my Router Bits and Forstner. :yes4:







2manytools said:


> I have been in the tool business since 1981 and have been interested in cryogenics for decades.
> 
> As I see it there are several problems with cryogenics they keep it from becoming widely used.
> 
> ...


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## Cherryville Chuck (Sep 28, 2010)

The quote you used is that "they cannot promise predictable results " and 300 below will refund your money if it doesn't. That would be a comforting statement but how would you prove that it didn't work?


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## Marcel M (Jun 14, 2012)

Cold Treating and Cryogenic Treatment of Steel
Revised by Earl A. Carlson, Lindberg Heat Treating Company

Introduction:

Cold Treating of steel is widely accepted within the metallurgical profession as a supplemental treatment that can be used to 
enhance the Transformation of austenite to martensite and to improve stress relief of castings and machined parts. Common 
practice identifies -84 °C (-120 °F) as the optimum temperature for cold treatment. There is evidence, however, that cryogenic 
treatment of steel, in which material is brought to a temperature of the order of -190 °C (-310 °F), improves certain properties 
beyond the improvement attained at cold-treatment temperatures. This discussion will explain the practices employed in the cold 
treatment of steel and will present some of the experimental results of using cryogenic treatment to enhance steel properties.

Cold Treating of Steel:
Cold treatment of steel consists of exposing the ferrous material to subzero temperatures to either impart or enhance specific 
conditions or properties of the material. Increased strength, greater dimensional or microstructural stability, improved wear resistance, 
and relief of residual stress are among the benefits of the cold treatment of steel. Generally, 1h of cold treatment for each inch 
of cross section is adequate to achieve the desired results. All hardened steels are improved by a proper subzero treatment to 
the extent that there will be less tendency to develop grinding cracks and therefore they will grind much more easily after the 
elimination of the retained austenite and the untempered martensite. 

Hardening and Retained Austenite:
Whenever hardening is to be done during heat treating, complete transformation from austenite to martensite is generally desired 
prior to tempering. From a practical stand-point, however, conditions vary widely, and 100% transformation rarely, if ever, occurs. 
Cold treating may be useful in many instances for improving the percentage of transformation and thus for enhancing properties. 
During hardening, martensite develops as a continuous process from start (Ms) to finish (Mf) through the martensite formation range. 
Except in a few highly alloyed steels, martensite starts to form at well above room temperature. In many instances, transformation is 
essentially complete at room temperature. Retained austenite tends to be present in varying amounts, however, and when considered 
excessive for a particular application, must be transformed to martensite and then tempered. 

Cold Treating versus Tempering:
Immediate cold treating without delays at room temperature or at other temperatures during quenching offers the best opportunity 
for maximum transformation to martensite. In some instances, however, there is a risk that this will cause cracking of parts. 
Therefore, it is important to ensure that the grade of steel and the product design will tolerate immediate cold treating rather than 
immediate tempering. Some steels must be transferred to a tempering furnace when still warm to the touch to minimize the likelihood 
of cracking. Design features such as sharp corners and abrupt changes in section create stress concentrations and promote cracking. 
In most instances, cold treating is not done before tempering. In several types of industrial applications, tempering is followed by deep 
freezing and retempering without delay. For example, such parts as gages, machineways, arbors, mandrils, cylinders, pistons, and ball 
and roller bearings are treated in this manner for dimensional stability. Multiple freeze-draw cycles are used for critical applications. 
Cold treating is also used to improve wear resistance in such materials as tool steels, high-carbon martensitic stainless steels, 
and carburized-alloy steels for applications in which the presence of retained austenite may result in excessive wear. Transformation 
in service may cause cracking and/or dimensional changes that can promote failure. In some instances, more than 50% retained 
austenite has been observed. In such cases, no delay in tempering after cold treatment is permitted, or cracking can develop readily. 

Process Limitations:
In some applications in which explicit amounts of retained austenite are considered beneficial, cold treating might be detrimental. 
Moreover, multiple tempering, rather than alternate freeze-temper cycling, is generally more practical for transforming retained 
austenite in high-speed and high-carbon/high-chromium steels. 

Hardness Testing: Lower than expected HRC readings may indicate excessive retained austenite. Significant increases in these 
readings as a result of cold treatment indicate conversion of austenite to martensite. Superficial hardness readings, such as 
HR15N, can show even more significant changes. 

Precipitation-Hardening Steels:
Specifications for precipitation-hardening steels may include a mandatory deep freeze after solution treatment and prior to aging. 

Shrink Fits: 
Cooling the inner member of a complex part to below ambient temperature can be a useful way of providing an interference fit. 
Care must be taken, however, to avoid the brittle cracking that may develop when the inner member is made of heat-treated steel 
with high amounts of retained austenite, which converts to martensite on subzero cooling.

Stress Relief:
Residual stresses often contribute to part failure and frequently are the result of temperature changes that produce thermal
expansion and phase changes, and consequently, volume changes.
Under normal conditions, temperature gradients produce nonuniform dimensional and volume changes. In castings, for
example, compressive stresses develop in lower-volume areas, which cool first, and tensile stresses develop in areas of
greater volume, which are last to cool. Shear stresses develop between the two areas. Even in large castings and machined
parts of relatively uniform thickness, the surface cools first and the core last. In such cases, stresses develop as a result of
the phase (volume) change between those layers that transform first and the center portion, which transforms last.
When both volume and phase changes occur in pieces of uneven cross section, normal contractions due to cooling are
opposed by transformation expansion. The resulting residual stresses will remain until a means of relief is applied. This
type of stress develops most frequently in steels during quenching. The surface becomes martensitic before the interior
does. Although the inner austenite can be strained to match this surface change, subsequent interior expansions place the
surface martensite under tension when the inner austenite transforms. Cracks in high-carbon steels arise from such
stresses.
The use of cold treating has proved beneficial in stress relief of castings and machined parts of even or nonuniform cross
section. The following are features of the treatment:
· Transformation of all layers is accomplished when the material reaches -84 °C (-120 °F)
· The increase in volume of the outer martensite is somewhat counteracted by the initial contraction due to chilling
· Rewarm time is more easily controlled than cooling time, allowing equipment flexibility
· The expansion of the inner core due to transformation is somewhat balanced by the expansion of the
outer shell
· The chilled parts are more easily handled
· The surface is unaffected by low temperature
· Parts that contain various alloying elements and that are of different sizes and weights can be chilled
simultaneously

Advantages of Cold Treating:
Unlike heat treating, which requires that temperature be precisely controlled to avoid reversal, successful transformation
through cold treating depends only on the attainment of the minimum low temperature and is not affected by lower
temperatures. As long as the material is chilled to -84 °C (-120 °F), transformation will occur; additional chilling will not
cause reversal.

Time at Temperature: 
After thorough chilling, additional exposure has no adverse effect. When heat is used, holding time
and temperature are critical. In cold treatment, materials of different compositions and of different configurations may be
chilled at the same time, even though each may have a different high-temperature transformation point. Moreover, the
warm-up rate of a chilled material is not critical as long as uniformity is maintained and gross temperature-gradient
variations are avoided.
The cooling rate of a heated piece, however, has a definite influence on the end product. Formation of martensite during
solution heat treating assumes immediate quenching to ensure that austenitic decomposition will not result in the
formation of bainite and cementite. In large pieces comprising both thick and thin sections, not all areas will cool at the
same rate. As a result, surface areas and thin sections may be highly martensitic, and the slower-cooling core may contain
as much as 30 to 50% retained austenite. In addition to incomplete transformation, subsequent natural aging induces stress
and also results in additional growth after machining.
Aside from transformation, no other metallurgical change takes place as a result of chilling. The surface of the material
needs no additional treatment. The use of heat frequently causes scale and other surface deformations that must be
removed.

Equipment for Cold Treating:
A simple home-type deep freezer can be used for transformation of austenite to martensite. Temperature will be
approximately -18 °C (0 °F). In some instances, hardness tests can be used to determine if this type of cold treating will
be helpful. Dry ice placed on top of the work in a closed, insulated container also is commonly used for cold treating. The
dry ice surface temperature Is -78 °C (-109 °F), but the chamber temperature normally is about -60 °C (-75 °F).
Mechanical refrigeration units with circulating air at approximately -87 °C (-125 °F) are commercially available. A
typical unit will have the following dimensions and operational features: chamber volume, up to 2.7 m3 (95 ft3);
temperature range, 5 to -95 °C (40 to -140 °F); load capacity, 11.3 to 163 kg/h (25 to 360 lb/h); and thermal capacity, up
to 8870 kJ/h (8400 Btu/h).
Although liquid nitrogen at -195 °C (-320 °F) may be employed, it is used less frequently than any of the above methods
because of its cost.

Cryogenic Treatment of Steels:
The value of cryogenic treatment of steel and other materials has been debated for many years; even today many
metallurgical professionals have serious reservations about its value. Notwithstanding these concerns, it is the intent of
this discussion to review some of the current literature and practices of those who believe that cryogenic treatment
enhances steel properties.

Cryogenic Treatment Cycles:
Typical cryogenic treatment consists of a slow cool-down (~2.5 °C/min, or 4.5 °F/min) from ambient temperature to
liquid nitrogen temperature. When the material reaches approximately 80 K (-315 °F), it is soaked for an appropriate time
(generally 24 h). At the end of the soak period, the material is removed from the liquid nitrogen and allowed to warm to
room temperature in ambient air. By conducting the cool-down cycle in gaseous nitrogen, temperature can be controlled accurately and thermal shock to the
material is avoided. Single-cycle tempering is usually performed after cryogenic treatment to improve impact resistance,
although double or triple tempering cycles are sometimes used.

Case Studies of Cryogenically Treated Steels:
Resistance to abrasive wear was investigated in a parametric study. Five tool steels were tested after conventional heat
treatment, after cold treatment at -84 °C (-120 °F), and after being cryogenically treated at -190 °C (-310 °F). 
Cold treatment at -84 °C (-120 °F) improved the wear resistance by 18 to 104%, but the cryogenic treatment results show 104 to 560% improvement.


Text taken from: ASM Handbook Vol 4 Heat Treating p 487-489. Published in 1991


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## Cherryville Chuck (Sep 28, 2010)

Marcel M said:


> Cold Treating and Cryogenic Treatment of Steel
> Revised by Earl A. Carlson, Lindberg Heat Treating Company
> 
> 
> ...


Good article Marcel. However, carbide isn't steel. Is there a study that proves the process improves the properties of carbide?


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## Marcel M (Jun 14, 2012)

Cherryville Chuck said:


> Good article Marcel. However, carbide isn't steel. Is there a study that proves the process improves the properties of carbide?


I could find nothing in the ASM handbook regarding carbide but I thought that this would help others not familiar with the process to understand how it works. In the event that the OP decides to use this hardening process on his HSS tools he will at least know if it is worth the effort. Just trying to help and educate.


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## Cherryville Chuck (Sep 28, 2010)

I guess the jury is still out on that. Maybe it would be worth doing on chisels and turning tools.


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## Marcel M (Jun 14, 2012)

Okay Charles, I must admit that it took a bit of digging but I believe that I have an answer for you. I have dealt with this question as related to machining ferrous materials but never gave it a thought as it pertains to wood and wood composites. (See Attachment)


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## harrysin (Jan 15, 2007)

Interesting results but only industry would benefit, it would take a very long time for the average hobbyist to achieve a cost benefit.


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## Cherryville Chuck (Sep 28, 2010)

Thanks Marcel, that was interesting. I did see some issues in the study that make it unclear whether the cryogenic treatment would work for router bits.

Quote- One dominant reaction is the
chemical degradation of the cobalt
binder at lower temperatures. At higher
temperatures, oxidation of both the WC
grains and cobalt matrix occurs. The
cryogenic treatment apparently reduces
the chemical degradation of the cobalt
matrix at the lower temperatures.
Consequently, alloying the cobalt
binder, such as the new corrosion/oxidation-
resistant carbide grades, substantially
reduces tool wear.

The test was done at only 500 rpm. I would have preferred to see the test done at some higher speeds to see if the wear differential from treated to untreated still manifested at speeds closer to what a router will turn. This part is made more unclear by the statement that "At higher temperatures, oxidation of both the WC grains and cobalt matrix occurs." Also, the treatment was done on C2 grade carbide only. I'm pretty sure that many new bits are C3 grade and I know that some saw blades, at least, are using C4 grade. The article admits that newer carbide grades are using alloys for a binder that are capable of withstanding higher temperatures and are less likely to react to contaminant chemicals in the mdf tested, and obviously in other materials too. So the jury is still out IMO.

By the way, when I was reading about carbide to see if it had any austenitic or martensitic properties I came across something that is worth noting. The article I read said that carbide readily dissolves in dilute solutions of hydrogen peroxide. So if you hear anyone say that they are going to use H2O2 to clean router bits tell them not to!


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## Marcel M (Jun 14, 2012)

More interesting reading.

Wood Machining - Google Books


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## Marcel M (Jun 14, 2012)

Cherryville Chuck said:


> Thanks Marcel, that was interesting. I did see some issues in the study that make it unclear whether the cryogenic treatment would work for router bits.
> 
> Quote- One dominant reaction is the
> chemical degradation of the cobalt
> ...


Yes, I agree Charles. I too would like to see a study based on high feed/speed wood machining. I just wanted to present the study and let the reader form their own conclusions and to that end this is the best study that I could find on this subject.


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