Chipping after shaving HRC issues? Custom Razors

This is a long story and im going to start from the top just so everyone knows the big picture to get your thoughts!

i have been making my own blades for the last 2 years and havent had a bit of issues with edge retention after shaving and never had to worry about rockwell testing... I recently purchased a slab of 52100 and been working with it. i finished 5 razors and all of them went right along as all my blades have, i got them to their final edges which went fine as well... i shaved with the razors and i found chipping all over the blade... i then checked the razor after stropping the next time just in case it was bad technique there, still chipped after shaving with the razor, all 5 did the same thing.... i got the blades tested and they were 55-58 HRC which i thought was too low and this was my issue... i then gave up on the 52100 and got me some 01 tool steel, i made 6 razors and only final ground 1 just to test prior to doing the rest of the blades... sure enough the edge was chipping after shaving! i just went to get all my 01 tool steel razors tested and had them range from 59-61 HRC the blade in question was 59-60.... So now im pretty sure thats hard enough but whats causing this issue?!

Here is how i am HT'n my blades... i got the 52100 up to 1675 quench in peanut oil that was at 150 degrees... tempered the 52100 back to 425 2 cycles on the first batch... the second i tempered back to 375 2 cycles ... both had issues...

the 01 i normalized in 3 cycles and quenched at 1550 then i tempered those blades to 350 2 cycles...

now there are a few things i am thinking is the issue...

1st of course is im grinding way too hot ruining the temper of the blade... i thought this but i really dont get this blades all that hot, really im talking 1-2 pass then dip.... takes a long time but ive always been that cautious.... still i plan on making a make shift coolant with an IV drip when i go home and grind tonight...

2nd i think the rockwell testing isnt correct because they are testing the shank of the blade when its the edge that really matters... i am going to ask about testing the edge of these blades rather than the shank

3rd i dont know if this is possible but i wondering if i am grinding the edge way too thin... i dont think this is it but maybe?


i have taken the blades to a local heat treat and they will be working these 52100 blades for me... i am hoping that fixes it


Anyway i know its been a while since i posted here and i really look forward to using the plethora of knowledge here to see your thoughts and what to do to alleviate!

Thanks,
Fonz

I am by no means any sort of hardening expert, but many blades i have seen were HRC65.

I think if the edge was ground too thin, you would have cracking and honing issues...

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Originally Posted by dinnermint

I am by no means any sort of hardening expert, but many blades i have seen were HRC65.

I think if the edge was ground too thin, you would have cracking and honing issues...

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yeah i was just reading around on the forum and found people having razors that were 55 HRC and were fine with them... the hardness of this blade doesnt sound like the issue here... of course unless im mistaken about 55 HRC being okay...

I'm leaning toward over heating during final grinding its just i really dont grind them hot so it surprises me...

What angle are you at ??

What about if your issue has nothing to do with the making but the finish and honing. Bear with me for a background theory. You can damage steel below the surface. That is how they can use acid to recover removed serial numbers. So what if your chipping is done by something you do in your final prep of the blade. Like doing the initial bevel set with a somewhat course diamond hone. Or maybe the material on your finish belt on your grinder. There are a ton of variables. What comes to mind is two years in and this problem pops up. What else have you changed?

Have you tried to hone with more than a layer of tape?
Do 2 or 3 layers fix the problem?

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Originally Posted by gssixgun

What angle are you at ??

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Originally Posted by mainaman

Have you tried to hone with more than a layer of tape?
Do 2 or 3 layers fix the problem?

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i see what ya'll getting at... i really thought i was at a good angle for what i was making but this is definitely out of the box thinking i was looking for! so many many moons ago i was given a standard, and that standard was to make 8/8 blades with 1/4 steel 7/8 7/32 steel and 6/8 in 3/16... so i dunno what angle that makes it but the rule of thumb is that... should i still go home and throw 2 layers of tape and give it a go or is that angle good?

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Originally Posted by RezDog

What about if your issue has nothing to do with the making but the finish and honing. Bear with me for a background theory. You can damage steel below the surface. That is how they can use acid to recover removed serial numbers. So what if your chipping is done by something you do in your final prep of the blade. Like doing the initial bevel set with a somewhat course diamond hone. Or maybe the material on your finish belt on your grinder. There are a ton of variables. What comes to mind is two years in and this problem pops up. What else have you changed?

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exactly! 2 years and never had this issue! i use better belts that's for sure! im setting the bevel with a worn out 400 atoma.... aside from that alot of the ways i grind my razors and everything are pretty much the same... not change at least from what i can remember...

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Originally Posted by Dafonz6987

i see what ya'll getting at... i really thought i was at a good angle for what i was making but this is definitely out of the box thinking i was looking for! so many many moons ago i was given a standard, and that standard was to make 8/8 blades with 1/4 steel 7/8 7/32 steel and 6/8 in 3/16... so i dunno what angle that makes it but the rule of thumb is that... should i still go home and throw 2 layers of tape and give it a go or is that angle good?

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You lose nothing by trying 2 layers. If the edge holds then you have two variables to figure out only,: 1. how wide to make the blade for the spine thickness you are at to increase the angle and avoid chipping. 2. The HT might be off, although chipping does not occur at low hardness. You should see problems with edge holding and bevel setting if you HRC is too low.

What is was getting at is if you recently changed your belt from one model to another. Like you just started using zircon belts or a ceramic. There was a thread not that long ago about makers discussing that time saved using a diamond plate to the initial bevel set did not always save time because it sometimes causes chipping. These are other possible areas you can look for solutions. Try setting the bevel with an 800 grit hone.

This is the Google box calculation


(2 * asin(.181 / (2 * .620)) * 180) / pi = 16.786646


The red is the width of the spine the green is the height of the blade from where it touches on the hone... plug that into Google search and voila Math !!!


or let's just plug in your 6/8 calc figuring the height at .740 rather than .750 for the full 6/8 height...


(2 * asin(.188 / (2 * .740)) * 180) / pi =14.5956583

This is about 1.5° low from the accepted 16° target / average we found on Vintage razors, some razors target 17°

At 6/8 each layer of tape adds about .66° to the measurement so you need 3-4 layers to bring it into spec... HT Temper and Steel can absorb some of the variance but building razors to accepted spec makes life easier


This is why we are known around the internet as "Know it Alls" on SRP :rofl2:


ps: I only checked the 6/8 size you can play with the others and see where they come in at

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Originally Posted by mainaman

You lose nothing by trying 2 layers. If the edge holds then you have two variables to figure out only,: 1. how wide to make the blade for the spine thickness you are at to increase the angle and avoid chipping. 2. The HT might be off, although chipping does not occur at low hardness. You should see problems with edge holding and bevel setting if you HRC is too low.

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After u mentioned the tape I came straight home to one of the blades... I was really anxious and excited, had the problem I've been having really be as simple as bevel angle... immediately slapped 3 layers of tape and honed... edge was chippying... then i bread onifed the blade a bit and honed again... it was chipping... I went ahead and took pictures in hopes this would help....

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Originally Posted by RezDog

What is was getting at is if you recently changed your belt from one model to another. Like you just started using zircon belts or a ceramic. There was a thread not that long ago about makers discussing that time saved using a diamond plate to the initial bevel set did not always save time because it sometimes causes chipping. These are other possible areas you can look for solutions. Try setting the bevel with an 800 grit hone.

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Thanks! Will do! Any suggestion works!

Quote:

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Originally Posted by gssixgun

This is the Google box calculation


(2 * asin(.181 / (2 * .620)) * 180) / pi = 16.786646


The red is the width of the spine the green is the height of the blade from where it touches on the hone... plug that into Google search and voila Math !!!


or let's just plug in your 6/8 calc figuring the height at .740 rather than .750 for the full 6/8 height...


(2 * asin(.188 / (2 * .740)) * 180) / pi =14.5956583

This is about 1.5° low from the accepted 16° target / average we found on Vintage razors, some razors target 17°

At 6/8 each layer of tape adds about .66° to the measurement so you need 3-4 layers to bring it into spec... HT Temper and Steel can absorb some of the variance but building razors to accepted spec makes life easier


This is why we are known around the internet as "Know it Alls" on SRP :rofl2:


ps: I only checked the 6/8 size you can play with the others and see where they come in at

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I don't take someone educating me as someone acting as a know it all... I am always open to anyone's suggestions as I wasn't born with all the knowledge on how to make razors, so educate away

On another note I'll have to wait for my math queen to come home and teach me what ur showing me �� Never been the best at math

How are you heat treating your blades? The reason I ask is that I have a digitally controlled electric kiln and I added a thermocouple temp probe and was shocked be the temp variation on the screen, it was 20 c off where the razors were sitting so I now have temp probes measuring in three different zones just to be sure. Also 1550f seems way to high for 01 that's about 843c and if your probe is off it could be way higher, I harden my blades at 805c for example.
Also have you snapped one of you blades or a test piece to have a look at the grain structure? That helped me a lot because I realised that something was off as I was getting chipping etc, so started looking at my heat treating procedure which once I mastered sorted it out.
Also another consideration is your tempering has to be spot on again you need precise temp control.
And as for blade angle I have found that it needs to be above 16 degrees or the edge can be too thin ,believe it or not some of my best shavers have been at 18-19 degrees.
Hope this helps a bit.
Ps there is a great bevel angle calculator on www.coticule.be it helped me tremendously as you can plan in advance how high your grind should be with the thickness of stock you are using for example everyone thinks that 1/4" stock is great for 8/8" but if you grind right up to the spine you are at around 14.3 degrees without tape which is no good and who wants to use 3-4 layers every time they hone not me!
Edward Brice

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Originally Posted by Dafonz6987

After u mentioned the tape I came straight home to one of the blades... I was really anxious and excited, had the problem I've been having really be as simple as bevel angle... immediately slapped 3 layers of tape and honed... edge was chippying... then i bread onifed the blade a bit and honed again... it was chipping... I went ahead and took pictures in hopes this would help....



Thanks! Will do! Any suggestion works!

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It is hard to tell without having the blade in hand, but it is possible you have not quite set the bevel yet?

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Originally Posted by EdBrice

How are you heat treating your blades? The reason I ask is that I have a digitally controlled electric kiln and I added a thermocouple temp probe and was shocked be the temp variation on the screen, it was 20 c off where the razors were sitting so I now have temp probes measuring in three different zones just to be sure. Also 1550f seems way to high for 01 that's about 843c and if your probe is off it could be way higher, I harden my blades at 805c for example.
Also have you snapped one of you blades or a test piece to have a look at the grain structure? That helped me a lot because I realised that something was off as I was getting chipping etc, so started looking at my heat treating procedure which once I mastered sorted it out.
Also another consideration is your tempering has to be spot on again you need precise temp control.
And as for blade angle I have found that it needs to be above 16 degrees or the edge can be too thin ,believe it or not some of my best shavers have been at 18-19 degrees.
Hope this helps a bit.
Ps there is a great bevel angle calculator on www.coticule.be it helped me tremendously as you can plan in advance how high your grind should be with the thickness of stock you are using for example everyone thinks that 1/4" stock is great for 8/8" but if you grind right up to the spine you are at around 14.3 degrees without tape which is no good and who wants to use 3-4 layers every time they hone not me!
Edward Brice

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I am using a kiln with a pyrometer, otherwise the kiln is analog lol... I broke one of my blades long ago and found a pretty nice grain structure, i actually was going to buy an upgraded kiln but after this whole fiasco I'm almost thinking against it... of course if the conclusion of all this is bevel angle then I may still get one lol

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Originally Posted by mainaman

It is hard to tell without having the blade in hand, but it is possible you have not quite set the bevel yet?

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Yeah I slept on it last night, I'm back at it again today... so I was thinking if I had a poor angle too acute of an angle to begin with how much would I need to bread knife off in order to get rid of it... maybe I'm over thinking it now, let me know what u think.... also I'll be trying again today...

Alrighty played around more with ur it yesterday, my wife went over it and explained the math to me. The razor that failed on me the first time all I needed was another piece of tape making it 4 and an angle of 17 instead of 16.

I then worked on the 8/8 blades and same thing, I actually turned it into a 7/8 and angle up to 17 and boom... in one sense I'm glad this was my mistake as I don't have to buy new kiln... but boy do I feel dumb, I remember being taught this stuff when I first started but I took that rule of thumb and figured I could leave it at that....

Well thanks gents thanks again! On the plus side since I was struggling to make these blades I now have 10 completed and 15 rough ground lmao... now time to go back to work :)

I would definitely get yourself a high temp thermocouple just so you can double check your temps, and as far as bevel angle you need to measure the thickness of the spine and also the measurement from the bevel to the the top of the grind line and plug it into the calculator on coticule.be and you will get the bevel angle, it also shows you what the angle will be with 1,2,3 layers of tape which is helpful.
In my experience you generally get a chippy edge when you have a high Rockwell hardness in conjunction with a really low bevel angle.
It's a bit like baking cakes eventually you will get your own recipe that works for you and your equipment and all will be good. Ed.

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Originally Posted by EdBrice

and as far as bevel angle you need to measure the thickness of the spine and also the measurement from the bevel to the the top of the grind line and plug it into the calculator on coticule.be and you will get the bevel angle, it also shows you what the angle will be with 1,2,3 layers of tape which is helpful.
In my experience you generally get a chippy edge when you have a high Rockwell hardness in conjunction with a really low bevel angle.
It's a bit like baking cakes eventually you will get your own recipe that works for you and your equipment and all will be good. Ed.

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The formula to calculate the angle was posted a few posts above and the OP already worked through the iterations.
Seems that he had success.

For sure! What you said earlier about the design of the razor needs to fit what I'm doing rather than having to use all that tape to get achieved! I really didn't take that into consideration when getting this second batch laser cut... thanks again!