Thinning without permanet cooling

[LukasFromGer]

Sorry beforehand for any grammatical mistakes, Im German and its a bit difficult to translate it well enough.

As a beginner, you read far too much information and in the end you don't really know what is right, what must be or what can be. I plan to buy this belt sander in the near future, since it fits perfectly in my small space I have available, the price is in my budget and I only heard good things about Pawel. Unfortunately, the belt length is uncommon in Germany, but this seems to be the best you can get under 500€.

However, I make only kitchen knives, and those need to be thinned out. Now I have often read that without cooling the temper of the steel is destroyed. My previous knives (3-4 in number) I have cooled and thinned with a ceramic belt and repeatedly immersed in water. When it was too hot for my fingers or I felt it was starting to get too warm, I would dip them in water.

With the belt sander, it seems that the only way to install a rotary control/frequency converter is through extreme detours, and although I am a trained electrician, I have no idea about this and don't trust myself to do it (Horay to the great apprenticeship system in Germany). Let alone to lay new cable if additional residual current circuit breaker or circuit breakers are necessary. I also do not have a 3 phase power outlet available, because I am a tenant and can't (not allowed to) rewire. This means I would be thinning out at full speed with the above mentioned belt grinder.

My question: Is periodic immersion in water enough? Is there any way to determine whether you have destroyed the temper by making it too hot?

 

[Crag the Brewer]

Here in US we can get single phase in, 3 phase out from our electric controls/drives.
Also you Could look at pulleys for lowering your speed.



You are going to get different opinions, but many people have been making knives for many years the way you want.

Don't let the steel get warm. Dip in water Every pass.
Perhaps hand sharpen on a stone with water after grinding your bevels.

* If you destroy the temper edge, it will be weaker.

 

[LukasFromGer]

Might be lost in translation, but we either have single phase 230V (phase, neutral and protective earth) or 3 phase 440V (phase 1, 2 and 3 plus neutral and PE)

The sharpening is done with stones. But the im talking specifically about the bevels.

But since you mention many people do it with the dipping in water method, I'm gonna assume it's sufficient

 

[Stacy E. Apelt - Bladesmith]

You can purchase a VFD variable Frequency Device. It takes normal single please current and converts it into variable Hertz 3-phase. You will have to change the motor to 3=phase (or order it with 3-phase.

The reason budget grinders are lower price is they leave off the more expensive features like VFD and 3-phase motors. Chinese VFD's can be bought at reasonable prices.

The other solution is to install a water drop om the belt to keep it wet (use waterproof belts). Ot even better, to install a cheap clone of the Kool-mist system. It uses water and air to make a very cooling spray right on the belt where you grind. You would need the Kool-mist sprayer setup and a reasonable air compressor.

 

[LukasFromGer]

You can purchase a VFD variable Frequency Device. It takes normal single please current and converts it into variable Hertz 3-phase. You will have to change the motor to 3=phase (or order it with 3-phase.

The reason budget grinders are lower price is they leave off the more expensive features like VFD and 3-phase motors. Chinese VFD's can be bought at reasonable prices.

The other solution is to install a water drop om the belt to keep it wet (use waterproof belts). Ot even better, to install a cheap clone of the Kool-mist system. It uses water and air to make a very cooling spray right on the belt where you grind. You would need the Kool-mist sprayer setup and a reasonable air compressor.

The problem with the VFD is that you need a smal electrical cabinet with the new breakers etc. and to be honest, I just dont want to put that much extra work. And as far as I have seen it's a bit troublesome to get the VFD working on the 1phase motor/variant of the belt grinder I want to buy (Other german forums also talked about it).

The mist variant is something which was just suggested to me as well. Buying a cheap air compressor and the "mistifyer" on Aliexpress seems reasonable

 

[Cushing H.]

The problem with the VFD is that you need a smal electrical cabinet with the new breakers etc. and to be honest, I just dont want to put that much extra work. And as far as I have seen it's a bit troublesome to get the VFD working on the 1phase motor/variant of the belt grinder I want to buy (Other german forums also talked about it).

The mist variant is something which was just suggested to me as well. Buying a cheap air compressor and the "mistifyer" on Aliexpress seems reasonable

I am surprised this is the case. In my case, i have (US) 120 volt single phase plugs with just ordinary 20 amp breakers in my wall box). The VFD plugs into the 120 v single phase socket, and the conversion to 3 phase (for output to the motor) is done inside the (relatively small) VFD itself. No rewiring of the house supply needed. I would be surprised if there are not VFDs that will accept 220v input and do the same conversion to 3phase output (stacy would know about this i think)

Btw - your english is excellent!

 

[Ken H>]

As long as the blade doesn't get hot enough to burn your bare hand, and there is no color change on the blade the temper shouldn't be affected at all. Sounds like you're doing a good job. We're talking about a flat profiled blade here, not the sharpened edge.

 

[Lorien]

^a lot of cutlery friendly steels temper around 175C, so dunking in water when grinding primary bevels is really just to keep from burning up your fingers- in my experience
hand sharpening is probably you're only good, dependable option if you have a machine like you described

 

[Stacy E. Apelt - Bladesmith]

There may be some confusion what a VFD is. It is a small box that is filled with electronics. It has a power cord, and terminals for three-phase output. On the outside it has a dial and a few switches. You plug it into a standard wall socket (for me that is 120VAC, 20 amps) and hook the three-phase motor of the grinder to it. From there all you do is turn the VFD on and set the desired speed. there is no electrical cabinet or special breakers, wires or power lines as it only needs normal shop voltage and current. Without knowing the power type in your area I can't tell you which VFD you want, but the local makers should be able to tell you the model and number. The VFD is usually placed on a post at the grinder, or sometimes on the wall next to it.

You should order the grinder without the motor and then add a VFD/motor package. This eliminates almost all wiring and setup. EBay has them as well as Amazon and lots of other places.

 

[JoeBusic]

Sorry beforehand for any grammatical mistakes, Im German and its a bit difficult to translate it well enough.

As a beginner, you read far too much information and in the end you don't really know what is right, what must be or what can be. I plan to buy this belt sander in the near future, since it fits perfectly in my small space I have available, the price is in my budget and I only heard good things about Pawel. Unfortunately, the belt length is uncommon in Germany, but this seems to be the best you can get under 500€.

However, I make only kitchen knives, and those need to be thinned out. Now I have often read that without cooling the temper of the steel is destroyed. My previous knives (3-4 in number) I have cooled and thinned with a ceramic belt and repeatedly immersed in water. When it was too hot for my fingers or I felt it was starting to get too warm, I would dip them in water.

With the belt sander, it seems that the only way to install a rotary control/frequency converter is through extreme detours, and although I am a trained electrician, I have no idea about this and don't trust myself to do it (Horay to the great apprenticeship system in Germany). Let alone to lay new cable if additional residual current circuit breaker or circuit breakers are necessary. I also do not have a 3 phase power outlet available, because I am a tenant and can't (not allowed to) rewire. This means I would be thinning out at full speed with the above mentioned belt grinder.

My question: Is periodic immersion in water enough? Is there any way to determine whether you have destroyed the temper by making it too hot?

Tell Pawel to change the motor to 3 phase and connect a VFD. It's a little over 500€ and it will make you happy. VFD is gold here.
Periodic immersion in water is OK. Just as it gets thinner, cool it after every pass. If it doesn't burn your fingers, it's OK. Just take care of the edge. When thin it can burn before your fingers.

 

[LukasFromGer]

Tell Pawel to change the motor to 3 phase and connect a VFD. It's a little over 500€ and it will make you happy. VFD is gold here.
Periodic immersion in water is OK. Just as it gets thinner, cool it after every pass. If it doesn't burn your fingers, it's OK. Just take care of the edge. When thin it can burn before your fingers.

So basically this one? I mean it also has the advantage to turn it. But the belt length is still not common. I just took a look and VFDs for 1phase 230V and 1,1kW are stupidly expensive

[...]

Yeah you are right, I talked shit. There are VFDs for 230V, Pawel even sells them. I was somewhere else with my head and thinking (I was thinking about CEE connectors, 440V). The problem with the belt grinder I want to buy seems to be the capacitors for the motor. In another German forum someone bought exactly that grinder and also wanted to install a VFD, but got basically told "It's difficult since the way your motor is connected/build with the capacitors, it gets tricky". So the suggestion to get it without the motor would be the best case and getting a motor & VFD combo seperately.
Ill have to see. Im limited with my budget, but even more so with the available space. And I still need to get a work bench, so far I only have some cheaper heavy duty shelves changed to be a workbench

 

[JoeBusic]

Chinese VFD's are cheap. CCa 50€. Belts are not a problem. There are people who makes them in size.

 

[Stacy E. Apelt - Bladesmith]

The biggest problem you face is your budget. You want to spend 500€ on a grinder, but that is just barely enough for a low-level grinder. Variable speed and a three-phase motor will around 250€ add to that.
Your best plan would be to save a few more Euros and order the Pawel grinder with the three-phase motor and VFD setup already installed. You will never regret this decision. It takes the same space, draws the same power, but it can be slowed to a crawl or run at really fast speed for hogging a knife profile and bevels.

 

[JoeBusic]

The biggest problem you face is your budget. You want to spend 500€ on a grinder, but that is just barely enough for a low-level grinder. Variable speed and a three-phase motor will around 250€ add to that.
Your best plan would be to save a few more Euros and order the Pawel grinder with the three-phase motor and VFD setup already installed. You will never regret this decision. It takes the same space, draws the same power, but it can be slowed to a crawl or run at really fast speed for hogging a knife profile and bevels.

I second that. The grinder is the center of the universe.

 

[Blankblank]

Sorry beforehand for any grammatical mistakes, Im German and its a bit difficult to translate it well enough.

As a beginner, you read far too much information and in the end you don't really know what is right, what must be or what can be. I plan to buy this belt sander in the near future, since it fits perfectly in my small space I have available, the price is in my budget and I only heard good things about Pawel. Unfortunately, the belt length is uncommon in Germany, but this seems to be the best you can get under 500€.

However, I make only kitchen knives, and those need to be thinned out. Now I have often read that without cooling the temper of the steel is destroyed. My previous knives (3-4 in number) I have cooled and thinned with a ceramic belt and repeatedly immersed in water. When it was too hot for my fingers or I felt it was starting to get too warm, I would dip them in water.

With the belt sander, it seems that the only way to install a rotary control/frequency converter is through extreme detours, and although I am a trained electrician, I have no idea about this and don't trust myself to do it (Horay to the great apprenticeship system in Germany). Let alone to lay new cable if additional residual current circuit breaker or circuit breakers are necessary. I also do not have a 3 phase power outlet available, because I am a tenant and can't (not allowed to) rewire. This means I would be thinning out at full speed with the above mentioned belt grinder.

My question: Is periodic immersion in water enough? Is there any way to determine whether you have destroyed the temper by making it too hot?

Something i do to get my knives that last little bit of thinness. Is i switch to thinning on stones after grinding. It also reveals any low spots from the grinder. And allows me to adjust the amount of convexity i add more precisely. Also, not having to worry about .2mm thick bte blades from heating up on the grinder is another benefit (even going really slow it can heat up quickly)

 

[FredyCro]

Too much pressure and dull belts TOGETHER with speed burn the edge. Your grinder runs 19 m/s which I would say is normal (upper) medium speed. Run that with medium pressure and fresh belts and dip and there will be no burning the edge. Take care not to pull the tip completly over the belt but stop in middle. Smaller grits heat up the blade faster. Leave the tip thicker and work on at it last, deeping frequently in water and using minimum amount of pressure.

 

[LukasFromGer]

The biggest problem you face is your budget. You want to spend 500€ on a grinder, but that is just barely enough for a low-level grinder. Variable speed and a three-phase motor will around 250€ add to that.
Your best plan would be to save a few more Euros and order the Pawel grinder with the three-phase motor and VFD setup already installed. You will never regret this decision. It takes the same space, draws the same power, but it can be slowed to a crawl or run at really fast speed for hogging a knife profile and bevels.

Yeah I see that now and you are right. I also need to spend money on a adequate workbench with a wood plate, some better way of dust removal than my cheap workshop vacuum I have now and some other tools which I collected over the years and are pretty shitty. I think I'll save for the second grinder I quoted, which is 500€ and can turn sideways. And directly buy the VFD + emergency stop combo from Pawl.

Something i do to get my knives that last little bit of thinness. Is i switch to thinning on stones after grinding. It also reveals any low spots from the grinder. And allows me to adjust the amount of convexity i add more precisely. Also, not having to worry about .2mm thick bte blades from heating up on the grinder is another benefit (even going really slow it can heat up quickly)

I might get flak for this but I absolutely hate using whetstones. I have one with 240 grit and one combo of 1000/6000 but I never really got the hang of it and it's not mediating for me at all. Just annoying. For flattening with stones I would need to read into and buy like a flattening stone or something. But generally you are right, using them is the safest bet and shows where you put in low spots.

 

[LukasFromGer]

where are you in Germany? I travel to Hamburger for work every so often and um. Honestly you can ask the guy above, Blankblank , I do actually help people out financially if they have enough drive so. I don't know you but If you need um. I have a lot of random parts and stuff etc, my point is I would have no problem meeting up with you and assisting in some way possible. Really don't. It's just dependent on where you are in Jermany and entirely up to you.

Im actually located in near Bremen so not far off. Although I do appreciate your help and will remind myself of it, I think your time would be better spend on elsewhere. I need to get the basics of knife making first and some training for myself. I think the feedback here was great but also helped to grasp that I need to save up way more money/budget and start basically at the bottom. Right now I only worked with extremly cheap tools and at the earliest with the a file jig like the one from Gough (?), but that's too time consuming for the spare time I have after work.

Oh I laughed at him for hours (Were kinda friends) it should be done on a grinder but it requires a pretty special attachment that is a belt backed "rotary platen" which I have from Beaumont (shit company btw), but it does work for very slight convextivity? Pretty well. Its this. It gives you the ability to do a lot actually..not cheap however.

It allows tension of the belt via a very shit system and on mine they have grade 8 bolts on the wheels and 5 on the steel-alum interface ahaha. Backwards.

I dont quite get how that attachment helps thinning Also adding attachment after attachment and tool after tool just extends the list of stuff I need to buy. Combining the stuff which people here and on the german knife forum suggested puts me well over 1000€, and that will take some time to get to.
It's kinda funny how you get from like 20€ of material and tools for a file jig which is great for the first few times/knives, to like 1000-1500€ if you want to upgrade. But money well spend and this is the first hobby I found myself really interested in

 

[LukasFromGer]

Chinese VFD's are cheap. CCa 50€. Belts are not a problem. There are people who makes them in size.

I would also need to add an emergency stop and put both in a small dust/water proof cabinet. But I found a german custom belt website which is not unreasonably expensive, so that and if nothing helps, "importing" belts from Poland directly works too

 

[LukasFromGer]

[...]

While it took me 131k, A literal top of the line setup for you would be around 7,500$ USD. Medium - 5k. (You want to do it right but cheap)

I do greatly appreciate it and dont really have a problem with meeting someone, am almost 30 myself. The thing is Im just in the progress of setting up everything and buying more and better tools. But you should have send your contact infos to me directly via message I think. Putting your phone number is kinda risky.

and investing like several thousand euros is just way out of my league at the moment and even so in the near future. Especially with everything else getting more expensive.

I might contact you via discord though if I have anything further to ask, since it's the easiest and quickest way!