Easy Reprofiling

Couple of good answers right there.
The best teaching always includes the "why".

rm41400 said:
yeah I’m gonna say it’s probably not your answer… 2000-3400 is it’s range with no water vs I don’t know maybe 200 rpm on the Tormek. Some alternatives to the Tormek might be worth looking at as mentioned above if you want to save$.

maybe others are more skilled with the bench grinder than I am but it’s not my go to for finished heat treated knives/ straight razors.

Another option is a dremmel. I did some rough work on some kamisori and regular straight razors and it was a nice balance between speed and finesse.

I was eyeballing a cheap harbor bench grinder with the dremmel attachment today. The slim profile of the handle would really allow you to work the length of the blade better.
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That really answered my question. The speed difference is what I was not aware of. That's a different kettle of fish.
The grinder with the dremmel attachment is one of the ones I was looking at too.
However, I already have a dremmel, I might give that a try for my "rough cuts"


Jason B. said:
Belt sanders and power tools in general will remove metal quickly which leads to over ground and under ground sections so I would not recommend it at all. Even if you were to send them to someone like me for machine sharpening I would expect you to understand that its a machine process done by hand and eye, and even with a skilled hand the grind lines can be good but never as good as hand ground on a stone. On high speed belt grinders care needs to be taken with harder steel, they will burn faster, just an fyi.

Waterstone type grinders that run at slow speed are GREAT for this task and eliminate all worries of heat build-up. I have yet to use a Tormek but have used Japanese style flat and angled waterstone grinders and they do a wonderful job but again it takes good grinding skills to use, things can go from "this is great" to "how do I fix this" real quick. Tormek's guide system can help but one pass on a slow wheel is still like 100 on a stone.

Regardless of the route you take I think abrasive choice will play a larger role if the blades are as hard as you say they are (64-66HRc). This means grinding will be unforgiving and any sort of hard bonded wheel is going to glaze over quickly. Softer waterstone type wheels will wear quickly and also glaze if containing an inferior abrasive (cheap wheels).

For hand sharpening a cheap diamond plate like the CKTG 140 grit diamond plate for $30 will rip through hard steel and is something I use often for very damaged bevels. If diamond stones are not your thing then a Shapton Glass 120 is one of the fastest and cleanest cutting waterstones on the market, PITA to keep flat but a monster on hard steels. I mention clean cutting because most waterstones of coarse grit get sandy or too muddy and wash out grind lines and tbh, are not made for that type of grinding.
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My plan had been to remove material with the grinder but to do a "finish cut" on a large stone to true up the edge.
I worked as a machinist for decades. I can do a fair job of drill sharpening on a grinder and am not too terribly bad at shaping steel on a belt sander. I've made a few knives.
Still, removing a fair amount of material while simultaneously dunking the blade isn't what I expected. I was hoping for a grinder which would nearly eliminate the overheating problem so I could get into the zone on the shaping.
Yours and the previous post have convinced me that that is not achievable with less expensive means.
The higher speed of a simple variable grinder coupled with the cheap wheels glazing quickly (and thus overheating more quickly due to rubbing) have ruled the cheaper grinders out in my mind. Even dressing the wheel regularly wouldn't be enough.
 
One thing I'd mention is that Knife Grinders Australia uses (in addition to Tormeks) variable speed grinders at their lowest speed, in conjunction with CBN wheels and their proprietary honing coolant, which is available for purchase, at least for now. Sadly, the head of KGA recently passed away, so I don't know what the future of his company is.

Honing coolant: http://knifegrinders.com.au/11Shop.htm
 
nevertakeadayoff said:
I love sharpening my knives. I hate wasting time.

I would always spend at least 45min getting a mirror edge using an EdgePro/Hapstone system. And because it took so much of my precious time, I would be selective with how and when I used it after I was done.

Now, with the Tormek, I no longer hesitate to use the blade because it's only 5 minutes on the Jap stone to get the edge back. Reprofiling a blade with the other stone is about 5 minutes, too. It's sickening to think about reprofiling a blade on the Hapstone. I hate wasting time. If you do, too, get something like the Tormek.
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Is the Japanese wheel for the Tormek hard enough to polish something like Maxamet? From what I understand, the standard grinding wheel isn't hard enough to reprofile your very wear-resistant blades? So with a T-4 you'd need to use CBN or diamond wheels for super steels? If so, that really starts to add up. OTOH, it's not that much more than some of the higher end fixed angle systems we're talking about.

Regarding fixed angle systems, we should be clear about something. It might take 45 minutes to get a mirror finish on a blade when you're sharpening at the existing edge angle, but it can take HOURS to reprofile a single knife from, e.g., 20° to 15°. And I mean, as much as 3-4 hours with a very tough steel.
 
3D Anvil said:
Is the Japanese wheel for the Tormek hard enough to polish something like Maxamet? From what I understand, the standard grinding wheel isn't hard enough to reprofile your very wear-resistant blades? So with a T-4 you'd need to use CBN or diamond wheels for super steels? If so, that really starts to add up. OTOH, it's not that much more than some of the higher end fixed angle systems we're talking about.

Regarding fixed angle systems, we should be clear about something. It might take 45 minutes to get a mirror finish on a blade when you're sharpening at the existing edge angle, but it can take HOURS to reprofile a single knife from, e.g., 20° to 15°. And I mean, as much as 3-4 hours with a very tough steel.
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The hardest steel I've sharpened is S30V. Never had Maxemet steel.

I believe the SG stone will do just fine on any steel. Press harder or take more time on it. More of the stone will wear, naturally. I use a 400grit diamond stone to flatten it out and the SB-650 fine side to keep it fine. I'm not interested in the diamond stone they just released for the T4 because I don't know how to flatten it out like I do with the SG/SJ.

The SJ is polishing stone, it is soft. I flatten it out with a 1000grit diamond stone at least once every time I use it (which also cleans it). I also press really hard on it with the blade.

I've had the Tormek for 2 months. I feel like I've got it dialed in. I don't give a shit what I do with blade because it is sooo easy to get it back with a mirror finish.
 
nevertakeadayoff said:
I'm not interested in the diamond stone they just released for the T4 because I don't know how to flatten it out like I do with the SG/SJ.
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The beauty of the diamond and CBN wheels is that you never have to flatten them, in addition to them cutting virtually any steel.
 
davek14 said:
My plan had been to remove material with the grinder but to do a "finish cut" on a large stone to true up the edge.
I worked as a machinist for decades. I can do a fair job of drill sharpening on a grinder and am not too terribly bad at shaping steel on a belt sander. I've made a few knives.
Still, removing a fair amount of material while simultaneously dunking the blade isn't what I expected. I was hoping for a grinder which would nearly eliminate the overheating problem so I could get into the zone on the shaping.
Yours and the previous post have convinced me that that is not achievable with less expensive means.
The higher speed of a simple variable grinder coupled with the cheap wheels glazing quickly (and thus overheating more quickly due to rubbing) have ruled the cheaper grinders out in my mind. Even dressing the wheel regularly wouldn't be enough.
Click to expand...

So, knowing you understand grinding and abrasives Ill say this. I use a kalamazoo 1x42 with Norton Blaze 120 ceramic grinding belts, its a slower speed grinder that is in the quality/affordable range. If you worked as a machinist you should have no problem using this and grinding bevels all day without even making the blades warm. The platen needs to be trimmed and I remove the top guard but besides that it is good to go. In your case I would probably recommend 80 grit belts and then maybe some Silicon Carbide stones. Silicon carbide would more easily handle the hard steel. Was never a fan of the norton brand sic stones so maybe the gritomatic sic stone? have not used them but they look good. As for belts, I can do about 20 cheap kitchen knives before the belt starts to dull and about 20 more and it needs changing. I would expect 6-8 very hard steel knives at best per belt.
 
Jason B. said:
So, knowing you understand grinding and abrasives Ill say this. I use a kalamazoo 1x42 with Norton Blaze 120 ceramic grinding belts, its a slower speed grinder that is in the quality/affordable range. If you worked as a machinist you should have no problem using this and grinding bevels all day without even making the blades warm. The platen needs to be trimmed and I remove the top guard but besides that it is good to go. In your case I would probably recommend 80 grit belts and then maybe some Silicon Carbide stones. Silicon carbide would more easily handle the hard steel. Was never a fan of the norton brand sic stones so maybe the gritomatic sic stone? have not used them but they look good. As for belts, I can do about 20 cheap kitchen knives before the belt starts to dull and about 20 more and it needs changing. I would expect 6-8 very hard steel knives at best per belt.
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Wow.
Maybe I'm missing something here.
You consider ~$300 affordable?
I just did a quick search. I have to assume I'm missing something.

I do like the fact that you have mentioned a belt sander and not a grinder, as I would indeed find avoiding an uneven edge on a belt sander easier.
 
davek14 said:
Wow.
Maybe I'm missing something here.
You consider ~$300 affordable?
I just did a quick search. I have to assume I'm missing something.

I do like the fact that you have mentioned a belt sander and not a grinder, as I would indeed find avoiding an uneven edge on a belt sander easier.
Click to expand...
Most professional belt grinders that are for knives/sharpening are in the $3000-$5000 range. These are usually 2x72 inch belt grinders with various available attachments. They also grind much smoother, have variable speed, higher torque and just a better tool.. but you pay for it.
 
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