Regrinding Knives?

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Dazen
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Regrinding Knives?

Postby Dazen » Fri Mar 06, 2020 6:28 am

I see a lot of you that regrind your blades and I was wondering what equipment y’all use? Is this something that I can just pick to do slight modifications, or do I need a full shop set up?

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Evil D
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Re: Regrinding Knives?

Postby Evil D » Fri Mar 06, 2020 6:35 am

Depends on what you mean by regrind. If you mean a full blade grind regrind, I have a knifemaker who does them for me. If you mean tweaking the shape of blades and regrinding the spine and such I do that myself usually with a Dremel and/or a mini bench grinder.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
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emanuel
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Re: Regrinding Knives?

Postby emanuel » Fri Mar 06, 2020 9:12 am

I use a small belt grinder, 1x30 belt 375w. Nothing fancy or expensive, just some German brand that had good reviews on Amazon, but if you're american it seems like the one made by Harbor Freight is very popular. You can find these made by different manufacturers and they're all in the range of 60 to 100 dollars. For small blades it's amazing. Some good quality ceramic belts and it will regrind even Maxamet or other ultra hard steels relatively quickly since there isn't that much material to be removed to begin with, so even this low power bee can do work.

Worth every penny imho, what I might add is to be careful for the first 5-10 regrinds, use it on some inexpensive, cheap pocket knives. You will make a few mistakes, biggest one being grinding the spine thinner, which you don't really want to do :D Also, cool your knife every few seconds, and don't be cheap on the belts. When they stop cutting properly, change them. Not only will this save up time, but also cut the steel instead of just burnishing and overheat the blade. This is even more important on very hard steels (63hrc and up). If you're still not convinced, 1-2 knives regrinded by a knifemaker cost as much as this entire setup...

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Re: Regrinding Knives?

Postby Larrin » Fri Mar 06, 2020 9:22 am

Regrinding knives is not an easy thing to do. It requires quite a bit of practice.
http://www.KnifeSteelNerds.com - Steel Metallurgy topics related to knives

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emanuel
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Re: Regrinding Knives?

Postby emanuel » Fri Mar 06, 2020 9:26 am

Larrin wrote:
Fri Mar 06, 2020 9:22 am
Regrinding knives is not an easy thing to do. It requires quite a bit of practice.
Indeed, but practice has to start from somewhere. It isn't easy at first but not hard to learn. These cheap and low power grinders are a great start for a casual consumer. That is if he wants to learn, if not and money isn't an issue, he can just send his knives to people that do these services and pay $50-100 per knife.

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Dazen
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Re: Regrinding Knives?

Postby Dazen » Fri Mar 06, 2020 9:31 am

Evil D wrote:
Fri Mar 06, 2020 6:35 am
Depends on what you mean by regrind. If you mean a full blade grind regrind, I have a knifemaker who does them for me. If you mean tweaking the shape of blades and regrinding the spine and such I do that myself usually with a Dremel and/or a mini bench grinder.
I guess I mean regrinding the spine. Depending on how that goes I may take it a bit further.

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emanuel
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Re: Regrinding Knives?

Postby emanuel » Fri Mar 06, 2020 9:35 am

Either way, make sure you do these changes on some knives you don't care about first, or you might regret it.

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Dazen
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Re: Regrinding Knives?

Postby Dazen » Fri Mar 06, 2020 9:35 am

emanuel wrote:
Fri Mar 06, 2020 9:12 am
I use a small belt grinder, 1x30 belt 375w. Nothing fancy or expensive, just some German brand that had good reviews on Amazon, but if you're american it seems like the one made by Harbor Freight is very popular. You can find these made by different manufacturers and they're all in the range of 60 to 100 dollars. For small blades it's amazing. Some good quality ceramic belts and it will regrind even Maxamet or other ultra hard steels relatively quickly since there isn't that much material to be removed to begin with, so even this low power bee can do work.

Worth every penny imho, what I might add is to be careful for the first 5-10 regrinds, use it on some inexpensive, cheap pocket knives. You will make a few mistakes, biggest one being grinding the spine thinner, which you don't really want to do :D Also, cool your knife every few seconds, and don't be cheap on the belts. When they stop cutting properly, change them. Not only will this save up time, but also cut the steel instead of just burnishing and overheat the blade. This is even more important on very hard steels (63hrc and up). If you're still not convinced, 1-2 knives regrinded by a knifemaker cost as much as this entire setup...
Thank you for the info! I’ve got a lot of older knives to practice on.

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emanuel
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Re: Regrinding Knives?

Postby emanuel » Fri Mar 06, 2020 10:00 am

Dazen wrote:
Fri Mar 06, 2020 9:35 am

Thank you for the info! I’ve got a lot of older knives to practice on.
If you really want to try this yourself, have a look at some youtube videos about it. Seeing how it's done will help way more than anything you'll find written anywhere and give you a mental foundation on how to start your trial.

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Re: Regrinding Knives?

Postby Nate » Fri Mar 06, 2020 5:18 pm

I've had a 1x30 from Harbor Freight for a few years and would echo the other comments in general. I rigged up a simple drip line with a micro valve for fine adjustment. This low-tech water cooling has a lot of advantages.

While I've had a lot of success with it, the HF 1x30 is wicked fast and not very forgiving. Something different I've considered recently are the various angle grinder belt sander attachments on the market. With a variable speed grinder hooked up I could see this working well. However I'm a little concerned able the exact size(s) of the belts and the availability of high-quality ceramic belts in what may be odd sizes. If I can confirm a specific model uses the same belts as the WorkSharp belt sander attachment, I'd probably jump on it, but so far I haven't found much info on people using these for knifemaking or mods.

Here is one example of these attachments (not an endorsement):

https://usa-m.banggood.com/Drillpro-Ang ... gJL4vD_BwE
:spyder:

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Re: Regrinding Knives?

Postby Knivesinedc » Fri Mar 06, 2020 11:04 pm

Nate wrote:
Fri Mar 06, 2020 5:18 pm
I've had a 1x30 from Harbor Freight for a few years and would echo the other comments in general. I rigged up a simple drip line with a micro valve for fine adjustment. This low-tech water cooling has a lot of advantages.

While I've had a lot of success with it, the HF 1x30 is wicked fast and not very forgiving. Something different I've considered recently are the various angle grinder belt sander attachments on the market. With a variable speed grinder hooked up I could see this working well. However I'm a little concerned able the exact size(s) of the belts and the availability of high-quality ceramic belts in what may be odd sizes. If I can confirm a specific model uses the same belts as the WorkSharp belt sander attachment, I'd probably jump on it, but so far I haven't found much info on people using these for knifemaking or mods.

Here is one example of these attachments (not an endorsement):

https://usa-m.banggood.com/Drillpro-Ang ... gJL4vD_BwE
Ha. I can definitely agree with you on the HF belt sander. It is fast and will pull a blade away from you quickly if you don't keep movements smooth and light. However it is also a workhorse. I've been using mine for the last 3 years or so and it always gets the job done. After learning on the HF sander, using variable speed tools is a breeze haha. I have been considering investing in a higher quality model at some point but my ol HF gets the job done every time so I've never seriously looked into upgrading.

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Re: Regrinding Knives?

Postby Evil D » Sat Mar 07, 2020 4:34 am

Doing a proper blade regrind takes some serious skill. Big Chris did a Military for me and he was so precise that he didn't need to reapply an edge bevel and the amount of bevel he left was so small it would take a very stable hand to achieve.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
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Re: Regrinding Knives?

Postby Jazz » Sat Mar 07, 2020 8:49 am

I use diamond files, Dremel with diamond bits, sharpening stones, sandpaper in varying grits, and either polish with a felt wheel, or just use my strop, if the spine will work on that.

My most recent slight mod. Dragonfly spine point...

Image
- best wishes, Jazz.

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Re: Regrinding Knives?

Postby kwakster » Sat Mar 07, 2020 10:18 am

Or you can do it by hand.
This user Spyderco Stretch laminated blade with HAP40 core @ 63-64 HRC had an edge measuring between 25-30 degrees inclusive.
The old & a bit pitted apex was removed on a Chinese 3000 grit diamond plate to create a very narrow and continuous light reflection all along the edge, then the blade was thinned by hand using 1 full sheet of 400 grit wet & dry on a semi-hard rubber backing with WD40 as a lubricant, right up to the still flattened edge, and then refined & apexed to an ever so tiny burr on 1/2 sheet of 1000 grit wet & dry on the same backing with again WD40.
The burr was then carefully stropped off on a piece of hard cardboard with a bit of 1.0 micron mono-diamond paste.
The new edge measures ~20 degrees inclusive and is reverse chest hair whittling sharp with just a bit of tooth.

Before:

ImageImage

After:

ImageImage

ImageImage

ImageImage

ImageImage

Image

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Dazen
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Re: Regrinding Knives?

Postby Dazen » Sat Mar 07, 2020 1:42 pm

So y’all suggest something like this for $50, or spend roughly $150 for a variable speed one?

https://www.harborfreight.com/power-too ... 61728.html

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Re: Regrinding Knives?

Postby araneae » Sat Mar 07, 2020 2:36 pm

I have the older version of that HF model, my first burned up after 2 years, this one's probably on year 5.
So many knives, so few pockets... :)
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Just got:Rex 45 Para 3 LTWT, Harrier 2 LTWT

The "Spirit" of the design does not come through unless used. -Sal

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Re: Regrinding Knives?

Postby Stuart Ackerman » Sat Mar 07, 2020 3:02 pm

Everything you do to steel, affects it.

CAREFUL grinding with LOTS of cooling is required, otherwise the temper will be lowered at the thinnest parts, namely the edge and tip.

I have access to a Rockwell tester at work, and it "tells the story" when you have overheated the edge. :(

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Re: Regrinding Knives?

Postby Pancake » Sun Mar 08, 2020 3:35 am

Guys, do you know someone in Europe that could do a regring?
If you don't want to make a advertising for someone in this thread just PM me.
In the pocket: Chaparral FRN, Native Chief, Police 4 K390, Pacific Salt SE, Manix 2 G10 REX45
On belt: Bow River, Waterway

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Re: Regrinding Knives?

Postby PineyBoy » Sun Mar 08, 2020 4:44 pm

I started with a homemade grinder in metals class around '59 and ended up with a Grizzley 72" and a few smaller. My personal was a custom made 72. I really miss it.

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Re: Regrinding Knives?

Postby jpm2 » Sun Mar 08, 2020 5:30 pm

I use stones, files, and sandpaper... nothing powered... no chance of altering the temper.
It's slow, but I'm patient.


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