Community Sharpening Journal

[Coastal]

I have exactly this same belt sander question.

[vivi]

I may have missed it earlier in the thread, but what specific belt sander do you have? It seems like a really quick, handy way to sharpen once you get the hang of it. You're putting some really nice edges on these, and I similarly have drawers of older knives I'd love to put new edges on but don't really have the time/energy to put to the bench stones.

I'd be curious to hear any specific feedback you have on the make/model you own (or general advice on getting started) since most belt sander reviews aren't really geared towards knife sharpening.

https://www.harborfreight.com/1-in-x-30 ... 58359.html

https://www.harborfreight.com/power-too ... 69846.html

That's my setup.

[Josh Crutchley]

https://www.harborfreight.com/1-in-x-30 ... 58359.html

https://www.harborfreight.com/power-too ... 69846.html

That's my setup.

I recommend getting belts from Tru Grit abrasives because of the wide selection. They also have belts with butt joints instead of the lap joints found on most wood sanding belts at HF.
https://trugrit.com/product-category/ab ... size/1x30/

[endura3]

https://www.harborfreight.com/1-in-x-30 ... 58359.html

https://www.harborfreight.com/power-too ... 69846.html

That's my setup.

I recommend getting belts from Tru Grit abrasives because of the wide selection. They also have belts with butt joints instead of the lap joints found on most wood sanding belts at HF.
https://trugrit.com/product-category/ab ... size/1x30/

Awesome, thanks guys!

[TkoK83Spy]

I can see this turning into something bad. Guys destroying their knives left and right trying to follow vivi's lead! Definitely a totally different type of sharpening experience. I'd use cheap knives first to anybody considering it.

[endura3]

I can see this turning into something bad. Guys destroying their knives left and right trying to follow vivi's lead! Definitely a totally different type of sharpening experience. I'd use cheap knives first to anybody considering it.

Haha that's definitely a good plan. Not gonna try this on anything I wouldn't mind accidentally scratching to ****, messing up the temper on, or otherwise destroying until I'm pretty comfortable with the process.

[TkoK83Spy]

I can see this turning into something bad. Guys destroying their knives left and right trying to follow vivi's lead! Definitely a totally different type of sharpening experience. I'd use cheap knives first to anybody considering it.

Haha that's definitely a good plan. Not gonna try this on anything I wouldn't mind accidentally scratching to ****, messing up the temper on, or otherwise destroying until I'm pretty comfortable with the process.

I've messed up a couple myself in the past using a friend's years ago. Takes the right touch! Especially near the tip.

[Bemo]

I would add that if you get the leather strop belt, be super careful. While there's nothing like power stropping, that thing wants to grab your knife. A light, light touch please.

[kennbr34]

So I ordered a laser goniometer from Gritomatic and I am weirdly excited for it to get here. I have come to post about it here because I feel like this is the only place where there's a remote chance someone will understand my anticipation.

After years of estimating with calipers and trigonometry I am super curious to see how accurate my methods have been, how close to a desired angle my free hand result are, etc.

[Cycletroll]

I'm interested to see your results as well. Also if you find the tech worth the cost?

[Deadboxhero]

The CATRA hobbigoni shows more reflection data.

[Deadboxhero]

So I ordered a laser goniometer from Gritomatic and I am weirdly excited for it to get here. I have come to post about it here because I feel like this is the only place where there's a remote chance someone will understand my anticipation.

After years of estimating with calipers and trigonometry I am super curious to see how accurate my methods have been, how close to a desired angle my free hand result are, etc.

The laser, has no equal.

Be sure to take pictures and share.

[u.w.]

I may have missed it earlier in the thread, but what specific belt sander do you have?

https://www.harborfreight.com/1-in-x-30 ... 58359.html

https://www.harborfreight.com/power-too ... 69846.html

That's my setup.

I've got one of those as well, though mine is a greenish color.
I also have & use their (HF) blue 40 & 80 grit belts. Super handy tool!
I haven't really used mine for [knife] edges, except my lawn mower blade and hedge trimmers; but I do use it to shape/re-shape the blade shape(s) of my Spydies, among other knives. e.g. putting a point on my PacSalts/Salts/Enduras/Endelas/etc...
I keep a container of cold, if not icy, water next to me to dip the blade as I grind (sand).
Maybe I'll see how it does on [knife] blade edges at some point...

u.w.

[vivi]

I have the older green one too.

I bought it to reprofile Pacific Salt tips. Eventually I got more confident and tried other things with it like reoving the excessive jimping from manix xl liners, thinning the full primary grind of a cold steel srkc, and now using it on my edges.

They're very handy to have. After getting use to sharpening with it, I'm never going back to doing all my reprofiling by hand. Wish I started doing this sooner....saves so much time....

ps - I always keep a cup of ice water nearby to dunk the blades after each pass.

[vivi]

Cold steel SRKC. I gave it a 10 swipes per side on the sharpmaker fine rods at 20 degrees but otherwise same edge it shipped with. Felt a little thinner bte than the blacked out ones I bought maybe 2 years ago.

[kennbr34]

Well, I got the laser goniometer yesterday, and started to learn how to use it. There's a bit more of a learning curve than I expected, but I was figuring it out.

Measured a stock K294 Mule.

Then, as I measured many of my other knives, the battery finally started to drain and I went to replace it... And well... This is a bummer.

The battery was so tight in there it ripped the terminal right off the solder points on the board.

Waiting to hear from Gritomatic to see if they'll replace it. Sure hope so because I suck at soldering. But who knows if they'll pay to ship it back or not.

On the PLUS side I was able to confirm that my calipers + trig + angle wedge method was producing freehand bevels to basically exactly the angle I desired. On most knives I was dead on, others I was about 1 degree over. So at least that feels kinda nice.

[cabfrank]

That has to be defective. Things with replaceable batteries shouldn't break when you try to replace the batteries.

[Steeltoez83]

Stretch vtoku and polestar bd1n sharpened at 1k for toughness testing.

[kennbr34]

Well, good news is that I found a way to kinda-sorta fix the goniometer... Basically just stuck the battery housing back in there and shimmed it with a piece of aluminum foil. Still haven't heard back from Gritomatic, but I think I might end up modding it by supergluing the battery housing to the top of the case, so that I can just unscrew it and put a battery in, instead of worrying about knocking it off its solder points by sliding a battery in and out. I think they really should have designed it like that in the first place.




Anyway, here's a bunch of pictures of measurements of different blade and edge styles.

The first knife I tested was this scandi buffalo skinner. You can see how the beam is deflected into an elongated spot on the scale, which is because the bevel is a little convex. I'm not really sure if I should consider it 9 or 12 degrees per side, but I am guessing the latter. It makes more sense because the spot at the 9 degree makes are where the scandi bevel meets the flat of the blade, and as you can see it's a perfectly symmetric 9 on each side. On the other hand, one side is 12 degrees while the other is 13, which makes more sense to be the angle produced by me. Further images will also support this.




The next knife is a ESEE 3. I wanted to see how the coating would effect things, especially because the coating on ESEEs are particularly pourous.

I believe this is indicating that the primary blade grind angle is 5 degrees, and the edge angle is 20 degrees. I'll need to confirm with calipers later, but I remembered setting the blade on a 15 degree angle wedge to set the bevel, so that would make sense that it resulted in 20 degrees if the primary bevel is 5 degrees.





I also wanted to try a chisel ground blade, so here is a Cold Steel Safe Maker. Interestingly, it doesn't seem to show what the primary blade grind angle is. I'm not sure if maybe it's just obscured in the picture.





Here is a Kershaw Needs Work. This one has a relief bevel that I attempted to grind at 10 dps, and I attempted a 15 dps microbevel. The Needs Work's blade is also hollow ground, so this makes it particularly interesting to try to interpret these results.

From the 2-15 degree marks, the beam is very bright, but then it also extends very faintly to about the 25 mark. I think these results mean that the relief grind is at about 12-15 degrees (12 on one side, 15 on the other) and that the microbevel comes to about 25 degrees on each side.






Next up is a modded Izula with a convex grind and another microbevel. It seems like the microbevel makes a very faint reflection, which I suppose makes sense given its small size.






Next up is ESEE Izula. It's hard to see, but it also has a microbevel. I attempted the relief grind angle at 10 dps, and the microbevel at 15 dps.

Of course, when I did this, I used angle wedges that I placed the blade on. Given the 3.5 degree primary blade grind angle, that actually resulted in the intended edges being that much more obtuse than I had intended. So the relief angle is actually closer to 13.5 and the microbevel closer to 18.5, but there's also a very faint line extending through the 20-25 range so it isn't quite clear to me if I should consider that to be an even smaller microbevel on the main microbevel?






Here's a Kizer Sheepdog. This is a simple V bevel, but I wanted to see how the coating effected things again. This one is much clearer to see that one side is 12 degrees, and the other is 13, which make sense considering that I was aiming for 15 degrees per side by using an 11 degree and wedge to compensate for the primary blade angle, and expecting I would overshoot the angle.





Here's a Case Trapper blade which I forced a patina on. I don't think when I ground this one, that I realized I needed to account for the primary blade grind angle. Though considering it's a hollow ground, I'm not sure it would have helped. In any event, I remember using a 15 degree angle wedge.






This is a Kershaw 4150D, which is a San Mai blade with a VG1 core and clad on layers of 152N and 420J2. I was curious to see how the layers might effect the reflection, but it doesn't seem like it does much.

This is also a hollow ground blade, with a relief grind and microbevel.





Here's a Buck 119 that I reprofiled a long time ago as one of my first attempts at doing so, and you can see how the tip's bevel got away from me. I decided to see by how much, and so the first picture is the angle measured in the middle of the blade, and the second is measuring the bevel at the tip.

This left some quite interesting results to interpret. It seems that the hollow grind basically results in a 6 degree deflection, and the edge angle seems to be about 20-21 degrees per side.

The results at the tip are very similar, but it's interesting how the lines for the primary grind and the edge grind are not parallel. I think it's because I had to hold the belly of the tip in there at an angle, so instead of the laser crossing both planes at a perpendicular path, it's crossing them at a diagonal. Though, more surprising, is that the edge angle seems to still be about the same even though the bevel width is much wider there.





Meanwhile, here are some Mules. I mostly posted these to demonstrate the difference between one freshly reprofiled and beveled, and one that has been touched up a few times.

Both blades were placed on a 12 degree angle wedge. Adding in the ~2.5 degree primary blade angle, that means the edge angle should be 14.5 dps in a perfect world. Of course, there's more variance in that with free handing, so it's closer 14 on one side, and closer to 15 on the other.

Meanwhile, when I do touch ups, I don't use the angle wedges. I confirm the apex is in contact with the hone visually. So this seems to naturally lead to the angle being increased over subsequent touch ups. I knew this has been happening for a while, but was never quit sure to what extent.





Anyway, I hope this is interesting to some. I would love some help interpreting these results. Especially ones like the ESEE 3, Needs Work, the Izulas, and the San Mai Kershaws where they have faint lines extending into the 20-25 ranges of the scale. I don't know whether to disregard those or not. For example, the Kizer Sheepdog also has faint lines extending beyond very bright dots. So if I am to disregard the faint lines, at what faintness should they be disregarded?

[cabfrank]

Wow! Interesting for sure. A lot is beyond me, but great post.