Getting Started On Knife Sharpening Using the Harbor Freight 1x30" Belt Sander

[SpyderPhreak]

I've removed ALL of my guards, but left the table. I made this post elsewhere, but it's worth putting here too.

I like to rest my hands on the table, so I didn't remove it, but I did have to clear the area around where the belt passes through. If you didn't already, you'd also have to remove the black plastic side guard, remove the clear plastic top guard, and then carefully bend the upper part of the machine to create enough clearance for the belts to pass.

Even with all of that, every ScotchBrite belt that I've tried has been a bit on the small side, so they're really tight on the wheels, to the point that the motor will not start when switched on without a little assistance by hand.

Once they're running they work just fine, but you definitely want to be wearing PPE (as you should be anyway... ) as these belts shed a lot of crap that would otherwise get in yours eyes and nose.

Worn belts do cut more like a finer grit belt, so it can be useful to keep them around once they've worn to the point that they're not cutting as well. Just keep in mind that they'll heat up the edge a lot more like that versus a fresh belt of a finer grit.

 

[SpyderPhreak]

I also use the belt adjustment every time. This adjustment was probably the most confusing thing about the instructions, as to someone mechanically challenged like myself it didn't make sense that the same screw that moves the belt side-to-side also would tighten the belt. The secret is that the wheels are convex at the edge so that loosening or tightening also moves the belt side to side. If I can't get a tight belt all the way on without a struggle, I just turn the machine on and screw in the adjustment and it will center.

So, normal procedure:

1) screw out the adjustment screw all the way
2) remove belt
3) install new belt
4) screw in the adjustment screw two turns
5) turn machine on and check for center, if not centered, turn the screw one way or another until belt centers

Although you are supposed to turn the adjustment screw in after turning on the machine, I've found that I can just turn in the screw two turns and then turn on the machine and be centered or close to it.

I loosened my tensioner pulley pretty much all the way. Because the wheels are rounded and not flat, the belts will self-center, especially after a bit of use. This makes it a lot faster to change out belts since I don't ever need to mess with the tension.

 

[Cackmandu]

Spyder, a few questions on convexing a Mora scandi grind with this sander. I've seen a few of these and it looks like a great little project, but I have zero experience.

Just wanting some guidance on what belt to start with and the belt progression to get a polished finish and how long to sand with each belt.
Would you attempt this only with the carbon model or would it also work with a stainless model as well.

 

[postoak]

I hear a lot of guys say the Work Sharp will convex the edge. The 1 x 30 sander does NOT -- unless you want it to I guess. I'd also be interested in the technique for convexing with one. It doesn't seem to me that the belt is loose enough to do this without some additional technique.

 

[Bobby3326]

I hear a lot of guys say the Work Sharp will convex the edge. The 1 x 30 sander does NOT -- unless you want it to I guess. I'd also be interested in the technique for convexing with one. It doesn't seem to me that the belt is loose enough to do this without some additional technique.

It depends if you're using the platen then no you're not really convexing it , if your using the area above it then just like using a work sharp you're going to end up with a convex edge. That area has a lil slack in the belt and the slack is what creates the convex.

 

[bgentry]

Does a 1/16" wide convex bevel change cutting performance? Does it affect longevity, toughness, sharpness, or anything else? What if your edge bevel is 1/8" wide? Most EDC and western kitchen knives have bevels in this range or smaller.

Brian.

 

[postoak]

I mostly use the belt above the platten. There isn't much slack, at least with new belts. Visually, it looks like I'm producing a v-edge.

 

[Bobby3326]

Does a 1/16" wide convex bevel change cutting performance? Does it affect longevity, toughness, sharpness, or anything else? What if your edge bevel is 1/8" wide? Most EDC and western kitchen knives have bevels in this range or smaller.

Brian.

Honestly I can tell the difference on certain knives...The benchmade Bushcrafter is an example of one, when I convexed the edge on it I could immediately see and feel a difference in performance making feather sticks. There was allot less drag, and seemed to just glide thru the material, also would bite deeper into the wood more easily.

As far as edge longevity the difference was negligible, but as far as maintaining the edge stropping was noticeably more effective with a convex over the factory v-edge.

 

[SpyderPhreak]

Here's another post I made elsewhere, but want to put the info here too. It's about keeping your leather stropping belts clean.

FWIW, I've had the best results using a small square of some 120 grit sandpaper. Roll it into a tube about 3/4" diameter, and lightly drag that across the leather belt while it's running. This will remove any excess old polishing compound. Rolling up the sandpaper prevents you from putting too much pressure against the leather and damaging it.

In the future, don't let the belt get quite so loaded. Just a little bit of compound goes a long way, and gently clean the belt when you start seeing black streaks. HTH.

 

[SpyderPhreak]

Spyder, a few questions on convexing a Mora scandi grind with this sander. I've seen a few of these and it looks like a great little project, but I have zero experience.

Just wanting some guidance on what belt to start with and the belt progression to get a polished finish and how long to sand with each belt.
Would you attempt this only with the carbon model or would it also work with a stainless model as well.

A Mora is a quick knife to sharpen on this grinder! Almost as fast as most kitchen knives, due to the thinness. Care must be taken!!!

With thinner knives, I usually skip the 240 Trizact (A65) and start with one quick pass with the 600 Trizact (A30), and then proceed as usual to the 1,200 Norax (also a quick pass) and then to the strop. To get the convex edge, use the area of the belt halfway between the top roller and the top edge of the platen.

It won't be a large radius convex with such a small, thin edge, but it is still convex. The convex of a small edge like you will get on a Mora won't be easily visible, but it's there.

It doesn't matter carbon versus stainless steel. The belts don't care.

I hear a lot of guys say the Work Sharp will convex the edge. The 1 x 30 sander does NOT -- unless you want it to I guess. I'd also be interested in the technique for convexing with one. It doesn't seem to me that the belt is loose enough to do this without some additional technique.

I mostly use the belt above the platten. There isn't much slack, at least with new belts. Visually, it looks like I'm producing a v-edge.

It depends if you're using the platen then no you're not really convexing it , if your using the area above it then just like using a work sharp you're going to end up with a convex edge. That area has a lil slack in the belt and the slack is what creates the convex.

Bobby has it right. As I mentioned above, to convex your edge, use the area of the belt halfway in between the top roller and the top of the platen. To get a flat V-edge, use the area of the belt in front of the platen.

Keep in mind that the difference between a convex edge vs a v-edge will be pretty hard to see in a smaller edge on a thinner knife.

Does a 1/16" wide convex bevel change cutting performance? Does it affect longevity, toughness, sharpness, or anything else? What if your edge bevel is 1/8" wide? Most EDC and western kitchen knives have bevels in this range or smaller.

Brian.

In a thin, acute edge, you won't see too much difference between the two geometries. IMO, it stands out more as the angle grows more obtuse, up until you get to about 50-55 degrees inclusive. After that, it doesn't matter a whole lot.

Honestly I can tell the difference on certain knives...The benchmade Bushcrafter is an example of one, when I convexed the edge on it I could immediately see and feel a difference in performance making feather sticks. There was allot less drag, and seemed to just glide thru the material, also would bite deeper into the wood more easily.

As far as edge longevity the difference was negligible, but as far as maintaining the edge stropping was noticeably more effective with a convex over the factory v-edge.

Well said, that part I bolded is especially true! :thumbup:

 

[Bobby3326]

Thanks, the ease of maintenance is the main reason I convex most of my knives, especially ones used for Bushcraft tasks. As you said on thinner knives visually you can't really tell the difference between a v edge and a convex edge. However take identical knives one with a v edge the other a convex and start carving with em and you'll be able to feel the difference in how they perform.

 

[HeavyHanded]

Here's my current HF set-up. I swapped out the OEM motor for a reversible DC with variable speed controller. I used standouts on the platen and intend to replace it entirely with a full bridge from one end to the other. The extra bracing lets me run it either upright or horizontal.

My biggest beef is the drive wheel and idler pulleys have a bit too much crown, makes my coarse belts run with a high spot in the middle. I intend to whip up some extra hold down wheels on either end of the platen to deal with this, and/or shave some of the crown off the idlers and drive wheel. For the money its not a bad unit at all even with the factory motor, though slowing it down makes it a much nicer tool. A nice variety of belts can be had for it relatively cheap, so pretty versatile in that respect.

Not the biggest fan of the edges off the belt but they are plenty serviceable. I mostly use it for bevel setting and regrinds, doing the medium and fine work by hand. I often wet the rougher belts down with a tap from a sponge. If they need cleaning an old synthetic wine cork works great.

Edit to add:
Most used belts
60 and 120 Norton Blaze
320 and 800 SiC
leather belt with Flexcut Gold.

If using 100% HF, most often I skip the 800 and go right to the leather after 320.

More often I transition to waterstones after the 120 and finish on a Washboard.

 

[FOG2]

I too have the 1x30 and would love to slow it down. Can you give me an idea on the cost of your mod?

 

[NJBillK]

Heavy, I also was curious if you could get into what size DC motor and what size PWM you are running? What does "C" and "CC" stand for on your setup (lol)?

I have a 1x30 as well and I have been able to manage with it, but a PWM acting as a VFD would be a nice touch, especially considering I have a 1.5hp and 2hp motor just laying around.

The 2hp might be going into an eventual 2x72, but lack of funds prevents the purchase of wheels...

I currently run a Norton blaze 60, Trizact 120>240>400>medium Scotch-Brite belt.
(Not for sharpening, but for making knives.)

 

[HeavyHanded]

I too have the 1x30 and would love to slow it down. Can you give me an idea on the cost of your mod?

It was free...I stripped it off a piece of equipment that was about to be thrown away and had very light use. My guess is the motor and controller for it would likely be about $250 total but that's just a guess and off the shelf pricing. With a bit of digging could probably get away with a lot less.

Heavy, I also was curious if you could get into what size DC motor and what size PWM you are running? What does "C" and "CC" stand for on your setup (lol)?

I have a 1x30 as well and I have been able to manage with it, but a PWM acting as a VFD would be a nice touch, especially considering I have a 1.5hp and 2hp motor just laying around.

The 2hp might be going into an eventual 2x72, but lack of funds prevents the purchase of wheels...

I currently run a Norton blaze 60, Trizact 120>240>400>medium Scotch-Brite belt.
(Not for sharpening, but for making knives.)

I'm not sure of the HP, the motor doesn't have a plate. Based on the diameter I'm guessing it is around .75 or maybe 1HP max. The speed controller was stripped right out of the same machine, I just mounted it in another box, along with the Dr Frankenstein switch to reverse the inputs to the motor for bi-directional (two double throw switches linked by a bar).

"C" and "CC" are clockwise and counter. This motor was originally mated to an old drill press that ran 8" abrasive disks like a platter. It worked great but too many draw backs overall for what I needed. I might rebuild it with the motor the HF came with and give it to my daughter for grinding semi precious stones.

[video=youtube;r4N_j3c3MtM]https://www.youtube.com/watch?v=r4N_j3c3MtM[/video]

 

[SpyderPhreak]

Very nice setup HH!!! :thumbup: Great work! I have a similar DC motor and control board I tore out of a treadmill that I'll eventually turn into a nice grinder kinda like you've done. My plan is to weld up a sturdy steel frame and source my own wheels to make a 1x72 or maybe a 2x72 variable speed grinder.

 

[FOG2]

Thanks for the info. I need to find a free one like you did as thats to much money to spend on a cheap grinder imo.

 

[Cackmandu]

Well I'm off, got the grinder today, going to start practicing with the axes until the Trugrit belts arrive, happy sharpening!

One thing guys, I probably misstated what i was wanting to do with the Mora, I said convex when I should have said re-profile the blade itself. I am looking to smooth the top edge of the scandi grind out of the blade essentially rounding that edge to make the upper edge unnoticeable, hope that's not too confusing! So again I ask the question will this sander do that job?

 

[HeavyHanded]

Well I'm off, got the grinder today, going to start practicing with the axes until the Trugrit belts arrive, happy sharpening!

One thing guys, I probably misstated what i was wanting to do with the Mora, I said convex when I should have said re-profile the blade itself. I am looking to smooth the top edge of the scandi grind out of the blade essentially rounding that edge to make the upper edge unnoticeable, hope that's not too confusing! So again I ask the question will this sander do that job?

With the right belts it will make short work of it, but I'd recommend getting two Moras just in case you pooch the first one. One of my future projects is to turn a Mora classic into a wharncliff - lightly dull the existing edge and grind a new primary into the spine. Should turn out one wicked thin edge.

I did this regrind of a TOPS C.A.T. with Norton Blaze 60 and 120 belts on the HF - the 60 pulls off steel so fast and clean it makes little balls of steel wool. As it comes from TOPS is way too overbuilt, now perfect for EDU.

 

[Cackmandu]

Thanks for the follow up HH, I used the 80 belt that came with the sander on the axes and man you're right it takes the metal off, very impressed! You're right about the backup Mora (and who doesn't have a backup Mora), I mean even if I fudge it up, it'll be fun just seeing what the sander can do, and good practice! One other question above the 1200 grit and the green compound what belts make/grit or micron would you go with to take those fine scratches out and get that more mirrored finish? TIA