Harbour Freight 1" x 30" belt sander: initial impressions and questions

"Interesting you should mention fatigued metal on the edge. I've had some experts recently tell me that's not an issue with knife edges. They claim there isn't enough plasticity in a hardened edge to induce fatigue. Obviously, I believe otherwise or I wouldn't have mentioned it. "

I'll have to bone up on fatigue. What is usually called fatigue in knives I tend not to think of as the technical definition of fatigue. For knife edges, I just figured it was meant that the edge had deformed a few times and was more likely to break off, like bending a coat hanger back and forth. My technical definition of fatigue: incremental crack movement every time the cyclic load goes above a critical level. I dont really see this being possible at the very edge of a knife, but I havent looked. I tend to think of fatigue in terms of thousands of cycles, sometimes millions, although there is low cycle fatigue. I am just not that familiar with that particular type.
 
Jerry Hossom said:
There are some great pix in the Verhoeven paper, showing the power of buffing and how much steel it can remove. It doesn't matter how you do it, whether a buffing wheel or a leather belt, polishing compound cuts through steel VERY efficiently and can round over that nice sharp edge in a heartbeat. See page 33. That's after just 2-4 passes.
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Thanks, Jerry. If there's any particular diamond compound you prefer, you might drop a post. Right now, my final finisher is 0.5 micron chromic oxide. It doesn't seem to make much headway on the the tiny carbides right on the edge. I can see their rainbow glint under the 'scope.

Chop hanging hairs - easy. Split hairs - never could do it.
 
I'm not sure what steel you're using, but at 40x you're not going to resolve the carbides in most steels. You can also get that rainbow diffraction from very fine scratches on any reflective surface.

I use that same 0.5 micron chromium oxide compound that you use on my leather belt, but only after the blade edge is close to polished at 15 microns. If it's a small knife, blade 3" or less, I usually go to 5 microns before the leather strop. I'm honestly not sure that very fine polishes add much. I got pretty much the same results with a generic White Compound (Aluminum Oxide).

I use Norton Norax belts which are similar to 3M Trizacts for finishing and sharpening. The abrasive is very even and regular so the finish from these belts is excellent. Unfortunately these belts aren't available in 1 x 30 sizes, at least not that I know of. A worn 15 micron Silicon Carbide belt also gives a very high polish, but in all cases you have to approach those final belts after sanding at several steps before you get there. A common mistake for new knifemakers and I suspect new knife sharpeners is to rush things, hopping from a wire edge at 220 grit to a few passes at 15 microns then stropping and thinking you have a polished and even finish. If you start at 220 grit, you really need to go to 320/400, then 500/600, then 800/1200, then worn 15micron SiC or 16 micron Norax/Trizact, then strop. Skipping steps may work for Verhoeven, but it has never worked for me and from what I'm reading is not working for a lot of you.

The other thing that tends to happen when you sharpen through a number of steps is that you get angle creep. You sharpen at 20 degrees per side at 320 grit, then at 600 grit you tend to slightly increase the angle so you can get that wire edge back quickly, then you do that again at 15 microns and you're suddenly at 25-30 degrees per side (most often 30, sometimes more) and wonder why you're not popping hair. You cheated. Won't work.

Ask me how I know these things... :D
 
http://rshughes.com has Trizact belts in 1x30 sizes, but they're often stocked in different warehouses which ends up making the shipping a killer for the typical obsessed sharpener. The belts last a long, long time, but will eventually wear out and lead to a "cry now; cry often" situation. But if you just get their 16 and 6 micron Trizact belts; use a&h abrasive closed-coat AO belts for rebevelling; and those Lee Valley 3M belts for the intermediate steps (400, 500, 1200), it could well work. Going from the Trizact 16 micron to the 6 micron belt leaves a very sharp and shiny edge that can either be used right away or get teased on a loaded strop for that last bit of sharpness.

Just want to edit and add that Dave Martell often resharpens knives with a worn 600 grit SiC belt from a&h abrasives either as a single step or right before finishing off the edge with kyo-sha SiC paste on a felt buffing wheel. I've tried using a worn 600 grit SiC belt and so long as the bevel doesn't need extensive reshaping, it's quick and easy. Haven't tried the SiC paste, though.
 
If you can get Trizacts, do so and substitute the Trizact 45 and 30 for the 3M 400 and one after that. My sequence in Norax (same numbers as Trizacts) 45, 30, 16 and 5/6, then strop. That would equate to roughly 400, 800, 1200, 2000.

Felt wheels are pretty agressive, and in my experience seem to enhance the cutting efficiency of whatever compound is on them. I don't doubt they work, but I'd be cautious using one for the final strop.
 
Jerry,

I really should do a separate post on that inspection system. But since I can't photograph through the scope, I need to prepare some sketches and I'm a terrible artist.

Briefly though, the keys are collimated light and polished surfaces. We used this in the silicon chip industry, and you could see sub-micron defects with naked eyes (really!) on a polished silicon wafer. Those mercury vapor lamps were bright enough to give your temples a bad sunburn, but the main beam completely reflected away from your eye, leaving visible only the scattered light from any surface defects or particle contaminants. They glowed like pinpoint little suns. My B&L light source isn't as bright, but combined with a microscope (my $5 surplus AO scope), it actually works better.

When I use my HF sander, I use it for frequent inspections on the edge. I'm also able to confirm angle control - just tilt the blade and watch for the blinding reflection.

Ray
 
Ray, why don't you pack up that system and send it to me for an extended evaluation period so I can see how it works firsthand? :D
 
This thread is highly informative...if you want a polished edge.

I'd like to try using my 1"x30" to make a more "toothy" EDC edge. I was thinking of using the 20 micron belt I got from Lee Valley (3M aluminum oxide) and then stropping it up (by hand, not on the belt sander). What do you think? The edge is currently polished though in need of stropping or re-grinding as I just mentioned.
 
Leave off stropping on leather if you're wanting to avoid a polished edge (why risk it?! Life's too short!). Try stropping with the edge parallel to wet newsprint or dry felt (or the suede side of a strop) to catch and remove the burr without polishing away that toothy edge. Actually, it'll work on polished edges, too, if you're wanting the sharpness of an aligned edge with the added traction of chompy teeth, it'll help.
 
mikeymoto said:
This thread is highly informative...if you want a polished edge.

I'd like to try using my 1"x30" to make a more "toothy" EDC edge. I was thinking of using the 20 micron belt I got from Lee Valley (3M aluminum oxide) and then stropping it up (by hand, not on the belt sander). What do you think? The edge is currently polished though in need of stropping or re-grinding as I just mentioned.
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20 micron, hand strop, should be just fine for what you want.

Us polished edge folks are like wine connoisseurs debating the merits of a Mouton Rothschild '29. Your preference is really more practical. I noticed that Shun seems to put exactly that kind of edge on their most expensive Elite-series kitchen knives.
 
Jerry,

For the hobbyist, is there a decent quality 2X72 belt sander in the $150-$300 range? And if so, would it offer enough advantage over the 1X30 HF sander to justify the cost??

Obviously, I'd love to have a $2,000 variable speed professional grinder, but that would be a little ridicoulous for my uses.:eek:
 
If all you want to do is sharpen knives, the 1 x 30 is really all you need and is certainly easier to use than a larger belt grinder. The budget priced 2 x 72 that I've heard most positive comments about is the Grizzly, a bit above the range you mentioned but it includes a buffer capability as well.

http://www.grizzly.com/catalog/2007/Main/133
 
Jerry Hossom said:
If all you want to do is sharpen knives, the 1 x 30 is really all you need and is certainly easier to use than a larger belt grinder. The budget priced 2 x 72 that I've heard most positive comments about is the Grizzly, a bit above the range you mentioned but it includes a buffer capability as well.

http://www.grizzly.com/catalog/2007/Main/133
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Thank you! The 1X30 works pretty well. And all I want to do is sharpen, so I guess I'll just stick with it! :cool:
 
One of the knifemaker's supply houses sells graphite material that you can glue to the platen. It will reduce heat and slightly cushion the work, resulting in smoother grinds.
I think the guys sharpening on the slack portion of the belt are missing something. Using the platen is the way to sharpen.
 
Sheffield has that graphite canvas for the platen. It's Catalog #GBC1. 2" wide. It costs $2.00 a foot (enough for several Harbor Freight 1 x 30's). While you're at it, get a catalog. Sheffield is a good place to do business, but they are not especially net friendly. The online catalog is .pdf. Easier to just call. 800-874-7007

The graphite will indeed make the belt run more smoothly on the platen, and will help keep the belt cooler. My favorite place to sharpen on the HF is just above the platen, however. There is enough slack to create a convex edge and the belt is still stiff enough to avoid too much rounding.

There is no "right" way about this stuff. Try everything and see what gives you the best results.
 
Jerry:

Others here have referred to your tutorial on this subject. Would you mind posting a link?

Thank you,

-John
 
I also am interested in you posting a tutorial, It would be of great use to all!

armilite,
 
This is what I wrote elsewhere. Maybe it should have a thread of its own since what's here usually leads to more questions and answers that finally make it all clear.

This assumes you have a 1x30 or 1x42 belt sander. They can be had from discount equipment suppliers such as Harbor Freight or Enco for as little as $40. Get one. You'll find a lot of other uses for the sander so the money is well spent.

Now go to Lee Valley Tools for sharpening belts. http://www.leevalley.com/wood/page.aspx?c=2&p=...,43072 I'd suggest the following to get started. (Started as in these will probably last you forever.) Understand that you don't use all of these on all knives or steels. It usually depends on how bad the edge is and if it's tool steel or high alloy stuff.

Aluminum Oxide Belts: 180, 320, 500, 1200.

15 Micron SiC belts (get two, you'll probably use these exclusively after you get your knives sharp to start with.)

Leather Honing Belt. This is what makes owning a belt sander worth it. It's basically a power strop and can put a fine polished edge on a blade in no time. You might want to get two. Use one with compound for polishing and keep the second one clean for just stropping.

Then go to

http://www.popsknifesupplies.com/compound.html

Buy the 525 white compound. It should last you for the rest of your life. You might also want to get some of the HF1 compound which is finer, and for very fine edges on small knives could be a good choice. While there, brouse around. There are many other ways to spend money, including getting your own Bader BIII Variable Speed Grinder.

Start with the finest belt first and move to more aggressive belts as you get a handle on how they cut. If you have some cheap kitchen knives, they're great for learning on. Once you get a feel for this you'll be starting with a belt that's close to what you need for each kind of knife and how dull it is. 500 grit, 1200 grit then 15 micron is probably good for most knives. If the edge is in pretty good shape, jump right to 15 microns and be done with it. If it's in really bad shape start with 320, or if you are entirely reprofiling the edge on a large knife use the 180.

What you are going to be trying to do is to raise a fine wire edge along the blade, holding the blade at about 15-20 degrees to the belt (edge down). You'll know what a wire edge is when you first see it. It will look like the edge is falling off, and in a way it is. Use a light touch until you see how each belt cuts, and gently press the edge into the belt with the edge held on the belt in a slack portion just below the top idler wheel or above the platen at the bottom. (Oh yeah, throw away all the safety shields; they just get in the way.) You want a slack belt, but not too slack so stay near where the belt is supported or has backing.

In all cases, except with the leather polishing belt, take one pass of the edge across the belt, then dip it in some water (a bucket is nice) and wipe dry. Repeat. This will be a drag when you get started, and when you get a feel for how the heat builds up on the edge you can probably take 2-3-4 passes before dipping. But DON'T let the edge get hot. DON'T let the edge get HOT!! This isn't all that difficult or threatening to the blade; you just need to be aware of heat build up.

Once you have a very fine wire edge with the 15 micron belt, put on the leather belt and apply some white compound, not too much. Strop the edge against the leather belt - at the same angle. This will polish the edge and strip away most or all of the wire. If some wire is still there, you can remove it with a wad of paper towel run along the length of the edge.

Play with angles as you see fit. depending on the type of knives and whether you want hair popping sharp and seriously tough. In either case you will get a convex edge which is inherently tougher than flat bevels. Don't try to get the most insane, hair popping edge the first time you try this. You won't. It takes a little skill and time to get a feel for how the belts cut the steel, and for how they interact with each type of steel and kind of edge. That said, you'll probably get the sharpest edge most people have ever seen in less time than you thought possible.


Hope that helps.

I'll add that getting the 16 and 6 micron belts that Thom mentions above is well worth doing. The closer you get to a polished finish with the abrasive belts, the less likely you are to screw up the edge when you strop on the leather belt. Unless it's really soft steel, the wire edge at 5 microns is almost invisible, and fragile so it's pretty easy to remove. http://rshughes.com/ (BTW, that's the worst site I've ever seen for finding what you want. I wasn't able to, but they're probably there somewhere; other Trizact belts were.)
 
The 1" x 30" Trizact belts aren't on the site, but if you call their toll-free number, they should have them (did when I called). The things you learn when calling 3M directly and pestering them for custom belts.

Fall and dry air are on the way. Prepare for some static electricity on your sanders. Seems to get me most often when I use the SiC belts, but then I use those belts most often.
 
How do the 15 micron SiC belts and the 1200 grit A/O belts compare? I was under the impression that they were roughly equivalent. I need to scrape up some cash and order some of these.
 
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