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

Discussion in 'Maintenance, Tinkering & Embellishment' started by SpyderPhreak, Jan 12, 2016.

  1. SpyderPhreak

    SpyderPhreak Rocketman for hire Platinum Member

    Apr 13, 2004
    Posted elsewhere, but I decided it would be a good idea to make a dedicated thread here in M, T, & E for this. Hope that's OK.

    Here's something I've been meaning to post for awhile, and this seems like a good place to put it. :) It's been sitting on my computer for some time now, but when my brother recently wanted to learn to sharpen on the HF 1x30", I finished compiling it all (mostly). It wasn't meant to be so much of a "how-to" on belt grinder sharpening (there are plenty of good, thorough write-ups on that already; I recommend the one by Jerry Hossom, titled "Sharpening My Way", posted on some other forum, but you'll have to Google that on your own), but I wound up adding a section at the end describing how to do this anyway. I hope it helps!

    For belts, I like to go to TruGrit. IMO, they have more stuff under one roof than anywhere else I've found, and their customer service is great. Here is the link for all of their 1x30" belts.

    For starters, I'd recommend at least 2 of the "Surgi-Sharp" leather stropping belts (Item #LTHR130-LEATHER, $16.50 each). Once you use a particular polishing compound (or diamond paste) on one of the leather belts, that's all you should EVER use on that particular belt!

    For really rough work (spine re-profiling, etc.), I recommend a ceramic belt because they don't heat the steel up nearly as much during cutting. I like the Norton Blaze in a low grit (Item #BNRT130-0060-980, $3.40 each; Trugrit only has down to 60 grit, but I wish they had 20 or 30). Get a couple. That's all you'll really need unless you plan to start making knives.

    Most of my edge sharpening work is done with the 3M Trizact "Gator" belts. If I haven't sharpened a knife before, I typically start with the 240 grit (Item #BL3M130-0240-A65CF, $3.65 each) to establish the edge profile (convex or flat), and once it looks/feels good I move on to a finer 600 grit belt (Item #BL3M130-0600-A30CF, $3.65 each). I'd recommend getting 2 or 3 of each of these, which should be enough to get you by for several years of casual sharpening at home for your family and friends.

    For my final pass, I use a Norton Norax belt in 1,200 grit (Item #BNRT130-1200-X16U254, $3.10 each). These belts are softer than the Trizact Gator belts, and they seem to wear out a lot faster, so I'd recommend getting 2 of these for each set of the Trizact Gators.

    There is now a ceramic version of the Norax belts that I want to try (Item #BRNT130-1200-X16U936, $4.00 each). Being ceramic instead of Aluminum Oxide, and having a heavier-weight backing, it should last longer and work better than the regular Norax belts, but I don't know for sure yet having not used it before (though that will change very soon). ETA: After some use, I've decided that I don't like the Norton Norax ceramic 1,200 grit belts for knife sharpening. The ceramic is just too aggressive for a knife edge IMO. Takes off steel really fast, and gets the steel pretty warm relatively quickly when I was testing them on some cheap stuff. I'll be sticking to the regular Al Oxide Norax 1,200 grit belts for sharpening. The 1,200 ceramics would be great for knife making, however.

    A person could also get the 3,000 grit Norax belts too (Item #BNRT130-3000-X5U254, $3.20 each), if they wanted to get a really, really mirror-polished edge. Personally, I think the 1,200 grit is plenty before going to the leather strop, but that's just my opinion.

    Now, for the newer 3M diamond micro-finishing film belts. These are especially useful for some of the more modern "super steels" with high carbide content (especially Vanadium carbides) like S110V, etc. And boy, these belts are expensive! :eek: I think a good grit progression (similar to above) would be the 45 micron, 30 micron, 20 micron, and then the 9 micron. Unfortunately, that's about $60 in belts!!! It's up to the individual, but I'm not personally spending that much! I opted for the 30 micron and the 9 micron (Item #BL3M130-0030-675, $14.00 each; and Item #BL3M130-0009-675, $17.05 each), and just start off with the Trizact 240. I'm really happy with how well these diamond film belts work on S110V, M390, etc. Highly recommended!!!

    Finally, a person should get some polishing compound for the leather belts. I use the green Chrome compound (Item #KNBCGREEN, $9.75 per block), which I think is sufficient. You get a HUGE block for that $10! More than you'll probably ever need. I've considered getting some finer compound, but I don't think it's really needed. Diamond micron paste could also be used here, but again, being diamond it can get really expensive.

    There are also Scotch-Brite belts available. These are good for doing a satin finish, or nicely blended convex zero-edges. However, they won't work on the HF 1x30 without modifying the sander a bit because they're a little small and they're so thick. I wouldn't recommend bothering with them until you've gotten a bit of practice in on the sander, but they're worth mentioning. The HF 1x30 requires a bit of modification and removal of the safety guards in order to use them.


    Here is a pretty decent .pdf version of a grit to micron conversion chart that might come in handy. Save it and print it.


    Without being so wordy, here is my typical 4 stages to sharpen a knife I've never sharpened before:

    • 1.) 3M Trizact Gator 240 grit (A65)
    • 2.) 3M Trizact Gator 600 grit (A30)
    • 3.) Norton Norax Aluminum Oxide 1,200 grit
    • 4.) Green Chrome compound on leather belt

    If I have sharpened a knife on the belt sander before, rarely do I have to ever go back to the 240 grit Trizact. Usually it only needs the 1,200 Norax at worst, and a lot of the time I only need to strop with green compound on the leather to bring back a hair-poppin' edge. :cool: :thumbup:

    Of special note, before we go any further, take care NOT to ever let the blade even get warm while sharpening! I like to keep it COLD! Check the edge after every pass and be sure it isn't warm to the touch. This is extremely important, as you could harm the heat treatment of the steel if you're not careful!!! I keep a bucket of some cold water and a towel nearby to keep the blade cool while sharpening (I cut the top off of a plastic 1-gallon milk carton and fill that with cold water). I don't have too much trouble with this when my garage is 30 degrees and below in the Winter, but when it's 90 degrees and more in the Summer it becomes quite important.

    To begin, I like to eyeball the edge angle before turning the grinder on. This gives me an idea of what the factory edge was set to, and I can decide if I want to thin it out or go thicker. A protractor or edge guide can help here, but after some time, you'll get a pretty good feel for the angle just by looking at it and the gap between the knife spine and the belt (of course this also is a function of blade height too). Something to remember with a convex edge is that the edge itself is at a bit steeper of an angle than the blade is as laid against the belt due to the "wrap-around" inherent in a convex edge. If your belts are flexing the proper amount, it shouldn't be any more than about 5º-7º more (inclusive) than a flat grind would be.

    When sharpening, move the edge at a constant rate across the belt as you go, and don't go too slow! Unfortunately, the little 3,400 RPM HF 1x30 moves that 1" belt pretty darned fast, at about 40,000 - 42,000 inches per minute (~700 inches per second, which is ~60 feet per second or ~40 miles per hour :eek:), so it can heat up the edge pretty quickly if you aren't careful. Do NOT ever stop in one spot!!! A good rate to move the knife edge is at about 1" per second, or maybe just a touch faster. Just keep it moving steadily. Also, don't push too hard against the belt. Let the belt do the work for you; light, consistent pressure is key here, and will help to prevent removing steel at too rapid of a rate and heating the edge too much.

    When you get near the tip of a knife, lift the handle and rotate the knife along the radius of the belly, carefully keeping the same edge angle. It is important to keep the edge of the blade perpendicular to the belt as much as possible where the cutting action on the belt is taking place, at all points along the edge as you move, otherwise you will not maintain the same edge angle. Unfortunately, it is pretty easy to screw this up near the tip of a knife, especially with larger knives with big bellies, and either fatten or flatten out the edge here. This just takes practice to master. Also, do NOT drag the tip of the knife all the way across the belt. This will result in rounded tips, which you do not want! Instead, when the tip reaches the halfway point (at most) while moving across the belt, pull the knife toward you and straight away from the belt. This will yield nice pointy, sharp tips. :D Finally, it is much better to make two smaller passes than one heavy pass. Usually you only need multiple passes with the first, coarsest belt, and even then it's usually only the very first time you sharpen a particular knife.

    ETA: One final note; do NOT leave any belts on the machine when not in use, especially the leather ones. They will stretch a bit, which will negatively affect performance later on.

    I know that's a HUGE post, but I hope that the information is useful to folks. It's been a work in progress for well over a year now, and I think it's a decent write-up. Take care! :thumbup:

    PS - Here's a condensed list of what I'd recommend, at minimum, to get started, for ease of printing/writing a list:

    • 2 x #BNRT130-0060-980, $3.40 each (Blaze 60)
    • 3 x #BL3M130-0240-A65CF, $3.65 each (Trizact 240)
    • 3 x #BL3M130-0600-A30CF, $3.65 each (Trizact 600)
    • 6 x #BNRT130-1200-X16U254, $3.10 each (Norax 1,200)
    • 2 x #LTHR130-LEATHER, $16.50 each (Leather)
    • 1 x #KNBCGREEN, $9.75 per block (Compound)
      SUBTOTAL: $90.05

    • ? x #BNRT130-3000-X5U254, $3.20 each (Norax 3,000)
    • ? x #BRNT130-1200-X16U936, $4.00 each (Norax 1,200 CERAMIC)
      (I don't recommend these ceramic Norax 1,200 belts for knife sharpening after trying them out.)
    • ? x #BL3M130-0045-675, $14.25 each (45 Micron diamond)
    • ? x #BL3M130-0030-675, $14.00 each (30 Micron diamond)
    • ? x #BL3M130-0020-675, $12.95 each (20 Micron diamond)
    • ? x #BL3M130-0009-675, $17.05 each (9 Micron diamond)
    Last edited: Feb 1, 2016
    lex2006 likes this.
  2. Cackmandu


    Aug 24, 2015
    Thanks for the post, I'm headed in this direction!
  3. Cackmandu


    Aug 24, 2015
    double post
    Last edited: Jan 13, 2016
  4. SpyderPhreak

    SpyderPhreak Rocketman for hire Platinum Member

    Apr 13, 2004
    You're welcome.

    You're welcome!

  5. postoak


    Dec 23, 2011
    Very timely as I just got all the belts I ordered in yesterday. My sander came with an 80 grit belt which was good for doing my axes and hatchets. I also ordered:

    220, 600 grit

    9 micron (variously reported as 1200-1500 grit)

    4 leather belts and the black, green, white fine, and white ultra-fine compounds (As you said these will last a long, long time!)

    I am sure this is way closer spacing than I need, but it can't hurt, and actually, I think I would like something in the 900 grit range also.

    I also bought a cleaning stick.

    My experience so far is that the sander is far less noisy than I thought it would be and it's easy to control the blade going across. I was afraid putting a blade against the belt was going to be like sitting on a bucking bronco. I think you could actually use this inside on your kitchen table.

    I did use the 80 grit belt on some cheap knives and establishing a burr with it is ridiculously easy -- like one pass per side easy. Now that I have the other belts in, I will use the 80 grit belt only for axes.

    I wish I knew the micron equivalent of these compounds but even the person I bought them from didn't know and he said he had asked the rep and he didn't know either.
    Last edited: Jan 13, 2016
  6. Zidfeldts

    Zidfeldts Gold Member Gold Member

    Dec 28, 2010
    I always dunk my knives in cold water after every pass.
  7. postoak


    Dec 23, 2011
    Do you then dry off? Does it hurt to put a wet blade against these paper belts?
  8. Skimo


    Mar 28, 2009
    No and no.
  9. bflying

    bflying Gold Member Gold Member

    Mar 4, 2014
    Maybe I missed it, but can someone tell me approx how much time it takes to change out belts?

    It seems that every time I try to do something like sharpening on anything electric, I end up murdering more projects than I consider successful. I've finally got the learning curve of a few manual sharpening systems down. But every now and then I run into something that needs such an extensive re-profile (usually from abuse, or a mod-gone-bad), that it would literally take hours with my current stones. Would love to get it close on a belt (or similar), then finish up and fine tune on something like my KME.
  10. postoak


    Dec 23, 2011
    It takes less than 30 seconds to change a belt.
  11. SpyderPhreak

    SpyderPhreak Rocketman for hire Platinum Member

    Apr 13, 2004
    While you can use the regular Aluminum Oxide belts meant for wood on steel (like the one that came with the machine), it is not a great idea. They tend to heat up the steel more than necessary. You really should get belts specifically meant for steel if you're going to sharpen anything thinner than ax heads. Also, the cleaning stick won't do much if you're grinding steel, as it doesn't tend to build up in the belts like something like Aluminum or wood would.

    Careful there. I dry mine off. Takes a couple seconds. Some of the belts will handle being run wet, but others won't. While it's likely that a little bit of water won't really hurt them, repeatedly getting them wet will degrade them over time if they're not meant for water.

    Yes, changing belts happens rather quickly, especially if you have removed the plastic safety guards (do so at your own risk). Takes less than 10 seconds for me. I usually hang the belt on the top wheel, push it over the drive wheel, then grab the belt and move it in the regular direction of travel as I push it over the rear guide wheel. If the wheels are moving (by hand!) as you put the belt onto the last wheel, it will go on much easier.

    Also, something of note, I do not have the rear tensioner wheel tightened at all. Because these wheels are rounded, the belts will mostly self-center as they move around the belt path. It doesn't work as well when they're brand new, but they quickly stretch a tiny bit and will easily self-center after that.
  12. bgentry


    Aug 3, 2009
    On my 3/4 x 12" belts on the WorkSharp Ken Onion, the cleaning stick seems to make a huge difference. It removes the black or gray from the belts, which is built up metal. I've felt the difference in grinding action before and after. I think it also really helps with belt life. I have several sets of belts, but I haven't retired a belt yet and I've done around 200 blades on mine, many of which required a lot of work.

    On the up side, nice write up of the process and recommended equipment. :) I love the Norax belts on my WSKO.

  13. SpyderPhreak

    SpyderPhreak Rocketman for hire Platinum Member

    Apr 13, 2004
    I have a cleaning stick too, but have never noticed it making any difference on the belts I use, so it has just sat in the drawer for most of 3 years. I'll try using it again and see if my opinion changes.

    Thanks for the compliment! :thumbup:
  14. postoak


    Dec 23, 2011
    I've only used the cleaning stick once so far, but it took a great deal of crud off the belt.

    I don't know if it has been warned, but everybody says to not leave the leather belts on the wheels as they will stretch.

    Also, I forgot to point out I have removed not only the side guard but also the plastic shield at the top wheel. It seems safe enough to me, and I wear safety glasses. If you take those off and put them on for every belt change then the time to change a belt might go up to 2 minutes.
  15. postoak


    Dec 23, 2011
    I don't know about different types of belts yet. I got all mine, except the one that came with the sander, from Popsknifesupplies, so I am hoping I got ones for steel.
  16. Jens Schuetz

    Jens Schuetz

    Jun 24, 2013
    On a 4 inch grinder I removed the guard as well. Why? Because I needed to unscrew more than 5 screws for a belt change. Who engineers that stuff? Even winged screws would have been a huge improvement. Anyways changing is smooth now, but a big disadvantage is steel dust entering the machine where it probably should not. I got an extinguisher close by....
  17. postoak


    Dec 23, 2011
    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.
  18. postoak


    Dec 23, 2011
    Another thing, with the 80 and 220 grit belts, heating the blade was not an issue. When I jumped to 600 it was!
  19. Bazzle


    Dec 17, 2013
    Great post. I'm sure it will help many!
    My system is a little different. I use a 1"x42", it takes maybe 5 seconds to change a belt and be running again. I generally start with a 120 Zirconia Alumina, A45, A16 and sometimes A6 or A3.
    I think the Zirc belts are far better than the Ceramics and while they work for some, I only use leather or scotchbrite belts to touch up the inside of serrated knives.
    I get all of my belts bulk, 50-200 at a time for my mobile service.
    I keep a cleaning stick in my van, but rarely use it unless I've sharpened something really nasty. It's more useful when using my 2"x42" grinder shaping knife handles.
    Safety glasses are always good! Consider dust collection.
  20. Bobby3326


    Mar 16, 2013
    I have 3 sets of belts I use for my blade grinder, my original ones are well worn and have deteriorated a good bit, then a less worn set, then a practically new set. I only use the newest ones if I'm sharpening highly wear resistant steels or if I need major stock removal as they cut the fastest. Other than that I'll use the middle set for my primary grits, I'll use the x65 followed by the well worn x65 and follow thru the progression doing the same. By doing this it kinda closes the gaps in between the grits.

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