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

The leather belt and some white Sears buffing compound are what I've been using to finish for a couple of years now. I get the cleanest edges, and they appear to last longer off the sander than off the Sharpmaker. I recently got a hair shaving edge from a blade by grinding into the edge with a worn 320 grit belt without the leather. It took a light touch and I was careful not to let the belt grab. I think the biggest benefit to using the sander is reprofiling edges. I've reprofiled a couple of kitchen knives to about 10 degrees per side and then went to the sharpmaker to remove the burrs at 15 per side. The sander also makes it easy to remove the beaten down and fatigued metal from the edge of abused knives so crisp edges are easier. One caution: this thing will make small blades into steel toothpicks, and big blades into small blades in short order if you arent careful. I generally sharpen knives on the sander that have been damaged (all the kitchen cutlery) or have broken tips. Aside from that, they get the fine white Sharpmaker stone touch up until that stops working, then the brown, then the fine india, then the 800 grit waterstone, then if that doesnt work, they go on the sander. It takes practice, and a couple of knives to get down to a science. I generally go from a worn 320 belt, to the leather w/ compound and increase the angle 2-3 degrees to ensure that the leather removes the burr. Also, it generally takes 10-12 passes per side to remove all the burr using the leather belt. Read Verhoevens sharpening study about the use of the leather clad wheels to see what can truly be done with care and some sub-micron diamond paste.
 
me2 said:
Read Verhoevens sharpening study about the use of the leather clad wheels to see what can truly be done with care and some sub-micron diamond paste.
Click to expand...

I'd be interested if you have a link. You know what they say about curiosity and cats. Thanks for the post.
 
I'd advise a lot of caution starting with a 320 grit belt. Worn or not it is a lot more abrasive than is needed to touch up most knives and such abrasive as is left on even a worn belt is larger in size than you want the scratches to be before you go to a polish. I've also recommended not sharpening with the edge running into the belt, simply because I think it is an unnecessary risk, no matter how practiced you are.

I think the problem some of you may be having is that you could be rushing the process from coarse through fine belts, then expecting the leather belt to make it all good. Once you have a wire edge at 15 microns (or less), it should be pretty easy to strop off the wire, needing no more than 3-4 light passes per side. If you can get a cheap magnifying glass, 5-10x is fine, look at the edge during the process. Each of the belts flexes a bit differently so you may be getting a slightly steeper angle with one belt than another. Then the leather belt flexes differently than all the rest, plus it tended to be compressed so the leather pops up behind the trailing edge and can round it over if you're not careful. More pressure equals more compression, equals a greater liklihood of the belt bulging up behind the trailing edge and rounding it. You want to avoid that bulging tendancy at all costs. It probably kills more edges than anything else.

The leather clad polishing wheel Verhoevens used is good except it requires another piece of equipment and can have some of the same problems as the belt. If you want hard backed leather as you get with a wheel, use the leather belt on the platen. I've used both the leather wheels and belts and think the belt gives me better control (subjective) even though the quality (evenness) of belts available for 2 x 72" grinders is lousy.

Try spending more time at each of the finer grits, particularly 1200 or 15 microns. I think your stropping issues will become much less troublesome. Also, don't use much pressure with any of the belts. Let the abrasive do the work; it doesn't take much pressure to do so. Deflecting the belt more than just a little is bad. You completely lose control of your angle when that happens.

Finer belts are usually all you need unless your edge is way out of whack. Even then, a kicthen knife should never take more than 5 minutes to hair popping sharpness. If you are sanding longer than that, something's wrong.

Just for the record, I personally think you get the best view of the angle you're using and have best control of the blade, by using the sander just as it is received and designed to be used, with the belt running down in front. Looking down on the blade/belt angle gives you are good sense of where you are. Holding your elbows against your body while you are holding the blade anchors everything and gives better stability. That's why these machines are designed that way.
 
Thanks for taking time to post the advice, Jerry. I'm not going to dismantle my HF back-mount, but your angle control opinion has an experienced ring to it.

Oh, and by the way, I'm working on a post that describes using a collimated light source with a 10/20/40x stereo microscope. If you like, I'll send you a PM when I post it.

Ray
 
Please do that Ray. While you're at it, send me one of those 10/20/40x stereo microscopes to go with it... :D

I look forward to reading it.
 
LOL!

I got mine about 25 years ago from a surplus sale at Fairchild Semiconductor. I think I paid $5 for it, including a custom inspection mount. New, the darn thing goes for about $750. The Bausch and Lomb collimated light source cost me about $125 on Ebay.

Life is full of ironies, isn't it?
 
Thanks everyone for all of the helpful advice. I'm getting better results now, and it's clear technique is responsible for how good an edge turns out. I look forward to even better results as I use it more.
 
I've been using Jerry's method since I first read his tutotial.

all I can Say is: IT WORKS!:):):p:):)
 
Thanks for all the tips guys...had good success so far. With a little more practice I get it down.
 
"I'd advise a lot of caution starting with a 320 grit belt."

Yes, it does tend to chew up knives, but when I started, that was the finest that was readily available to me. I havent had any trouble going from that to the leather belt w/ compound, but I havent tried the 500 or 1200 grit belts either, so I dont know what I'm missing probably.

"Finer belts are usually all you need unless your edge is way out of whack. Even then, a kicthen knife should never take more than 5 minutes to hair popping sharpness. If you are sanding longer than that, something's wrong."

I'm currently reprofiling a cleaver to 10 degrees per side, roughly. It sure has taken longer than 5 minues, but reprofiling a cleaver may be the "something wrong" you speak of.
 
Yeah, cleavers are just plain wrong no matter how you cut it, but people have convexed machete's on these things so anything's possible. :)

Try the finer belts. I think you'll find getting that hair popping edge is a lot easier and will use up less steel in the process.

http://www.leevalley.com/wood/page.aspx?c=2&p=48040&cat=1,43072

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. :D
 
I haven't tried to salvage a knife that most folks would consider ruined, so I've had no use for really coarse belts. So far, I've not had to use anything coarser than 500. I have a 320, just in case, but I doubt I'll ever use it.

My most often used belts are 20 micron, 15 micron and 9 micron. especially the 9 micron.:D
 
Jerry,

Yes, they are 3M, and I got them from Lee Valley. They weren't catalogued, and I ordered by grit size, i.e., 500, 1200,1500 etc, but the 20,15 and 9 micron 3M belts showed up in the order.

I've been really pleased with them.

Ben
 
Jerry, forgive me for butting in, perhaps with something all too obvious, but my 3M 180, 320, 500, and 1200 grit mylar belts are backside-labeled 80, 40, 20, and 9 micron, respectively. Why Lee Valley lists them by grit is a mystery to me.

Ray
 
Jerry Hossom said:
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. :D
Click to expand...

Your old "friend" used to make the same point about fatigued metal at the edge. You two actually agreed on something?! :D
 
Not really agreement, you need deformation to cause fatigue. If you don't believe hardened steel can deform, it can't fatigue. Hey, polymer chemists know about that stuff. It's the same thing in your world.

In fact, it's a strength-related issue we didn't agree on, but I'm not going to argue that here.

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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