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

Does anyone make mylar belts in ultra fine grit like 2.5 micron or finer?? These would seem be especially nice if made with something like diamond or CBN. :):D:)

Or am I missing something here?:confused:

Ben
 
The 15 micron SiC belts use a harder, sharper, and more friable abrasive than the 9 micron AO belts. They start as a coarser 1000 grit, but quickly end up finer after a few sharpenings.
 
thombrogan said:
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.
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Amen to that. I did wonder if it was just me and my machine that it happened to. I really get it with the finer grit belts 500 and above. I really dislike doing the shock dance, and for this reason I mainly only use my belt sander now for coarse work.
 
Ben,

I've got some spare Surgi-Sharp 1x30 belts and I just ordered some 0.25, 0.5, and 1.0 micron diamond paste. I've gotten some advice privately that suggests that this might not be the best combination.

I'm not aware of anything finer than 3M's 9 micron (1200 grit) belt, but I haven't throw away those I've worn out. They're probably closest to the sub-2.5 micron belts you're asking about.

Get some of your own and grind away :D

Ray
 
The sharpening paper linked to by Verhoeven earlier in the thread shows him (or his students) getting edges finer than .2 microns when viewed from the edge. This was done using the finer diamond pastes on the Tormek leather wheel, which admittedly turns quite slowly compared to the surgi-sharp belts on a sander. These are however the finest edges I've seen measured by actual edge dimension.
 
You said you did write on this subject. Would you please post the link where I may view it. Or does anyone else know how I might find same.

I bought a HF belt sander and met with failure so I gave up !

Thanks,
armilite
 
What I wrote is pretty much the same as what I posted above. Describe what you mean by failure. The most common mistakes are using too large an angle or starting with too fine a belt on a blade that is very dull and needs the edge completely reshaped. In both cases you may never see a wire edge, which is the most common complaint I hear.
 
The biggest plus that a Tormek has over belt sanders/sharpeners is its slower speed. It is almost impossible to make a fatal error with it. I have gotten fairly adept at using the leather wheel to put the final edge on a knife, but for longer knives, the other wheel still gets in the way.

The best of all worlds would be a variable speed belt sander with a leather belt. Probably 2 inches wide.

Does anyone make a variable speed belt sander?
 
Not for under $1000 that I'm aware of. You can always swap the motor, replacing it with a variable speed DC motor of sufficient power to do the job. For sharpening you don't need much power so anything 1/4-1/3hp or larger would probably work fine. If all you're doing is kitchen knives and folders you can probably get away with 1/10hp but it would be slow.

For small knives 1" wide is ideal. Once the belt width exceeds the length of the blade you spend an unpleasant amount of time grinding skin off the thumb you are using to support the point. Ask me how I know... :)
 
Ray,

I've got two surgi-sharp belts, and 6, 2.5, and 1.8 micron SiC paste, and 1.0 and .5 micron diamond paste, and .5 micron CrO.

But I guess it's just my technique, or lack of experience, but I find the leather belts EXTREMELY difficult to work with.

Usually, after sharpening on sanding belts, I power strop, and then have to use the 9 micron belt again and then strop again.

I almost always succeed eventually, but sometimes I have to sharpen the blade 3 or 4 times, due to the leather belt dulling it.

I guess I just need more experience!:(

Ben
 
You're probably over stropping. It should take just a couple passes after 9 microns to remove the wire edge.

Frankly, I think the focus on very fine pastes is a bit of overkill. You can probably do away with the pastes altogether and just use the natural abrasive qualities of the leather for the final strop. On the other hand, I always found that I did fine with just a generic white compound.

There might be a difference in focus among us. When I sharpen a knife, I do so with an expectation it will be used for cutting real things, not trying to sever free-hanging toilet paper or a silk scarf falling through the air. Too fine an edge is a weak edge; you can make a knife cut toilet paper but go instantly dull when the edge scrapes against bone.

Separate the academic interest from the practical utility. Both are worthy objectives, but I'm inclined to be referring to just one of them when you might be looking for the other. I want my edge to cut through chicken bone and still be as sharp as when it started.

Try lowering your crosshairs a little and see if that helps.
 
Jerry Hossom said:
You're probably over stropping. It should take just a couple passes after 9 microns to remove the wire edge.

Frankly, I think the focus on very fine pastes is a bit of overkill. You can probably do away with the pastes altogether and just use the natural abrasive qualities of the leather for the final strop. On the other hand, I always found that I did fine with just a generic white compound.

There might be a difference in focus among us. When I sharpen a knife, I do so with an expectation it will be used for cutting real things, not trying to sever free-hanging toilet paper or a silk scarf falling through the air. Too fine an edge is a weak edge; you can make a knife cut toilet paper but go instantly dull when the edge scrapes against bone.

Separate the academic interest from the practical utility. Both are worthy objectives, but I'm inclined to be referring to just one of them when you might be looking for the other. I want my edge to cut through chicken bone and still be as sharp as when it started.

Try lowering your crosshairs a little and see if that helps.
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First let me say that I know just enough about sharpening to be stupid.

But there is an element of knife sharpening that I perceive (and maybe incorrectly) to be a very important factor that is not often discussed on these forums.

In my opinion the best edge is one that thatnot only has the right angles but one that is also polished. A ragged bevel will reduce the sharpness of a blade.

The best way to get a polished bevel is by using a leather strop. But if you are not using the leather strop correctly you will be dulling the edge as you polish the bevel.

The leather must be firm (a leather wheel) or if a belt is used, must have support behind it so that some pressure can be applied without causing the belt to become concave (which ends up rounding/dulling) the edge.
 
I agree, but remember that knives have been mirror polished with white compound. It may well be that using the platen with the leather belt could help resolve some of the tendancy to dull the edge during stropping.
 
Ben Dover said:
Ray,

I've got two surgi-sharp belts, and 6, 2.5, and 1.8 micron SiC paste, and 1.0 and .5 micron diamond paste, and .5 micron CrO.

But I guess it's just my technique, or lack of experience, but I find the leather belts EXTREMELY difficult to work with.

Usually, after sharpening on sanding belts, I power strop, and then have to use the 9 micron belt again and then strop again.

I almost always succeed eventually, but sometimes I have to sharpen the blade 3 or 4 times, due to the leather belt dulling it.

I guess I just need more experience!:(

Ben
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Ben,

You might try a combination of a lighter touch and a much shallower angle. Drop the platen, too, to get it out of the way, and don't make more than 2 quick passes on each side before testing the edge. Those Surgi-Sharp belts vary quite a bit in elasticity, especially if they've soaked up oil. The more elastic the belt and the more passes, the easier it is to round the edge. If the belt is too elastic, replace it.

I've been getting good results, but it's not unusual for me to see scuff marks on the spine of the blade ... sometimes I go that shallow. You'll know when you're getting it right. Suddenly the edge just gets scary sharp. It happens fast, especially if your 9 micron belt is a bit worn.

Luck to you,
Ray

Edit: PS: Once you've rounded the edge, it's a lost cause. You probably need to go back to a 20 micron belt for the redo.
 
armilite said:
You said you did write on this subject. Would you please post the link where I may view it. Or does anyone else know how I might find same.

I bought a HF belt sander and met with failure so I gave up !

Thanks,
armilite
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armilite, the reason that Jerry is not giving you the link is because it's to another forum, and that's considered bad form here. He's simply playing by house rules. But if you can think of another knife forum, then it shouldn't be hard to find. Of course, then you would have twice as stuff to read. :rolleyes:
 
Jerry Hossom said:
I agree, but remember that knives have been mirror polished with white compound. It may well be that using the platen with the leather belt could help resolve some of the tendancy to dull the edge during stropping.
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I love the white (aluminum oxide) compound that came in my $6 Sears assortment!

I'm getting handier with my SurgiSharp belt and last night, I got my first "tree topping hairs" edge. When I heard other guys talking about getting an edge that will cut off arm hairs without even touching the skin, I was thinking they must have ridiculously fine edge bevels that probably wouldn't hold up to any other use.

Ha! I was wrong again. Last night I did some power stropping on my ol' Blackjack Woodsman (factory convex edge on 52100 steel) and noticed it would slice hanging paper like nothing. Just for the heck of it, I ran it up through my arm hair at about half height and I could feel it snagging and cutting. Sure enough, the blade was covered with severed hairs. :eek:

I consider this a major milestone in my sharpening life. :D :thumbup:

Stay sharp,
desmobob
 
A new question for this thread. Any of you that regularly sharpen on a sander find that the edge near the plunge grinds ends up with a different shape, sort of recurved? If so, do you know how to stop it from happening?
 
me2 said:
A new question for this thread. Any of you that regularly sharpen on a sander find that the edge near the plunge grinds ends up with a different shape, sort of recurved? If so, do you know how to stop it from happening?
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It's a problem. It's also why I keep a set of carefully flattened Norton waterstones, rarely use anything coarser than 20 micron (500 grit) belts, and always use a light touch. Setting up the bevel geometry is when you're at risk. Once that's done, edge maintenance is pretty safe.
 
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