Should I buy a Belt Sander? Advice

B

beakman

Joined
Dec 21, 2005
Messages
29
Greetings,
I noticed in a post the other day that you could pick up a belt sander at Harbor Freight for about 30.00.
Not to bad a price . I could hook up a speed control to it so I would not have to worry about taking the temper out of the steel.
I've had no luck at all with the Lansky system and am going to buy an Edge pro in the future. In the mean time would I be satisfied with the edge the sander will give?
Maybe I won't have to shell out the 200.00 bucks if the sander works.
Opinions Please !!!!

Eric,
beakman3@aol.com
 
I use a 1800 rpm belt sander and it works great. Just keep the blade moving.
I have heard that slowing down a sander using a speed control can cause the motor to malfunction. Hopefully one of our electrician brothers can answer this issue.
 
I bought a Harbor Freight 1" X 30" belt sander for the purpose of quickly removing thick factory convex edges. I followed the exact and detailed instructions given by knowledgeable and experienced people here but could not get the metal removal I read about, let alone FAST metal removal, even using a 50 grit belt. My Razor Edge Coarse Hone is much quicker and more effective, for some reason. I still don't know why. :confused:
 
Mtn Hawk said:
I bought a Harbor Freight 1" X 30" belt sander for the purpose of quickly removing thick factory convex edges. I followed the exact and detailed instructions given by knowledgeable and experienced people here but could not get the metal removal I read about, let alone FAST metal removal, even using a 50 grit belt. My Razor Edge Coarse Hone is much quicker and more effective, for some reason. I still don't know why. :confused:
Click to expand...

What type of abrasive is it in the belts you use?
 
The Harbor Freight belt sander has worked very well for me. Get the AO and SIC belts for metal grinding. Check yourself on some old blades first.
 
Mtn Hawk said:
... could not get the metal removal I read about, let alone FAST metal removal, even using a 50 grit belt. My Razor Edge Coarse Hone is much quicker and more effective, for some reason.
Click to expand...

That sounds like the old joke about the guy cutting wood with a chainsaw and complaining it is much harder than using an axe. A belt sander turns at a rate which basically is about 100 time as fast as you even rapid hand honing. Thus even if you use similar abrasives it is way faster. I only use really cheap belts, usually 80-100 grit and it is many times faster than x-coarse DMT, 200 silicon carbide waterstones, etc. .

The first thing I would check is if the belt you are using can actually cut the metal so just use it manually by just looping it over a piece of wood to make a file. It should be very aggressive. Now increase you honing speed and take note of the speed of metal removal. The belt sander will just continue this process because it is many times faster still. Thus the problem is either the belt can't actually cut the metal or you are pressing way too light.


beakman said:
In the mean time would I be satisfied with the edge the sander will give?
Click to expand...

A belt sander is just freehand sharpening where you rig the stone to move so it is generally easier to control the angle however I see it more for shaping vs sharpening due to the extreme speed of metal removal. Use the sander to reshape edges and then finish and maintain them on the lansky.

-Cliff
 
I would say that if you can get the HF 1”x30” for $30 or less – go for it. There are MUCH better grinders than this (if you want to pay much more money) but for starting out this is a very good value. If you decide to progress in your knife work later, you can always buy a better grinder – you will still find many worthwhile uses for this one.

This grinder comes in handy for many things besides knife work.
It is small enough to be portable.

I have had mine for a couple of years and it has worked GREAT. If my motor ever fails I would not hesitate to pick up another one of these grinders.

I don’t think it would be worthwhile trying to hook up a speed control. If you are careful you should not have a problem with overheating the blade. I use mine for re-profiling work and then put on the final edge with a stone or the Sharpmaker. It works much faster than my 220 waterstone or any of my DMT diamond plates.

Plan on spending some money on decent quality belts from somewhere other than HF.

I agree with Lanza. Buy a couple knives from Goodwill to practice on.

--SAK
 
I bought the same sander for the same reason. 2 things to note up front. First, practice on some old knives. Second, dont count on the knives lasting very long if you sharpen them every time on the sander. I ruined about 3 knives before I got the hang of it. Unfortunately, one of the ruined knives was a Benchmade Ares. I sharpen edge trailing (like stropping) on a 220 or 320 grit belt. I did go to 120 first for a friends kukri. Then you can finish with a stone, by raising the edge to a little higher angle and cutting off the wire edge that forms. I use a "fine" Norton, which is actually about 400-600 grit. Or you can buy or make a leather belt for the sander and get some honing or buffing compound and strop the edge using the sander. This will remove the wire edge and leave a smooth edge cabable of cutting a hair held between your fingers. I use the sanding belt without the platen and the leather with the platen. The leather belt tends to stretch, so something behind it makes it easier to be consistent. Again, this will wear knives out quick if its all you use. I generelly touch up knives with the Norton or my Sharpmaker from Spyderco. My usual edge angle is about 15 degrees per side off the sander, although this seems a bit too thin for my TSEK, but works great for my Kershaw Vapor II.
 
If you are using the belts sold by Harbor Freight then you are aleady starting out wrong. Buy the metal grinding belts from Lee Valley Tools and you will never regret using the Harbor Freight grinder. Convexes and touches up any edge in minutes and does a perfect job of it. It takes longer to change the belts than it does to sharpen any knife.

Practice on some cheapo blades first especially in the tip area of the knife to avoid rounding them. Also, with good belts you don't need to put much pressure at all consequently you won't be generating much heat to affect the temper of the blade. Move the blade thru fairly quickly and wait a couple of seconds between passes and heat should not be an issue. I have never had to water cool mine between passes but it certainly doesn't hurt to especially when you are starting out. Lots of old posts over on the Jerry Hossom forum. Jerry turned on lots of folks to these grinders and their potential.

All of my kitchen knives are convexed and the edges seem to last much longer between touch ups and keeping them sharp is ridiculously easy on a ceramic stick stropping backwards to maintain the convex edge.

Good luck.

Alex
 
Alex, how much better do the metal grinding belts work than standard AO? I've been using whatever I could get at the local woodworking store, which is about 220-320. I've wanted to try the finer Lee Valley belts (> 320). Will the 1200 give a better edge than the 320, with stropping afterward as described above? Also, I used the 80 grit belt that the HF sander came with to reprofile several knives for the 20 degree slot on the Sharpmaker, although I suspect the low quality belts have something to do with the flapping that put scratches up the side of a couple of blades. I also found this happening when I left the belts on the sander, so now my sharpening belts get removed afterward. My grinding belts I'm not so picky about, but they are in the 40-60 grit range. If its what you want and you are very patient, I've ground about 5 blades using the HF sander too. I dont recommend it for grinding more than 1/month, but it can be done.
 
Use quality belts. www.jantzsupply.com has them, I believe. There should be no reason to use belts with grits under 320, unless you are doing very heavy stock removal. A good 400 grit belt, used properly should do anything you want-as far as sharpening or rebeveling an edge. Smooth the grind up with a decent bench stone, or one of those jig things. Don't overheat the blade.
Loose strings from your belt mean the belt is frayed and should be replaced. Wood working belts don't work well on metal.
Bill
 
I use quality belts for my 2 x 72 and have found the Lee Valley belts to be just fine, and Jantz doesn't have much of a range of grits for 1 x 30". Lee has belts all the way down to 15 microns (~1200 grit) which are needed for a fine edge finish, In addition they have leather belts which simply can't be beat for a really fine finish to your edge.
 
Thanks, Jerry. I rarely use the 1X30, and haven't bought belts in quite a while.
Bill
 
Me2,
The 3M aluminum oxide belts from Lee Valley are the best I have tried. Although they are a bit more expensive so far I have managed to not wear any of them out while convexing the edges of at least 25 or so knives including several machetes, goloks, and axes. I bought one of each of the 3M up to 1200. By the time you get to the 1200 you are putting on a mirror like finish on the edge in just a couple of passes.

You probably would be smart to pick up a couple of the cheaper blue zirconia belts for heavy duty reprofiling like you would be doing with trying to convex a machete or big knife for the first time. It will save wear and tear on the more expensive 3M belts and make the process much quicker.

Additionally, I also removed the belt support on the HF grinder so the belt would have slack in the middle for convexing when I push in on it a little while sharpening.
 
I agree with Alex's comments except for maybe one. I suggest keeping the short platen (belt support) at the bottom of the belt since it allows you to shape the amount of convex you get by moving closer or away from it. The belt is stiffer near the top of the platen, looser as you move upward. Try it both ways, then decide.

On those blue zirconia belts, use them cautiously and try a trash knife with them before you jeopardize a good knife. They cut steel easily and quickly, especially on thin blades. As Alex said though, they are great for convexing the edge of a machete.

If anyone here can find a source of Norton Norax belts for 1 x 30" sanders, you will think you have achieved knife sharpening nirvana. These are very uniform structured abrasives which run cool and evenly for a long time, and are available in sizes down to 5 microns. They are not waterproof though so you have to wipe the blade after each dip in the bucket. 3M has similar belts, called Trizacts. I use Norax from 45 microns down, after using AO 400 to get that far. 45, 30, 16, then 5, and you will have an edge that will amaze you. As for the wire edge, at 5 microns you can strop it off on your jeans.
 
Way-O--

Aluminum oxide

Cliff Stamp said:
That sounds like the old joke about the guy cutting wood with a chainsaw and complaining it is much harder than using an axe. A belt sander turns at a rate which basically is about 100 time as fast as you even rapid hand honing. Thus even if you use similar abrasives it is way faster. I only use really cheap belts, usually 80-100 grit and it is many times faster than x-coarse DMT, 200 silicon carbide waterstones, etc. .
Click to expand...
I didn't say my results were logical. I simply stated them.

The first thing I would check is if the belt you are using can actually cut the metal so just use it manually by just looping it over a piece of wood to make a file. It should be very aggressive. Now increase you honing speed and take note of the speed of metal removal. The belt sander will just continue this process because it is many times faster still. Thus the problem is either the belt can't actually cut the metal or you are pressing way too light.
Click to expand...
The belts I use definitely cut metal. They are from a major hardware chain and appear to be of good quality. As you said in a post above, my intention was to use the belt sander for shaping the relief grind and freehand the microbevel.

I experimented with holding knives (all were Swamp Rat SR-101) at different pressures. At first I held them lightly against the belt because I was afraid of removing too much metal with one pass, and/or overheating, but neither one happened. I do not like convex edges so held the knives against the belt as it passed over the platen. Maybe that had something to do with my poor results as most people seem to hold their knives against the unsupported part of the belt. I was reprofiling with the edge down, holding the spine just off the belt to get a low-angle relief grind, but even dozens of passes at considerable pressure removed very little metal. I was quite surprised how quickly a coarse benchstone removed metal and attained a burr, compared to the belt sander.

I don't have many knives, and if I need to hog off a lot of metal from a knife it will only be one time, so I'm happy with the benchstone (Razor Edge Coarse Hone), but would still like to know why I am not getting the positive results from a belt sander that others do.
 
There's a couple different types of AO belts made... 'open' and 'closed'. Open are made for wood, have only about 50-70% grit coverage, and will wear out quickly (on metal). Closed have 100% coverage, and are designed for metal removal. If you're finding them at a standard hardware store, and they're not marked otherwise, they're probably open.
 
Mtn Hawk said:
I do not like convex edges so held the knives against the belt as it passed over the platen.
Click to expand...

I do the same for initial shaping as I find the slack region is too obtuse as I usually run 5-10 degrees for the shoulder of the edge.

I was reprofiling with the edge down, holding the spine just off the belt to get a low-angle relief grind, but even dozens of passes at considerable pressure removed very little metal.
Click to expand...

Again, the first thing you need to do is just check the cutting ability of the belts manually to ensure they are able to cut into the metal. The sander just moves them much faster than you could hope to by hand so has about a factor of a 100 in terms of metal removal. If it isn't significantly faster than any manual stone then the belts simply can't cut the metal, it is just basic math.

This assumes of course you are trying to do similar grinding and not heavy reshaping on the belt sander by bleeding the edge right into the primary and comparing this with just lower the edge angle on the benchstone. These could be of similar speeds because it takes a massive amount of time to work the primary grind simply due to the increased contact area.

-Cliff
 
cbwx34--

Thanks. I didn't know that. The label says the belts are for metal, but also for wood, painted surfaces, and fiberglass. It seems likely that since these belts can be used for much softer surfaces they probably aren't going to be optimum for metal removal. This could very well be my problem. I'll buy some belts from Lee Valley, as recommended above.

Cliff--

Thanks for the info about sharpening against the platen. I wasn't sure about that.

I was getting some metal removal using the HF belt sander, just not much, or fast. My goal on the belt sander and benchstone was the same: to get a low-angle "V" relief grind from a thick convex edge. I wasn't particularly trying to bleed the edge into the primary but there was a lot of metal to remove, especially since one of the knives was a Battle Rat. I think after reading cbwx34's post that there is a good chance that is my problem. Before that I thought all belts were pretty much the same, other than the different grit designations.
 
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