belt sander suggestions

Joined
Dec 16, 2002
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16
What type of belt sanders are you using to sharpen your blades? What grit works best? Do you grind into the edge or away?...I've just got to know :)
 
Sharpening is not a highly demanding application of a belt sander. Almost anything will work a lot easier than manual sharpening. About a 2" wide belt is optimal. A narrower belt may not do as even a job along the length of the blade, a wider belt drags on the edge to a degree that the blade shifts around some as you work. Again, you can get a less even (or smooth) result.

Having said the above, I actually use a cheap 4" x 36" sander intended for wood working. It runs slow and drags, but it only cost $70.00. I primarily work edge forwards. This leaves less of a burr and I think it heats the edge less (more heat gets transfered to the area behind the edge and less right at the apex). If I am working on something that is grossly dull (like a bayonet that has never been sharpened) I start with 50 or 60 grit belts. When I rough down kitchen knives at the local soup kitchen I start with the 60 grit. On knives that I care about more I use 120 to 220 grit. If I'm in a hurry I use 90 grit to start. I finish all my edges with a diamond bench hone and ceramic rods. I don't finish with the sander.
 
I use a Kalamazoo 1x42" belt sander. If the edge isn't too dull, I'll use a 400 grit Trizact belt to get a burr and then buff it off with a buffer using a loose buff w/green rouge. If the edge is really chipped or very dull I'll use a 220 grit belt or even a 120 if it is in really bad shape. You learn quickly what grits to use as you sharpen more knives. This method is very quick and puts a good edge on a blade. If you want to have a toothy edge after you get a burr up use a smooth steel if you want a more polished edge after you get the burr up use a leather hone. With practice you will come to use what works best for you, as there are many different ways to sharpen a blade. I work with the edge down.
This method puts a durable and long-lasting edge on a blade and works good for me.
 
I have a sears 2x42 grinder that I use for knife making and sharpening. I work edge down. You don't want to be pressing an edge upwards into a belt moving downwards- that spells trouble!

Any grinder with readily available belts is fine. Order some belts from a knifemaker's supply place- go ahead and order a range of grits and chalk it up to knife nut experimentation. 60 or 90 grit, 180 (or 220), 320, 400, 600, and finer if you can get one (usually measured in microns at that point). THis initial belt sellection will quickly let you see what you liek and what you don't. I usually go with a 200ish belt and then strop a bit (or buff) to polish off the burr, but not polish off the micro-teeth. It works very well. The finer grits are super for putting on a polished edge quickly.

So, ont he whole, I'd say get whayever grinder you have the $$ for. Something liek the Sears oen I have is nice because of the versatility0 I can make a knife or two, sharpen, use it for wood working projects, etc. A smaller 1x30 isn't as versatile, but if you just want a dedicated sharpenign machine, a 1x30 and a stack of belts is cheaper than my 2x42!

Write down exactly what you'd like out of your machine and you'll find it easier to pick among the options.
 
Crayola, not sure if I am reading your first paragraph right, but edge up is the way almost everybody I have seen grind and/or sharpen on a belt grinder do it.

Todd
 
If you are asking about sharpening your blades, I don't know that a belt sander would be the answer. For putting an edge on a new blade it is used by makers, but for sharpening an existing edge there might be better choices, less likely to remove too much metal too fast. There is a cardboard wheel that some of the knife supply houses sell that I am told works well. There is also the edge pro system which many sharpeners rave about. It uses stones and is hand powered. Try Knife and Gun in Arizona, I believe they may have both these systems.
 
Using a belt sander to sharpen existing knife edges actually can take off less steel than other methods, is the guy is good with the belt sander. You can use a fine grit belt, say 600 or better, and you won't be able to even tell any steel was removed.
 
..thanks guys these replys help. I'll search for this topic as suggested. One other thing I'm curious about is buffing for a fine smooth edge. I take it we would be talking about using a cloth-type buffing wheel...would a rouge compound (alum nitraoxideium..?? :) be something one would apply to the buffer wheel? Thanks again..great forum by the way.
 
If you want to go cheap. A sanding disk and a drill works pretty damn good for just sharpening.
 
Hey Crayola,
How limited do you feel by your Sears 2x42??

In talking to a lot of folks it seems as if this size/type grinder may be too limited for a developing knife maker.
The cheap skate in me wants to get one, but Ive got to admit, the 2x72 burrking sure looked sexy. Its $1000 for the basic and $1900 for the variable speed!

Id be highly inclined to get a cheap one for a while till I get a little more serious.
So what do you think $200 well spent or better to save up for a larger one.

Also I have to agree, an amateur like myself could really screw up a blade on a beltgrinder quickly.
Best to try basic methods first for most folks. Till you get bit by that insidiuos knife making bug...
 
I know this is a bit of a ressurection, but it the last post was only 2 months ago, so it isn;t too bad!


nabok: I grind my blades with the edge up, but I sharpen with the edge down. I figure that a buffer can catch an edge and throw a knife, so a belt sander might be able to as well. So I will put my edges on holding the blade with the edge downward. Works for me! I can even see the burr pop uo pn some steels.

MC Chan: The Sears is a great option I think for a person who wants to try knifemaking, but isn't super gung-ho about it yet. I'd love a Bader! But they are expensive, and you don't want to shell out those bucks and not yuse your grinder. What the Sears allows you to do well is sharpen knives, lawnmower blades, axes, etc. You can customize your production knives too. With the Sears and a drill press you can make all kinds of back spacers for folders, different handle scales, etc. That is a great way to get into playign with knife making. Now if you want to make blades, the Sears I find is great too, but here is where its limitations come up. You can only flat grind or convex grind. The platen is junky, but functional. It is slower to use than a 2x72. Variable speed sure would hep when finishing blades!

I have trouble finishign on my grinder, so I use it as a fast file. I use it to profile and rough grind blades, but then I'll take a fine file and draw file my blades to make them perfectly flat. After hest treat I will grind up to 220 grit or maybe 320 grit if I can get the belts and then switch to hand sanding.

Overall I think it is a great beginner machine for the person who wants to make a few knives and see if they like knife making. I have made 15 or so knives, from 3" belt knives to 8" chef's knives. I know now that the price of a Bader isn;t expensive, for me it will be worth every penny. So I am very satisfied with it.

If anyone does get a grinder liek that with a disk on the side, e-mail me and I'll tell you a great trick!

By the way, I missed this thread because I've been working on my thesis! When I am not grinding knives, I'm working on my masters thesis. judging by the 2 months it has taken me to respond, guess how much knife making time I have had :(
 
I use a Grizzly...2" X 72", only bout $300. Not as good as the $1,000. + units, but fits my skill level just fine. Got belts as fine as 6,000 grit, that will put a polish on your blade!
 
what is your secret to the belt sander with the disc on the side. I am looking into buying one. This is only a few weeks behind so its not too late to thread hop. Also i couldnt pm you.
 
Here's my disk trick! Thanks goes to Less Allen (maker near me)who taught me this.

The disk sander is awesome for grinding blades and for fast removal of handle material. What sucks about it is that those adhesive sanding disks can get expensive, and you would want to use different grits on your disk sander, but you may not want to just rip off a 120 grit disk you just put on 5 minutes ago to go for a higher grit.

What you need is contact cement, 3M feathering adhesive, and a sheet of rubberized cork. Now, this mod is one lots of makers do, and these supplies can be found at most knife maker supply places, so don't worry. The feathering adhesive is a spray. I use a tube of stuff simply because I can get it in a store where I get supplies from. On my tube (not called feathering adhesive) it still says disk adhesive though. The rubberized cork may come in 12"x12" sheets, and it is like 3/32" thick. Remove any table or guard from the disk to allow you to work. You contact cement the sheet to the disk and then use a sharp utility knife to trim the excess rubber off. Try to do a quality job here, but you don't need super precision. With the cork cemented on, all you need is that adhesive, wet/dry paper, and a hear source (a heat gun or a propane torch is great). Apply some adhesive to the cork, a good helping for this first time is good. Stick on a sheet of wet/dry paper and use your utlility knife to trim off the excess paper. Save the trimmings! The trimmigns are great for sanding handles! And, voila! You have a disk ready to go. When you want to change paper, you heat the old paper quickly, which loosens the glue, but not the contact cement! peel off the old paper, slap on a new piece, trim, and go. Replacing worn paper takes maybe 20 seconds! Now it is easy and cheap to step up through grits too.

I hope this helps!

Edited to add: after a few changes of paper, you'll need to add a bit more glue. Don't worry about exactly when to do this! You'll know easily when the time comes.
 
Nice trick Crayola,
Ive heard of it before but nice to get the shopping list.
I'll just add those items too the bottom of the long wish list.......
RIght behind a decent grinder.
I ended up going the cheapest route on beltsanders. 60 bucks for a Harbor Freight is hardly worth thinking about.
After you get it you can think about how hard it is to get decent results with such a beast. The Platten is so useless its counterproductive and a four inch disc is too small to put much surface area on.

However its a cheap basic grinder that can actually do some work.
I quickly put an edge on everything neglected about the house and reground many kitchen knives before starting on my knife blanks.
My hats off to anyone with the patience to turn out a decent knife with this machine (You know who you are).
I found it frustrating in the extreme. The belt is vibey and slack and getting straight grinds requires an act of heroic caffiene induced mastery over the vagueries of the machine.

Im seriously considering making my own grinder.
If I had a source for a cheap 10inch contact wheel Id have already started.
Meantime I look with avarice at 1 horsepower variable speed motors and pulleys and gear drive set ups. My local coffee roaster has an Italian Coffee Roaster with a drive set up that looks especially appealing :)
 
Hehe, I know the frustration! I wish I had a nice Bader BIII, but I must do with my Sears 2x42. At least it isn't a $60 harbor freight :)

One thing a person may want to do is think of their grinder as a fast file, not as a one stop knife shop. I have had all kinds of finishing problems on my machine. Typically I stick to 320 grit or under and hand sand my finishes. After grinding I will take a file to the knife and drawfile the grinds perfectly flat. I find that this makes my hand sanding go by much faster! Who woulda guessed that keeping your flats flat makes sanding easier :) I like to finishw ith 320 grit paper and then with a synthetic steel wool. I find the finish to not reflect light too much, to be soft looking, wears scratches well and can easily be refinished.

I hope this helps!
 
Ouch, that was cruel!!

Well my friend at least grinder envy comes in many flavors... the owners of HFs and I may make easy targets for one with a Sears grinder.

But think how contemptuous we are to those with real grinders.
Im still not sure I could justify $1500 for a grinder but I sure think they are cool.
Oooooooooh Bader ....
:cool:

I have yet to use files for blade shaping... Too lazy. Also my shop is my living room. (Im not sure if my CD player will ever be the same again).
Ive heard that if you use etchant on them even cheap files work quite well.
 
Harbor Freight has a 1x30 belt sander that's always at a low price.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=38300


You really don't need anything larger for sharpening and if you have small knives or curvey-bladed ones, you won't want a 2" or 4" wide belt. :eek:

I have used my 1x42 for sharpening, putting on edges, etc. for a long time. It's a great little workhorse and you can use it to make wood handles for tools, etc.

Oh, and on this kind of machine you always sharpen EDGE DOWN.

If you get one of these, let me know. I have written a lot of information on using these. In fact, check out this video of me putting a convex edge on a khukuri with my 1x42:

http://www.pendentive.biz/blades/grinding2.wmv


Best of luck and keep us posted.

Dan
 
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