Belts for dummies

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
5,786
I know everyone more or less uses a brand of belts based on what they like, but let's talk generalities for a moment if we can. Any day now my Coote will come knocking on the door, and I don't have belts yet. I've looked at Pop's and he carries ten thousand different types. He's out delivering mail right now, so he was no help (yet)! So, what grits, brand and type of beltsm, as well as how many, would you recommend for someone new to a belt grinder (2x72 with 10" wheel) assuming:

1) Mostly flat grinds on platen, maybe will mess with some convex grinding, probably won't screw with the hollow grinding until the other skills are in place.
2) I need something that is cost-effective and good for the money. I will be grinding simple 10xx steels.
3) I will be doing all profiling and grinding on the machine, as well as as much finishing of handles and blades as possible without resorting to hand tools! :D

I'd like to get enough belts to finish at least 10 knives before I have to mess with another order (or can you get that many from one set of belts?). Are there specific types of belts that work better for certain types of materials?
 
Without being accused of being a butthole, do a search. I bet you get the same answers as the last time you asked, plus there are dozens of other posts that answer the question.
I've said it before and I'll say it again. Ask 6 knifemakers what belts are best and you'll get 7 answers :)
 
Pop will give you the best advice you need, and he will have all of the belts ready to ship too. He's one hell of a guy. I've been driving down every weekend to go see him, and just shoot the bull...
Best thing to do, is try a bunch of different belts from Pop, and just see what you like. You can't go wrong with most 3M and Klingspor belts. Pop will tell you.
 
Kit, sorry about the redundancy. I was hoping someone would just bite the bullet and let me in on the secret! :rolleyes: How about grits, at least? I just watched Kim Breed's grinding video and they were using a 60 grit belt, then jumping to 120. Is this the way to go, or is using something really low like 36 grit better, then 60, then 120 and on up? Razorhunter's advice was good, to just buy some different ones and try them out, but the range of materials (Trizact, Ceramic, aluminum oxide) is also confusing and the search just doesn't yield the info I need...
 
Chiro,
Like I said, every knifemaker will grind differently. I've not ground anything on your grinder so how can I tell you what belts to use. My method is 80 grit 967, 120 grit Klingspor LS312 and 400 grit LS312, for folder blades. I doubt this method would work for you since my blade grinding is done after heat treat.
Paul's advice was sound.
 
I'll update with the general advice Pop gives me so maybe this will help others down the road. Thanks, Kit.
 
I can't say for your particular machine, but I'll tell you what I use/buy at a time. A couple of 40 or 50 grit, a couple of 80 grit, a couple of 120 grit, a couple of 220 grit ...or anything in stock close to those numbers.

After that I switch to hand sanding ...generally 320 or 400 grit, then 600 grit, then course and fine steel wool.

There! The secret's out! :)
 
is your machine variable speed?? Boy have you ever asked a loaded question.... and as Kit has said, it's been discussed many times here. Pop's advice is of little help; it's just another opinion. As Kit said, your grinding is going to differ from everyone's elses. I grind a lot of flat ground blades that are 1.5 inches in width and 8 to 12 inches in length and I always start with a an angle grinder!! The scale on a freshly forged blade is rockwell 60 or so. Don't even waste a single pass with a 36 grit belt on one unless you've removed the scale. You can buy a 4 inch cheapass angle grinder for 25 bucks or so; I use a Dewalt. I strart actually grinding big blades with a 36 girt Norton 961, or a 3M 977F. For the rest of grinding I use Klingspor, and Hermes belts of various sorts. I will tell you two things: don't buy cheap belts and secondly, the single bigest mistake people make when grinding is using worn out belts. This dosn't mean "a belt used a few times"... no. It means don't use a worn out belt even if you've only made two passes on each side: worn out is worn out. If the belt is not cutting, throw it away. That's why I've asked about variable speed; grits under 120 need to run slower to be able to get a "bite". Running a 320 at high speed is just a quick way to loose $2.80 in less than two minutes. If your machine is single high speed, I'd not even buy anything less than 220 grit. Lastly, the best advice I ever got about belts was:
"use them as if they were free!"
 
Thanks, anvilring. Does the scale/angle grinder thing apply to hot rolled steel, too? I use a lot of cheap 10xx steel with the mill scales still on it. Or is that thin enough to not be a problem? To answer your question, I will be using step pulleys, so I have some variations available on speed, but not true variable speed. I don't know the math on this stuff, so I honestly can't tell you the range of belt speed. High 800's RPM for the low end seems to be sticking in my head, but I don't know.

I will experiment and see what happens! Thanks!
 
I bought some of each kind from TKS to see what I liked. I'm ready to order more, becuase the finer grits don't last as long and I'm going to experiment some more.
So far I love 3M ceramic belts because they cut efficiently running slow. You get less heat and less grit flying across the shop, clean, cool, and they seem to wear really well. So far I have them in 50,120 and 220 IIRC.

I've also tried a few aluminum oxide belts. These are about par for the belts I get for my 4X36 sander. In terms of wear....they suck. Couple blades at best. They're cheap though, and they run pretty smooth. Good for finishing, but plan on buying more than one at a time.

Silcon carbide belts. Only have one of these, it came with my grinder.I'd say its just ahead of aluminum oxide in terms of performance. Cuts a little faster, wears a little longer. Also pretty smooth. I need to see what they cost before I decide if I'm picking them over AO.

3M micron belts. These things are the cats ass when it comes to finishing. Super thin, super smooth running. They clog faster than you'd beleive though. Grinding wet blades seems to make it worse. I haven't tried washing one yet to see how much they bounce back, but so far it looks about the same as AO in terms of wear.

You really just need to grind with some and see what you think. You also need to decide how many times you want to change belts grinding one blade. You can do it with a few different grits,or one of everything offered. Its all a trade off, more grits should get more blades per belt, but your using more belts. In the end, your going to be buying lots of belts if you make many knives.
 
is real thin. That's not a problem, not much anyway..... Scale on forged stuff is thick and hard!!

mitch
 
Alright, here's what Pop advised: use cheap belts to begin with because you won't really notice the difference. He recommended the 3M aluminum oxide ones. After watching Kim Breed's DVD on grinding, it seemed like a good idea to also get some more flexible belts for rolling the choil in, so I switched to Klingspors for the 120, 220 and 400 grit belts.

He said the way to go, ultimately, is ceramic because you can really put a lot of pressure on them, but to upgrade once I know what I'm doing. So, we'll see. If I ever get this motor and everything off the ground it'll be a miracle. My files are looking better and better everyday, to be honest! :D
 
chiro,
If you are just beginning to grind blades, buy 25 A.O. 50grit belts set down in front of your grinder and make the sparks fly. Don't worry to much about making that heirloom piece right off, just grind and pay attention to what works. When the ends of your fingers stop looking like raw meat you are making progress.
old stubby fingers,
Fred :D :D
 
When the ends of your fingers stop looking like raw meat
Click to expand...

I've just got to make sure I don't drop pieces of my hands all over my patients during the day! :barf: May be bad for business! I have a bit of an advantage in that I've made a decent number of knives already, but the belts and the speed will take some getting used to. Practice, practice, practice!
 
I agree...everyone has a different opinion. I know...I asked the same question you did. And did a load of research. Everyone had a different combination of belt brands and grits. Some guys swear by one brand while another guy swears AT them. :p

Here's something I wish I had done earlier. Buy the belts you think will work best. Now, on the back of the belt or on a card with a corrasponding number keep track of how it performs for you. How many blades did you get out of it. how long were the blades, type of steel. Hardened or not. When did it start to slow down on grinding ability. Did the edges roll the way you wanted. Make a couple of knives then evaluate what you've got. If you don't think you got the best out of your belt, try a different one and keep track of that.

When you've got the best combination of belts post the results...so I can try 'em. :D
 
Shappa, that's great advice! Since I never throw anything away my belt research should start to pile up quickly! :D
 
Depending on your steel and grinding methods you have to find a combination that works for you. We start with 60 or 80 grit ceramic belts then go to 120 to HT then 220 and up. The 36 grit leaves deep marks and will require longer at 120 or you have to use a grit inbetween. On stock removal blades we use the cheapies from industrial abrasives. Buy one get one free. This will allow you to play with the grits on your steel and not bankrupt your belt budget. :D
 
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