Grinding Belt question

Josh Dabney

Josh Dabney

Joined
Nov 23, 2008
Messages
437
I initially ordered all Klingspore Silicone Carbide belts in grits from 60-400. I'm getting alot of skidding of the blade both onto the spine and over the edge. (I'm grinding O1 edge up completly freehand). It seems to me that these belts load up fast and the grit gets worn smooth. It sure seems to me that there is plenty of grit still on my 60 but it's only cutting good with heavy pressure applied with the push stick. Eventually I'm gonna order Blaze belts in 60 & 120 and Gators from there up. I've already been cautioned about using worn belts and have pitched a few already but I'm wondering if these belt issues are whats preventing me from staying in the groove even once it's well established.

1. Am I crazy and it's only a lack of grinding control on my part.

2. Am I using the wrong grit type for carbon steel. (Blade not hard enough to "sharpen" the grains once smoothed out)

3. Is my belt trashed even though it appears to still have alot of texture

4. Should I stop grinding and order the new belts or just keep practicing

If anyone is interested in writing a grinding belt tutorial it would be a fantastic addition to the Newbie sticky thread.

Thanks for your comments -Josh :D
 
Silicon carbide belts don't hold up near as well as alox belts when grinding steel, about 30% less grinding than alox when grinding O-1.
I freehand everything too.
Del
 
I agree with Delbert, SC belts aren't good for much until you get past 400, they just don't last for heavy grinding. The one thing I can think the low grits ones might be good for is giving a more even, smooth finish in the same grit after grinding with an AO, ceramic or structured abrasive.

I use 80 or 60 grit 3M ceramics for my initial grinds, I find that these are the best middle ground between performance and cost for hogging. I haven't tried blaze belts, but I love the Trizact CFs and currently use an A100 after 80 grit and before 400AO. I am planning to switch to all CFs to 600, but will still use ceramics for initial grinding. You will probably only need to buy one of each grit you want in the CF belts, they last quite a while and you'll be out a lot less money if you don't like them.

The nice part about the used ceramic belts is that you can use them for quick hogging of handle materials, tool making, profiling etc. I always keep several "worn out" 80 grit bels around to burn up on things I don't care about.
 
You have identified the problem in that the grains are too hard to break down under grinding pressure and resharpen themselves. This is not an uncommon problem, some of the super abrasives also suffer from the same problem.

My answer is to use aluminum oxide or aluminum oxide mixes for all the belts in my shop.

George
 
I LOVE blaze belts, i use them in 50 grit at 4000 SFPM and it just plain eats steel alive.I have found that the courser grits like faster speeds. I have not uses your belts on grinder so i have no experience with them but thy might work OK for handle material. I have found out on belts that you get what you pay for.
 
I use silicon carbide belts for sharpening. Your best bet is to go with 3M Gator belts. I also like Norton zirc belts.
Scott
 
Belt choices are pretty personal, the mix that some guys use won't work for you even working the same steel. I'm guessing it's a matter of the pressure, speed and geometries that make us all different at the grinder. I use Blaze 40 and 80s then go to Gators to A45 then to hand sanding.
 
Will Leavitt said:
Belt choices are pretty personal, the mix that some guys use won't work for you even working the same steel. I'm guessing it's a matter of the pressure, speed and geometries that make us all different at the grinder. I use Blaze 40 and 80s then go to Gators to A45 then to hand sanding.
Click to expand...

hay will, where did you find the blaze 40. i was using 60 for a long time then i scored 40 50 grit belts for way cheep. but i have not seen any 40. do you have much of a problem with grit striping?
 
To all,
I had my suspicions about my belts. Originally thinking harder grain = longer lasting but I've read and learned alot since then. Thanks for confirming my thoughts. I think my grinding is comming along other than skidding up onto the spine and digging deep chunks. I have managed to get some nice straight wave free grind lines but end up getting things outta whack trying to fix the spine. Some better cutting belts I think will help me alot.

P.S.- I'd be plain screwed without advice from nice folks like yourselves !!!

Thanks again -Josh :D
 
JTknives said:
hay will, where did you find the blaze 40. i was using 60 for a long time then i scored 40 50 grit belts for way cheep. but i have not seen any 40. do you have much of a problem with grit striping?
Click to expand...

J,
Got them from Tracy, the belt backing says 40..... nah... I mainly use them after forging so they eat through scale and stuff. I'm probably going back to 977s though. I really don't like the way the Blazes feel as they grind, too "gummy" for me and they make nasty splinters, didn't have that problem with the 3M products. It's not a longevity issue, they last as long if not longer than 977s, I just prefer the 3M products and I can get them all from Pop's. I'll have to find some other stuff to buy from Tracy though, I want to keep him in business. :)
 
Apologies if I'm going over basics you already know, but grinding a short 45 degree bevel down to your scribed edge lines with a worn out belt before beginning the master bevels will keep a lot of the abrasive grains from stripping off of that nice new belt. As for finish grinding with finer belts, they will last a lot longer and you will have better control if you slow your SFPM down quite a bit. Your wire inlay looks great, by the way!
 
Josh Dabney said:
P.S.- I'd be plain screwed without advice from nice folks like yourselves !!!

Thanks again -Josh :D
Click to expand...



A handy tip more to do with construction strategy than grinding technique:

Most folks grind their profile, then the bevels. Try leaving some material around your profile. Grind your bevels - then finish your profile. It eliminates any roll at the intersection of your grind to the profile and keeps things crisp. It also tends to remove certain grinding errors from the finished blade. This approach has helped this hack machinist to grind like a knifemaker pro.
 
Gossman Knives said:
I use silicon carbide belts for sharpening. Your best bet is to go with 3M Gator belts. I also like Norton zirc belts.
Scott
Click to expand...


Hey Scott, I've found that SC belts work excellent for touching up solid carbide drill bits, e-mills etc.
Much, much better than the old standard green wheel.

If you have a tool grinder set-up with a diamond wheel, that is most definately the correct & most precise way to go about doing re-sharp on solid carbide.
If not, the SC belts work great !! and can extend the usable life of your carbide tooling many times over :thumbup:


:cool:
 
What a difference a belt makes ! Holy cow, my mentor gave me an aluminum oxide 80 grit belt to try out and WOW, No skidding onto the spine ! No skidding onto the edge ! Just a crisp clean cut and a lighter weight backing that actually rolls over creating a nice smooth plunge with minimal difficulties. I hollow ground a small paring blade in about 15 minutes with near perfect symetry. I had no problem controling my grind height and making very small adjustments working the grind towards the spine without ending up full height or more.

I was thinking I had a long long way to go in the bevel grinding department while fighting the silicone carbide belts but I now feel like I'm well on my way to getting some good crisp symetrical grinds. I certainly have alot left to learn but I'm sure happy with the results I managed tonight. I'm looking forward to getting a new stock of belts and keeping at it. :D

Just thought I'd give an update of my progress to those who are so generous in sharing their wisdom

My plan is to wear my wire inlaid knife at the blade show so if ya see me please say hello. I'd love to meet yall in person.

-Josh
 
Thanks for the tip David. :thumbup: I'll keep that in mind.
Scott
 
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