View Full Version : Grinding Tips
04-12-2010, 07:01 AM
This was posted on another forum I belong to and written by Tim Galyean:
Here are a few hollow grinding tips that I thought I would share with you.
1. Start slow.
2. To start out dull the edges of your belts, especially the 60 grits. you will get nice a nice radius at the tops of you plunges.
3. Radius the corners of your contact wheel with a file so there is about a 1/16" radius in the corners.
4. Put a slight crown in your contact wheel. It really helps out when putting on a false edge. You can see the light gap between the tip and the belt so your false edge comes right to the tip.
5. Grind your false edge with a 120 grit belt to start. You are not removing that much material and it is easier to control and clean up.
6. Work your plunges back. Dont start them where you want them to end up, work them back as your bevel height increases.
7. Learn to work your push stick. To raise your bevel height put a little bit of heel pressure with it.
8. Keep your hands in your gut!
9.When trying to clean up the plunge area try to use your little finger on the hand that you have your push stick in for a rest. Steady yourself with it. It is very hard to just go right up to the plunge without being steady.
10. Keep your hands in your gut!
Also, here is a link for knifemaker's terminology: http://www.jayfisher.com/knife_anato...rts,_names.htm
If you have any tips to add, please do. 2thumbs
04-12-2010, 02:01 PM
I'd add use a smaller wheel for your false edges. It gives you a lot more control and it's easier to stay in the groove. I don't use a push stick because I want to feel how hot the steel is getting. It tells me if I'm pushing to hard. Great thread.
04-12-2010, 03:52 PM
Here are some tips I posted on another forum:
Use a gentle, but firm touch. If you just float the knife on the belt, you will not get a consistent grind. Also, if you push too hard, you'll make mistakes.
Let the belt do the work, but control where the belt works. Watch where the sparks are coming from on the belt. Are they coming from the edge or from the middle. Try to keep them in the middle of the belt until you have more control with what you're doing. You'll eventually learn what it feels like to grind in the middle vs. the edge and when to use what part of the belt.
Lock your elbows down to your side. Develop a consistent stance and uses your body movements more so than your arm movements. Keep a water bucket under your platen so all you have to do is reach down to dunk the blade. Keep it cool. A hot blade will cause you to hurry or to jump.
Have good lighting at your grinder.
I grind edge-up. Watch the junction of the edge and the belt. You'll be able to tell where on your blade you are grindng by the space between the edge/belt.
Don't grind your bevel all at once. In other words, it doesn't start at the same angle that it finishes. Start with a 45 degree bevel on the edge that takes you down almost all the way to your desired edge thickness. Then walk that bevel up the blade towards the spine gradually. As you get closer to finished bevel heights, switch to a higher grit belt for more control.
Use a height guage or edge scribe to mark your blank before grinding. You can either mark the center line, or as I do, mark two lines about 1/32" apart form each other. This keeps your edge centered and gives you a reference as to where you need to take more steel off.
To avoid the 2" line, you'll eventually learn to very subtely lift the tip-side of the blade as you move into the plunge area. This takes practice to avoid carving a gouge in your plunge. Until then, focus on keeping the sparks in the middle of the belt and not stopping in any one area.
Hopefully, these tips can help you out a bit. Good luck and happy grinding!
04-12-2010, 07:15 PM
Check your work often, especially when beveling. Try to make sure things are flat and even. I still sometimes have nice bevels near the tip and plunge, with a slight "hump" in the middle of the blade. Try to avoid this from the get-go rather than fixing it later. But don't panic, it certainly can be fixed.
I find it helps to start near the tip and get the distal taper pretty close before doing the actual bevels.
If your budget allows, get a cheap dial caliper from Harbor Freight or somewhere, around $15. I got mine NIB at a garage sale for $10 IIRC. It's not pro-grade, but good enough to let you measure thickness and check for evenness/high- or low-spots better than your naked eye.
I often use a 90-degree welding magnet to hold the blade when roughing-in tapers and sometimes, bevels. It gives me a better, steadier hold on the blade when it's parallel to the belt.
Clean your belt often, just as you would with a file. Those big eraser-looking rubber things do help belts cut cleanly and last longer.
Check out Harvey Dean's Flat-Grinding DVD if you can. He's really down-to-earth and explains things in a non-technical way that's clear and concise. It has lots of good close-ups and camera angles that really let you see what he's doing. There's a section at the end about fixing goofs that's worth the price all by itself.
04-16-2010, 10:33 AM
Nice post Dave. 2thumbs
04-16-2010, 01:57 PM
Thanks for all the tips , I think you all have touched on about everything i've been having trouble with.2thumbs
04-16-2010, 02:06 PM
Cool! Now come show me how to grind a blade! huh1....Not having a good grinding day....:eek:
04-16-2010, 04:11 PM
Number 2 of the original post is gonna be a real help for me...I been beating my head against the drill press for a long time trying to figure that one out! huh1:cool: Thanks for posting this Dave! -Matt-
04-16-2010, 08:26 PM
My grinding could be described as , digging holes, then grinding down to make it go away, then nick the edge, make it go away, and ......:running dog:
I'm happy when there's something left.
04-20-2010, 04:19 AM
cool thread...how do you dull the edges of your belt?
scrap metal, a file...?
one thing that helps alot... use fresh belts
dull belts can **** everything up easily
I know because Iīm a cheap ******* who uses belts til they almost fall apart :running dog:
04-20-2010, 07:47 AM
Great thread I think I'll make a poster of it and post it next to my grinder.
04-20-2010, 08:19 AM
You're right, zz... every time I change a belt I go "dang, I shoulda changed that 15 minutes ago, this is much better". I'm learning to judge better when they start to get dull.
04-20-2010, 12:33 PM
Such a poster is a really good idea.
Iīll make one too LOL
I think it also depends on the belts.
I īm testing some new ones with some sort of ceramic corn.
They feel pretty dull but on high speed they eat away metal like no tomorrow.
On low speed they suck
Iīm not only cheap when it comes to belts the main problem over here is that you canīt order single belts to test
I have to order at least 6 or 20 per grit
No fun when you have to order 20 belts and donīt even know if you will like them
So I stick to 6 per grit
Anyway good thing is God gave us two arms so i do hand sand a lot.
Shaping, rough grinding to 150 grit ...beltgrinder
The rest... hand sanding
Good thing about hand sanding is not only that it safes belts it also give you more control over what you are doing
When I started knifemaking I thought everything has to be done with the grinder
But I think thatīs not right.
Everyone got his own way of knifemaking
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