How do you get a sharp, crisp grind line?

jaegar

jaegar

Joined
Nov 5, 2004
Messages
280
I'm having trouble getting crisp grind lines on my knives. When working on the belt sander it looks fine, but when I go to polish, it just about dissapears:
1icwfd


The flat grind is even fainter than in this picture.

Here is my set up that I work with:
1icwlz


Do yall have any suggestions?

Thanks

~Brian
 
(Great job posting pictures).

Hint one: when grinding the only pressure you should on the blade should come directly over the belt. That means your thumb. One hand steadies the blade and pulls. The pressure comes from from the thumb pressing, and the thumb is right over the belt. Yes it gets hot and yes your index finger on that hand has to hold the blade up.

Hint two. Handsanding will wash out the grind lines, unless you are very careful. Instead, attach the sandpaper to a sheet of glass and move the blade. Nothing makes a crisper line.

Steve
 
Lawdy-Lawd! Take off that durn polarfleece jacket aforn ye git yeself caught on fire, son! :eek:

Looking at your grinding style, however, I'm thinking maybe you could pull your elbows in and lock them to your sides. Many of us with an ample gut, tend to use that. Above all, your work will improve with practice. Keep your chin up, because your work will get better! :D
 
Yeah, That picture wasn't the greatest, I usually do have my thumb on the blade...I'll work on making it more consistent.

Thanks for the glass idea, I have some plexiglass that I'll try that with.
As for the fleece...well it was a little chilly out there. Next winter I'll have a blue jean jacket or carhart or something, but for now, that's the only light jacket I have :D
I'll remember that though. I usually don't wear loose clothing in the shop, heard way too many bad stories.

~Brian
P.S. sorry about the size on the pictures, I thought if I shrunk it down you wouldn't be able to see enough detail.
 
A handy little gadget I built when I started grinding ,consisted of a bubble from a small level that I glued to a block of wood.The block, square on one end
but had an angle on the other that I glued the bubble to. On the square end I glued a small but strong magnet. When I attached this rig, with the magnet to the blank I was grinding the bubble would float when I was at the right angle. This took a bit of time to match the angle to my grinder but once I had the proper angle it was easy to switch the rig from side to side and grind good coresponding angles. Once I had a set angle to work from I would go to the mitre box and cut another block to either steepen or flaten out the grind.
A series of 4 blocks a degree apart with these bubbles on top would allow me to grind the big and small blades alike. If interested I'll post pics Fred
 
Yes very interested, please post pictures.
I've heard of something similar by Bob Terzuola. He didn't have a bubble level, but used a spring grip (I forget what you call 'em...it'll come to me) and a screw to hold the blade in place. There was some other stuff on it of course, but I forget exactly how it worked. I'm very interested in that because not only are my grind lines not looking the greatest, it's hard to get even ones free hand on the belt grinder...practice! :D
Thanks for the help

~Brian
 
hint 3 Sharp belts! But I havent gotten too many crisp lines myself but I am on my way...and soon you will be there too!
 
Yup, that's one problem.
I'm currently using some old belts ready for the trash...how did you know :D
I'm just waiting on a little cash to get some new ones.
 
I think the comment about the polar fleece jacket was addressing the fact that it is made out of polyester, or some other flamable fabric.....not how loose it fits.
 
blade runner said:
I think the comment about the polar fleece jacket was addressing the fact that it is made out of polyester, or some other flamable fabric.....not how loose it fits.
Click to expand...

Yeah I know, I was just elaborating the comment. Also so someone wouldn't comment on that other fact :D
Like I said, it was a little chilly in the shop then.

~Brian
 
How fine are you goin on the belt, grit wise? The futher you can go, the less hand sanding on the glass or granite plate. You can use grafite tape to soften the platen enough to use very fine belts. Having two seperate platents for this not a bad idea if kept very similar in configuration.. Can you slow your machine down for the finer grits? Really does help...... M. Lovett
 
You need to get a better platen for that grinder. Email Darren Ellis for a piece of pyrocream (SP?). Epoxy that to what you have now. Will make things alot better!
 
I can't slow my grinder down, it's approx 4400 FPM, if I read the specs right.
I would go down farther on the grit, just not money right now for belts. :(
I took this one down to 120, but for some reason it's leaving REALLY deep scratches. 100 grit sandpaper is finer than what it did. Probably due to an old belt. As to the platen: Yes, I do want to make a better one. Please expound on making it softer for finer grits... :confused: I don't understand. I realize those belts are thinner, but how does a soft platen help? Thanks.
And Yes, I would like a piece of pyrocream (Sp?), I just need Mr. Ellis' E-mail. About how much does that stuff cost?

I can use a peice of granite to sand? What about the polished flat side of G-10? I'm guessing all I'm looking for is something hard and extremely flat, with little or no texture. Is this correct?

Thanks everyone for the help.

~Brian
 
While we are on the subject of platens, I was thinking about grinding down the right hand side of the platen so that it is the exact width of the belt. This would allow using the edge of the belt more. Will this idea work?
Thanks
~Brian
 
I have a grinder just like you do. Dont bother with the platen. Just get a better one. You wont waste your time.
As far as belts. Use 60 grit, 120, 220, 320,400. Hand sand back to 220 then move back up in grits to whatever you want.
Bad thing is that the thing is too fast and will eat up belts quick.
Call a local saw/ tool sharpening place and ask if they sell abrasive belts. That way you may find a place to get better ones than sears and it still be local.
 
I took the pictures today[ Tues ] I'll upload them by Friday. They will appear in a new thread in this forum. Titled The bubble jig.
Fred
 
Mr. Goode,
You have the Craftsmen 2x42? Or one similar?
Originally you said to Epoxy pyrocream onto it. Do you mean make a completely new one, or are you still refering to this?
And, where do I find some pyrocream (sp?)
Thanks.
~Brian
 
Hmmm... i guess this is hijacking, but I don't want to start another topic- do I need to say mr. Good, gray, I dunno Don's last name, but is that needed? Anyway, It's gonna be good to hear this, because I'm probably in the same place Jaeg is. Should I just not go with the craftsman, and which is a CHEAP (you think this is bigish, you should see the line of tags on the word) grinder to replace it- less expensive than a badder, kmg, and I'm so broke at this point- even a grizzly.
 
Grind lines that really stand out are those hollow grinds done with a small diameter contact wheel ( 6" or 8" diam). The reason these stand out so well is the difference in angle of light reflection between the flat and the grind.

Sharp transitions also help but require hard surfaces to finish both the grinds and flats properly
 
You must log in or register to reply here.
Back
Top