Flat Grind Question

[axeldoomeyer]

I started my first knife last week, and I got the profile of the blade cut out and I started grinding on my 4x36 grinder... I know... I should get a 2x72; however, I don't have the money to spend on a 2x72 right now. I scribed out the grind lines on the blade and I started grinding; however my flat grind is not flat it curves from the upper grind line and the edge. I made a flat grinding jig that keeps the blade at the propper angle to the belt but the grinds are curved. I guess the question is how do you keep the grinds flat? Any help is greatly appreciated.

 

[Will52100]

Basicly I don't, I grind as flat as posible, and a flat platten helps, pryoceramic platten linner realy helps as it's very very flat and doesn't wear. I true it up with a flat steel bar and sand paper, but on the edge I switch to a wood sanding stick with hard leather padding to get a convex to the edge and to give the whole blade a slight convex shape, it looks flat till you turn it and realy look at it.

Take your time, make sure your platten is flat, and don't be afraid to use files to true everything up.

 

[axeldoomeyer]

Thanks, I have been doing a little file work to make the lines of the blade more visible and crisp. I am trying not to rush it. I am so excited about this blade I almost wet myself. HEHE... When using a file, is there any way to keep the file at the proper angle, other than by eye?

 

[Ilovetoolsteel]

I started my first knife last week, and I got the profile of the blade cut out and I started grinding on my 4x36 grinder... I know... I should get a 2x72; however, I don't have the money to spend on a 2x72 right now. I scribed out the grind lines on the blade and I started grinding; however my flat grind is not flat it curves from the upper grind line and the edge. I made a flat grinding jig that keeps the blade at the propper angle to the belt but the grinds are curved. I guess the question is how do you keep the grinds flat? Any help is greatly appreciated.

I grind the blade about 85% of the way then I draw file the flats. It takes about 10 minutes on each side of the blade.

 

[LonD]

... When using a file, is there any way to keep the file at the proper angle, other than by eye?

The short answer is yes… there is a way to keep the desired angle other than by eye. Lacking a proper grinder all of my work is done with files alone. I also don’t have the skills developed yet to “freehand” file and keep everything straight and even. I have a bad habit of rolling the file and the resultant uneven lines caused me a ton of frustration during heat treatment (warping). All you need to do is rig yourself up a jig to hold the file at a specific angle. It’s no substitute for working on developing freehand skills but it’s better than screwing up a perfectly good piece of steel. My jig isn’t elegant but it does the job every time and will give you an idea of how you might set one up. I got the idea from another knifemakers website but can’t recall who it was otherwise I’d give him full credit due.


My improvised filing jig:
http://img204.imageshack.us/my.php?image=jig0074uu.jpg

 

[blgoode]

I think that your main problem right now is that your using the factory platen (the thing that the belt rides over) I made my first knife on a 4 x 36 and had to file the flats flat. Use a magic marker and draw file. You wull see the low spots fast! :thumbup: