Flat grinding advice?

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It's all good. I was pissed when I did it. Went out the next day and threw it on the back of the bench. Picked up another blank and finished out one of my best knives yet. Just gotta laugh about it and move on.

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I'm only 1.5 knives into my journey as a learning knife maker, but what I did was this:

Using some high school math I figured out what angle I should be grinding to achieve a 0.020" edge and the grind height I wanted. It's pretty easy trigonometry, if you remember it. If not, I can make a drawing to refresh you. Once I had that, I used a miter saw to cut a wood block to that angle (3* in my case). Then, hold the blade against the block, and slide it across the belt. It was very easy, and made my first real blade come out nice.
 
Thanks! I actually have an aluminum jig rigged up where hypothetically if I set my platen to the right angle.. It would be dead on. Even with an angle cube there's not quite the precision to nail a full flat grind at such a steep angle.. So I'm attempting to work on my free hand skills. The necessary angle works out to about 1.43 degrees.
 
OK.. Revisit my mistake knife. Here was before:

PeHulfX.jpg


Now after on that side:
Fl0wZmR.jpg


Now :( originally good side:
wSoRyGj.jpg


Got it all looking good.. Switched to 220. The 220 belt was thinner than the previous 120. It allowed just enough gap between the platen and tool rest that the spine pulled into the gap and got stuck just for a split second.. Causing that dimple in the spine in the last picture. Thoughts on best way to fix it?
 
Looks great, you really have some nice grinds there! As for that "dent" in the spine, you can try to take a couple millimeters off of the concave portion on the spine in that area, and then just take a few more passes on each of the bevels to add a tiny bit of distal taper going towards the tip to grind out the dimple. Or, if it's not "too" thin yet, you can try to just take a few passes on the bevels before taking a bit off of the spine profile to see if that alone will work. Also, if it does become a bit too thin on the edge, you can always grind on the edge a little to thicken it back up for HT etc.

Great job sticking with it and fixing up the grinds. Tweaking the grind lines and the profile just a tad (or sometimes more ;) ) are just a part of the whole learning experience. It may not be exactly as you originally planned, but at least you'll still have a finished working knife instead of adding one more to the scrap bucket lol.

~Paul
My YT Channel Lsubslimed
... (It's been a few years since my last upload)
 
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Nice work! I would just grind out the dimple and make the recurve in the spine a little more prominent.
 
Another knife done. Mostly happy with this one. Scribed a 15 thou edge.. Didn't nail it still.. Ended up about 10 thou at the tip and heel. Ended up hitting the belly on the belt to bring it back to maybe 5 thou. I attempted doing a 600 grit satin... Wow, serious work. I'll probably do most my next few knives with a belt finish. Anyway, here it is at 400 grit and then satin.
yhDUOIt.jpg

lzJqzDX.jpg

aia65ah.jpg
 
Drew.Haynes said:
OK.. Revisit my mistake knife. Here was before:

PeHulfX.jpg


Now after on that side:
Fl0wZmR.jpg


Now :( originally good side:


Got it all looking good.. Switched to 220. The 220 belt was thinner than the previous 120. It allowed just enough gap between the platen and tool rest that the spine pulled into the gap and got stuck just for a split second.. Causing that dimple in the spine in the last picture. Thoughts on best way to fix it?
Click to expand...
I realize this is an old thread but I am right there having this problem...My blade is looking more like your original. Do you remember how you corrected that? How do you grind it vertically on the platen and not mess top your plunge?
 
You need to start a new thread. This is a four year old conversation. Drew hasn't posted in a couple years.

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