Grinding on the edge of the platen

PEU

PEU

Gaucho Knifemaker
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Aug 6, 2006
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Today I tried a new (at least to me) technique for quickly removing material on the flat platen, instead of going full flat on the platen I left the belt slightly to the right so it has no backing and grinded the flat that way, quickly noticed that is way faster than using the normal technique.

Have you ever tried this, or even better, can you improve bulk grinding speeds on the flat platen?

Here is a YouTube video I made today

Pablo
PS: Not April 1st related :)
 
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I have always ground that way and it helps with the 2" problem
 
I had to do similar when I did a 72" radius (yes I know 36" radius actually) hollow grind on a very recurved blade for my youngest daughter... It turned out well.
 
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AVigil said:
I have always ground that way and it helps with the 2" problem
Click to expand...

I knew/imagined this was no big discovery, but nevertheless I was curious. Then I thought of ways to improve the platen, say for example to serrate it, like the serrated wheels that hog faster. Did anyone try it?

Pablo
 
I don’t know that running a belt off the side of the platen has any real scientific advantages for metal removal performance but whatever helps you to get the best belt to metal contact in your grind is always a plus. My guess is that this better helps you to get your plunge lines going well and as such, your more comfortable with a higher pressure pull. Anyway, interesting for sure and thanks for sharing your trials video!

As others mentioned , I use this method on some grinds as I find that this can help with the 2” bump. The bump is a direct result of over focusing on the plunge lines and not seeing the other side of the belt. I have also done this in a 10” serated wheel to feather in the plunge area at advanced grits.

Stay safe!
John
 
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I think the advantage is that you are exerting the same amount of pressure you would apply on a flat platen but in a small section of it, so the net result is more pressure by sqin/mm2 and more hogging.

Dunno what the 2" bump is as we use here 3" wide belts :)

Pablo
 
In Kyle Royer's latest YouTube video he rough grinds bevels on a large sword. He doesn't overhang the belt, but he uses a 36 grit and mentions using strong pressure towards one edge to "hog" off steel more quickly.
 
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Saw the video, maybe I unconsciously took the idea from it, nevertheless, its a good idea. I would like to know more tricks for quick hogging on a flat platten

Pablo
 
I remember watching a video on hollow grinding (I think it was Zac Buchannan) where he mentioned using the edge of the wheel to do the majority of grinding, so that is what I do...carried that over to the flat platen recently as well...seems to work. I do go back to full contact at higher grits or when I am approaching the final grind height.
 
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I wonder if someone modified a flat platten to have a removable bump for this purpose. I'm itching to try it, not sure if the belt will hold.

Pablo
 
If you want really fast then convert your grinder to work with coolant and rough grind using a jig under flood coolant... Angle is locked in and you can use an insane amount of pressure to hog steel. Saves me a TON of time
 
REK Knives said:
If you want really fast then convert your grinder to work with coolant and rough grind using a jig under flood coolant... Angle is locked in and you can use an insane amount of pressure to hog steel. Saves me a TON of time
Click to expand...
Not sure if I'm after fast, fast is good let's be clear, but what I noticed is the effort is much less that hogging on the flat platen.
If you knew that my shop was more than a decade ago my work office in a 5th floor in downtown Buenos Aires and it has oak flooring (the clients who know about floors cry when they see it now lol) Wet grinding is not a choice for me, cooled platen yes, considered it many times, as I already made a liquid cooled press to put the knives right after hardening

butcher_block said:
i do it so often that ive been thinking of making a platen slightly rounded just for hogging
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Can you share a photo of your setup? Thanks!

Pablo
 
on my old 1x42 i just used a pice of 1" pipe as the platten dont hve a picture. on my KMG the curve could be much less due to having much more HP
 
I'm just a complete novice and that's why I just read here more than post. I can see why this works in hogging off material faster but I would think instead of a 2" bump you could see a 1/2" bump. Enquiring minds want to know why this isn't true?
 
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Yes, I discovered this sort of through trial and error. It works.

JV Knives said:
I don’t know that running a belt off the side of the platen has any real scientific advantages for metal removal performance
Click to expand...

Concentration of force.
 
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Actually, I may have misread this.

What I do for hogging is I'll start with a coarse grit (used to be 36 grit, but my supplier just introduced 24, and I love them, at least for MagnaCut, but I bought them for getting my feet wet with 3V), and tilt the blade slightly so the handle is a bit lower than the level of the belt, and the tip a big higher. Then I dig into where I want my plunge, give substantial force, and start hogging, with lots of dipping in the buck. Once I start nearing my target geometry I clean that up with flat passes on the belt instead of tiled, then progress grits from there with flat passes.

I'm not sure if this is the same thing you described PEU PEU . But I do take the edge of the belt right to the edge of the plate for the initial hogging phase or I'd just be rubbing the belt against glass, and I don't have million platens and a millions years to make a knife.
 
Sorry, but can somebody me please articulate the "bump" being discussed? I'm finding this thread to be super useful but I don't know what you guys mean by that.
 
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