KMG flat platten question

C

Chant

Joined
Jan 27, 2006
Messages
279
In an attempt to flatten my flatgrinds, I've moved the platten on my KMG out beyond the wheels, as in the attached pics. I ground a rounded edge on the top and bottom of the platten first.

I've tried it out at half-speed, holding the knife vertically with point down, and it seems to work OK, though the belt gets warm.

Is this safe to do? If I try to run full out (I'm using 120 and 240 grits - Norton), will I end up snaping my belts or burning out the motor?

If it is safe, would it still be safe if I moved the platten even further out (the further out I get it, the closer I can safely get to the plunge without accidentally messing up my ricasso).

Thanks in advance for any advice.
 
The platten should be just even with the plane from one wheel to the other.If it stands proud of that line (like you are doing) it will destroy the belts.This is NOT SAFE! The more the projection the worse the danger.
 
bladsmth said:
The platten should be just even with the plane from one wheel to the other.If it stands proud of that line (like you are doing) it will destroy the belts.This is NOT SAFE! The more the projection the worse the danger.
Click to expand...

Darn. Thanks for the quick response. I'll set it back up properly before running it again.
 
Jeff, "Hats off" to thinking outside of the box. I think it is great for guys to use unconventional thinking in the shop. I wish I could do it more often. The KMG is just another tool in which it's uses are only limeted by our imagination.

As with anything else...as soon a someone says "that can't be done" someone else will say..."I've been doing that for a long time". So always keep and open mind.

The platten should be just even with the plane from one wheel to the other.If it stands proud of that line (like you are doing) it will destroy the belts.This is NOT SAFE! The more the projection the worse the danger.
Click to expand...

Yep, I tend to agree, However I do run my platen out just a bit in front or the top wheel. Not much, just enough for clearance so the work piece doesn't touch the wheel. My lower roller is tangent with the platen and it is a 2" contact wheel. The further the platen protrudes, the heavier the friction and the more the belt seam takes a beating.

...but can be a great set-up for flattening blades and tangs.

Don't worry about burning up the motor... your VFD will protect it. Too much load for too long and it will shut off with a fault. Also, you can glance at the status lights...when grinding. When they turn solid red, you've reached the peak current output as set by the trim pots. This will give you an idea of how much load you are putting on the drive. But again, this stuff is industrial quality and is designed for abuse.
 
Thanks, Rob. My small-wheel attachment is on the way :thumbup: -- I have some ideas that might work better with that.
 
I spaced my platens out to run proud of the belt too. It's good to have them push out. Makes for less chatter and better, flatter grinds, without dips in them

To go even one better, you might want to invest in a pyroceram platen liner too. Your grinds will be even better and it will be a lot smoother doing them. The heat to the belt and platen will be way less and the drag on the machine cut in half.

You round the top and bottom of the pyroceram liner too, to ease the belt on and off of it.
You can get it here.
http://forgegallery.elliscustomknifeworks.com/
 
Mike Hull said:
I spaced my platens out to run proud of the belt too. It's good to have them push out. Makes for less chatter and better, flatter grinds, without dips in them

To go even one better, you might want to invest in a pyroceram platen liner too. Your grinds will be even better and it will be a lot smoother doing them. The heat to the belt and platen will be way less and the drag on the machine cut in half.

You round the top and bottom of the pyroceram liner too, to ease the belt on and off of it.
You can get it here.
http://forgegallery.elliscustomknifeworks.com/
Click to expand...

Thanks much. I've been wondering where I can get the ceram liners I've been reading about here. I'll definitely order a couple.
 
rfrink said:
Yep! Another shameless plug for Darren Ellis. He's 1st class!
Click to expand...


Aw shucks Rob, stop, you're making me blush! :o

Seriously though, that means a lot to me coming from someone I respect so much. Thanks Rob.

:)

-Darren
 
All good advice. I took my lead from Harvey Dean who suggests leaving the platen about 1/16" in front of the wheels. This minimizes drag while also ensuring flat grinds and that you won't grind a big wheel-shaped divot into the flat of your blade.

John
 
my platen is just shy in front of the wheels......and this does destroy belts faster. Had a 60 grit belt slap my hat and glasses dfown my face Saturday. Had a 36 grit slap my backside too :) May need to move mine back in a bit :)
 
I've always glued a piece of graphite belting on the front of my platens. The belt is about 1/8" thick, which makes it stick out ahead of the wheels.

That pulls the belt up tight, and the graphite belt absorbs the bump from the belt splices and acts as a lubricant. Makes for very smooth, bump free flat grinding. :D

Am I the only one left who uses graphite belting?:jerkit:
 
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