Help with "reverse hollow grind"

S

syvmn

Joined
Apr 5, 2009
Messages
169
I have a HF 1x30 belt grinder and its been working out pretty well. The problem I have been having lately is kind of a reverse hollow grind. When I apply the knife to the belt it tends to bow in. I notice it most when I'm trying to grind scale off or scratches off of the middle of the knife. It will hit the top and bottom but leave the middle untouched.

What do you guys do to fix this? I took all of the guards off of the grinder but I think maybe I have to put the backing plate back on. The only problem is that it doesn't lock down very well and isn't really strait. Maybe I need to grind it down a bit.

belt.jpg
 
Oh no no no, that's not awesome at all. THIS is awesome.

reading.jpg


My girlfriend and my 28lb kitty "Monster Truck"
 
I agree. that is one fat cat! ... the girl is pretty phat too nice score:thumbup: :D

to fix the bow in your backing plate use a hammer and flatten it as best as possible or epoxy a ceramic tile to it for increased ridgitity and flatness

Jason
 
JasonSCarter said:
to fix the bow in your backing plate use a hammer and flatten it as best as possible or epoxy a ceramic tile to it for increased ridgitity and flatness

Jason
Click to expand...

His problem is he took the platen off completely. Put the platen and table back on.
 
syvmn said:
The only problem is that it doesn't lock down very well and isn't really strait. Maybe I need to grind it down a bit.
Click to expand...


He said it wasnt straight to begin with... I just told him to put it back on and how to fix it. :)

Jason
 
NO, NO, NO.....now you've gone and ruined a perfectly good little convex grinder!
Do ya think his girl knows that the cat ATE his last girlfriend?
-Mark
 
Well I took the platen thingamajig and ground off the sides a bit to straiten it. I'm still not really convinced I need the table though. Its not like you can get the thing level anyway, at least not with any accuracy. This seems to have fixed my convex problem. Woot Woot!

One for the road...
bigkitty.jpg
 
The table is nice for profiling, you don't need it for grinding. You will want a platen, even if you're going to convex grind.
 
syvmn, I use the same grinder you do. The platen should be on the grinder all the time. If you need a slack belt area - use the area between the platen and the top wheel. I take the table off for grinding bevels, but I put it back for profiling, shaping bolsters etc. You need to make sure that the table has the angle you want with the platen (most of the time you want it to be 90 degrees). I also use a little modification - 1/4"x3"x12" aluminum plate bolted to the table.
 
Yes, put the table and platen back on. You ,might want to make a more sturdy platen from thicker metal.
The grind you were getting is called a convex grind, BTW.

I had a 28 pound Main Coon Cat named Bobcat. He had tufts on the ears , striped face, splotched body, and a spotted belly. He looked so much like a bobcat it was amazing.
Stacy
 
Aww so pretty, I'm on the look out for a maine coon kitten myself , perferably a tabby, like the cat I had when i was growing up =) I think I'm finally ready for a pet at my house and i love kitties, because then I could go away for a few days and just leave extra food instead of finding a sitter like i'd have to for a dog.
 
Yup, cats are nice. I've left mine for 3-4 days before. When you come home they just look at you like they're thinking "Dang I thought we finally got rid of him".
 
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