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G'day. My Norton 4000/8000 is starting to look thicker on one end of the 4000 side. (sloping)I think it is flat as I lap it on glass with that metal grains that you mix with water. Does having a sloping stone cause major problems? Should I try to square it up? Obviously i'm doing something wrong to get this slope. Any ideas?
Thank you
Brian :thinking:
Though it may be more comfortable for the hone to be "square", as long as the top of the hone is flat it shouldn't matter. You just have to adjust your hand to keep the blade flat on the hone (hone with the slope).Quote:
Originally Posted by bj64
Or you could prop up the "thin" side with a book (as we say in the machining business put a shim under it) so the hone appears flat and you be good to go.
You mentioned lapping with "metal grains that mix with water"... what's the metal grains? I am not familiar with that.
We usually lap the Norton 4000/8000 hone with 600 grit wet dry sand paper (you can get that from the auto shop).
Sometimes a hone may slope but that normally happens;
1) After many lappings
2) You pres too hard on the hone while lapping
3) using very low grit sand paper or that "metal grains that mix with water"... removing too much material too fast from the hone... making it difficult to control the "squareness" of the hone.
Hope this helps some.
I know of using fine metal shards on a hone when honing plane and chisel blades, but never heard of it for lapping a hone.
The sloping is from either too much pressure at one end when lapping, too much pressure at one end when honing or both.
Thanks guys. the lapping system is something I got when I bought a 'stone pond' from Lea Valley ( veritas). It came with a glass plate and micro beads( sorry don't know how to describe them) seems to the job though except when go to town on it at one end.
Thanks again.
Brian
The powder is standard silicon carbide lapping grit... 90x if I recall correctly. If your stone is getting thinner at one end, you are putting too much pressure on one end of the stone or you are holding it the same way each time you are lapping. Flip the stone back to front to even out the lapping pressure when you do the flattening. If for example you use a straight back and forth movment, the leading edge of the stone when pushing the stone away from your body will typically wear faster because it's running into fresh grit as well as the friction will tend to *pull* the stone closer while the rear portion rides on top of the grit + the slurry ground off from the front part of the stone which becomes slightly less abrasive. Flipping the stone front to back every few strokes will stop this from happening.
It's nothing to worry about though, no need to correct it just for the sakes of getting it even again, just try and adjust for it when you next need to flatten the stone and no, it does not need to be flattened every time you use it. That would just waste the stone away as that 90x powder is pretty aggressive.
Regards
Christian
Yes I haven't really been paying much attention to my lapping technique.
Thanks Kaptain
Brian
As stated, turn the hone 180 degrees often. Also use circular strokes in alternating directions and let whatever grit you choose do the work (i.e. use relatively light pressure).
I would just put the majority of pressure from my palm on the high side when lapping on sandpaper.