grinding horizontal or vertical?

[inferno]

so i just wanted to know how you guys grind.

I have a small floor sander grinder at home that i use in the horizontal orientation with upper side of belt going away from me, and i find this quite good. its almost like grinding on stones. and i have lots of experience on stones so i guess my brain is already wired up for it.

i can also mount mine vertical. but i have never tried it to be honest. but i think this will also be good.

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if i was getting a kmg or similar i would definitely run it vertical with the plate attachment. but i guess horizontal would work here too.

then we have the wheel. grinding on a contact wheel. i guess this quite nice too. if you learn it.

whats your preferred grinding orientation and why?

 

[kbright]

It depends. The important point is to feel comfortable and in control of the blade angle and applying pressure. I usually do distal taper on a horizontal platen, I feel I can control the pressure better in this orientation. For bevel grinding, especially near the tip, I use a vertical platen. When I make mistakes, cut a groove, I usually fix it on the vertical platen, but then need to even out the wave on the horizontal platen. I have multiple grinders, including a KMG.

I have a 10 inch contact wheel that I use for blade profiling, faster than a flat platen. The wheel can also be used for hollow grind bevels, which are currently out of favor. Belt grinders generate heat, have a bucket of water ready for cooling hot steel.

 

[inferno]

yeah i also feel control is the most important thing when grinding after HT. i dont feel i have full control with really high revving stuff. those are for pregrind imo.
the setup i'm running now is maybe 20cm lower than my eyes so i can see all thats going on. its not at "hip height" that is normal height for grinders. i feel this is a big advantage to keep control.

regarding heat: i was just out grinding today just outside my front door with the floor sander. put a 40 and a 60 grit belt on there.
and i could grind for a quite good bit of time before i needed to cool the blade. i grind with thin medical rubber gloves.
i could go maybe 2 minutes with medium pressure. but if i really pushed it i could take the blade to very very hot in like 5 seconds. but then the machine revs down to 50% or so.
my machine max out at 250m/minute i think. and real industrial grinders are at 34m/s or 2000m/minute.

i have one of those 2000m/minute grinders at work and its almost completely unusable because of the belt speed. it overheats everything in about 3-4 seconds no matter what. it melts steel.

 

[kbright]

Most full time knifemakers have a variable speed controller and 3 phase motors on their grinders. You can slow things down and have less worry about burning the edge. I grind until I feel the heat burn my fingers, then dunk. I also don't go past 220 or A65 on a high speed grinder after heat treat; finer grits increase the heat generated. I use "draw filing" by hand with the blade clamped and sandpaper wrapped around a bar; sort of inverted water stone grinding. Water stones for the edge.

 

[milkbaby]

I prefer vertical with the edge up so I can more easily judge the contact point by eye. Also less likely to take the edge too thin when I can see it. Everybody is different though.