Scissors chatter

[Fineline]

Hi,
I'm facing a problem sharpening scissors and I hope I could tap on your experience.
I find that when the bevel is about even, the scissors tend to bounce against the wheel.
The strange thing is that it does not happen in all cases even though the settings are the same.
It is less pronounced when the stone is graded fine but it takes forever to get a burr.
I'm not sure if the material of the steel itself is a major factor.
I've also tried truing the wheel without success.
Eventually, I gave up and ground the scissors away from the wheel by placing the scissors jig on the horizontal USB.
Anyone has experience this before and what are your ways to overcome the hard bouncing?
Thanks.

[Herman Trivilino]

When that happens to me I vary the amount of force I'm exerting as I push the tool against the grindstone. It also helps to move the tool so that different parts of it are in contact with the grindstone.

I think what's happening is that the surface of the tool has been ground to match the surface of the grindstone. Somehow resonance is set up and the tool starts vibrating like crazy. It's worse at more blunt angles. I notice it with scissors and mower blades. Also if I'm just smoothing the edge of a piece of steel after I've cut it. I take it as a sign that no further grinding is needed as the surface has reached perfection. Hopefully a burr has been raised!

[grepper]

Are you talking about the squealing, fingernails on the chalk board, annoying vibration?

It happens to the best of us.  Start watching @ 2:30 and keep watching:
https://www.youtube.com/watch?v=HGFeBd8ZspM

It happens to me too, but it does not seem to be detrimental.  I've found that if you attach the jig closer to the edge it can help reduce the amount of vibration.

[Fineline]

Thanks Herman and Grepper,
It's not the noise that it's making, it's actually bouncing the scissors off the wheel;
something like driving along a road full of bumps or pot holes. That's what makes
me true the wheel just to be sure. As soon as the scissors contacts the wheel, it gets
'kicked' off even though I let the scissors very gently touch the wheel. I've also lowered the
jig to be just clear of the wheel.
No one encounters any 'kick backs' before?

[grepper]

I've had knives kick back, but never scissors.

What angle are you sharpening at?7

Is it just one pair of scissors, or do others do it too?

[Fineline]

60 degrees. Not all kickback. That's what puzzles me. I'll make notes next time.

[Herman Trivilino]

It's not the noise that it's making, it's actually bouncing the scissors off the wheel;

That's caused by the vibration. The same thing that's causing the noise. Just apply lighter pressure to stop the bouncing.

[Jan]

I have found useful the TORMEK tip, that for grinding scissors ,,the best working position is sitting on a chair in front of the machine."

[Ken S]

Jan, I believe working at a proper height and orientation to the Tormek is more important than generally recognized.

Ken