Very Pointed Shears
When any shear gets sharpened many times they get thinner toward the front of the blade.
The effect this has on the shear is they will fold the hair, its noticeable more on 10 inch shears than 8 inch.
As you see in the comparison of the top shear to the bottom one, the blades of the top shear are a bit thinner at the tips. Both shears are the same brand and model.
When the tips get that thin the shear will sometimes fold the hair.
Tension can be adjusted to make them cut, but when going from breed to breed they may fold again.
They may work good on small dogs because the hair on most small dogs will lay flat.
The coat on bigger dogs is quit the opposite, its lays on its self or lays in "bunches". When you try to cut it folds, good example is around the feet.
Why does it fold the hair? Because the tips are too pointy and there isn't enough metal left at the tip of the shear blade to make it rigid and stable, so the blades push away from each other thus folding hair.
Fixing Pointed Shears So They Work Correctly Again
A good sharpener, especially one who uses shears in grooming, will see and anticipate a shear folding hair if it has narrow tips.
The fix is very simple and non-evasive, most times you can't tell the difference when cutting.
The tips should be ground back 1/8th inch or so to give the tips enough width and rigidity again so it will cut tough coat without folding anymore.
When I see shears that look like hypodermic needles, I call the customer and discuss options. If your shears get in this condition they become very dangerous not only to your client, but to you as well.
If the shears are in need of something, I usually get the "OK" to do the "Fix" on them.
Below is an illustration of what has to be done to get more width at the tips of the blade.
If the tips are fixed as shown, your shears should work properly again. By looking at this shear, most good sharpeners can tell you've used them for many years and they are probably your favorite shear.
Sharpening once usually isn't the problem, shears get this way from being sharpened over many years. Let the sharpener fix them while they are being sharpened. Shears can only be fixed so many times when in this condition, so now may be a good time to just "let go" and find a good replacement.
I get 1000's of shears to sharpen every year, and I see some very bad decisions made by fellow sharpeners. This condition is probably the worst that can happen to someones shears, its called "The Grinding of Handles".
I know you've seen this on your shears sometimes and this can be avoided 99% of the time. Who ever did this to these handles doesn't know the correct way to adjust shears. Imagine someone doing this to your expensive Kenchii shears....OMG!
As shears get sharpened the tips will eventually get a "gap" over time and won't close all the way. Cutting with them like this will snag hair at the tips. You check for this by closing your shears, and if they are open a tiny bit at the tips, the handles need adjusted outward to let the blades close all the way again. The fix is very simple, you bend the handles outward enough until the tips close all the way again. Now the exception to this rule is cast iron shears. If the handles need widened, then grinding them like shown may be the only way to get them to work. If you try to bend cast handles they will snap like a potato chip.
Choose a good sharpener even if you have to mail out, there are plenty of us out there.
Be Safe, Have Fun, and Read Those Labels :)