sharpening chipper blades

[Mr Ed]

What they call hollow ground knives. A hollow grind is always better on most machines, but its more expensive to set up for sharpening, and your blade edge is'nt as strong. Chips better though, just as a hollow blade hunting / skinning knife cuts better

[Simon]

i seem to remember a few years back timberwolf started to recommend the blades were sharpened with a concave surface rather than straight surface....if i also recall right didnt they change their mind on this? whats the current recommendation regarding that?

 

Timberwolf recommend a hollow ground bevel because it acts more like a planer than a chopper, this is kinder to the blades but does weaken the knife edge.

 

Becareful though, the angle still requires to be set at 42 degree for the 35/150 and 41.5 degree for the 190 with a slight radius.

[Mr Ed]

Hey Simon, Good to see you.

[Stumper]

What I prefer to do is a double hollowgrind. That is...I hollowgrind the thick part of the bevel without getting all the way to the cutting edge then grind the actual cutting adge at a "blunter " angle. This produces a sharp edge that has a bit of steelbehind it so it is strong but the bulk of the blade cleaves though with decreased resistance ( This is more of that hunting /skinning knife technology which Ed was mentioning.)

[Mike]

When we ran TW hire machines we found we got better blade wear with a flat ground blade. The hollow grind is more efficient when the blade is sharp but as Simon says this makes the blades edge weaker. Once damaged the blade wears much quicker. Again Simon is right when he mentions angles. You won't beleive the variants we get in. Bad economy as all you end up doing is sharpening twice as much blade away to correct the angle.

[Shansen]

I have a disk chipper and I touch up the blades 3 or 4 times in the chipper with a hand grinder and then one of those carbide knife sharpeners that you draw down the blade. Then I send them off to be sharpened at an Industrial sharpening place for $32

[bob]

i seem to remember a few years back timberwolf started to recommend the blades were sharpened with a concave surface rather than straight surface....if i also recall right didnt they change their mind on this? whats the current recommendation regarding that?

 

when we got our tw250 we decided to send them back to our tw dealer as if anything went wrong they always blame wrong angle or not hollow ground and were amazed when they came back flat ground we could have same done local for half price so i phoned tw and were told they are not worried as long as we run sharp blades rather than dull ones they were happy so we are now flat grinding local :bongsmi::bongsmi:

[Kev Stephenson]

when we got our tw250 we decided to send them back to our tw dealer as if anything went wrong they always blame wrong angle or not hollow ground and were amazed when they came back flat ground we could have same done local for half price so i phoned tw and were told they are not worried as long as we run sharp blades rather than dull ones they were happy so we are now flat grinding local :bongsmi::bongsmi:

 

Who do you use Bob??

[bob]

i do my own but work use the same as you kev saw and tool

[bill]

i do my own but work use the same as you kev saw and tool

 

 

bob, do saw and tool sharpen blades? how much?