Chippers

[Husky288XP]

Do you guys have your chipper knives ground so that the knife is a double edge, a knife with a back taper? I have heard of a local guy that does this, and he claims that his knives last alot longer then the single edge knives.

 

[BigJohn]

Does it cost more? I wouldn't buy into it. Watch what get thrownin there. If take care of the blades and don't go shoveling rakeings up from the road and throwing them through a set of blades can last a long time.

At one time we were running a 250 xp hard everyday. We neve aloud to throw anything through but brush and logs. Once a month or so one guy would just dress them up a bit with a file. Granted we did mostly poplar trees.

The one boss who took care of the chipper was a penny pincher and excesive compulsive who would get down on his knees and prostectic leg that he chipped once and pick up all the little sticks.

 

[Ax-man]

My Morbark manuel mentions this, supposed to be good for dead material. keeps the edge on the knife for a longer period. Never have tried it myself.

Larry

 

[NeTree]

You mean a microchamfer?

 

[Stumper]

I've tried a microchamfer/tiny back bevel. Generally I just sharpen with a compound bevel on one side only. (I do a slight hollowgrind at the original bevel angle then put a second, blunter bevel at the edge.) That grind cuts better than the original and is more ding and chip resistant.

 

[Newfie]

Back bevels are for chisels and planers. A chipper knife is similar but hardly doing the same type of job. With the intense demand of a chipper application you run a greater risk of breaking off your edge with the back bevel. At least that's the way I understand it.

 

[Tree Machine]

Am I understanding the microchamfer to be ground from the backside of the bevel, like this?

 

[Stumper]

Well Jim, apparrently you've tried it. What'd you think? I had no problems with a teeny one but was disinclined to pursue it. -Since the chipper works as a bypass cutter against/past the anvil/bedknife it just seemed wrong. Back bevels ruin scissors and papercutters. -Of course the chipper has a clearance rather than actually working against the bedknife so maybe I was worried about nothing.

 

[NeTree]

No, more like this:

 

[Tree Machine]

Been doing it for years. All you say is correct about the back chamfer. You want to chamfer the backside in as little as possible. As the knife wears, the bypass gap between knife and anvil increases and chipping efficiency wanes a bit, but not a lot.

There is nothing that chips as fine as a brand new knife, but it's only brand new until the first initial resharpening. I try for the first half dozen or so sharpenings to NOT put on a back chamfer. When I do put on the back chamfer, it is a light pass, more or less to knock the burr off. Then you give em a couple strokes with the carbide knife saver and you're sizzling sharp, ready again for action.

Too much of a back chamfer is a bad thing. A little is OK.

I get your picture, ne, mine get the chamfer from the other side, like this:

 

[NeTree]

It looks big in the picture, but that's only for illustrative purposes. In reality, it's only a few mils wide.

 

[Stumper]

Erik, Your illustration is what I do-except I'm doing it on a 5" circular wheel so that both bevels are slightly hollowground.

 

[Tree Machine]

agreed

I do hollow-ground the front face, as per Stumper.