Gm220 blocks up with leylandii.

[PeteB]

Were you chipping close to the machine? If the flap is right down then the chips can struggle to get out. Is there a change in shape of the chute as it changes direction? A bulge or some such may cause the chips to ricochet into each other. Check the pulleys as a worn pulley will reduce belt grip....some had a limiter fitted so that the engine didn't drop too far.

[Mick Dempsey]

Hi Pete, no flap was nearly wide open, I know about that one.

The pulley thing, that's a good shout.

Thanks

[Ty Korrigan]

I think that the disc blade system needs the shear bar to be absolutely bang on to get this conifer through.

 

Bang on the money Mickolas!

I was running disc blades until recently when we chipped 100m of 2m high conifer hedge.

Almost no wood, just thin whippy material that got chopped into 24m3 of string!

You've seen the slight rounding of our shearbars on the other thread.

I now know it doesn't take much wear to make a great deal of difference.

Pre-soak the shear bars in de-grippant (I can't remember the English for free-ing up oil)

Ours where proper gummed in, no rust, just crusty plant juices.

Best of luck

Ty

[Ty Korrigan]

Oh, and yes to the flap angle.

Chipping in tight corners we've blocked on conifer when the flap angle was to severe.

Ty

[Tom D]

Check there isn't a bit of the discharge chute bending over on the inside, if you get a burr on the inside, even a surprisingly small one can cause blockages.

[Mick Dempsey]

Ok Tom, will do. I'll be doing the same as you Stu when we get a moment.

 

Thanks to all.

[monkeybusiness]

Not sure if it affects the 220, but 1928s have a thin steel flap that partially closes off the flywheel chamber exit (it is profiled so when closed/bolted down it sits above the flywheel itself, preventing chip from escaping the draft chamber before passing through the flywheel). If you open the top of the flywheel cover and look up towards the exit chute you should see it as a narrowing. These can break off and get folded out of the way or ejected entirely, and they make a massive difference to chipping performance.

Also, when the exit flap is set for maximum throw (ie wide open) you can sometimes have a slight gap that opens between the flap and the chute - stringy conifer can get trapped in here and lead to blockages.

Tight belts are a must though, and I'd also check that the flywheel hasn't moved away from the anvil (it shouldn't have done - if it has then this needs investigating/rectifying immediately!).

[monkeybusiness]

 

That restriction on the right is what I'm talking about. Have you had any luck finding your fault?

[Mick Dempsey]

I've been on holiday, just come back.

I'll have a look at that flap thingy, but I'm convinced it's the shear bar.

6 months ago it chipped this stuff just fine, no bother. Even now, anything but leylandii goes through as good as ever.

The shear bar is fairly worn anyway, does anyone know if they can be turned?

We're putting a new one in the TW this arvo, so we'll have our eye in for the GM in a few days.

[monkeybusiness]

Every GM shear bar I've done has been turnable, but I've had a couple come out cracked in half. They are pretty dear but don't need replacing very often. They can be a pig to get out...