Help a homeowner with his chipper?

[old_oar]

First, I really appreciate any help, and the professionals willing to reach out. I can answer questions in other forums but not here!

I have a barely used DEK Brushmaster 15 hp chipper - single blade on a rotating disk, leaf chute on top. Total run time is less than 20 hours.

It's been in storage inside for a year, and I tried using it this past weekend, and it won't chip without using considerable force to push the wood against the blade. I don't remember it working like that last year.

I sharpened the blade (although it seemed pretty sharp), minding the angle, and it was sharp enough to cut paper after I was done. I'm pretty confident that the angle of the blade now is incredibly close to how it came out of the machine, and it did not look worn down when I took it out.

It still won't chip properly after sharpening. No debris wrapped around the shaft, and if there's an adjustment on the machine for angle or depth, it's not obvious to me.

The distance between the blade and the reinforced sidewall is just shy of 1/4". I tried chipping two small, dead and dry branches and it left burn marks on the blade, which I didn't see before.

I'm not sure what to do here and looking for suggestions. Set it on fire at the end of the driveway? Use it as a planter?

Thanks to anyone who can weigh in!

 

[Del_]

One-quarter inch sounds like a large gap between the knife and the bed. Do you have a spec for that? Also the bed against which the knife cuts needs to have a square Edge. If it is rounded even the large chippers perform poorly. Are you sure the bearings are good on the disc that holds the blade? If the bearing is loose the knife will run away from its work. By-the-way that is a really small chipper.

 

[old_oar]

Thank you Del!

I do not have a spec for the gap. Hours of internet research and trying to get someone at DEK haven't been successful. I've called them more than 12 times, trying all sorts of extensions with no luck, not even being able to get a receptionist or salesman. I called two retailers who used to sell their machines and still have them on websites, but they don't have manuals (other than the shipping/install ones) either.

That's a good idea to check the bearings. I don't have a spec for runout or anything, but it's worth a look.

I know it's a small chipper, I'm a homeowner trying to get rid of yard waste once a year, and I thought it would be adequate. With all this effort, I might be better off carving the brush up with a penknife!

 

[old_oar]

@Del_ I checked the bearings, and there's no movement at all. I'm pretty familiar with replacing automotive bearings and I've also replaced some on my furnace, and these shaft bearings seem basically new to me.

There's no square bed for the knife to cut against, here's a photo of the opening, it's oval.

IMG_6178

• old_oar
• Nov 19, 2019

What about shimming the blade so that it runs closer to the edge of the body (which is serving as a bed to the knife)?

There doesn't look like there's anything missing in the chute that would make the cut angle square to the blade.

Thanks again!

 

[Marshy]

Are you certain the blade went in the same as it came out? Maybe its flipped over? I'm not an expert, just a far reaching though... maybe it's just the wood species and moisture content. Did you try a piece of green wood?

 

[old_oar]

@Marshy - I think the blade is correctly placed. The bevel is towards the inside of the machine, so the angled edge is facing the direction that the wood chip travels after it's cut.

I did think it might be in backwards, but the "face" of the blade has countersunk hex heads so there's nothing for the wood to get stuck on. If it were upside down, the sharpened end wouldn't come in contact with the wood.

It would help to have a manual!

As far as wood, I've tried a bunch of different types, and none of them are big either.

I put washers between the blade and the plate that turns so the blade is closer to the body of the machine, lessening the gap to about 1/8" I would guess. It cuts a little better, but still doesn't "grab" the wood as it did before.

For reference, here's the size of the chips coming out now, with a dirty penny for reference.

Thank you!

 

[Del_]

When I mentioned 'square edge' I wasn't talking about the shape of the opening. The thickness of the metal making up the bed knife gets rounded from use use on all chippers. This lets material 'bend' some as the knife hits it. I've had bed knives rebuilt with welding and then ground and filed square again. The bed knife in my chipper has four square edges and can be remove to provide a good square edge. Yours is a part of the chipper and would likely have to be dismantled to have the edge rebuilt. From your photo the edge doesn't look bad.

 

[old_oar]

@Del_ Ah, now I understand and that makes sense. Thank you for that.

Maybe I'll clean that edge up to see if it has any effect on the chipper's efficiency. Time to file . . .

Thanks!

EDIT: the edge is already pretty square and sharp, with not much buildup of tar at all, so I left it.

 

[Kewadin]

I have a mid 80's Troy Built Tomahawk w/8hp B&S and your problem could be a loose belt. I can usually tell when it doesn't develop that high rpm sound.

 

[old_oar]

@Kewadin - thanks for the idea. I did check the belt and it seems to be normal tension to me and not slipping. Again, i don't have a manual to see if there is a spec. Thanks again.

EDIT: I did check the belt, and it's as tight as I dare make it.

 

[Kewadin]

My machine has a throw lever that brings the belt tight to start turning the flywheel. It also has a belt adjustment screw to tighten as needed. When adjustment gets maxed out you might need a new belt.

 

[old_oar]

My machine has a throw lever that brings the belt tight to start turning the flywheel. It also has a belt adjustment screw to tighten as needed. When adjustment gets maxed out you might need a new belt.

This machine adjusts the belt tension by sliding the motor either closer to or further away from the rotating shaft. There's plenty of adjustment left, the belt is still almost new, and it fits tightly on both sprockets. The machine seems to spin up to the proper speed too. Thanks for the suggestion!

 

[old_oar]

Screen Shot 2019-11-20 At 15.59.59

• old_oar
• Nov 20, 2019

These are the only instructions I have for the belt.

 

[Kewadin]

I looked up your machine and it mentions a centrifugal clutch is used to protect the engine. Maybe it slipping under load?

 

[old_oar]

I looked up your machine and it mentions a centrifugal clutch is used to protect the engine. Maybe it slipping under load?

That's a good thought, thank you. If the clutch is slipping, then it would lead to the machine not feeding branches and needing pressure to get the branch through?

 

[old_oar]

I looked up your machine and it mentions a centrifugal clutch is used to protect the engine. Maybe it slipping under load?

@Kewadin - Thank you! I took the clutch off and it's completely jammed, the rubber bushing around the bearing seems to be melted too. Hopefully this is the problem. I don't have an parts manual, no one at DEK will answer the phone on any extension, so I'm going to make another post to see if anyone can ID this centrifugal clutch. I haven't had to deal with these since I was a kid with go karts . . .

Thanks again!

Anyone know what clutch this is and where to get one?

IMG_6214

• old_oar
• Nov 21, 2019

Trying to identify this centrifugal clutch from a DEK 15HP Chipper.

IMG_6215

• old_oar
• Nov 21, 2019

Trying to identify this centrifugal clutch from a DEK 15HP Chipper.

IMG_6216

• old_oar
• Nov 21, 2019

Trying to identify this centrifugal clutch from a DEK 15HP Chipper.