Chipper Jimna Chipper: Cutter Bar to Blade Gap

[weldingisfun]

If you own a Jimna Chipper I would sure appreciate your input.
The Operator's Manual calls for a gap of between .010 to .030 inch between the cutter Bar and the blades. That just can't be correct!
The gap between the two set by the factory is nearly 1/4 inch. When I did a test run with the factory setting, many small twigs passed through or were shredded. I would be concerned about jamming if I cut a lot of "bushy" branches. I will be shredding mostly cedars and junipers.
What gap have you set between the cutter bar and blade?
Also, what size Allen wrench does it take for the cutter bar mounting screws? I have metric wrenches and sockets, but no metric Allen wrenches.

 

[LarryD]

I had the same problem when I first used mine as well.

I think I got the gap set at .025 but will have to check tonight when i get home. I'll also see what hex head fits.

Another thing I had to adjust was the plane of the pulleys. Had to put a couple of shims under the PTO shaft pillow block to get the two pulleys in the same plane. It wasn't a big deal but I could see the beginning of undue wear on the belts.

 

[SPYDERLK]

I think it works/feeds better with a large clearance. I run it about 0.080.
Larry

 

[LarryD]

Well, I wasn't able to check the gap on the chipper (it's up against the wall in the shed) but I did get the 5mm hex wrench in enough to confirm that is the size needed. Looks like you're gonna have to by a set of hex wrenches, Oh the joy of owning machinery.

I have run some pretty small twigs through mine and have also had to clean the pulley that connects the feed roller assembly to the main shaft. Lots of stringy stuff accumulates there. I don't really worry about it though, just sort of clean/check things out when greasing everything.

 

[moeh1]

Yes, the gap is supposed to be quite tight, my old gas chipper was even less. Too big a gap actually requires more power and leads to much quicker dulling of the blades. My chipper had about .060 runout between the 2 knives, so I ended up shimming one. I thought it was front shaft misalignment, but I couldn't improve the situation , so I used a piece of sheetmetal as a shim under one blade.

 

[dirtrod]

Mine too had the gap set to ¼ inch as delivered to me; it was VERY prone to clogging with that large gap. I closed mine down to the suggested .030 inch and it has not clogged since.

 

[Ranch_Hand_Supp]

If you own a Jimna Chipper I would sure appreciate your input.
The Operator's Manual calls for a gap of between .010 to .030 inch between the cutter Bar and the blades. That just can't be correct!
The gap between the two set by the factory is nearly 1/4 inch. When I did a test run with the factory setting, many small twigs passed through or were shredded. I would be concerned about jamming if I cut a lot of "bushy" branches. I will be shredding mostly cedars and junipers.
What gap have you set between the cutter bar and blade?
Also, what size Allen wrench does it take for the cutter bar mounting screws? I have metric wrenches and sockets, but no metric Allen wrenches.

I sell my Jinma wood chippers serviced and blade adjustment is one part of my service. I also find them with 1/4 inch or so gap.... to much gap.

The gap effects the size of the chip , operation and wear on the machine [belts, feed drive etc.etc].

The thickness of a dime is close to .030. I think that is good gap for the Jinma 6 inch chipper when chipping hard and soft wood. The blades also try to pull the wood into the chipper.

The Allen wrench for the Anvil [cutter bar] is 5mm and 16mm for the nut. Hold the bolt with the allen and loosen the nut with the wrench.

Ronald
Ranch Hand Supply

 

[moeh1]

Ranch hand left out one point, it is tough to reach both ends by yourself and get the clearance right, this job goes much faster if you get a helper - I didn't have that luxury and it wasn't fun.
Best of Luck with it!

 

[Ranch_Hand_Supp]

Ranch hand left out one point, it is tough to reach both ends by yourself and get the clearance right, this job goes much faster if you get a helper - I didn't have that luxury and it wasn't fun.
Best of Luck with it!

No, I was giving my opinion on the anvil gap, wrench sizes and a wrench tip.

But, if you remove the four bolts that hold the feed shoot on .... you can reach the bolts then or at least I can. A helper is always nice. It has to be a one man job in my shop when we service them prior to the sell.

Ronald
Ranch Hand Supply

 

[weldingisfun]

Thanks to everyone who contributed. I knew I could rely on you.

Moeh1, I understand what you are saying about a helper. I am blessed in that regard, I have a helper who has been by my side for the last 39 years. While she doesn't know exactly what I'm doing half of the time, she always does what I need her to do if I explain the how and why to her.

Ranch_Hand_Supp, thank you for your input. You must be a tall fella with long arms. I'm not sure I can do that kind of reaching even with the feed chute removed. But like I told Moeh1, I have the best helper anyone can find. You have been most helpful. Thanks again.

I should also mention that the guys at Affordable Tractor Sales, Tommy and Jerry have helped too. I have spoken with them on the telephone so you didn't see that in this thread. In fact, Jerry is sending the 8mm x 1.5 grease fittings (zerks) that I need to change out the Chinese zerks. No one within 20 miles of here carries the 1.5 thread pitch. All they have is the 1.0. I've even asked them to order them for me and was told, "no can do".

Just an observation, for what it is worth. In the two metric socket sets that I have, 1/2 and 3/8 drive, there is no 16mm. Most of the fasteners on the chipper are 16mm. That must be a common size for the equipment built to metric specs? That is probably also why our tool manufactuers don't include them in the sets. A Kobalt (Lowes) 1/2 drive metric socket set goes for about $17 -$18 for ten sockets (10, 11, 12, 13, 14, 15, 17 18, 19, 20 mm). The 16mm socket sells for $3. Hmmmm!

 

[Ranch_Hand_Supp]

Ranch_Hand_Supp, thank you for your input. You must be a tall fella with long arms. I'm not sure I can do that kind of reaching even with the feed chute removed. But like I told Moeh1, I have the best helper anyone can find. You have been most helpful. Thanks again.

I should also mention that the guys at Affordable Tractor Sales, Tommy and Jerry have helped too. I have spoken with them on the telephone so you didn't see that in this thread. In fact, Jerry is sending the 8mm x 1.5 grease fittings (zerks) that I need to change out the Chinese zerks. No one within 20 miles of here carries the 1.5 thread pitch. All they have is the 1.0. I've even asked them to order them for me and was told, "no can do".

Just an observation, for what it is worth. In the two metric socket sets that I have, 1/2 and 3/8 drive, there is no 16mm. Most of the fasteners on the chipper are 16mm. That must be a common size for the equipment built to metric specs? That is probably also why our tool manufactuers don't include them in the sets. A Kobalt (Lowes) 1/2 drive metric socket set goes for about $17 -$18 for ten sockets (10, 11, 12, 13, 14, 15, 17 18, 19, 20 mm). The 16mm socket sells for $3. Hmmmm!

Hey weldingisfun, I a 5 foot 9 with tired sore fingers and back...lol

No doubt, the Affordable Tractor boys will/can take care of you !

On a side note, a 5/8 will take the place of a 16mm.

Good luck with your Chipper.

Ronald
Ranch Hand Supply

 

[joe48]

Little history lesson, I had a coop job incollege as an agr engineer intern, working for PAPEC Machine Co.
If you're an older farm boy from the NE ,you'll recognize the name as the premier silage choppers in the 50s and 60s. They even made units for Case ,IH, John Deere, etc. and also held most of the original patents on self unloading forage wagons.
Anyhow we spent a lot of time working on the importance of blade shape ,angle or bevel of the grind, CLEARANCES between blade and anvil.
The long and short is : the tighter the clearance can be kept and the sharper the blade and the edge or corner of the anvil can be, the more efficent the machine will work and the less horse power will be required.
Picture an old pair of scissors that that have dull blades or too much gap or bent blades ,trying to cut newspaper, they just pull the paper in and jam and don't cut. Same thing with wood ,branches or corn stalks.

AND MOST IMPORTANT be very carefull where your fingers are when working on things like this, those blades will cut fingers a whole lot easier than branches !!!!!! I have ten fingers , but know some folks that don't!!!!!!

 

[weldingisfun]

Setting the gap between the cutter bar (anvil) and the blade is easier to do with some sort of guage. I have discovered that the plastic ID card I wear to work is exactly .030" thick. It works perfectly. Oh, I used an old one, not the one I wear everyday.