Chipper Jinma 6" pto chipper, seized bolts

[Brit24]

I inspected the blades and found 2 or 3 the bolts were standing slightly proud of the blades. I can't for the life of me get them to move. I suspect they have been bent slightly because they were being struck by wood.

Anyone have experience with getting these suckers out?

 

[5030]

Go get yourself a 3/8 drive socket with the hex insert and wrench them out. You'll never do it with a regular (allen) hex key. I have the same chipper but an 8". Matter of fact I'm taking a break from using it right now. Lowes will have a Kobalt one. Take the nuts off the backside first and soak them down with P Blaster. Fastenal will have the 8.8 Holochrome replacement flat head bolts and the nuts as well.

 

[quicksandfarmer]

The hex head is only for keeping it from spinning while you put a wrench on the nut on the back. If you try to loosen it using the hex head it will strip out. The hex head is only good for limited torque, if the bolt is frozen it may strip. I would try PB Blaster and an impact wrench. If that fails you can try an easy-out to keep it from spinning, or drill them out.

 

[Brit24]

Thanks for replies. I did get the nuts off, but the hex-head screw is stuck fast even with the nuts off - I'll try going with bigger wrench, but suspect it will round out the heads, so may be I'm going to have to drill them.

 

[5030]

Remove the nuts (you already have), soak them with P Blaster or Liquid Wrench (preferrably) overnight and then try the hex socket on the heads while tapping the back end of the bolt (where the nut was) with a punch and hammer, it will be a 2 person job. On a Jinma, the cutter fits in a pocket so all the bolts do is keep it in the pocket.

if you are removing the cutters for sharpening, you need to hold the included angle at 27 degrees. I sharpen mine on a surface grinder in an angle jig. Gets them perfectly square and razor sharp too. The bed anvil needs to be set 0.030" to the closest knife (the width of an ordinary credit card. When I sharpen my blades, I take the bed anvil and square it on an angle plate and take a couple grinds to remove any nicks. The secret to a good running chipper making nice sized chips, is sharp knives and proper anvil to knife clearance.

 

[carmedic310]

Remember to coat the new bolts with never sieze before replacing them

 

[5030]

I just made another huge pile of chips. Best 1100 bucks I ever spent. I did modify my Jimma a bit. I had an issue with viney stuff wrapping around the end of the shaft where it comes through the end plate and it was building up and popping the drive belt off (PITA to put back on) so I machined a piece of flat sheet hot rolled (1/4" thick) with a bore about 0.020 larger that the stub shaft sticking out and welded that to the back plate. That keeps the viney stuff in the housing. I was chipping Eussian Olives bushes and grapevines today (grapevines are the ones that popped the belt), no issues at all, everything stays inside where it belongs.

I had to make a set of extension feet for mine and I added runners too. The chipper sits way too low for the big tractor I use it on, I'm running it on a 100 pto horse Kubota, about 3 times what it needs. I can chip a full 8" hardwood log, no issue, don't even slow down. Normally I don't. I don't heat with wood but I have a guy that takes all my wood and splits it and sells it to campers. he 's the parts manager at the dealer where I get my net wrap and bailer twine so he gives me a deal....tit for tat so to speak. I chip everything under 2". he gets the rest.

 

[Brit24]

I've made progress - I got the stuck bolts out, but they were badly stripped in the process. I thought the thread would be damaged too, so ran a chaser through, and that only stripped the tool as well, which was puzzling.
It rurned out the blades themselves were out of alignment and the toughened steel was stripping any bolt put through.
Once I took everything off and cleaned out all the compacted wood, I could get the blades back on properly aligned.
What a monumental PITA.

Lesson learned - release all all blade bolts gradually together, not one at a time.

I had to take the feed roller off to get at everything, and now facing putting it back on. A lot of this would be easier with two people, but I have to do it on my own.

Any tips on how to get that spring compressed and the rods back together without busting another vein?

 

[5030]

Put the assembly on the gearbox / clutch end and grab the feed roller end in both hands and pull back, when the square drive is over the feed roller end (but not on, rotate the feed roller until it lines up and drops in. Wear an old shirt and gloves and plan on tossing the shirt afterwards. I keep mine extremely greasy (I dip mine it heated grease when it's off the machine.

Woodmaxx has a nice bellowed replacement for a price.

Fastenal will have your bolts (and nuts, be sure to get insert nuts). Circle C and Woodmaxx has them too if you can wait a while (for shipping). If you are going to sharpen the blades, I suggest taking them to a machine shop with a surface grinder to grins them square and at a 27 degree included angle. it's almost impossible to do by hand... it is impossible actually. I run my blades in the shop I own on one of our toolroom grinders in an angle jig.

Properly sharpened, the come out razor sharp, literally. It's good steel and takes a nice edge.