YAJCMT: Yet Another Jinma Chipper Modification Thread

[rswyan]

Got the feed roller lift/pivot converted over to foot-operated.

Cut two 10" pieces of (I think) 1" Schedule 80 pipe and welded them to the ends of the feed roller pivot arms @ a 45 degree angle. Then took the handle that I cut off of the forward portion of the feed roller pivot arms and used the O/A torch to heat it and bend it (in 4 places) to fit into the pipe I had welded on.

Also cut the rear portion of the feed chute apart and the modified the mounting tabs so that the rear side panels would be parallel to those on the front portion of the chute. This will require adding some additional metal to the bottom panel to accommodate the increased width:

Hopefully this last mod will allow the chipper to pull material in a little easier.

 

[rswyan]

Cut out the plastic bearing for the rotating chute last night.

I measured the bottom flange and then scribed a line using a set of dividers, sizing the O.D. of the bearing slightly less than the OD of the flange, and the I.D. of the bearing slightly more than the I.D. of the flange:

 

[rswyan]

Initially I tried cutting the oil-filled UHMW polyethylene with the Sawzall. This didn't work so well ... mainly because the teeth on the blade were facing the wrong direction, pulling the plastic upwards, leaving "fuzz" and obscuring the scribed line. And because it didn't take much to make the plastic ... smoke ...

So I tied a jig saw blade in a pair of Vise Grips (I don't own a jig saw ... but I do have some blades ) ... not really workable since the blade wouldn't stay in without cocking ...

I finally settled on a fine tooth hacksaw blade, which I hand held. It didn't take too much of that torture on my index finger before I donned an old welding glove.

This was very time consuming (1/2 hour or more ?) to cut the O.D. ... but I was able to follow the scribe mark pretty closely and the kerf was small:

 

[rswyan]

For cutting the I.D. I decided to try using something else that had a motor on it ... since I wasn't real keen on spending another 1/2 hour (or more) and expending all the effort. So I broke out my Craftsman Roto-zip tool.

It ended up being a lot more messier, but I was able to get it reasonably close (close enough) and it was a whole lot quicker:

I cleaned up the I.D. and O.D with a rasp and several different files. Ain't pretty ... but like I said: close enough ...

Tested out the bearing by placing it on the lower flange and sticking the lower part of the chute on top and rotating it ... works great ... kudos to TBN member 445A for the bright idea ... :thumbsup:

 

[Brad_Blazer]

Good thread, I have one of these chippers too and will be following, waiting for some good video of the unit in action.

A coping saw would be ideal to cut your plastic by hand. I have a nice scroll saw that works pretty good on plastic. A jig saw would also work. They do pretty good on metal too.
I got this HF cheapie and so far so good using their multi-pack of bi-metal blades. You can even fasten it under a piece of plywood with the blade sticking up for projects like this.
5 Amp Heavy Duty Tool-Free Variable Speed Orbital Jig Saw
T-shank All Purpose Jigsaw Blade Assortment 30 Pc

Edit: I see you're already done! Nice work with the roto-zip. Those things can be hard to control.

 

[rswyan]

After that I decided to change out the gear oil in the feed roller gearbox ...

What came out initially looked fairly decent - pretty clear ... but I decided to dig a little deeper ... so I took a blowgun and blew a little compressed air into the fill hole on the gear box. Got more oil out with some water mixed in.

I continued to feed it compressed air and as I was doing so I started getting dark crud/mud out ... which eventually turned dark black.

I got a 120 cc syringe and shot two loads of kerosene into the box, blowing it out in between each load. Looked pretty clear after the 2nd one ... may give it another before I put any gear oil back in.

Also got the 2nd knife blade and anvil removed, and several more rows of teeth sharpened on the feed roller (only 3 rows to go !)

Plan to power wash the unit later today to get any remaining crud off of it..

 

[rswyan]

Good thread,

Thanks.

I have one of these chippers too and will be following, waiting for some good video of the unit in action.

I'll have to see if I can borrow a phone that does video from someone ...

A coping saw would be ideal to cut your plastic by hand.

LOL ... yeah ... (you'll get a laugh out of this: I actually have a coping saw ... but no blades :confused2

I have a nice scroll saw that works pretty good on plastic. A jig saw would also work. They do pretty good on metal too. I got this HF cheapie and so far so good using their multi-pack of bi-metal blades. You can even fasten it under a piece of plywood with the blade sticking up for projects like this.
5 Amp Heavy Duty Tool-Free Variable Speed Orbital Jig Saw
T-shank All Purpose Jigsaw Blade Assortment 30 Pc

Nice ... :thumbsup:

I used to have an old Black and Decker ... was a nice little unit ... should have held onto it. But yeah ... I think I need something along those lines for the non-straight cuts.

Edit: I see you're already done! Nice work with the roto-zip.

Thanks !

Those things can be hard to control.

Yup ... that's exactly why I was hesitant and didn't use it initially for the O.D.

 

[LarryD]

I like the mods you're making to the chipper. I often thought about making a rotating chute for mine, just has not been high enough on the list.
The only real issue I've had was the fly wheel was not true in the housing. I noticed the paint getting burned on the upper left portion so I removed the face (front?) and adjusted the pillow blocks so everything was true. It's worked fine ever since. I also keep the blades sharp. The local saw shop charges $20 for the 2 knives and $10 for the bed plate. I have two sets so it's always ready to go.
I don't experience clogging of the chute. Chipping is small Fir and Alder branches and I can stuff an armful at a time. I wonder if tree species plays a roll in how well these work?
Can't wait to see yours finished and in action.