YAJCMT: Yet Another Jinma Chipper Modification Thread

[rswyan]

Before I put the tube into place on the bottom flange I stuck some washers down on the flat "ledge" ... to shim up the tube and provide clearance so that the tube wasn't dragging on anything in the lower part of the bottom flange.

The tube extending into the bottom flange helped to align everything and alleviate the tube edge being in the chip discharge path:

 

[newbury]

Q - Why did you choose the rings w/o holes?

It looks GOOD.

 

[rswyan]

Q - Why did you choose the rings w/o holes?

Because with the clamp design that I'm going to use they really aren't needed.

The clamp ring will be a piece of 1/8" x 1" flat stock that has been formed into a circle/ring that fits around the outside of the flanges. It will have a long nut (aka coupling nut) welded to it on one end and a piece of small diameter tubing welded on the other.

A piece of of threaded rod - which fits thru the small diameter tube and has a "T" handle welded on the one end will be used to draw the clamp tight. The clamp will also have "tabs" (1/8" x 1" x 1") welded to it on top and bottom, which serve to capture the two flanges together vertically.

So to tighten it and hold the discharge chute in a fixed position you just screw the T handle in, and even when it's somewhat loose for adjustment/rotation, the flanges are still captured together to prevent the discharge shoot from falling over/off.

It looks GOOD.

Thanks !

 

[rswyan]

This is the (unfinished) band clamp which will secure the upper flange on the chute to the lower flange on the chipper itself:

It's made from a piece of 1/8" x 1" flat stock that I formed by bending it around a 125 cf shielding gas cylinder. The forming isn't perfect ... but it doesn't really need to be: when it's tightened up it conforms to shape of the flanges. I did give it few taps with hand sledge the first time I tightened it around the flanges ... just to try and conform it to a little better fit.

I used a couple of metric coupling nuts (one longer, one shorter) and some metric threaded rod ... all extras that were left over from the install of the rooftop AC unit on my van. One nut is welded to some 1" angle (also trimmed on one side) which itself is welded to the band.

The rods on the "t-nut" were what was left of the pins that I had to drill out when I shortened a couple of load bars to fit the van. Also used some 3/8" I.D. steel brake/fuel tubing that I had lying around ... it is welded to another piece of 1" angle (also trimmed on one side)

On the tubing I really would have preferred to have used something with a little thicker wall ... but this will probably work fine. If it don't then I'll cut it off and weld on something heavier.

The thread rod is just screwed in to the coupling nut that is welded on the angle/band. Dunno ... probably will Loctite it in there. Didn't really want weld it ... seemed a little too permanent.

Still need to weld on the tabs on the band to finish it.

 

[rswyan]

In the picture below is a piece of 1/8" x 1" flat stock that I formed with a hammer around a piece of 3 1/2" O.D. pipe ... it is the mounting surface for the chute rotation handle and serves to spread any force exerted over a larger area of the 6" tube.

Beating it around the 3 1/2" pipe got it fairly close ... and a pair of large hose clamps (52's) strung together got it close enough to tack in place:

 

[rswyan]

Tacked:

(That rusty old thing just below it is the 3 1/2" O. D. pipe that I used to form it )

 

[rswyan]

Stuck it on the pipe rollers and welded her up:

 

[rswyan]

Looks like I missed getting a shot of the T handle that is used to rotate the chute ... you can barely see it in the bottom of the picture below, just to the right of the rollers:

The image above was actually intended to show the loop handle that I put on so that the force applied to turn the chute would be balanced and there would be less of a tendency for the chute to bind while being rotated.

 

[rswyan]

Probably pretty much done on the chute rotation handles ... might add a couple of rods for braces on the t-handle tho':

 

[rswyan]

One of things that I felt really needed some work was the feed roller ... specifically the teeth. So the other day while I was Harbor Freight I picked up a 4 piece set of (large) files for $8 which included a double-cut coarse triangular file.

As I see it, the problem(s) are several fold:

1. The teeth themselves are small ... based on what I've seen on other wood chippers.

2. The tips of the teeth are too large, are mostly flat (rather than pointed) ... and have too much surface area to allow easy penetration into the wood.

3. The teeth are irregular and inconsistent in size.

So I attempted a little "dentistry" ... originals towards the left (and very bottom right), sharpened top and towards the right:

We'll see how this works ... if it works at an acceptable level then fine.

If not, it could be time for a more serious rework.