Jinma Model 6 Chipper and Adjusting Anvil

[Michael_C]

I am trying to adjust the anvil on the Jinma chipper, but I don't think my approach is good. I'm using a piece of sheetmetal with a single bend, going down it's length, as a shim. The blades are not vertical with the bottom of the blade being roughly .100" closer to the anvil than the top. I place the shim between the anvil and blade and have the flywheel rotated such that the left side of the blade is at the top of the anvil. The top of the anvil is just below the middle of the blade when you look at the right side.
When sliding the anvil towards the shim, the left side is backed by the bottom of the blade, and the right side is backed by ~ the middle of the blade. This could result in ~.050" difference between in gap from left side to right. If I use a .020" shim, the blade will contact the anvil on the right side. If I use a .050" shim, I get a light rubbing on the right side when rotating the flywheel.

What's the best way to adjust the anvil/blade gap? Adjust when the center of the blade is aligned to the top of the anvil? Or, set the gap on left side, first and then the right side? Some other approach??

 

[mikester]

Can't you shim only one side of the anvil?

I don't know of its the photo but your blades look backwards? Cutting edge to the front?

 

[TMGT]

Adjust the right side with a feeler gauge while the cutting edges against each other, then rotate the flywheel and adjust the left side.
Have the bolts tightened just enough to cause some drag on the anvil but still able to move easily.

It might take a couple tries depending on how well the anvil will adjust for you. Also don't forget to check the clearance on both knives! Adjust to the tighter one, better to have one with a little extra clearance then one too close.

I don't have my manual with me but .100 is way too much. .010-.030 is the spec. I believe.

 

[5030]

Use an old credit card. That will give you about 0.030. Heat the card with a heat gun and bend it into a 90 degree bend so it lays on the anvil so you don't have to hold it. The machining tolerances on the Jinma are a little sloppy so set the clearance on the closest knife.

Knives only mount one way as the bolt holes are countersunk on one side only.

 

[Michael_C]

Adjust the right side with a feeler gauge while the cutting edges against each other, then rotate the flywheel and adjust the left side.
Have the bolts tightened just enough to cause some drag on the anvil but still able to move easily.

It might take a couple tries depending on how well the anvil will adjust for you. Also don't forget to check the clearance on both knives! Adjust to the tighter one, better to have one with a little extra clearance then one too close.

I don't have my manual with me but .100 is way too much. .010-.030 is the spec. I believe.

Thank you for the guidance - I will try your approach.
The .100 is the approx tilt of the blade from the top to the bottom of the blade, and not the gap between the blade and the anvil. My shim stock is .025" thick - when I used a single thickness, the blades would touch the anvil on the right side (when rotating the flywheel by hand).

I used a dial indicator (Pic below), to determine how much the surface of the blade tilts from top to bottom. I set the anvil using two thicknesses of shim (2 x .025") to determine if the blade angle and my approach to adjusting the anvil was the problem. The blade, on the right side, just clears the anvil, but rubs on the bolt head.

My goal is to have the tightest gap to be set to .025" - a bit on the high side of the range (.015-.030), but better than it was.
I am assuming the blade tilt is not a problem, and is most likely useful to reduce drag between the wood being fed and the blade.

 

[Michael_C]

Use an old credit card. That will give you about 0.030. Heat the card with a heat gun and bend it into a 90 degree bend so it lays on the anvil so you don't have to hold it. The machining tolerances on the Jinma are a little sloppy so set the clearance on the closest knife.

Knives only mount one way as the bolt holes are countersunk on one side only.

Thanks for the tip on the credit card and confirming you don't have a choice on how the knives are mounted.

 

[TMGT]

If you just replaced the blades did you clean out the blade pocket REALLY well? It doesn't take much for them not to seat correctly. I use a pick, scraper and wire brush, then blow it out and wipe it down.

And yes, the angle of the blade is supposed to be there, that's why using a single, wide feeler gauge doesn't work well as you find find out!

I really struggled to get my anvil clearance right until I figured out the method of setting each side separately.

Thanks for the tip on the credit card and confirming you don't have a choice on how the knives are mounted.

 

[5030]

If you need new countersunk bolts or locking nuts. PM me. I have a couple full boxes of them in the shop.