Chunker diameter

I finally started gathering the pieces for my future chunker. I have a 30 to 1 gear box with 1.25 inch diameter input and output shafts, a 7.5 hp electric 3-phase motor, (going to use a phaser to convert 240 single phase) and I have most of the heavy duty steel I think I will need for the frame. Still need to buy a cheap trailer to use as a foundation.

Anyways I have this 8 inch diameter .250 inch thick pipe I was going to use for the blade and was not sure of any detrimental effects of using a smaller then normal diameter blade. Obviously it will cut quicker, but other then that any real big issues that would otherwise point me towards using a 12 inch pipe???

Everything else being the same, I believe a smaller cutter diameter will increase torque/force at the cutting edge, but decrease the amount of slicing per turn, if that makes sense.

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Good morning Joseph .

I think the 8 inch pipe would work OK . :joy:

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Hello Joe,
I built my chunker using a piece of 12" well casing I had leftover from the firetube. The thing I am finding is if you try to cut a 2 x 6 the top of the cut ends up being a pointy piece. As I cut I keep thinking I should have gone with a bigger diameter. My thoughts are with a 8" cutter, you might not be able to cut anything wider than a 2 x 3 if you consider the cutter shelf will probably start around the center of the cutter diameter.
Just my 2 cents. MikeyB


If you have a truck repair shop close you can probably pick up a used brake drum for cheap maybe free the one I have is 16 in dia. But haven’t put power to it yet.

Now all we need is someone too do a psi required too chunk wood test.or some way too test.

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Hypothetically, one could build a chunker that incorporates a heavy-duty scale in the anvil, but I would think that a scale heavy enough to measure the estimated tons of force, would be much larger than a standard chunker.

Hello all I am new here but have been working with pipes for many years. From 1/8" to 36" diameter for all kinds of uses. I do think an 8" will work but problem is thickest. !/4" walls of mid steel pipe are not real strong when used for a sideways pressure. Maybe if a cutting edge is put on spiral type cutting blade on pipe and harden would be a little stronger. If a 12" pipe was done same way, thicker wall if can find, cutting speed maybe would slow enough for wall thickest not to be a problem, would still need to be harden.

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THANKS BRIAN H,you a probbly right, Their is probbly a chart or some specs out there to go by on sizeing, i gess trial and arr will work ,long as there is room too ad bigger gear box if needed.

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