Need Strength of Material Advise to Fix wood Splitter

Gordon Gould · May 12, 2014

I have a 22 ton (@3000 psi) splitter that opens to over 26". It has an automatic kickout return detent valve. I cut my wood 18". This morning I put a stop on the splitter to kickout the return detent at about 20". It appeared to be working great until I heard a snap after splitting 1/2 cord. The wedge bolt broke and the wedge holes were strectched in the pull back direction. Here is my stop - a 3/8" plate bolted down with 3/8" Grade 8 bolts. I thought I could drill additional holes to set the sop at longer lengths. The original stop was internal to the ram.

Here are the deformed holes. It appears to me that the holes stretched because of my stop and then finally the bolt broke. The wedge side plate material is 3/16" and the bolt was a 1/2" grade 5. The bolt does not see shear in the split direction because the ram end contacts a header in the wedge.

The valve is supposed to release at 1000 psi or about 12,500 lbs. Can I make this work reliably with a 1/2" grade 8 bolt and beefed up wedge? If so how thick do I need to go on the wedges side plates ?? Or should I just scrap the idea and go back to the drawing board ??

Thanks, gg

SPYDERLK · May 12, 2014

!/2" is not going to be adequate long term unless its a good tight shear joint and 3/8 ears. Also the bolt shank must amply cross both shear zones. That splitter presents a hard design to work with. ... Im not sure, but I think there may be clamp on collars for the ram that could bridge out safely to the cyl edge. That way you would contain all force w/i the cylinder. It would take a good squeeze to hold 12K#.
larry

CalG · May 12, 2014

For my money on a repare (and it's not ;-)

Double up the damaged holes inside and out Looks like you might have extra room on the inside between the ram and shear flange. Use it all! Adding 3/4 inch to each side should ease the strain a bit.
Compression appears to go onto the ram end IIHIC. Correct? Make sure it does to give that bolt a break on the heavy work.

Then, Split the wood through and through so there will be little pull out strength requirement.

When I split, I find the lest inch or two is always a final "I give up" on the craky pieces. Pulling back 4 inches shy of through would not be my choice.

But then, My splitter has a fixed wedge, and a moving push pad. (love the four way when it's right)

Winmac · May 12, 2014

I think you need a different solution, I'd suggest a linkage from the movable knife that will knock the valve into neutral on return stroke at a pre set distance.

It can be as simple as a metal rod with a lockable collar, the rod would slide through a paddle on the valve lever, once the collar strikes the paddle it trips the valve.
I have one on my splitter and it really cuts down cycle times, I'm 300 km from home so I can't offer any pictures.

Gordon Gould · May 12, 2014

Thanks for the technical info and the kind replys.

When I saw the broken bolt and thought about it I realized that I hadn't appreciated the fact that the bolt saw very little shear until I added my stop plate.

That adjustable linkage sounds like a good idea - thanks !!

Gordon Gould · May 30, 2014

Winmac said:
I think you need a different solution, I'd suggest a linkage from the movable knife that will knock the valve into neutral on return stroke at a pre set distance.

It can be as simple as a metal rod with a lockable collar, the rod would slide through a paddle on the valve lever, once the collar strikes the paddle it trips the valve.
I have one on my splitter and it really cuts down cycle times, I'm 300 km from home so I can't offer any pictures.

I took your suggestion - Thank you very much !!

I am just a backyard mechanic and this is what I came up with