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Rock auger bits

673moto

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Dec 5, 2019
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Anyone have input on rock auger bits?
The ground around here is 95% rock it seems and destroyed my standard bit on the first hole!
I’ve searched some online for a bullet style bit but not really sure what to look for and as these bits are north of a thousand each I’d like to get a decent one.
Any recommendations?
Perhaps somewhere local to Northern California?
Just looking to finish the 500’ of fencing at my place without having to wait on something that a company online says they have in stock but then ends up being on back order for months! (Gotta love things these days!)
 

Junkyard

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Claremore, OK
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What kind of rock is it? What size auger? I could probably scrounge some pockets and teeth we’ve swapped out that would work for you. Key is the angle you set them at and more importantly the ability to put downward pressure on them. Most rock shears fairly well, the one exception I’ve encountered is dolostone. It doesn’t shear well but hammers great.

Honestly I could send some teeth and you can weld them direct and run until they’re shot then cut off and replace until you’re done.
 

673moto

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What kind of rock is it? What size auger? I could probably scrounge some pockets and teeth we’ve swapped out that would work for you. Key is the angle you set them at and more importantly the ability to put downward pressure on them. Most rock shears fairly well, the one exception I’ve encountered is dolostone. It doesn’t shear well but hammers great.

Honestly I could send some teeth and you can weld them direct and run until they’re shot then cut off and replace until you’re done.

that would be awesome!
I’m not sure what type of rock it is...let me do some googling...it does fracture rather easy into jagged pieces.
 

KSSS

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Idaho
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excavation
Wow! Thats a problem when trying to drill a post hole.
 

Junkyard

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If it fractured fairly easy it should drill decent. Only thing is you’ll want a “stinger” on the center of the auger or it will wander all over if you’re on a bigger piece or something hard. When we hit uneven rock or a hole that’s got rock in one part of it we use a core barrel, think giant hole saw, so we can stay centered.

I think I have a bucket of C21HD’s that I could pull some out of. Might be C31HD’s, I don’t recall. Either way they’d work like a champ. Pick a cheap dirt auger or find another cheap one to weld them to. If need be I can help with pics etc to show the angle
 

Junkyard

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If you want to get fancy we can get pockets for you to weld into the auger flights so you can swap the teeth out. There’s an art to the angles, more so in core barrels since they’re working in a groove and an auger can move around a bit. You’re not going for precision so it won’t be super important.


8AD539D9-CE4D-4D02-B44E-7B5F47931E23.png
 

673moto

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If you want to get fancy we can get pockets for you to weld into the auger flights so you can swap the teeth out. There’s an art to the angles, more so in core barrels since they’re working in a groove and an auger can move around a bit. You’re not going for precision so it won’t be super important.


View attachment 254257
That’s intense looking!
Think I should weld in pockets or just throw caution to the wind and weld those bullets right to the auger?
How long would those bullets last on average?
I think you’re spot on with not needing anything too precise... I’m just shooting for an 8 or 9” auger to drop 4x4 posts into.
if you’ve got a handful of those things and truly don’t need them...send them to me and I’ll send you $$$
 

Junkyard

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That’s intense looking!
Think I should weld in pockets or just throw caution to the wind and weld those bullets right to the auger?
How long would those bullets last on average?
I think you’re spot on with not needing anything too precise... I’m just shooting for an 8 or 9” auger to drop 4x4 posts into.
if you’ve got a handful of those things and truly don’t need them...send them to me and I’ll send you $$$

Their lifespan depends on a couple things. How slow can you turn your auger and how much down pressure (crowd) can you put on it? It’s not unlike drilling a hole in steel with a twist drill bit. Too much speed and pressure will take out the bit.

If you can keep a fairly steady speed, say 60-80 rpm and put some decent pressure on them I bet you can darn near do all your holes. It might be wise to do pockets on the stinger and a handful of the first few teeth because they’re going to do the majority of the work.

I have a stinger made up for the bigger C4’s I can send pics of so you can see how to do that if needed.
 

673moto

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Their lifespan depends on a couple things. How slow can you turn your auger and how much down pressure (crowd) can you put on it? It’s not unlike drilling a hole in steel with a twist drill bit. Too much speed and pressure will take out the bit.

If you can keep a fairly steady speed, say 60-80 rpm and put some decent pressure on them I bet you can darn near do all your holes. It might be wise to do pockets on the stinger and a handful of the first few teeth because they’re going to do the majority of the work.

I have a stinger made up for the bigger C4’s I can send pics of so you can see how to do that if needed.
Thanks!
Would appreciate some pics, I see those bullet teeth are $10 each... I’ll save you the hassle of waiting in line at the post office and I’ll order some online.
how much crowd force is required? Think a mid size skid steer is up to the task or should I maybe adapt the auger to fit my mini excavator?... although I hear rotational force is bad for the pins/bushings?
 

Junkyard

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A skid steer should be enough. If the lead time on teeth is too long let me know, it’s no big deal to throw a dozen in a box and send them.
 

Jimbo

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Mar 22, 2010
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S.E. New Mexico
Guys, understand the flighting on a standard dirt auger will be less than 1 half the thickness of the rock auger. This may or may not lead to twisting or tearing of the flights, rendering it useless. A true rock auger is pretty pricey, but well worth it if you have enough holes to drill. As said above, when attached to a skid steer/ctl, slow speed and down pressure are your friends
 

673moto

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NorCal
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Guys, understand the flighting on a standard dirt auger will be less than 1 half the thickness of the rock auger. This may or may not lead to twisting or tearing of the flights, rendering it useless. A true rock auger is pretty pricey, but well worth it if you have enough holes to drill. As said above, when attached to a skid steer/ctl, slow speed and down pressure are your friends
That’s one thing that’s been holding me up.... I find when I half ass things the results match.

And neighbors dogs got into our yard this morning and had a chicken for a snack... looks like I’m just gonna fork over a chunk of change for a pengo rock auger and play the waiting game
 
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