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Post anvil in cement


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Hi everyone.

I am currently using a post anvil set in a wood stump. However there is a couple of problems with it. It is a bit light on the base, so can move around a bit. and it has a tendency to skew when hammering on it and so I'll have to knock it back into position.

I would like to take my post anvil and set it in concrete, but am debating how to go about it. I'm thinking a 20 l pail, build up on the bottom of the pail with wood blocks until the stump is the right height and then pour in the concrete. I would also like to reinforce the concrete to give it a bit more shock resistance but unsure how to go about the reinforcement.

So essentially. Is my 20 liter bucket of concrete a reasonable idea and if so, what's an appropriate way to reinforce it?

Thanks for any help!

Bjorn

 

 

 

 

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Can you give us a photo of your current setup?

Concrete generally doesn't have great impact resistance and can crack or spall under multiple impacts, so your bucket-of-mud idea might not be optimal. However, one of our members did a project a couple of years ago making a swage block with a steel skin filled with concrete, and I believe that it worked pretty well. He did pay a lot of attention to internal bracing and a special mix, so that would be worth looking at.

You might consider a heavy metal stand that could hold the anvil rigidly while giving you some more stability. 

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At work at the moment, but I'll take a photo when I get home. The post is long enough that I could secure it almost on the bottom of the bucket. I was a bit concerned that a bigger container would force me too far back from the anvil and limit my choices in positioning myself in relation to the anvil. I could probably find something bigger though. My stump is smaller than the bucket. It is surprisingly difficult to find the stumps and scrap metal to put an anvil together here in North queensland.

The crumbling of the concrete is certainly my biggest concern, but my current setup is also getting frustrating to work with.

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Thanks. That was an interesting read. I was thinking along the same lines in that the post anvil itself will not be directly on top of the concrete, but the concrete will add mass and stability. I am losing a lot of energy from my hammer blows with my current setup.

It's not impossible that I could take my anvil, stump and all, put it in a bucket and cast the whole thing in cement. (Just for a reference to what size stump my post anvil is actually mounted in. I'd be a bit concerned that that setup would quickly crumble.)

I think a 20 litre bucket would add about 40 kg or 80 pounds to the mass, and as long as I can do that in a way where the base doesn't crack, I reckon I'd be golden. At least better than what I am doing at the moment and at least until I can get a proper/better anvil).

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Interesting. So, you say:

10 hours ago, Bonnskij said:

it has a tendency to skew when hammering on it and so I'll have to knock it back into position.

Might the problem be solved by securing the post more firmly in the stump? How far down inside the stump is the bottom of the post, and how is it currently fastened?

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I tried setting my post anvil in a bucket of concrete when I was first staring out. I made an elaborate frame of rebar and steel scraps to position the post anvil in place and reinforce the concrete. Alas, within a few weeks the concrete stared cracking and then breaking up so the post began to wobble around in the base. Eventually the sides of the bucket split and the whole thing pretty much fell apart. Long story short, concrete isn't ideal for long term exposure to impacts. Eventually it will break apart and you'll end up with a bucket of rubble.

Now if you were to make a new stand with dimensional lumber and an open cavity for a block of concrete that could probably work to give it some extra mass.

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Dimensional lumber stands give you an easy method to create a hole that fits the post exactly and then holds it tight. (Mine were made using rough sawn  oak boards from a scrapped horse trailer---scrapped long enough ago there isn't even any odor!)

Not a post anvil but here is an example of one in my shop.  You could cut the internal pieces while they are still "loose" and then snug them down around your post anvil with the bolts.

bottomfuller1.jpg.c6dc6b23f1276cb32c4d68c81ba77b53.jpg

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Another option would be a steel or plywood box shaped like a truncated pyramid and filled with sharp sand.The sand would (1) allow you to set the height at whatever is comfortable, (2) provide mass and rigidity (especially if you have a removable top that fits snugly around the post), and (3) be easy to disassemble for moving, adjustment, or modification. 

Something like this:

image.jpg

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12 hours ago, JHCC said:

How far down inside the stump is the bottom of the post, and how is it currently fastened?

This was my first thought also. I think the area of the base of the stump is preferred over the area of the bucket for stability. If the anvil is moving around in the stump, then setting it deeper should help the problem, could also set it in calking compound to tighten it up.

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It is probably not deep enough. I probably made it too tight a fit too, so I'm not sure if it bottoms out a hundred percent. It is very slowly skewing as I work, but enough to be annoying. 

Appreciate all your suggestions.  I'll abandon the concrete idea and will probably build a new set up with either dimensional lumber or a plywood pyramid with sand.  

Thanks everyone!

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If you go the plywood route, make sure to reinforce the joints with 1" x 1" strips glued and screwed in place. The last thing you want is a seam breaking and leaking sand all over!

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If it's loosening up and cocking in the current stand why not use wedges to straighten and tighten it? Shims used to true up door frames and window sashes are: cheap, have long tapers and made from cedar so they last a long time. 

Frosty The Lucky.

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Sure wouldn't want a sand leak! I got some big sheets of plywood I got from work, so that would be a cheap option to try at least. 

I've tried making some wedges and also filling in with epoxy. Neither has been a very long lasting solution. Might make some steel wedges and give another go though.

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