Power hammer build

[Benona blacksmith]

You will probably still hear and feel it in the house. My neighbor can feel my hammer 100 yards away he cant hear it though (?). Luckily that is my closest neighbor and he is in his 70's and grew up next to a blacksmith shop and used to run the bellows for him so he doesn't mind....except for the one time I worked till around 11pm!

Nice work on the hooks and I'm glad you kept with the post and didn't let our criticism get to you. I built a 60 lb hammer with a hollow anvil filled with sand and oil and I was extremely unhappy with it. I rebuilt it to 85 lbs with a 500lb anvil and it was a lot better and later replaced the 3/4 hp motor with a 1 1/2 hp motor and it was an incredible difference. I have since replaced it with a self contained hammer.

[Ted Ewert]

You're probably right that I won't be able to completely isolate the vibration, but some is better than none. I've got bedrock under the slab, so I'm hoping that large mass might not transmit as much of a shock wave as packed soil would. Who knows. 

I would like to eventually build a pnumatic hammer, but I'm still in the infant stage of the power hammer world. I have to say that it's a lot of fun to use, and a big time saver.

I still have to build some more dies. My next one will be a fuller. I'd also like to build some sort of quick change mechanism for the dies, but haven't figured that one out yet. 

[tylerdewitt]

You claim your anvil is working flawlessly beyond expectations, yet your garage floor and building are vibrating to the point of shaking things off shelves. Are you ready to concede some of your previous arguments regarding inertia? 

Quote

Thomas: inertia should only be considered if the anvil has movement. For instance, an anvil which is just sitting on a stump. This anvil will have no movement since it will be securely bolted into concrete. Therefore, stiffness (rigidity) is the only criteria, other than noise, to be concerned with.

Resistance to a repeated vertical shock load is the only requirement.  Mass and inertia are irrelevant since the anvil is bolted to the floor and is not moving anywhere. Strength and rigidity are the primary considerations.

 As mentioned above, the argument of mass and inertia is a moot point, unless you think the earth moving itself is significant.

That vibration, aside from being annoying to neighbors, is lost energy that could go to deforming metal. I know you had trouble sourcing and moving a solid chunk, but it wouldn't have been that hard to laminate solid steel plates or bars. You might as well have put the mass here first, before pouring a concrete foundation.

A decoupled concrete inertia block will help. But you might as well have put the mass in the anvil to start.

In my build, I went to great lengths to design for minimal vibration, because I have neighbors quite near.
For a 100lb ram, 1400lb solid anvil, 2" steel base plate, (sort of)decoupled concrete inertia block, and I still wish I would have poured much more concrete. You can still feel some vibration it in the ground outside of the shop. You can read my build thread if interested:

https://www.iforgeiron.com/topic/49300-designing-a-50lb-guided-helve-hammer

 

[Ted Ewert]

10 minutes ago, tylerdewitt said:

You claim your anvil is working flawlessly beyond expectations, yet your garage floor and building are vibrating to the point of shaking things off shelves. Are you ready to concede some of your previous arguments regarding inertia? 

No. My anvil is working just fine. The concrete slab is what's giving me problems. The slab is what's transferring the shock to the rest of the house. If I disconnect the shock from the slab it won't do that anymore.

Why in the world would I want to spend the money to by 1400 lbs of steel, let alone try and move it, when I can tie into millions of lbs of bedrock with a moderate amount of concrete and rebar? The anvil and concrete will nicely transfer all the shock load into the bedrock, which is not going anywhere. It will also recover some of the wasted energy you pointed out. Nothing wrong with making the anvil massive if that's what you want, but it's not always necessary. 

I only have a 35 lb hammer, which is not particularly large. I don't think it's going to be too much trouble in my case to significantly reduce the vibration. 

I recently watched a video (all in German) where they changed out an anvil base for a water powered hammer (very old school). The base was a tree trunk, maybe 4 feet in diameter and about 6 feet long. They dug out the old one and had a hole about 5 feet deep. They positioned the new base and packed soil around it.

Not only is this a solid base, but it transfers the shock deep into the earth. The shockwave is travelling downward, so the deeper you make the hole the less likely it is that any of the energy is going to come back to the surface. 

[tylerdewitt]

Quote

Nothing wrong with making the anvil massive if that's what you want, but it's not always necessary. 

Not always necessary, but in most cases the most effective and predictable way. I see inertia as a property and purpose of the anvil itself. Better to address the problem here before considering the foundation.

If you can easily make bedrock your anvil, then great. In most cases it's going to be a lot more difficult. Reducing shock/vibration is generally hard. Adding mass to an anvil is a no-brainer solution.

Readers can decide what's most time/cost effective for them.

[Ted Ewert]

I agree. If you're on soft dirt, a large mass above grade may be the best option. All we're really trying do here is to minimize vertical displacement. However that's accomplished is dependent on the individual circumstances and preferences.

I've been toying with the idea of drilling holes in the slab below my anvil and driving steel rods down to the bedrock. I would then grind them to within an eighth of an inch of the slab, and mount the anvil on those. Maybe 6-8 "pilings" would be enough. I might try it just to see if it works. 

[Latticino]

Another potential issue that may come up if you attempt to attach your current composite anvil to a more fixed point (bedrock...) is that the existing system does have a small degree of shock absorption from the flexing of the shop slab.  If the base of the anvil becomes more fixed, you may run into new shock loads on your concrete anvil, potentially degrading it faster.  Only time will tell whether this kind of composite anvil will hold up.  Of course in the end it comes down to a cost/benefit situation, and it might be cheaper to replace every 5 years of heavy use rather than make one out of laminated steel that doesn't pay back in time.  That's up to you.

I can't stop thinking about jack-hammers breaking up concrete pads...

[ThomasPowers]

Not much throw on a typical jackhammer, just repetitive shocks...

[Frosty]

About annoying the neighbors, rock transmits sound much better than compacted soils, you can look up how seismology works for an explanation. In short it's the transition between solid bodies that absorbs energy, hence volume and velocity diminish. In the case of an anvil energy rebound.

Frosty The Lucky.

[Goods]

If you are worried about vibration transmission to the neighbors, the best thing to do is to have rubber like isolation pad between your concrete hammer foundation and the bedrock. You’ll loose the mass benefit, but you may not have things falling off the shelves. (At work, all our large power presses, 100~2000ton, all have isolated large mass foundations with rubberized isolation mounts between the press and the foundation. The largest presses move a fair amount each hit and you can really feel it through your feet when you are on the press foundation, but step over a few feet onto the shop floor and the vibration  drops at least ten fold.

It’s your setup do what works for you! I’ve been enjoying following the progress!

David

[Benona blacksmith]

What do you estimate your concrete anvil weighs?

[Buzzkill]

You do realize his anvil isn't a concrete anvil so much as I-beam which has the channels filled with rebar and concrete.  As I understand it the concrete merely provides some additional inertia value and sound dampening.  Even if the concrete does fail it will not result in a catastrophic failure for his hammer.

[Ted Ewert]

On 1/9/2020 at 7:45 PM, Benona blacksmith said:

What do you estimate your concrete anvil weighs?

It's about 100 lbs. Buzzkill is correct as the concrete bares no load. 

David. I currently have a rubber mat under the anvil. The problem is that the slab acts like a trampoline. It's sitting on sand, which gives enough to allow deflection. As with your presses, I need to isolate the shock. 

The rock can't be more than a foot below the slab. I tried to drive a grounding rod in just outside the garage and only got down about 6 inches before it stopped cold. 

I'm going to try the pilings tomorrow and see what happens. If that doesn't work I'll start digging. 

[Ted Ewert]

I wanted to clarify what the difference in power distribution is between a crank and a cam. The following wave forms roughly represent the comparative linear velocities imparted to the hammer by each device:

 

The blue line represents a crank

The black line represents a double action cam

This chart represents 360 degrees of rotation. The vertical axis represents linear velocity, horizontal axis is degrees of rotation. We'll say that the 180 degree mark represents the point of impact of the hammer.

As you can see, the maximum linear velocity the crank imparts occurs at 90 degrees. At that time the velocity decreases to zero at the point of impact. This slowing is also acting as a drag on the hammer.

On the other hand, the cam continues to increase the velocity of the hammer up to the point of impact. This significantly increases the energy imparted to the work, and also increases the efficiency of the hammer. The cam is similar to a pneumatic hammer in this regard.

The crank imparts zero linear velocity at the point of impact while the cam is at its maximum velocity. This is the key difference between the two. 

The cam also reflects a much smoother load on the drive train, allowing better clutch performance and reducing wear.

I have heard that people are generally disappointed with the performance of their hammers when using a VFD. I would speculate that the crank is a major contributor to the lack of performance. I think a cam would work much better.

The design of the whole drive train can be simplified with a cam, since it needs far less spring to store and release energy than a crank does. That could be a separate thread in itself. 

I hope this information has been helpful, as I have found the cam to be a major improvement over the crank.

 

[Benona blacksmith]

So its 1:3 ratio. So when looked at in perspective it's like using a 1 lb hammer on a 3 lb anvil. There is a reason real hammers use solid mass for an anvil. It's definitely not because of its cost effectiveness. The video you seen with a wooden anvil was a trip hammer that was made way back in the day before they had the readily available materials we have now and that machine would have been better served with a solid anvil. But what do I know. I'm just a hillbilly in west Michigan that has proved this myself with my hammer?

[Ted Ewert]

A lot of people here seem to be stuck on the idea that a large mass is the best or only way to attach an anvil. It does work just fine, but it is not the only effective way to mount an anvil.

Keep in mind that the only thing a large mass does is to reduce vertical displacement of the anvil. That's it. The reduction of vertical displacement can also be accomplished in a number of other ways. Take for example using a large base area. More area on the base will reduce the PSI across the surface, thereby reducing the amount of compression on the floor. This would work well on a dirt floor. 

A solid column buried deep in the ground will also provide ample stiffness. The depth would depend on soil conditions. A 6 or 8 inch pipe, filled with concrete and capped with a 3/4" or 1" thick plate would make a nice stand. 

I pounded in nine 5/8" rods below my anvil today and stiffened it up considerably. I didn't hit the hard rock I was hoping for (which seems to be everywhere else on the property where I try to dig a hole), but I did hit some good solid earth. We'll see how it holds up over time.

[Benona blacksmith]

Big Blu has scientifically proven what the optimal anvil weight for a given tup weight is.

I know your hammer runs good and moves steel. I just want to reiterate that a solid mass IS the best option. Even if you could get ahold of a large axle in the 250-300 lb range. I have a 3800 lb block of steel waiting for me to make a big hammer with. I will get a picture of it later along with a picture of my homemade hammer.

My main working anvil weighs 426 lbs. I can tell the difference between it and my 200 lb anvil. I dont even have my 100 lber mounted anymore.

[Ted Ewert]

I'd like to see your hammer, and that block of steel. You must have some heavy equipment, or a hoist, to move that stuff around. All I have is a hand truck a three strong sons (if I can rope one in) to help me move my equipment. 

I also need more space. I had to shoehorn this hammer into a small area close to the forge, which makes it hard to work on. I'll be retiring in a couple of years and would like to buy a property with a separate shop, or the room to build one. I need a place that I can make some noise without the neighbors or the wife complaining about it. 

All theory aside, the hammer I built is more than adequate for the stuff I make. It's a great time saver for drawing out tapers or flattening thick stock. It's a decent hobby hammer.

A lot of guys are in the same boat I'm in; limited space and limited access to heavy materials and the machinery to work it. I'm hoping this thread gives those guys some ideas on how they can also build a moderate hammer to fit their needs and budget. 

[Benona blacksmith]

I have no heavy equipment just a 1 ton chan fall and ingenuity. I move everything with rollers and leverage. 

This is the hammer I built with the 500 lb block of steel.

the 3800 lb block with my hand for reference and in the background you can see a pallet for reference. The motor is 30 hp and weighs 500 lbs and will be used for a rotary phase converter.

And the hammer I replaced the homemade hammer with.

[Ted Ewert]

Nice hammers! That's a big ol' piece of steel you have there. My back hurts just thinking about trying to move it.

What's all that white stuff on the ground? 

[JHCC]

Magic winter dust.

[ThomasPowers]

Dust? Dust is *brown*!  Next unincorporated town over from where my shop is is Polvadera  which translates as "Dusty".

[Ted Ewert]

1 hour ago, JHCC said:

Magic winter dust.

I've heard of that stuff. I see it in pictures along with Santa Clause. Must be left over from Christmas. 

[Benona blacksmith]

I really like the magic winter dust. It Keeps me cool while working in the shop. I'm debating on putting AC in the shop for working in the summer. I dont know how you guys closer to the equator can handle it. Maybe my blood is too thick? 

[ThomasPowers]

What impressed me the most about induction forges was the possibilities of having an air conditioned shop down here where it's warm a lot of the year.