Power Hammer shaking the entire house

[Tomas Benadik]

Greetings, gentlemen.

 

One important question for you, please:

 

My bladesmithing master installed power hammer in his shop - the type embedded in the floor in a deep pit, with proper cushioning (as per instructions). However, when it's put to work, the entire house is shaking - and since it's fairly old house, the end result is that he is unable to use the power hammer at all.

It was quite costly, so we're trying to figure out what else can we do to be able to use it. Recently, my master came across notion of some kind of "pneumatic absorption pillows", that could possibly solve this problem.

 

Do any of you, please, have some idea about what might help or where I might get pair of these "pillows"? The desired size is 28x28 cm (that would be about 11x11 inch).

 

Any info and help is much appreciated!

Many thanks,

Tomas

[Glenn]

We need more information.

 

What type hammer?

What was the construction of the foundation?

What is the type of soil or bed rock you are built on?

 

proper cushioning (as per instructions). Whose instructions. You may want to go back to the source and ask for additional information.

[dsloan]

I'm with Glenn, we need a little more information.

 

The one thing I've seen in the past is that the pad that the hammer sits on was not isolated from the ajoining concrete.  The same can be said what your pad of concrete sets on? 

 

A cushioning pad under the hammer I don't think will help.

 

Dave

[Steve Sells]

noise and vibration is always an issue, for some its minor, others like us cant use one because of the side effects.  Here is a thread started by Glenn after I talked to him on the phone about similar issues here    seems I need to build myself a press.'?do=embed' frameborder='0' data-embedContent>>   so it seems that I need to build myself a press.

[Tomas Benadik]

Greetings, gentlemen.

Apologies for my late reply.

 

Here's some more information:

- the hammer is KA-75 (http://www.ka75.com/)

- the foundation was a pit 1 meter deep (about 3,3 feet), about 1x1 meters wide.

- the pit was filled with cushioning materials - bottom 30 cm are from thick rubber plates, then 50 cm of thick cork plates

- the sides of the pit were cushioned with Nobasil (kind of isolation used in Slovakia)

- all of it was then fixed in concrete and the hammer was bolted to the floor

 

Does that help?

 

Many thanks!

[ThomasPowers]

More mass in the inertia block comes to mind.  The greater the mass the hammer has to "drive" the less it will move in all.  So a larger inertia block with the hammer well coupled to it might help.

[the iron dwarf]

you have 20cm  ( 8" for the americans ) of concrete under the hammer then the cushioning if the hole was 1m ( 39" ) deep, I am no expert but I think you need more concrete under it.

 

a 50 kg sahinler air hammer we had was installed on concrete 1.25m ( about 4 foot ) deep, there was over 2 cubic meters of concrete used for this and lots of steel bars.

 

one thing that will affect it is what the ground is like underneath, we had loosely packed ironstone, in the same building is a recording studio

[peacock]

Replace all of the rubber and cork with concrete, put about half an inch of rubber between the hammer and concrete bolt it down.  It should be much better.

[Frosty]

Without knowing what the soils are this is all speculation. However, I do enjoy speculation so my first thought is get rid of all the cork rubber and such, replace it with concrete. Of course enlarging the hole would really help, as said the more mass in the foundation the less the hammer can move it.

 

How far away is the house, if it isn't within a few feet you have some serious soils issues. For shocks to travel very far through soils they either have to be very densely compacted dry soils or stone. I those cases you'll hear it and maybe see a little bit of vibration in the house. If it's actually shaking the house my bet is a high water table in clayey or silty soils. Basically the hammer is liquifying the soils under and around it so waves can propagate. This is a BAD thing and not just because of the hammer.

 

Well compacted angular gravel of a good gradation is pretty much ideal for a light weight power hammer like a KA. A concrete foundation of course but a good gravel base is really good. My 50lb. Little Giant is on a wood base resting on a 6" concrete slab over well compacted gravel over dry glacial till. I can run my hammer even to the point of letting it strike too cool steel and Deb can't hear it in the house about 120' away.

 

Please let us know what the soils are under your place, I have a decent lay understanding of soils and foundation design. I drilled test holes for the headquarters materials, bridges and foundations section of the AK DOT geology dept for a good 20 years and picked up a bit. If I don't know what's what I know who to ask.

 

Frosty The Lucky.

[johnnie]

I have recently installed a 50kg Beaudrys Peerless hammer.

 

She is sat on aprox 1m3 of concrete. 2" high density foam walling the new concrete from the existing.

 

Lots of steel and straight on the mud below. The hammer was then sat on 3/4" exterior ply and bolted to the new pad using 20mm rag bolts.

 

My forge in in a 19th century barn with the same era barn joined on to it (our living room).

 

Bearing in mind all the surounding walls are built with stone and mud there is very little or no vibration anywhere other than the new pad. 

 

It sounds to me that the cork and rubber is sat on bedrock. I can't see why its vibrating the house so much.

[johnnie]

I have recently installed a 50kg Beaudrys Peerless hammer.

 

She is sat on aprox 1m3 of concrete. 2" high density foam walling the new concrete from the existing.

 

Lots of steel and straight on the mud below. The hammer was then sat on 3/4" exterior ply and bolted to the new pad using 20mm rag bolts.

 

My forge in in a 19th century barn with the same era barn joined on to it (our living room).

 

Bearing in mind all the surounding walls are built with stone and mud there is very little or no vibration anywhere other than the new pad. 

 

It sounds to me that the cork and rubber is sat on bedrock. I can't see why its vibrating the house so much.

Sorry for bouncing between metric and imperial.....

[Frosty]

Johnnie: Isolating the foundation from the existing floor with foam is a good move.

 

However, ANY "mud" under it will liquify when the hammer is working and shake your house apart in time. Pull your foundation block out and excavate till you're through the mud, fill and compact with angular (crushed) gravel till it's a meter or so below the surface then pour your concrete. Mud is BAD, get rid of it.

 

If the gravel is reasonably clean a high water table isn't a game killer as the water can move without liquifying the gravel the way mud will. This is called "liquifaction" a search will find more info than you will ever want.

 

Frosty The Lucky.

[johnnie]

Oh nooooo!!!! Not what I wanted to hear!!

The water table is 8meters below us but still mud is not good although it was thick clay by the time I'd finished digging. 

Will wait to see movement before digging out the slab.........

Thanks Frosty!!

[DSW]

If that's the case you may need to open up more floor and pour a larger spread footing to increase your surface area. Either that or drive piles or drill casons to go down to solid material to handle the loads. Typically not very practical inside.

[brian robertson]

My shop sits on a 75 ft deep clay layer. I poured 4 yds of concrete with rebar for the foundation for a 100 lb LG. When working large pieces of 4140, that hammer would "rattle the china" in a cabinet, in the neighbor's house 1000ft away. The little old lady said that I didn't break anything and she didn't mind because it sounded like soft wind chimes. She liked me as a neighbor.

 

Now that lady has died, the old LG moved on and was replaced by a Large Big Blu hammer, set on the same foundation and again when forging tough stuff, it will cause the new neighbors dvd player to skip. I have done a number of favors for the folks across the road and I try to never run the hammer after dinner. So all is well. The moral of the story is sub soil is everything when it comes to hammers.

 

I was told, in order to solve this issue, I would have to dig all the way through the clay, to bedrock and build back up with the appropriate foundation. Not gonna happen

[johnnie]

My shop sits on a 75 ft deep clay layer. I poured 4 yds of concrete with rebar for the foundation for a 100 lb LG. When working large pieces of 4140, that hammer would "rattle the china" in a cabinet, in the neighbor's house 1000ft away. The little old lady said that I didn't break anything and she didn't mind because it sounded like soft wind chimes. She liked me as a neighbor.

 

Now that lady has died, the old LG moved on and was replaced by a Large Big Blu hammer, set on the same foundation and again when forging tough stuff, it will cause the new neighbors dvd player to skip. I have done a number of favors for the folks across the road and I try to never run the hammer after dinner. So all is well. The moral of the story is sub soil is everything when it comes to hammers.

 

I was told, in order to solve this issue, I would have to dig all the way through the clay, to bedrock and build back up with the appropriate foundation. wot gonna happen

Thats what I thought, phew!

Thanks Brian, thats kinda reassuring.

[Ric Furrer]

My shop sits on a 75 ft deep clay layer. I poured 4 yds of concrete with rebar for the foundation for a 100 lb LG. When working large pieces of 4140, that hammer would "rattle the china" in a cabinet, in the neighbor's house 1000ft away. The little old lady said that I didn't break anything and she didn't mind because it sounded like soft wind chimes. She liked me as a neighbor.

 

Now that lady has died, the old LG moved on and was replaced by a Large Big Blu hammer, set on the same foundation and again when forging tough stuff, it will cause the new neighbors dvd player to skip. I have done a number of favors for the folks across the road and I try to never run the hammer after dinner. So all is well. The moral of the story is sub soil is everything when it comes to hammers.

 

I was told, in order to solve this issue, I would have to dig all the way through the clay, to bedrock and build back up with the appropriate foundation. Not gonna happen

Brian...get thee a hydraulic press for the larger work.

 

Ric

[brian robertson]

Ric, funny you should mention that. There is the makings of a 60 ton press in the driveway awaiting assembly and a space in the shop.

[Frosty]

You don't need to subex to bedrock or there wouldn't be but maybe 4-5 bridges in Alaska or maybe anywhere in the world. your power hammer is nothing compared to high speed traffic crossing a bridge.

 

If you're on 75' of clay best hope the water stays low. Of course you can drive piles and no they don't need to be 50tn. house support piles, let alone bridge piles. What's going to keep your hammer in place is skin friction rather than end bearing so you can drive a bunch, say 15-20 3/4" or 1" rebar length to physical refusal. Basically make yourself a reasonably heavy slide hammer like for driving fence posts and drive the bar till you can't make it move measurably for say 5-10 blows. Do NOT take a break while driving, once you start, hammer hammer hammer till it stops. aim for as deep as you can drive it, stand on something secure to get it started, 10' would be SWEET. Please don't tell me I have to tell you, to get a few buddies over to help, unless you're some kind of superman you won't be able to drive one to refusal, let alone a bunch. Get a keg of beer, throw a barn raising kind of shindig if necessary.

 

What will happen when you stop driving is the displaced soil will lose liquifaction and re consolidate (not quite the right term) around the bar and stick it in place like nothing's gonna move it again.

 

For every one you drive straight down drive one or two at an outward pointing angle, 10-15* is probably plenty. These are batter piles and prevent the foundation from tipping while spreading the width of the footprint. (NOT to be confused with a footer or footing.)

 

Oh yeah, what do do with a stick when it's driven as far as it'll go or you can stand. Cut it off a couple feet into the foundation block space, wire your foundation rebar to it and pour your concrete.

 

The wetter the clay the easier it'll drive so be prepared to weld on lengths and continue IF you can weld fast. You can make a round bar clamp with a piece of angle iron with a space cut from the corner so you can run a bead without welding the rebar to the jig. A "C" clamp or two will hold the rebar in the clamp but you gotta go FAST to weld it before the soils grab the bar. It'll be stuck when you start driving again but if you're not too slow it will free up again. The shock from the slid hammer will re-liquify the soils unless it's seriously locked up. If it's that locked up it may be locked up enough for the power hammer. You won't be dealing with just one piece of rebar under the power hammer either.

 

As a last note to you other guys reading this, please don't make me explain a floating foundation. Yeah there are bridges on soils so liquid the abutments and piers are resting foam core concrete floats.

 

Frosty The Lucky.

[DSW]

 I hadn't thought of going that route Frosty. I know it's often used to do heavy pier and bridge work.

 

An easier way to drive those bars would be a "pin" driver. They sell these that attach to chipping hammers/hammer drills as well as pneumatic tools like chipping guns or jack hammers. You'll often find party stores that set up those big tents using electric or pneumatic jackhammers with pin drivers to set those 1"+ rebar  tent stakes. Also a lot of electricians use smaller pin drivers on electric chipping guns/hammer drills to drive 5/8" grounding rods. I know Milwaukee makes the bits to drive 5/8" and 3/4" rods with an SDS max driver. I've got one of those to fit my Bosch chipping gun/hammer drill.

 

http://www.milwaukeetool.com/accessories/material-removal/48-62-4091

http://www.vulcantools.com/ground-rod-drivers/

http://www.factoryauthorizedoutlet.com/makita/makita-1-i-d-x-2-1-4-x-16-ground-rod-driver

[arkie]

DSW, can you drive a rod with one of the ground rod drivers you referred to using a sledge hammer?  Would the sledge damage the struck end?

[Frosty]

 I hadn't thought of going that route Frosty. I know it's often used to do heavy pier and bridge work.

 

An easier way to drive those bars would be a "pin" driver. They sell these that attach to chipping hammers/hammer drills as well as pneumatic tools like chipping guns or jack hammers. You'll often find party stores that set up those big tents using electric or pneumatic jackhammers with pin drivers to set those 1"+ rebar  tent stakes. Also a lot of electricians use smaller pin drivers on electric chipping guns/hammer drills to drive 5/8" grounding rods. I know Milwaukee makes the bits to drive 5/8" and 3/4" rods with an SDS max driver. I've got one of those to fit my Bosch chipping gun/hammer drill.

 

http://www.milwaukeetool.com/accessories/material-removal/48-62-4091

http://www.vulcantools.com/ground-rod-drivers/

http://www.factoryauthorizedoutlet.com/makita/makita-1-i-d-x-2-1-4-x-16-ground-rod-driver

 

Pin driver eh? It should work especially in wet clays just like a vibratory driver. A concrete vibrator should work as well and all a person would have to do is guide it.

 

Frosty The Lucky.

[DSW]

Arkie my guess is you'd screw up the end that would go in the tool beating on it with a sledge. Not sure what the gain would be. I'd probably just fab up a fence post driver if you wanted a guided way to drive bars. All it really is is some heavy large diameter pipe and some smaller side pieces for handles. I've seen some guys fill the capped end of the large diameter pipe with lead to gain mass so they drive opts easier. I've used these to drive those metal engineers posts used for wire mesh fences in the past. You get a good workout using one, but they are WAY better than swinging a sledge.

 

 

 

 

 

 

 

I also spotted ths pneumatic post driver when looking for images. This looks like another good option for driving long bars especially large diameter ones. I'd only seen the hand drivers above before.

 

 

http://gobobpipe.com/power-post-driver.htm

[DSW]

Frosty. I would of never thought of that use for a concrete Vibrator. We had 3 or 4 of them, from a small pencil vibrator we used to use on small stuff and steps, to a few with 2" heads that were 12' long for doing wall forms. 2 electric and one gas powered backpack model. Makes sense. We'd often use them on footings to help spread crete that was like a 1 slump that you could almost walk on, when they'd send us a hot load in the summer.

[arkie]

Arkie my guess is you'd screw up the end that would go in the tool beating on it with a sledge. Not sure what the gain would be. I'd probably just fab up a fence post driver if you wanted a guided way to drive bars. All it really is is some heavy large diameter pipe and some smaller side pieces for handles. I've seen some guys fill the capped end of the large diameter pipe with lead to gain mass so they drive opts easier. I've used these to drive those metal engineers posts used for wire mesh fences in the past. You get a good workout using one, but they are WAY better than swinging a sledge.

 

 

 

post.jpg

 

fence post driver.jpg

 

 

 

I also spotted ths pneumatic post driver when looking for images. This looks like another good option for driving long bars especially large diameter ones. I'd only seen the hand drivers above before.

 

 

http://gobobpipe.com/power-post-driver.htm

 

DSW,

 

We live in the country...I use the post drivers all the time for t-posts and small pipe.  :)

 

The ID of the post driver is much larger than rod and the rod just bounces around in it, so I just wondered if the pin drivers would be acceptable for say 1/2" to 1" rod.

 

I'll see if I can find some small ID heavy-wall pipe a couple of feet long and weld a thick end on it similar to post drivers.  Problem with small pipe is that it doesn't have much weight for pounding. I suppose one could slip the next size pipe over the first smaller one, weld it on the ends and increase the mass some that way.