Power Hammer shaking the entire house

[DSW]

OK that makes sense. I've seen that with small rods in big pipe.

 

Then the next thing I'd think about is getting say some 3/4" or larger pipe with the ID to match your rods, and welding a decent sized heavy plate on the end for a cap. The 3/4" pipe will stiffen the small diameter rod, and the over sized "cap" on the end gives you a bigger target to pound with the sledge. In effect what you made is basically the same as those Milwaukee pin drivers I listed. If I was going to beat on a pin driver, I'd choose one with a 1 1/4" hex shank for a jackhammer vs the smaller SDS max ones. With the extra material, you are less likely to beat the crud out of it and deform it as much. The larger shank would also lend itself to easy cleanup if you did need to fix it to put it in a jackhammer. Those SDS max bits can be a bugger to try and fix if they get really dinged up. Of course if you have to beat on one by hand though, I'll assume you don't really have a need to stick it in a power tool anyways.

[brian robertson]

Frosty, my hammers haven't moved on the 4 yd foundation. My point is that the shock wave travels through the wet clay great distances. Think Jello. Going to bedrock is the way to avoid that not to necessarily stabilize the hammer

[DSW]

 A larger surface area of the footing may cut down on some of that. Think of a water bed. If you put down a small square of plywood, say 6" x6" and hit it with a hammer, you get waves. Instead lay down a 4'x4' sheet and hit it with a hammer and you'll get less waves because the force is distributed over a larger surface area.

[thingmaker3]

According to page four of the manual (http://www.ka75.com/KA75_manual.pdf) the 8" thick block is not specified. You need half a cubic yard under the thing. (That's a bit under half a cubic meter for those using French measurement.) Your other option is a reinforced 8" thick floor. (Floor, not block.)

[swedefiddle]

Good Morning,

 

I have a KA75 and I can't see how someone would be complaining of shaking the house. I think the story is a little stretch.

 

If you are having such a problem, put a piece of Hi-Density rubber under the foot. I don't have mine tethered to the floor, I have a piece of hi-density rubber under it to stop it from leaving the room. :) :)

 

Grant Sarver designed these to be simple and take up very little space.

 

Neil

[ThomasPowers]

Is your "small" pipe is too light you are using the wrong pipe---think drill collar at 1.25 ID and 3.125 OD and 22 pounds per foot.

 

Shoot I once ran across some 1" ID, 1" wall pipe at the scrapyard, took it home and did a spark test on it which spooked me a bit as it was VERY BURSTY, like a file but a dark red in colour!  Still wondering what the heck it had been used for...

[Frosty]

Frosty, my hammers haven't moved on the 4 yd foundation. My point is that the shock wave travels through the wet clay great distances. Think Jello. Going to bedrock is the way to avoid that not to necessarily stabilize the hammer

 

Exactly. I'm afraid I used bridges as examples of stabilizing foundations with batter piles. the shock waves are severe because you're sitting on wet clay. Jello is indeed how it acts. This is laquifaction, vibration shakes the soil grains and water gets drawn in to fill the voids but it can't be driven out nearly as quickly so the soil grains are kept apart and can flow like a liquid. OR move in waves like a pond, etc.

 

Increasing the displacement of the foundation helps in two ways, first it's more massive so resists movement and secondly it displaces more soil so the vibration is diminished by acting over a larger surface area. In wet FS (frost susceptible) soils it IS hydraulics and behaves according to the same rules. PSI is = over all surfaces, so a ram of 2x the area moves with 2x the force but 1/2 the distance. (Yeah, I didn't specify a ram area, I can if anyone needs)

 

DSW: concrete vibrators work in sands and wet clayey or silty soils. They don't work worth spit in well compacted angular soils. They can however sometimes move a rock that stopped the penetration.

 

Frosty The Lucky.

[johnnie]

Exactly. I'm afraid I used bridges as examples of stabilizing foundations with batter piles. the shock waves are severe because you're sitting on wet clay. Jello is indeed how it acts. This is laquifaction, vibration shakes the soil grains and water gets drawn in to fill the voids but it can't be driven out nearly as quickly so the soil grains are kept apart and can flow like a liquid. OR move in waves like a pond, etc.

 

Increasing the displacement of the foundation helps in two ways, first it's more massive so resists movement and secondly it displaces more soil so the vibration is diminished by acting over a larger surface area. In wet FS (frost susceptible) soils it IS hydraulics and behaves according to the same rules. PSI is = over all surfaces, so a ram of 2x the area moves with 2x the force but 1/2 the distance. (Yeah, I didn't specify a ram area, I can if anyone needs)

 

DSW: concrete vibrators work in sands and wet clayey or silty soils. They don't work worth spit in well compacted angular soils. They can however sometimes move a rock that stopped the penetration.

 

Frosty The Lucky.

Frosty is this sort of thing your profession????

You sure as s#it know everything to know about foundations..

Words used that I've never heard of, very interesting reading though, thanks

[Frosty]

Frosty is this sort of thing your profession????

You sure as s#it know everything to know about foundations..

Words used that I've never heard of, very interesting reading though, thanks

 

I hardly know everything there is to know about foundations and soils engineering but I did work for the State of Alaska soils lab then Headquarters Materials geology section, bridges and foundations drill crew. So, for 20 years I was immersed in foundations design and soils engineering. All the words are in the dictionary but I make no claim I'm using the right ones in the right way. I know enough about soils and foundations designs to do a fair job or who to ask if I'm out of my depth. You won't find my signature on any reports even if I'm in them. Everything got logged.

 

Frosty The Lucky.

[Tomas Benadik]

Greetings, gentlemen.

Many thanks for all your suggestions - I'll run them through my teacher and will get back to you.

 

Frosty - I'll try to get more info about the soil(s) underneath.

Swedefiddle - well, it's a house built in about first half of 18th century (of course, rebuilt since then) and the shop is actually first room of the house. Meaning whoever comes to visit must pass next to forge and anvil :) It also means that the china cabinet etc. is *literally* next door.

 

 

Thank you all again,

Tomas