Impact on floor

[Metalsculptingben]

I have the opportunity to move into an old railroad depot. The floor is is cast concrete, but raised. It is supported by cast concrete beams and concrete post. The floor is two feet thick, but with a crawl space below. Would it be possible to put my LG 100# in there? With that being said does anyone know the force made by my power hammer against the floor?

[Charlotte]

Generally, the recommendation is to pour a separated base.  Over time the hammering of a 100# hammer will break up even an old concreate floor.    How long will it take depends only on time and the age and composition of the concrete.   Kinetic energy = Mass x velocity at impact.  There is also a momentum component transferred to the floor with is Weight times velocity.   That translates to the shake of the building.

Placed directly over one of the pillars and with a large hardwood pad under it you may be able to run the hammer until the land lord sees the cracks

I've seen people do that with smaller hammer on concreate slabs and have no problems. 

[Frosty]

Bob Bergman runs his 100lb. Bradly Helve on a bare 4" concrete slab floor on good base. Well, he did the one time I got to visit him in 07 I think, it was about 8' from a Nazel 3B on the same slab.

I wouldn't hesitate to put a 100lb. LG on a 24" thick concrete slab especially over a concrete pillar. It's a concrete span, think bridge deck in a factory. Any impact energy not cushioned by the HOT steel and absorbed by the sowblock and distributed by base's foorprint is pretty insignificant. It's not like you're dropping a 100lb steel shaft from 50' over and over.

Of course that's just my opinion, I could be wrong. Frosty The Lucky.

[mike-hr]

I restored a LG100 for a museum last year, and floor vibration came up. With the hammer setting directly on the slab, we could feel the shock in our boots from 15 feet away when the hammer was running flat out, forging 1 inch square. One of the guys had been foreman at a big company that had dozens of big punch presses clanging away all day, he suggested vibration isolation pads. They are an engineered wool or felt disc, one goes under the hammer bolt hole, another goes over the base with a big flat washer and nut. I did redneck telemetry after we got the pads installed, I filled several plastic drinking cups with water and distributed at various distances from the hammer on the floor. Kind of a Jurrasic Park seismograph. There were a few slight ripples 12 inches from the base, but farther away than that, nothing! We had various discussions about whether it was good for the hammer to be suspended by these pads over the mounting holes, with no support over the rest of the casting, but Bob the engineer assured us it was fine. anyway, these pads work very well, I'm sold on the idea.

[Kozzy]

Bob Bergman runs his 100lb. Bradly Helve on a bare 4" concrete slab floor on good base. Well, he did the one time I got to visit him in 07 I think, it was about 8' from a Nazel 3B on the same slab.

I wouldn't hesitate to put a 100lb. LG on a 24" thick concrete slab especially over a concrete pillar. It's a concrete span, think bridge deck in a factory. Any impact energy not cushioned by the HOT steel and absorbed by the sowblock and distributed by base's foorprint is pretty insignificant. It's not like you're dropping a 100lb steel shaft from 50' over and over.

Of course that's just my opinion, I could be wrong. Frosty The Lucky.

I think this might make the assumption that the concrete is decent quality stuff--which might not be the case.  I have to assume that an old railroad depot could vary from far over built to some pretty slipshod and questionable concrete back in the day.  Although 2' thick implies it was built like a tank, it may still have sub-par compression concrete with little (if any) reinforcing.

Older concrete was also often done with beach sand..or whatever sand they could mine locally...often worn rounded sand instead of sharp sand which reduces strength.  Similar with whatever gravel was used as the filler.  

Personally I'd take a close look at the structure and integrity of the existing concrete AND make sure my insurance was paid up.  Spread the load, absorb the shock.

Edited October 28, 2015 by Kozzy

[phabib]

I had my Hawkeye helve hammer mounted on a combination of a rubber vibration isolation pad with an inflatable vibration isolator on top of that and the hammer resting on the inflatable isolators.  That did a great job of soaking up the vibration, but the hammer could dance around at least an inch back and forth as it ran.  When the new hammer arrives I'm going to put in the big concrete block under it instead.

[plain ol Bill]

I run my Sahinler 110# on a 4" floor. I have the hammer sitting on a pad of 2x4 boards. Haven't had any problems.

[matto]

at the museum we run our 100lb lg on a 8" slab.  we use it 2 to3 times a week.  it has a 1/2" rubber stall mat under it and is bolted to the floor.

[Javan C.R. Dempsey]

1 tube of silicone between the hammer base and rubber stall mat. 1 tube of silicone between the stall mat and the floor.

 

Currently have my 75lb Bull which I've tuned for maximum destruction (i.e. stroke length and power), sitting on a similar configuration for the past year, although it's bolted to a 2" thick piece of wood between the stall mat and the hammer base, but no bolts running to the floor.  It's held up much better than when I previously had the whole ordeal bolted to a large isolated pad with red-heads.

 

I wouldn't have believed it, but with the silicone, it's immovable, and it's on a very shabby old 4" thick concrete slab which is uneven.  When I go to move, all I'll have to do is run a wire under the bottom to cut the silicone.

 

I run this hammer hard FWIW, day in day out.

[ZIG]

Your correct about using a stall mat and silicone.   It's amazing what that stuff will do.   I have worked in heavy industry,all my life. Been a Boilermaker over 25+ years., and have seen silicone do things that you wouldn't believe .  It will out last 1 inch thick tile . It will still be there and it's getting blasted with coal dust out of the pulverizer.   The silicone will still be there and the tile will be worn down to,the housing.   It absorbs the vibration and can take a beating.  

   I'm in the process of building a tire hammer and I gotta big crack in ,my shop floor, so I'm gonna cut out the concrete where I'm gonna place my hammer.   So it want crack the rest of the floor .  I'm gonna use the stall mats ,myself. And silicone .  So I appreciate the good news on using silicone ,and felt washers under the anchor bolts.    

  I'm gonna beef things up ,simply cause I need to cut some expansion joints ,for where my floor is cracked anyway.  Just so it don't bust it anymore ,plus it's unlevel now.   So that section must go.  Cause I'm to OCD to shim anything .  I've got to do,things as perfect as I can.