Will powerhammer crack slab?

[skunkriv]

You want a substantial foundation like JK has outlined above and poured with rebar and expansion joint all around like Welder19 says. Also you want to have your hammer bolted down, either set over J bolts poured with the foundation or bolted into something set flush or below the surface (like pipe with nuts welded inside.)

[bear Hill]

Chief Mcgee - Mass is everything and isolation is wonderful. I first set a 50 lb Little Giant on a 5" slab with wire in it......four months later one of the fasteners had pulled a 10" chunk of floor up with it. The next step was to pour a footing of 24 x 36 x 24" deep - hammer runs like a dream setting on this with 2 inches of hardwood block and a rubber pad. My Nazel runs on a 2 1/2" steel plate (with hardwood and rubber under the anvil) on top of an 8" floor........works - but lots of shock transfer(would be better isolated). My air hammers run on 2" plates with rubber pads under them and work well. The difference in a mechanical and an air hammer is linear guides verses toggle links on a spinning flywheel = off center spinning weight. My advice is to go with a heavy plate like mentioned above -or go with a poured foundation(prefereably isolated from floor by board perimeter). An other option is a wood bunk foundation (but it tends to burn with drops)

Ralph

[John N]

I would be wary of putting 2" of rubber under it, it will bounce - which is annoying to say the least, but will also result in a vertical hammering motion on the holding down bolts which will cause them to rip out or fail in no time.

If you are trying to attenuate the vibration I could write a thesis on it ! - the trick is plenty of mass, and having no point of your isolated interia block in contact with the surrounding ground - the vibration will find the contact point and transmit. If you google 'Fabreeka' it may show some isometric views of inertia blocks for a few ideas.

Sit down if you ask them for a price on any of the materials though

you can get away with a fairly thin slab, if you have a large contact area between the hammer and the slab - we scrape the timbers between hammer and slab to give as near 100% bedding as we can (think of a small contact area like a fullering die, it will break down the concrete / metal very quick !)

[Dodge]

Some power hammers need a substantial footing some don't. Rating of hammer weight is not the factor that determines this. I can't explain it as well as the Phoenix Power Hammer page does but it has to do with total mass. My tire hammer weight is about 1000# total with an anvil and base plate weight of about 600#, but is only a 35# hammer. I have no special footing but it does sit on a pad made from 2 x 4s laid flat with a 2 x 2 frame to contain the base. It sits on a standard thickness garage floor (residential construction: circa 1975) No ill effect so far.
Phoenix says even their 500# needs no special footing but again it has to do with total mass. Check out this link for better explanation. Phoenix Forginghammers : What is Cast Iron Fever? It mainly scoffs at cast iron hammers but the important idea is about the anvil mass so read the whole thing.

[John N]

that page is a load of total, complete bobbins (the cast iron fever bit) I would trust that no more for foundation advice than I would trust me for knitting advice.

If you dis-credit yourself on one piece of advice information / , how can you expect people to trust you on others ?

(John, @ Johns Hammer emporium, perveyor of some of the finest cast iron (well over 20,000 of em, still industry standard best) Massey hammers... )) -

(im not saying they are bad hammers, but tell me how many of them have been double shifted, tool steel forging for 50 years and still going strong....

[fat pete]

I would also call an admixture company that works with concrete, They have all kinds of additives to make concrete work better in different situations. My neighbor has a huge kiln (6, 3" burners) you can walk in it. They mixed some kind of cement especially for the weight and heat. Worth the research.

FP

[Chris Pook]

My 3b nazel sits on a wood base on my 5" slab floor. It hasn't cracked the floor yet, but I also don't use it every day. it does however pound the floor hard and you can feel it in the house 50' away.

I think alot of it depends on what the ground under you slab is like. At my old shop you couldn't feel the hammer 10' away standing in the shop with the hammer sitting on the same wood beams.

I'm going to be digging a pit and doing a proper foundation soon. Want to use it more often and don't want the neighbours fine china falling of the shelves.

I'm looking at using something like a concrete septic tank. Then using thick rubber bought from an industrial rubber supply place, then either forming a concrete block on top, or possibly a steel box filled with sand compacted and a steel floating cap on top (easy to remove if I ever move to a new shop/house, I had a friend who spent big $$$ on a foundation for a 400lb denmore hammer that had to move 2 years later).

[John N]

Chris, The best thing to use is an 'isopolymer cork' along the base, and a void filler (expended polystyrene will do) alternative strips along the base of your 'septic tank', then line the walls of your pit with a void filler, and a capping strip around the top with the cork material.

Seal it all up with duct tape and pour the inertia block. This leaves a 'floating' inertia block when the viod filler disintergrates.

Ive acheived measured 98% virbration attenuation on 3 ton (ram weight) hammers using this technique, its a 10th of the cost of 'spring box' foundation, the absolute best!

The 'cork' can be bought from Fabreeka, or James Walker ( TICO pads) - they charge you mega bucks if you get them to design the foundation (and they disclaim all liability as far as effectiveness goes , but the materials arent to dear if you know what your asking for.

Hope this helps a little.

[Chris Pook]

John, do you have any links to the material? I'll try and do some google searchign for a local supplier.

[Dodge]

Originally Posted by John N

that page is a load of total, complete bobbins (the cast iron fever bit) I would trust that no more for foundation advice than I would trust me for knitting advice.

If you dis-credit yourself on one piece of advice information / , how can you expect people to trust you on others ?

(John, @ Johns Hammer emporium, perveyor of some of the finest cast iron (well over 20,000 of em, still industry standard best) Massey hammers... )) -

(im not saying they are bad hammers, but tell me how many of them have been double shifted, tool steel forging for 50 years and still going strong....

To dis-credit MYSELF, I would have to admit I'm wrong , so let me clarify. I have no special footing under MY hammer to prevent cracking, because I don't feel it was necessary. The wooden pad MAY be serving that purpose, but that is NOT why I use it. I use it to contain the hammer as, because it is home made, it has a slight balance flaw I haven't cured yet. The pad with the frame seems to help keep it from "walking" in use. There was no threat of the floor cracking, that I could see, before the pad was used. (That was the original issue right? Not, which power hammer is best.) I know the phoenix link is mostly sales hype, and I don't care if its a good hammer or better or worse than cast. Perhaps it was a bad example, in retrospect. I simply wanted to relay the anvil mass issue. I thought that was what I said in the original post. I also said SOME hammers need a foundation, some do not. After re-reading the Phoenix page I have found that on their largest hammers, (1000# +) a footing is, indeed, required. I also agree that if you do pour a footing it needs to be isolated because if it were simply poured thicker under the power hammer than the rest of the floor, it would probably crack around the thicker area, isolating it anyway