Never used a hammer before on a mini. Just wondering what are the does and donts of using a hammer. I'll mostly be using it in rock. Are there special chisel points for different materials? Any special techniques to get the job doen faster? BTW this will be on 8000lb mini, just wonder what size of hammer I should look for and how do you know a used hammer is still good to go? Thanks
Do not dry fire it and keep it greased!
Always try to keep the point and the hammer at 90 degrees to the surface that you are breaking, do not use the hammer to pry apart the broken/cracked concrete e.g place point on the concrete, break into it and then lift it out vertically not drag it out (if you get what I mean!!) - sometimes the concrete will pinch the point and trap the hammer in the concrete - you probably will need to wriggle/pull the point about a bit to be able to lift it out. I find it helpful to always have the blade down facing the breaker to ensure when you attempt to lift the breaker out it lifts out rather than tilting the machine!! If it is a used breaker I would recommend getting it regassed and serviced if it hasn't been already to ensure optimum performance.
When greasing the breaker make sure that there is pressure on it, otherwise the grease can go up into the breaker. Warm it up by operating it at half throttle on light work before getting into the heavy stuff. Don't try and do too much with it, better off to break off small sections rather than go for a big chunk and trap the breaker tool. As strott said, don't ever use the breaker to lever off material, you can use the breaker to drag small sections of broken material away from the work area but use common sense. Before using the hammer put pressure on it by slightly lifting the front tracks off the ground, for more pressure put the blade out the back to put the full weight of the carrier onto the hammer. If the breaker is not breaking the material, stop and reposition the tool. Bashing away at stuff that is not breaking up will only blunt the tool and cause the tool to heat up. http://www.gorillahammers.com/hydraulic-breaker-sizing.shtml www.worktools.co.nz/Site/Files/c/.../Hammer greasing.pdf www.gearmore.com/partsbooks/HydBreaker.pdf psndealer.com/dealersite/images/huskiehammer/hh100-1000-2.pdf On a 4 tonne machine a 300-400kg hammer would be fine, don't try and fit a big hammer on it as you will have lifting issues. A second hand breaker is a gamble, they can be rebuild but check the nitrogen charge, if it holds pressure then at least you know the seals are in good condition. Grab the tool and wiggle it in the bore to see how much slop is in the bushings. If it has been stored on it's side for a while you can have flattened seals. If you go to look at a SH breaker and find it lying on it's side, you may well have to rebuilt it before use. Same goes for when you have it, make sure that you are able to stow it in an upright position.
Keep an eye on the temperature guage on the machine as well. The hydraulic cooler is probably right next to the radiator, and the hammer will make lots more heat in the hydraulic system than just digging, so the machine cooling system may overheat because it's not getting air as cool as it's accustomed to.
I know this may be difficult to answer but what would the average rebuild price cost for seals and a recharge. Also does the hammer work better in real hard rock like granite vs limestone? Thanks for all the great advice!
Does your machine have a cab? Think about protecting yourself and anthing else you don't want chipped or dinged that might be nearby.
Wear ear protection!!!! - cab or not!!
May depend on the type of tool you are using, for most jobs the standard narrow chisel will do the job but for the hard stuff you might need a pointy tool.
Both my hammers have the round pointed tool - never used a chisel on either of them!!
I've never seen a chisel on one myself. My guess is if it looked like a chisel in the morning, it would look like a round point by quitting time. :beatsme
Got a cab and I wear hearing protection that pipes in my XM radio! Hopefully the chips dont crack the front glass.
"Dry fire" means that you have activated the tool when there is no pressure on the bit. This is bad for the accumulator. Use your ears when running the tool. Changes in the impact rate indicate loading and unloading the bit. Unloading the bit is like dry fire. If you hear the tool slow down it's usually because you are not pushing straight into the point. The bit is binding in the bushings (do to side loading) and it doesn't allow the accumulator to work properly. I don't agree that you must ahve the tool at 90 degrees to the work surface. You must however have the hammer body along the same axis as the bit, and the force that you are applying with the carrier must also follow this axis. When attacking the rock it is always best to "work to relief". In other words start at the edge of the rock and work back to the middle, away from where you started. As you break the rock, break off pieces that will break off towards the edge. Take small bites at first and "test" it to see what you can get away with. As a general rule, harder rock takes a bigger hammer. You will quickly find the limits of a hammer that will fit your machine. These tools are made more for concrete (2500-3500 psi). The rock you mentioned can be around 9,000 to 15,000 psi and even over 20,000 psi for granite. Hammers are high wear items. Second hand units are a gamble. safest bet when buying used is to assume rebuild will be required. Many brands rebuild much easier and less expensive than others. Quality between brands can very greatly also. Make sure you are buying a brand that you can get parts and service for in your area.
^^Even when working from an edge the smaller hammer on the K008-3 can get stuck, as you say if it starts getting stuck then you just need to break away smaller chunks and alter your operating technique.^^ Really its just trial and error, each hammer on each machine will handle/work differently, just be mechanically sympathetic and follow the good advice from the users on here.
Just doing some research on the subject shows me the units are rated in Ft/lbs. For my 8000# mini would a 750ft/lb hammer be okay? I know the hammer weight is important and I dont want to tip the machine on end. Just wondering if the small hammers are worth buying or do I just sub out hammer work to a bigger size hoe...say a 120 size. I would hate to sit and hammer all day at rock that a larger unit can do in a few hours. Also for buying new any brands to stay away from?
Each model of hammer will have a minimum and maximum flow rate which it will work within - so you will need to get one that will work with the max auxiliary flow your machine puts out. Most hammer manufacturers give a guide as what machine carrier weights each model of hammer is designed to run on. Between this info and the hammer weights you should be able to choose a suitable one. Not to sure on brands in the US so can't help you on that front i'm afraid!!!!
I have broke a lot of lava rock (Basalt) with hammers from 500-1500. It can be slow depending on the type of rock. I have seen 300 size machines struggle with this type of rock so its all kinda relative. I use the hammers more for demo than for rock anymore. If your close on sewer or water line and have some rock in the way they work well. If its mass rock removal, blasting is much more cost effective as long as you can use bang. I would go as large as you can handle for your size machine, and 750 is as big as I think you dare go. Like mentioned, make sure that the flow requirements on the hammer match the machine. Its not as much of an issue on this size since the hammers USUALLY don't take much flow (there are some exceptions like the ESCO I had that wanted 35 gpm) normally around 12-15 is the requirement which most excavators in this class don't have a problem with. I have had good luck with Okada, and Stanley hammers with the Okada being my favorite.
I looked at a Tramac hammer and it seems unique in that it doesnt need nitrogen to function so maybe thats good. In any case thanks for all the great advice. Just need to find some dough now to spring for the hammer!