Hydraulic cylinder for air hammer

[rowdyripley]

Hey all, 

Been lurking for a while, finally building my utility hammer. It's going to have a 100lb ish tup and steam hammer type linkage. I'm going to weld 2x10 plates vertically to achieve the 1/10 anvil ratio and use an 8x1/4 square tube as the spine (possibly filled with concrete). I've seen a couple of guys mention using modified hydraulic cylinders (specifically Ken Zitur and MacBruce) and am wondering what goes into making that modification. I would love to have a more robust cylinder and rod for the application but heavy duty pneumatic cylinders are prohibitively expensive. 

 

[BeaverNZ]

The hyd cylindersare certainly more robust but you may have to reseal it as the seals used with hydrualics will probably have to much stiction or drag and you may loose alot of power/speed

[swedefiddle]

Good Morning, Ripley

Welcome to this world, enjoy the journey.

There is one way to find out, Do It!!  Air Hammers need oilers for the Compression Cylinder and the Working Cylinder. If you are talking about a single cylinder Air Hammer, they/it still needs lubrication. Any cylinder needs lubrication. Quite often the single cylinder Air Hammer, uses an aluminum body Air Cylinder. The cylinder does not take all the impact. On the larger Air Hammers, they use 2 cylinders, when the motor compresses the top of the compressor cylinder, the air pushes the working ram down. When the compressor piston is going down, it is compressing the air at the bottom of the cylinder and this pushes the working cylinder up. The only connection between the cylinders is compressed air. This may be too complicated for your simple question, Lavie.

Neil

 

[rowdyripley]

Yeah I suppose getting a cylinder and pulling it apart is my first step. I do eventually want to build a self contained hammer but figure I should start with a utility hammer and work my way up.

[Frosty]

Before you do any of that I highly suggest you look at patent drawings for some of the early self contained power hammers. I was accumulating parts when I happened on a good deal on a 50lb. Little Giant mechanical. 

Believe it or not a self contained hammer has a really simple valving system if you stick with the early patents, valving starts getting tricky with the "new and improved" models. Spool valves are tricky to make and plumb.

At it's base a self contained power hammer is about as complex as a see saw. Plumb them rod end to rod end and cap to cap end. There are details about that I won't go into. With them plumbed this way, move one piston and the other will move equally the other direction, just like a see saw. Clear so far?

 Need to control it yes? Plumb a bypass between the top and bottom pipes. Leave it open and the drive (Master) piston goes up and down while the driven (Slave) piston just quivers because all the air, hyd fluid, whatever is simply flowing from to to bottom of the master piston. Close the bypass and the Slave cycles with the Master.

Make sense so far? Controlling it is as easy as putting a valve in the bypass, open and the slave just sits there, closed and it cycles. 

There is more of course, putting two coupled valves in the bypass where it joins the connecting pipe works WAY better. It needs "dead" space at top and bottom of both cylinders so the pistons don't slam into the ends and destroy themselves. The bypass control valves need to be pressure relief valves to help prevent the system from overheating. etc. etc.

It gets more complicated but not much so long as you keep the hammer simple. For example I spent a lot of time trying to come up with a way to get the tup to idle in the up position without having a built in pressure reserve and a compressor mechanism to keep it charged. This is part of what spool valves do though early hammers did it without.

A utility hammer requires position sensor / switches and a more complex valving system. Early steam hammer patent drawings are a good place to see  simpler (Less improved) versions.

Frosty The Lucky.

[Goods]

I watched a YouTube video of the guys at Coal Iron Works talking about the effort that has gone into the self contained hammer and at the quad state they did an introduction/unveiling of it looking for feedback. Even with serious engineering work, it needs a lot of fine tuning. (I should have made it to quad state to hang out with them. I would have love to see Kurt putting it through a work out…

Keep it fun,

David

[rowdyripley]

Sooo....  I finally read the "read this first" thread. That bit about using Google to search instead of the search bar is golden. there is a lot of good information about this topic on several older posts that I couldn't find the conventional way. 

[BeaverNZ]

Before I stumbled apon my Massey I was thinking of making my own self contained power hammer. I had found the shematic of an Inslides patent 707246 aug 1902 and patent number 1524195  Jan 25 1925 and I had a really simple valving system from anvilfire.com by Patric Pelgroms of Belgium. Its amazing what I still have stashed in my filing cabinet, no wonder its so full of paper.