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Tool handles and simple machines

magneticanomaly

Titanium
Joined
Mar 22, 2007
Location
On Elk Mountain, West Virginia, USA
One of my favorite tools, this time of year, is the splitting maul.

When I was taught about the "simple (fundamental) machines", I recall the list as, wheel, lever, screw, wedge. After years of pondering, I think there are actually six, but not all of those four are really fundamental.

My list would be tendon, strut, lever and fulcrum, wedge, hammer, and hydraulics. Wheel is merely multiple levers that also act as struts. Screw is a wedge wrapped around a wheel. Hammer is kinetic energy storage and transfer; it acts like a "time lever", whereby you add energy slowly, over a long span of time (as a lever takes in energy over a long distance), and can release it quickly, (as the lever does over a short distance).

So the maul is a combination of hammer and wedge.

The weak point of a maul in use is the handle. I can use a maul handle for a long time, because i put into practice the understanding that the handle's functions are guidance, and to slowly and steadily accelerate the head as it flies around the arc of the swing. My very strong and not yet very graceful son breaks one every couple of days, because he uses the handle to mostly push the wedge though the wood, instead of letting slowly-stored-up energy do almost all the work.

I bought a very nice, shapely maul head at the scrapyard, on which someone had tried to solve the perishable-handle problem by welding a solid 1" bar into it as a handle. Some people say that such a handle hurts the hands because it transfers shock or vibration. I think it is because its large mass stores energy near your hands, which then delivers its own blow to the hands when it stops. The previous owner tried to mitigate the problem with many layers of duct-tape, and when that failed, it went to the scrapyard.

In my experience, it is less the absolute weight of the handle that matters, than the ratio of handle weight to head weight, which must be low enough that the center of effort (taking into account that stored energy goes up as mass x radius of swing squared) is within the head. This supposition is supported by my happy experience with a handle made of 1" sch 40 iron pipe in my 16-lb sledge.
I have had good success with helves for 8-lb mauls made of 3/4" EMT (thinwall conduit), reinforced through the head and a few inches down the handle with a slit-and -narrowed piece of 3/4" pipe. When they eventually crack, I weld them...the last one that finally irreparably failed right next to the head after years of service, was mostly welds for half its length.
I want to try a wooden handle again. I have some bolts of hickory that I have been drying. But here are my questions for the brain-trust here.
I want to enlarge the eye, which will allow fitting a fatter, stronger handle I guess I will use the milling machine, although it will be a bit if a challenge to securely hold the workpiece with no flat or cylindrical surfaces. I am not sure if I will add the tapers with a big rat-tail file or try to make eight tilted setups on the mill after the straight one.

But thinking about the slight tapers, needed to relieve the transition to the handle and allow wedging, led me to wonder if it might be practical to add enough taper to fit the handle through the eye from the far side, like a pick or adze handle, instead of into the near side of the head as is conventional for hammers.

Does anyone have an idea why this is not done for hammers? Why it would be a bad idea?
 
My best guess:

If your mattocks head (with the taper on top of the head) wiggles a little bit, it's ok - as long as it don't fly off (hence the taper on the top side - it's there to slow down the process of natural selection wherein people who are foolish enough to stand in front of the mattocks-wielder are removed from the gene pool)

If your hammer head wiggles a little bit, then you got problems. Glancing blows, crooked punches, wedges flying in random directions (and accelerating that natural selection process). So, there's a taper under the head for an affirmative seat (like a Morse taper) and a wedge on top to keep everything tight and the hammer head on.

So, my guess is the dividing line for taper on top/bottom of the head is "Does this tool strike the workpiece, or does it strike another tool?"
 
A blacksmith would make a drift of the size desired for the eye. Heat the head and resize the eye with the drift. Heat treat as desired.
 
The maul I have is the best one I have ever used. It really splits wood easy. The head is shaped like a large wedge of cheese. By large I mean 4.5" across the back, 4.5" deep, and of course tapering to a point edge that would be where the center of a wheel of cheese would be. The handle is heavy wall pipe with a quarter inch of foam where you hold it. I have used all the other types and this is the best. It never gets stuck as that 4.5" thickness is more than wood can withstand with out splitting.
 
Magnetic Anomaly:

Your post about the splitting maul and handles raised a few memories and lines up with some of my own thinking.

First of: I had come to my own belief that the force developed by a hammer or splitting maul is most often a function of the velocity of the head/striking face (or cutting edge) rather than weight. I go with the equation we learned as kids in HS physics for kinetic energy: KE = 1/2 M x V*2 . Clearly in this equation, the square of the velocity is what 'does the real work'. To my thinking, a longer handle = higher velocity, since the maul or hammer is swung thru an arc. The larger the radius, the higher the velocity.

On the other hand, there are times and jobs where there is no substitute for a heavy mass on a hammer head. Case in point: years ago, we had to re-wedge some rotor pole windings on a 300 Mw hydro generator rotor. I got the bight idea to make life easier on the crew and had them make a driver built on the 'steel' for a 90 lb air hammer (pavement breaker, usually used with bull points). We had 120 psig compressed air and plenty of it. The drive was straight downwards, length maybe 6 feet if I remember right. The air hammer was roped to the hook of a bridge crane to get it into position over the rotor poles. Surprise ! The air hammer could only drive those wedges just so far. It stalled. The mechanics all laughed and said there was no substitute for their use of 16 & 25 lbs sledges. The solid impact of the sledge hammers did the trick and drove those wedges home. In retrospect, if we consider the size & mass of the 'free piston' in even a 90 lb air hammer, the KE produced is probably fairly low. As I pondered this matter, I came to the analogy of two boxers: one lightweight boxer who wears his opponent down by throwing continuous flurries of lighter punches that might open a cut or rattle his opponent's brains; the other boxer is a heavyweight, slower but throwing a punch with a lot more behind it. The heavyweight throws punches that can put his opponent thru the ropes of the ring. That is the difference between an air hammer and a heavy sledge.

I suppose there is a kind of 'sweet spot" for determining handle length and head weight for optimal performance of a maul of sledge. It is a function of how the person using that maul of sledge is built, arm length, strength, and overall condition of their body. Can they stand properly and take a good overhand swing to get plenty of velocity on the cutting edge, or are they only able to take shorter swings ?

It is an interesting bit of applied basic physics and human physiology. I've been around some hand spiking of railroad rails, using spike mauls. These are 8 to 12 lbs heads which taper to a round (or squared) punch section. This gives a small striking face to contact the head of the track spikes, and a relieved area to get in alongside the railheads. Swinging a spike maul takes practice and skill. The best spike maul technique is the overhand swing. Seeing two guys driving the same spike, standing on opposite sides of the rail is always special. I've tried hand spiking, and even with holes pre-drilled in white oak cross ties, It is work for me. I have a buddy who can swing the overhand swing and sink track spikes in a matter of a few blows, no predrilling. He is lighter than me, about the same height, but more muscle and practice. He's 81 years of age and can still swing the spike maul with that overhand swing. In his case, it's MV*2 at work aside from wrist strength and overall skill. Connect with a rounded spike had a little off kilter and the spike maul will glance off and twist the user's wrists. I've never seen a spike maul with anything but a hardwood handle.

I am reminded of an old friend who owned/operated a machine shop in Wyoming. He was quite an inventor and gifted man. He told me a story of one of his inventions. It seemed the Union Pacific Railroad was having a high incidence of broken hardwood spike maul and sledge handles. My friend got the idea of making 'composite handles'. He got an old screw cutting lathe and rigged up what amount to the Blanchard 'gunstock lathe'. This turned the handles undersized but kept the profile and cross section. He then fitted a motor driven saw arbor to the lathe's cross slide. This was fed using the half nuts as if saw-cutting a fine pitch thread on the handles. The next step was to mount a spool of fiberglass cord with a friction brake on the toolslide of the lathe. The handles were coated with fiberglass resin, and the cord was wound under tension into the grooves cut in the handle. More resin and maybe 2-3 more courses of the cord followed. The result was a fiberglass reinforced handle with a hardwood core. The incidence of broken hardwood handles dropped way off. Subsequently, my friend said he began doing the same thing with hardwood baseball bats. He sold them to some of the big league teams for use during practice when plenty of wood bats got broken. This was back in the 1960's, and he told me the story about 1977, so the idea of fiberglass reinforced handles and bats is probably long forgotten.

I am also reminded of my first overseas job, in Ecuador. The crew had some sledge hammers made by welding maybe 1 1/2" steel pipe to large diameter steel round stock. The crew was made up of small wiry guys, members of some indigenous tribe. They accepted their lot in life as workers, mistreated and abused by US standards or any decent standards. I decided to take a turn with one of the sledges. I got a real bad jolt, literally. We were swinging against steel slugging wrenches.
When the head of my sledge connected with the striking face on the slugging wrench, I got a severe and painful jolt from my palms up my arms. I was swinging the sledge barehanded, as did the guys in my crew. How they stood that painful jolting with each blow of the sledge is something that I marvel at well over 45 years later.

If you want to open the eye of a maul head or sledge head, I'd suggest using a die grinder. A properly made maul or sledge head will be hardened and tempered so the striking face (or edge) is hardened, while the body of the head (and the eye) is a bit softer. Possibly, a carbide end mill could open the eye, followed by the die grinder to add some taper to it. Holding the head for the milling operation might be solved by tack-welding some steel flatbar to it with E 309L electrode. E 309L is kind of the "JB Weld" of the welding world in my book. Welding to the softer areas of the head to add some steel for clamping to the milling table should not hurt anything. Grind it off afterwards and no harm done, IMO.
 
...................... I decided to take a turn with one of the sledges. I got a real bad jolt, literally. We were swinging against steel slugging wrenches.
When the head of my sledge connected with the striking face on the slugging wrench, I got a severe and painful jolt from my palms up my arms. I was swinging the sledge barehanded, as did the guys in my crew. How they stood that painful jolting with each blow of the sledge is something that I marvel at well over 45 years later.

I.........
You have to let up your grip on the handle just as it hits. Not easy to do unless you have a long time to practice.... If you don't look out, you lose your grip and miss. But it is doable.

Also helps if you have some pretty significant calluses on your hands.
 
Thanks for your suggestion, Joe, of just using die-grinder to open the eye. Set-up time plus risk to cutter on the mill is probably not worth it.

And thanks for widening the discussion to hammers in general.

The hammer does not get the respect it deserves, being used as a poster-child for clumsy butchery. In reality, it is one of the most versatile and potentially precise tools, useful for everything from moving a workpiece .oo1" while squaring it on the mill table, to heavy forming.

You offered the mathematical statement of energy in a hammer-head, but also your story of the air-hammer versus the big sledge shows that there is more to it. Every blacksmith knows that a light hammer, regardless of how fast it hits (how much energy it carries), works the surface of the workpiece, while a heavy-enough hammer will work it to the center. My math is not up to expressing this rigorously, but I THINK perhaps it has to do with the fact that a fast-moving light hammer, as it contacts and begins to move the surface of the work, has to accelerate that surface to is own high velocity, which absorbs a lot of the hammer's energy (V^2) A slower blow (from a heavier hammer with same total kinetic energy) wastes less energy in imparting high velocity to the work, so more of the energy is left for the desired plastic deformation.
Maybe thus does not make sense, because the stored energy near the surface should eventually spend itself in deforming the material. Maybe yield strength is not independent of strain-rate...viscosity in plastic solids?

Any more thoughts from anyone about direction of taper/handle mounting? The eyes of adzes and picks are BIG, alowing lots of taper down to a reasonable-size gripping portion of the handle. My maul is not big enough to accommodate an eye that big..

I have seen the big pure-wedge splitters with steel handles..never used one.
 
I would go with Gbent's suggestion and have a blacksmith enlarge the eye. Why remove material when it can be reshaped by stretching? What I've been learning in my own blacksmithing journey seems to focus on eyes being drifted through, so they would not have tapered sides. Perhaps more modern technique produces a tapered eye?

--Larry
 
Eyes are always tapered in both directions. Handle is driven into the taper from the near side to tightness, then the far end is wedged into reverse taper for retention.
I like the idea of enlarging the eye hot without material removal. But making suitable drift would take a long as machining the eye. Also, unless you somehow keep the cheeks cooler than the poll and bitt ends, the cheeks will do most of the strietching and end up too thin. I am enough of a blacksmith to have encountered this problem, but not enough of a blacksmith to know how to avoid it!
 
Stihl makes a really great splitting maul. Not cheap, but very well designed. I added a short length of radiator hose wire clamped just under the head to mitigate those near misses. My buddy (who heats with wood) sniffed, "Training wheels!"
 
......................

But thinking about the slight tapers, needed to relieve the transition to the handle and allow wedging, led me to wonder if it might be practical to add enough taper to fit the handle through the eye from the far side, like a pick or adze handle, instead of into the near side of the head as is conventional for hammers.

Does anyone have an idea why this is not done for hammers? Why it would be a bad idea?
That is how tomahawk handles are fitted. The major reasons it is not done with hammers are ....

It limits how fat the handle can be without making the head too wide.

And

A heavy heady might come loose, slide down the handle and pinch the user's hand. Because of the taper and wedging a loose hammer handle will usually be noticed before it could "fly off the handle".
 
One of my favorite tools, this time of year, is the splitting maul.

When I was taught about the "simple (fundamental) machines", I recall the list as, wheel, lever, screw, wedge. After years of pondering, I think there are actually six, but not all of those four are really fundamental.

My list would be tendon, strut, lever and fulcrum, wedge, hammer, and hydraulics. Wheel is merely multiple levers that also act as struts. Screw is a wedge wrapped around a wheel. Hammer is kinetic energy storage and transfer; it acts like a "time lever", whereby you add energy slowly, over a long span of time (as a lever takes in energy over a long distance), and can release it quickly, (as the lever does over a short distance).

So the maul is a combination of hammer and wedge.

The weak point of a maul in use is the handle. I can use a maul handle for a long time, because i put into practice the understanding that the handle's functions are guidance, and to slowly and steadily accelerate the head as it flies around the arc of the swing. My very strong and not yet very graceful son breaks one every couple of days, because he uses the handle to mostly push the wedge though the wood, instead of letting slowly-stored-up energy do almost all the work.

I bought a very nice, shapely maul head at the scrapyard, on which someone had tried to solve the perishable-handle problem by welding a solid 1" bar into it as a handle. Some people say that such a handle hurts the hands because it transfers shock or vibration. I think it is because its large mass stores energy near your hands, which then delivers its own blow to the hands when it stops. The previous owner tried to mitigate the problem with many layers of duct-tape, and when that failed, it went to the scrapyard.

In my experience, it is less the absolute weight of the handle that matters, than the ratio of handle weight to head weight, which must be low enough that the center of effort (taking into account that stored energy goes up as mass x radius of swing squared) is within the head. This supposition is supported by my happy experience with a handle made of 1" sch 40 iron pipe in my 16-lb sledge.
I have had good success with helves for 8-lb mauls made of 3/4" EMT (thinwall conduit), reinforced through the head and a few inches down the handle with a slit-and -narrowed piece of 3/4" pipe. When they eventually crack, I weld them...the last one that finally irreparably failed right next to the head after years of service, was mostly welds for half its length.
I want to try a wooden handle again. I have some bolts of hickory that I have been drying. But here are my questions for the brain-trust here.
I want to enlarge the eye, which will allow fitting a fatter, stronger handle I guess I will use the milling machine, although it will be a bit if a challenge to securely hold the workpiece with no flat or cylindrical surfaces. I am not sure if I will add the tapers with a big rat-tail file or try to make eight tilted setups on the mill after the straight one.

But thinking about the slight tapers, needed to relieve the transition to the handle and allow wedging, led me to wonder if it might be practical to add enough taper to fit the handle through the eye from the far side, like a pick or adze handle, instead of into the near side of the head as is conventional for hammers.

Does anyone have an idea why this is not done for hammers? Why it would be a bad idea?
Are there any standards for hammer or axe eyes?
 
" I have a buddy who can swing the overhand swing and sink track spikes in a matter of a few blows, no predrilling. He is lighter than me, about the same height, but more muscle and practice. He's 81 years of age and can still swing the spike maul with that overhand swing."

My story - I bought a house in peekskill and wanted to run power, underground to the detached garage. I was tired of running a long piece of S cord out to 'plug in the garage' so I began trenching out from the house to the garage, about 50 or 75 feet - I wanted to have the trench a good two feet deep and a foot or so wide. There was a pretty good amount of rock, old brick (some kind of wall I believe) and various trash piles that were buried out there, that I had to dig across.

Now my neighbor to the south, an older (well at the time he seemed pretty old, I suspect right now I'm older than he was then) gent who used to work for County Asphalt, running an excavator. I asked if had a pick I could use, as I was getting badly hung up on some stuff in the trench. He came back to my yard with a well-used pickaxe. I began using it to break up the rocks and so on in the trench, but it was slow going and I was working up a pretty good sweat. Moses, my neighbor stood by, watching for a while. "Mind if I take a turn at that?" I gladly climbed out and gave over the pick. I stood there amazed as he made three times the progress in one third the time as I had, and he looked like he was barely working hard. He made every blow tell, and used the weight of the pick and the speed of the swing to do the real work.

Remember he was about 70 or so at the time. And I was about 35 or so. A real eye opener.

Well in the long run the power got run out to the garage, and while I was at it, I put a 3/4 inch polyethlyene pipe in there as well so now I have summer water out in the garage as well as lights and even some heat out there in the winter, for working on old BMW motorbikes when it's too snowy to ride them.
 
Jim:

I appreciate your story about your neighbor and the pickaxe. I learned along the way that there are several types of pickaxes: the 'railroad pick' (longer branches, one coming to a diamond point, one to a chisel edge), and the 'rock pick' (shorter branches, both coming to diamond points. The rock pick is what its name says it is for. The railroad pick tends to bounce and twist when striking on rock. There is yet another type of pickaxe used on the railroads. This has a tamping head on one side and the longer diamond point on the other. It is used for tamping ballast (crushed stone) along crossties when doing single tie replacements or other track work where no power equipment is used. I have both a railroad pick and a rock pick hanging in my garage. Truth be known, I rarely use either of them. When I need to dig a hole here in our Catskill Mountains, there is too much rock to use a pick. I use a digging bar, the kind with a tamping head on the top of the shank, and a wide chisel edge on the business end. I find that the digging bar plus a long handled shovel are the best combination for digging holes manually.

My wife and I along with some other members were doing some surveying in our congregation's cemetery a couple of summers ago. Over the years, despite a surveyor's map delineating plots and sections, there were a number of discrepancies. I volunteered to do some survey work to re-establish plots and sections with my helpers. I planned to put 3 foot lengths of number 4 rebar in the ground with aluminum marker caps (these come with plastic insulation bushings). We planned to put in permanent in-ground markers that could be found with a metal detector. I had no illusions (or delusions) as to what it would take to get those rebar stakes in the ground. I loaded my Lincoln engine driven welder on my pickup and got a 3 foot long masonry bit for my bigger Hilti drill. Using my transit and a 200 foot tape, we picked up off existing survey control at the cemetery corners and moved along. When we'd establish a plot or cemetery section corner or line, my wife, holding a "Gammon reel' and plumb would hold that point. A temporary piece of rebar was driven in 'to refusal' with a 3 lb hammer. After we had plenty of those temporary stakes in place, I got the pickup spotted, fired up the welder and started sinking holes with the Hilti drill. I hit plenty of rock. I then drove the rebar marker stakes to depth with an 8 lb sledge. If the going got a bit harder, I moved to a 12 lb. I know we put in well over 100 such markers. Some of the volunteers thought they could run the Hilti drill or swing a sledge. Wrong on both counts. I made a special anvil out of heavy round bar stock to hold the aluminum marker caps for stamping with letters and numbers. Amazing how people seem unable to swing even a 24 ounce ball pein hammer to strike the number and letter stamps to make a good crisp impression. I found myself hollering: "hit it like you mean it... hit it like it's your worst enemy..".

At some later point in time, I designed some reinforced concrete footings for a new main entry gateway. I made rebar cages and handed a detail drawing with the cages to the contractor who maintains the cemetery. He got into it with a backhoe. In digging for one of the footings, he hit a boulder. I suppose I could have drilled and resin-grouted in some rebar dowels, using that boulder as a footing. The contractor got his excavator on site and used it to pull up that boulder. It was nearly the size of one of those new Fiats. On another occasion, we had reason to do some excavation work and dug up one of my survey markers. We found the rebar survey stake had skewered a couple of good sized cobbles by way of the drilling I'd done.

Getting a grave dug in our cemetery is always something of a crapshoot. Either there is a clayey soil shot with cobbles, or possibly one of those huge boulders, and in the worst case, ledge rock. The cemetery dates to 1920, and every time we open a grave for a burial, we wonder how the oldtimers back in 1920 dug the graves. Under Jewish law, when a person dies, their body must be in the grave within 24 hours except on the Sabbath or high holidays. No parking the body in a 'receiving vault' or keeping it in refrigerated storage. It's a plain pine box, body in a shroud, no burial vault, no embalming. The result is even in the depths of winter, we open graves and bury our dead. One bitterly cold winter, a person died and was to be buried in our cemetery. We notified the contractor, and he came to dig the grave. He had to bring a generator and tarps to run the coolant heater on his backhoe and cover the engine to hold in the warmth. He got the backhoe started, scored the ground with a masonry saw and commenced digging. He hit ledge rock and busted a tooth or two on the bucket. A logger has the adjoining property to the cemetery, so loaned an excavator. It was subzero weather, and the controls on the excavator were a bit squirrely. Before the grave was dug to full depth and width, ledge rock was hit. A gasoline driven diamond saw was tried, but the water to cool the blade froze, and the blade burnt and warped. To add to the matter, the deceased was a large person and got an oversized casket. I measured from grade line to the neat line of the ledge rock and for the width and length of the grave vs the casket. It was an extremely close fit. About the only way I could see to get the grave any deeper would have meant line drilling the ledge rock and punching it with a bull point on a jackhammer. We ruled that out and went with the close fit.

As I wrote, the deceased was a larger person. It was the only time an undertaker ever furnished us with the weight of the body + casket. I knew our casket lowering machine has a friction brake worked by a centrifugal governor. I had adjusted it to a nice slow descent rate for average weight bodies and pine caskets. I did not want to tamper with that adjustment. The contractor got eight friends of the deceased who were members of the volunteer fire company, husky young fellows. We ran web lifting slings under the casket and put two guys on the each end of each sling as additional braking if the casket lowering device brakes could not maintain a slow descent. The contractor and I used 2 x 4's to guide that casket into the tightest fitting grave I'd ever seen. Per Jewish law, it is incumbent on mourners to take their turns throwing shovels of earth on the casket. This must be done at least until the casket is covered, though we usually pass the shovels until the grave is filled. As a member of our cemetery committee, I make sure to shovel a good bank of earth on the caskets. The soil being what it is, we usually get a load of screened soil delivered for the grave filling as no one wants to hear a cobble or boulder hitting the casket. This particular time, the load of screened soil froze in the pile. I anticipated this, so brought my railroad pick. I had to take my pickaxe to the pile of screened loam so the mourners could take their shovelfuls. Not only were we fighting with ledge rock, but the subzero temperature and wind chill really made things all the harder. Swinging the pick did provide a little warmth.
 
" A temporary piece of rebar was driven in 'to refusal' with a 3 lb hammer. After we had plenty of those temporary stakes in place, I got the pickup spotted, fired up the welder and started sinking holes with the Hilti drill. I hit plenty of rock."

Best rock detectors in the world: post hole digger or a Hilti Gun. Ya just sweep around with the post hole digger till you find just the place to put the post, and whammo, there's a piece of granite the size of a toaster *right* there.
 








 
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