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JEleazarian
Trad climber
Fresno CA
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Banquo, I wish all manufacturers and product developers had your diligence and conscience. I should add, though, that experience taught those of us who grew up in the piton era to take a spare hammer on any wall climb.
John
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Lorenzo
Trad climber
Portland Oregon
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Might want to consider adding a tang.
Here's a design of a hand made stone mason's hammer I bought over 35 years ago and just love. The tang adds a huge amount of strength, makes mishits to the wood a thing of the past, and allows a lighter handle. The tang is slightly cone shaped, opening towards the handle. It looks like the original maker took a steel tube, heated it, and drove an oval tapered drift into it.
Since my working days are over, I've thought of re grinding this tool into a pick, but the tool has done so well I won't disrespect the original intent. Some next generation Mason or craftsman will get a great tool.
This hammer head is made in three welded tool steel parts.
Cost me $20 BITD, which was a pile of money then.
Don't give up something you obviously love and take pride in. Make it better.
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couchmaster
climber
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Thanks for the heads up Dan! I don't want to have that occur on my DAMMERR so I'll stick to putting in bolts with mine. Have a lot to put in someplace. Wait, I have a fiberglass handle. Had the Yoshammer out the other day without a funkness and stuck the pick end into Plaidmans 5/8" angle I'd overdriven, and was surprised how much force I could get on it via just cranking. I was wondering what it would take to break the handle at that time, and bam, here's your PDF with all that info. Good stuff (that part, and your integrity part too)
Very interesting stuff, thanks for the info.
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Clint Cummins
Trad climber
SF Bay area, CA
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Good analysis.
It's a routine risk to break off a hammer head while nailing,
which calls for carrying a spare hammer.
With a partner, you can share a hammer if one breaks, but it could be slow.
When soloing it seems wise to bring that spare hammer.
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 2, 2015 - 02:52pm PT
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Lorenzo - the handle sleeve on your hammer only extends a little bit below the head. I'd estimate it amounts to about a 15% increase in strength. It needs to extend farther to make much of a difference.
There are some old Charlet-Moser piton hammers with a sleeve that goes through the head. I suppose they abandoned it because it was too many steps in the manufacturing. See this thread for photos:
http://www.supertopo.com/climbers-forum/1778506/Date-This-Chouinard-Yosemite-Hammer
Since I already have a batch of heads and handles made but not yet assembled, I am going to try extending the steel sleeve and see how it works. I'll have to ream out the heads to 1" so I can fit the tube through the head. Then turn down the shaft of the handle to fit in the tube. I'll extend the tube down the handle to where the handle flares out. This changes the moment arm in the test from 8.75" to 5.50" so the strength should go up 8.75/5.50 = 1.59 or 59%. My calculated strength goes from 150 lbs to 239 lbs. Which I hope will do the trick although a person could still break it I guess.
Hickory is pretty amazing stuff. My test load of 180 lbs equates to a bending stress of over 23,000 psi. Mild structural steel yields at 36,000 psi and good concrete crushes at 4000 psi. Steel weighs about 11x as much as the hickory and concrete about 3x.
The fiberglass handles look skinny but the manufacturer says the strength is 125,000 psi in bending which is at least 5x hickory and similar to high strength steel. It is about 3x as stiff as hickory.
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 2, 2015 - 02:53pm PT
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If you are afraid you will break your DAMMERR, bring it to me and I will cut the pick off - problem solved.
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stoneshirt
climber
Volcan,Panama
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Yea,had one of those early Chouinard Hammers,But really sorry to have let go of my Chouinard Ice Axe,with the Bamboo Handle!
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cragnshag
Social climber
san joser
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You forgot option #7: do nothing
This is my favorite option for many things...
I'm definitely guilty of using my hammer as a pry bar. One time I pried on an expando flake to help unstick a booty cam, but stopped short of yarding on the hammer because I had a feeling I might break the head off. Looks like I could have done that at 180 lbs of pull.
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ruppell
climber
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Banquo
One of the first things you learn as a carpenter is hammer handles break. The second thing you learn is hammers are for hammering and pry bars are for prying. I could take my 10 year old Stiletto 14oz and break that hickory handle in a second if I used it to lever something big. The point is it's not a design failure on your end it's an application failure on the users end.
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Lorenzo
Trad climber
Portland Oregon
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Banquo. The tang is not just a sleeve. It is welded to the hammer head , making the embedded portion of the handle about 2 3/8" embedded in solid steel. No joints after welding.
And where it inserts it is about 1 1/4"- by just under 3/4". ( oval cross section)
The sleeve itself is 1 7/16" tall. It may be a little misleading if you don't know the scale.
It's a 12 " long hammer OA stamped 16 oz, but it weighs out a little less, so just under 20% of the length of the handle is in the steel.
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Lorenzo
Trad climber
Portland Oregon
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Jul 2, 2015 - 07:02pm PT
Banquo
One of the first things you learn as a carpenter is hammer handles break. The second thing you learn is hammers are for hammering and pry bars are for prying. I could take my 10 year old Stiletto 14oz and break that hickory handle in a second if I used it to lever something big. The point is it's not a design failure on your end it's an application failure on the users end.
Haha. Yeah. I have had two Harts and a Stiletto broken by architects who wanted to " help" take down some temporary bracing before I could get to a bar.
None offered to pay for a new handle, or in the case of the now extinct Harts, to pay to have a new handle made. It's how I finally got good with spokeshaves.
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 2, 2015 - 09:37pm PT
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It is true that anything can be broken if one tries hard enough. I've pretty much made career out of that. I once tested 12" Square pretensioned concrete pile connectors in tension. Too bad it was before video recorders were common or we would have some great YouTube fodder. We had about eight 1200 lb blocks arraigned to stop the 20 foot long 12" square concrete missiles. It didn't work very well and we had 1200 lb blocks of steel ricocheting around like balls on a pool table.
http://www.pci.org/pci_journal-1980-september-october-5/?terms=venuti
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 3, 2015 - 02:33pm PT
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I broke a DAMMERR with a fiberglass handle. It broke at 310 lbs with the force applied at 10 inches from the top of the head. I had calculated 360 lbs based on bending strength. The lower strength is probably because I got a shear failure inside the head parallel to the fibers rather than a bending failure.
I have been using 3/4" handles which look a bit skinny but seem to be adequately strong and roughly twice as strong as the wood handles. A 7/8" handle is also available. The calculated bending strength for the 7/8" handle is 540 lbs. The shear strength is related to It/Q. The shear strength of the 7/8" is 1.406 times that of the 3/4" handle so I would predict the strength of the 7/8" handle to be: 310(1.407) = 436 lbs
Wood handle 180 lbs
3/4" fiberglass handle 310 lbs
7/8" fiberglass handle 440 lbs (estimate)
https://youtu.be/ftx8mrykFGk
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BrandonAdams
Big Wall climber
Yosemite, CA
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For what its worth, it was my Dammer that broke. I am in love with the hammer and greatly appreciate and respect dans desire to perfect his hammer. The head broke off while funknessing out a pin, though I had certainly done some earlier prying (perhaps weakening it). Talking with dan after the hammer broke has only further convinced me of his commitment to superior craftsmanship. He is aware of problems and takes seeking solutions seriously. If anyone is looking for a hammer or drill rig I highly recommend getting in touch with Banquo. I have no doubt that his tools are of the highest quality.
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 10, 2015 - 11:27am PT
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I have fitted a 7/8" fiberglass handle onto Brandon's broken hammer and will be sending it back to him. Estimated strength is 440 lbs as stated above.
I have also tried press fitting a steel sleeve over the wood handles. The sleeve fits into the head and is split inside the head so the wedge still works. The split in the steel ends in a drilled hole to relieve stress concentration and prevent the steel from cracking. The pin runs through the head, the sleeve and the wedge. I tested a one of these and it broke where the wood disappears into the sleeve at 420 lbs leaving a stubby steel handled (with wood core) hammer. The sleeve is drawn-over-mandrel medium carbon steel. OD 1.000" ID 0.880"
The sleeve is a very tight fit onto the wood which I can achieve because I turn the handle on a metal working lathe with 0.001" control. I made the wood diameter extra fat right where it disappears into the sleeve. I pressed the sleeve on with a hydraulic press when trying to hammer it on got too hard. To make hammers with bigger holes, I ended up annealing some heads, opening up the handle hole on the lathe, then re-hardening and re-tempering the head. I annealed them because I was going to ream them out with a HSS reamer which didn't work. I have a couple more to open up and I will try a carbide boring bar without annealing.
The "Iron Bound" hammer is a bit heavier at 26 Oz.
The Fiberglass handle one weighs the same.
The plain wood handled hammers weigh about 24 Oz.
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Roots
Mountain climber
Tustin, CA
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Jul 10, 2015 - 11:57am PT
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Looking good!
Seems the Iron Bound Hammer might even work (albeit handicapped) if the wood handle broke? -just to get out of a sticky situation..
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 10, 2015 - 02:07pm PT
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Yeah, you could still pound with it even after the handle is broken off.
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deuce4
climber
Hobart, Australia
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Jul 10, 2015 - 03:20pm PT
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Wow! Looks like an interesting solution. Looking forward to hearing how it evolves in the big wall test labs. Nice work.
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Banquo
climber
Amerricka
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Topic Author's Reply - Jul 10, 2015 - 05:35pm PT
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Deuce,
I should find somebody to test one and let me know how it works. If anybody has a big project and wants to try one I'd be happy to work something out.
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