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Thread: Sawsmithing hammers
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7th March 2016, 01:12 PM #16
Great success!!
It worked! HRC 52 in the center and 43 at the edge of the face. Preliminary readings are almost certainly low because I haven't polished off the scale yet.
Some in process shots. Note the cold spot in the center of the glowing head.
The metal cools from the face down toward the handle eye very nicely. Took about two minutes for the whole head to be black then I dropped it into the water and grabbed the next head out of the oven for quenching.
Abdul however was somewhat perturbed by all of this.
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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7th March 2016 01:12 PM # ADSGoogle Adsense Advertisement
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8th March 2016, 11:31 AM #17
Several of the heads I heat treated yesterday cracked in processing. I've decided to waste the whole batch because I don't have faith that those that look okay are in fact in good shape. Today I started over. I cut out another 16 heads and took one all of the way to completion to validate my methods. Here it is. Mass is 599 gm.
While I was at it I also cut some blanks for diagonal peen hammers. These will be combination stretching and straightening or narrow/wide face stretching hammers.
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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8th March 2016, 12:21 PM #18
I just completed the hardness measurements for this hammer head. My revised quenching method worked well.
The hardness at the center of the face of the hammer (average of 5 replicate measurements per ASTM) is HRC = 49.1, S.D. = 0.76. At the edge of the hammer face the hardness is HRC = 44.39, S.D. = 2.42 (curved area). At the back of the head near the eye the hardness is HRC = 35.80, S.D. = 1.34.
Hard in the center, softer at the edge and softest at the eye, all in one step.Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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8th March 2016, 06:46 PM #19
Is 49 hard enough Rob? What would be your ideal measurement for the center of the face?
Those were the droids I was looking for.
https://autoblastgates.com.au
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8th March 2016, 08:40 PM #20
Really great work Rob
Sorry not much to contribute tho
But am watching with interest
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8th March 2016, 11:33 PM #21
From what I understand the thinking behind hammers used on anvils is that they should be softer than the anvil face to avoid chipping it because it's cheaper to replace a hammer than an anvil. Information on the net suggests that anvil faces range from the mid 50's up to 60. The face of the smaller forging hammer from Glen Stollmeyer is just slightly harder than mine, right at HRC 50.8 on average. The larger GS hammer is softer at HRC 44.
I wanted my hammer face to be just a little softer than the 1095 steel it will be used on with the idea that a softer face may help reduce denting from imperfect blows. I could make these harder but doing so would increase the chance of chipping and I don't want to damage my anvils, they cost far more than the head of this hammer and I can't make anvils, yet that is.
The 4140 steel I'm using is tougher that the 1045 medium carbon steel that is often used these days. 4140 is commonly used for rifle barrels. If the data here (Varmint Al's Rockwell C hardness Testing Simulation by Finite Element Analysis.) are correct, the yield strength at HRC 49 should be around 210,000 p.s.i.
It's important to point out that none of the sellers of 'new era' hammers I've seen advertised elsewhere report the hardness of their products. I assume that this is because they're judging hardness by color or some other seat of the pants method.
I did a small series of tests on some hammers I have lying around with the following results.
Measured at the face center
Stollmeyer 1.5 lb dogshead = HRC 51
Stollmeyer 2.5 lb dogshead = HRC 44
Dogshead dishing 1.5 lb = HRC 52
Farrier 2.5 lb rounding = HRC 46
1lb twist peen sawsmith = HRC 45
20 oz. carpenter = HRC 37
48 oz. ball peen engineer = HRC 51
Most of these hammers are old and show signs of heavy use, thus work-hardening is responsible for some of the hardness measured. The Stollmeyer hammers are used, but not as heavily as the others. The 4140 steel used in my hammer work hardens as well thus the face hardness will increase as it is used.
I'll do more later.Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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9th March 2016, 10:26 AM #22
Thanks Matt,
I'm doing the best I can given my means. One of my goals is to dispel some of the magical thinking surrounding the issues I study - good for everybody to be able to separate the old wives tales from the facts.
Cheers,
RobInnovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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9th March 2016, 01:47 PM #23.
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I see the edge has a ~3X higher SD which suggests at least a couple of the measurements on the edge are approaching HRC47?. It would be interesting to se a map of individual HRC measurements at say 20-30º spacing around the edge to see if a specific part of the edge is harder and others correspondingly softer. If so, this may suggest the water jet is impacting and then eventually flowing over one side preferentially.
A water jet impacting at 90º can be made to reflect off a surface when fired directly in the middle of a shallow saucer shaped recess. This would keep most of the water off the edge. Of course the recess would have to be machined off later but that would not be too difficult.
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9th March 2016, 02:35 PM #24
Hi Bob,
I think the higher SD's at the face edge and eye area of the head also may be due to the curvature of the tested surfaces causing the indenter incidence angle to be somewhat different from normal despite my efforts to locate it carefully. The measurements in the center were on a surface normal to the applied force. Very close to the edges material flow may also become an issue. The only way to know is to take some measurements on a properly prepared surface.
I'm planning a test piece with a flat face to reduce the influence of the curved surfaces. Such a test with water quench only on one end before the final oil quench will also give me an idea of what the differential effects of water followed by oil vs. oil only quenching is. Something else to do...
Cheers,
RobInnovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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9th March 2016, 11:29 PM #25
Rob
Vintage hammers like this one selling for US$243.50 I gather are the reason you are making your own.
Simonds 2lb 6oz dog hammer.jpg
Vintage RARE Simonds Blacksmith Forge Doghead Hammer with Original Handle | eBay
Regards
PaulBushmiller;
"Power tends to corrupt. Absolute power corrupts, absolutely!"
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9th March 2016, 11:54 PM #26
Hi Paul,
That's a good part of my motivation. Nobody as far as I can tell is making sawsmithing hammers these days. There's a subset of blacksmiths that are making and selling specialty hammers but the prices are similarly high Farrier Supplies | Rounding Hammer | Blacksmiths Depot and they're not sawsmithing hammers.
A good rounding hammer will also work for saw tensioning Brian Brazeal Style Blacksmith 2 5 Pound Rounding Hammer | eBay but they're pricey too.
Most of the sawsmithing hammers I've seen for sale are on the heavy side for handsaw use. Finding the lighter weight sawsmithing hammers is a good deal more difficult than it is for hammers in the three to five pound range.
Cheers,
RobInnovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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10th March 2016, 09:42 AM #27
Yeah those wiredos that forge their own hammers are crazy.
image.jpegimage.jpeg…..Live a Quiet Life & Work with your Hands
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10th March 2016, 09:56 AM #28
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10th March 2016, 11:40 AM #29
Yes it is my main every day forging hammer made for a kenworth truck sway bar. Very very tough stuff. The eye is slit and drifted buy hand. It is a heavy hammer.
…..Live a Quiet Life & Work with your Hands
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10th March 2016, 11:44 AM #30
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