Jon Kerr

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About Jon Kerr

  • Rank
    Advanced Member

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  • Gender
    Male
  • Location
    - Benfleet, Essex, UK
  • Interests
    Learning more about Blacksmithing!

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  1. Jon Kerr

    My first year of blacksmithing

    Hi Patrick! Where abouts in Essex are you based? I'm from Benfleet, SS7, so if you every fancy meeting up to swing a hammer and have a beer please let me know! Keen to meet more local blacksmiths as I'm very new to all of this. The advice in your post make for interesting reading so thanks for that!
  2. Jon Kerr

    What did you do in the shop today?

    Love the jewellery stand Das, and the jewellery itself! Inspiring as always. I'll have to have a go at making some leaf jewellery for my family. Thanks!
  3. Jon Kerr

    Complete Beginner

    I'm sorry for all the stupid questions. The learning curve is incredibly steep without anyone experienced to forge with early on..... I need to find the cash for a class ASAP. I've been wondering about oxidation and fire regions. Obviously I have little to zero experience of these things and nobody to look over my shoulder and say "you're burning your steel". Does the axe look over-oxidized to anyone? I don't know how I would tell. I'm still concerned about my fire management, really. It's possible my JABOD set-up isn't exactly perfect in terms of size and depth of the firebowl. I was previously struggling to get things hot, especially if I stick to the "keep the stock horizontal" rule. Im finding it difficult to maintain the fire to stay hot enough at "ground level" (by which I mean, my JABOD dirt surface level, ie/ the top of the fire bowl) to get steel for forging temperature. With the axe, I allowed the axe to be buried a little lower than the ground level and had much fewer problems getting it hot. That also allowed me to use far less charcoal and forge for longer without adding more charcoal. I'm now concerned I might have been letting the fire die down too far (not enough charcoal to raise a mound), and shoving the axe right into the oxidising region of the fire. Is there any way to tell what by eye where each of the fire regions are? Another thing I noticed is a green hue to the flames at some point. This could be from staring at the fire too long, or it could be because it was getting dark and I've never forged in the dark before. Whats this? Steel burning? Firebrick burning? Normal?
  4. Jon Kerr

    What did you do in the shop today?

    I finished my axe tonight. Not good by any real blacksmith’s standards but I’m really happy with it as one of my first handful of projects. Details in my project thread so I wont repeat here.
  5. Jon Kerr

    Complete Beginner

    I finished my axe! Rubbish by most standards but I’m really proud of it. I decided to have a go at charring the handle. I also carved out some recesses for some decorative wrappped copper in a couple of places, just for aesthetics. (For anyone interested in the copper wire process. I drilled a small hole to poke the wire into to start, wound really tight, and drilled another small hole and cut the end just right to poke in to the end hole. Dab of superglue to secure. Held the wire really tight and worked great. No idea if this is a common method but it worked for me, and meant zero wire overlap.) This was my first try at heat treating. Its still not very hard in the end (tested with a file) so perhaps the steel is just shoddy. Unfortunately, during the final grind I discovered a hairline crack. I’m not sure what the cause is- I did introduce a cold shut during forging but I was sure I had ground it all out before finishing forging. Perhaps not. Or perhaps caused by quenching in water rather than oil.... Any comments and criticisms welcome.
  6. Jon Kerr

    What did you do in the shop today?

    I had a go at turning a small ball pein hammer into an axe. Really pleased with the outcome (my first axe!). Also wired up my blower with a foot pedal, which was super handy and conserved a lot of charcoal.
  7. Jon Kerr

    Complete Beginner

    I finally got back around to doing some blacksmithing..! In fairness, I’ve had a busy couple months since we just got married. In the mean time, I’ve been watching lots of forging YouTube videos and reading old threads on this site to try and soak up as much information as possible. Firstly, I wired up my forge blower properly. It needed a startup capacitor and I wanted to add a foot switch. It works great. I can actually control the air flow by turning the fan on and off rather than using the valve. I’ve been desperate to try my hand at turning a ball pein hammer into an axe/tomahawk, so thats what I tried to do today. I’m really pleased with how it turned out. No idea what the steel is so it may not hold an edge- in future I’d like to repeat the project and forge weld in a high carbon tip. For now though, I just wanted a simple axe for splitting kindling! Lessons learnt: I’ve started breaking my charcoal into much smaller lumps, approx 1” square. Much better. My forge is working much better with the blower and foot switch. Much quicker and easier to heat metal. My main problem now is my tongs are pretty rubbish, and I need to make a couple of new pairs for specific stock sizes. I’m having trouble hanging on to the workpiece, and its causing the stock to bounce. I can’t possibly turn the work piece between blows as I barely have hold of it as it is! Any tips/comments/criticism about the axe would be appreciated! Ive also attached some pics of my current set up for any other beginners who might be interested...
  8. Jon Kerr

    What did you do in the shop today?

    Daswulf- the Oobala is incredible. I absolutely love it. Bending the fingers like that into various gestures give so much life and character! I wish I lived closer, I'd totally commission you to make me one!!
  9. Jon Kerr

    Complete Beginner

    Ah I see, thanks. Is the same true of annealing? Is the "weakening" proportional to the carbon content?
  10. Jon Kerr

    Complete Beginner

    *sigh* True!- although if the legs were quenched after being in the forge (though not tempered), would that then increase their strength again? I have no idea how it works. I need to read a metallurgy book I think. ..................................................................... ITS STRONG ENOUGH FOR A FEW LOGS!
  11. Jon Kerr

    Complete Beginner

    Of course, you're absolutely right on all points! I do actually happen to be a structural engineer....! In reality, in my real job, I would do this sort of analysis in FEA (Finite Element Analysis) so i could take into account all the material properties, geomety, and plot stresses on the 3D model. My hand calc was incredibly crude and done more for amusement than anything else. In actual fact the yield strength I used should probably be even lower than 250MPa due to the weld affected area. Perhaps 180Ma would have been more appropriate. The bend in the leg is also a stress raiser and this would result in a concentration. The buckling of the bowl is indeed also a probable failure point! Its worth remembering though that the 180/250MPa is the YIELD stress, at which point the material starts to deform through the plastic region (and won't flex back). The failure stress, whereby something actually breaks, will be higher. With a 3 legged structure (much like a 3 point hoist/lift) you're likely to get a fairly even load distribution through the legs, even if the firepit was stacked off centre. By my hand calc, the "Factor of Safety" was 24. Even taking the lower yield strength of 180MPa (approx half my value), that leaves a Factor of Saftey of 12 (on yield). Even if the dish begins to buckle (and I doubt it), its highly unlikely that any catastrophic failure will occur causing burning embers to tip over the floor! All that said........ for anyone wishing to build a similar firepit, I would probably not copy the design of my legs. They were done that way more to account for my lack of forging skill than any other design choice. Taking Thomas Powers suggestion of an additional large scroll, (on each leg) to sit under the centre of the dish would be a good idea, though it would use at least double the material for the legs. Alternatively, welding stiffeners under the centre of bowl where it attaches to the legs wouldn't hurt.
  12. Jon Kerr

    Complete Beginner

    Beautiful! Thanks for the idea.
  13. Jon Kerr

    Complete Beginner

    Great suggestion thanks Snuffy! Anyone got any more? The flaming curmudgeons had me worried for a second so I even had to break out the pencil to prove it.....! (No disrespect to TP! All in jest.) For those interested (probably not many...!): Bending Stress is S=My/I (where M is Moment, y is distance from neutral axis, and I is Second Moment of Intertia). For a rectangular bar as in my firepit legs, I=bh^3/12 (where b is the width, 40mm, and h is height, 20mm). Since we're interested in maxiumum allowable mass in my firepit, we can rearrange S=My/I to give M=SI/y. The yeild strength of mild steel is in the region of 370MPa (so S=370MPa). Therefore, the maxumum allowable Moment M= 986642. Moment= Forcex distance, and Force=massxgravity. So F=1973N. Therefore...... The allowable mass on each leg before bending is (believe it or not) 200kg. Since the firepit has 3 legs, thats a total allowable mass of 600kg. There's no way we'll be putting more than 25kg (50lbs) of wood in the firepit at any given time, so we have a healthy Factor of Safety of 24. You never know... someone might one day wish to do a similar calc.
  14. Jon Kerr

    What did you do in the shop today?

    Good idea- Thoman Powers suggested similar. I think its a symptom of the photos, as I said its bigger than it looks and the stock is thick (half inch). I've just stood in the pit without the legs bending, and I weight 250lbs. The pit will never experience more than 50lbs of wood in operation.
  15. Jon Kerr

    Complete Beginner

    Like I said, the picture makes it look smaller than it is. Those legs will be easily strong enough to survive logs being thrown onto the fire. Scrolls to contact the ground is a good idea though, and definitely something I'd consider in future if I made a smaller version with thinner stock legs. I believe my buddy has already added a drainage hole, and has purchased a small circular grill to add into the bottom to allow some ash to settle out.