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Joe Fonzi

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  1. using a known steel that is weldable is better than taking a chance on rebar but i like the deformations in rebar makes it nice to hold on to and as long as it was "annealed" (we got red then cooled...i know i know close enough) you will really not have an issue in the HAZ (heat effected zone) of the rebar its usually not that high in carbon or that complex an alloy. it really is the geometry. as for rod penetration use 6010, 6011 or 6013 they are not as fussy with needing clean steel as 7018 and have deeper penetration than 70series rods. if you are using MIG then you are completely reliant on the geometry and cleanliness of the weld and material. that was a topic in my welding party i had on Saturday where most of my junior structural engineers got to experience what they are designing and asking fabricators to do. last one i demonstrated forge welding but we never get to spec that out, bummer. good luck. Joe
  2. the steps that described will definitely help on the metallurgy side especially given the wide range of carbon the rebar could have. many time weld failures are also due to weld geometry. if the rebar is cut flat and you are only fillet welding around it to the bar the stresses of hammering at high heat will always brake the weld. to gain longer life a full penetration weld will help. grind the rebar to almost a point at about a 45 deg angle and fill all that in with weld, then continue to build up the weld so it looks like the fillets you had before. a full pen groove weld with buttressing fillet. with that you do not have the incipient crack of the flat part of the rebar and no stress risers. good luck
  3. I've been using AutoCAD professionally for 26 years now and 3D solid modeling with it for 25 of those i think...it's a blurr now. we are also using Revit. the nice thing about AutoCAD is the solid (3D) modeling. I have modeled some of Peter Johnsson's swords because they have the documentation. I used the solid modeling because i can get mass properties such CG location, volume. It will also tell me from any given point the moments of inertia and more importantly the radius of gyration. From the that it is a simple calculation to find the corresponding COP. I vary the location and mass of the pommel to tune the location of the COP. i am about to HT my first sword and have been keeping a CAD model pretty accurately while i grind and shape the blade and it has been pretty accurate on the mass and CG. I've used those features of the program as a structural engineer so i have faith in the information as long as the modeling is correct. AutoCAD's 3D modeling falls short if you have complex curves, 2D it can do anything. Peter your documentation and information is wonderful Thank you!! for posting and publishing it. the CAD models and calculations have been pretty close to your published (or the reviews of) info of your swords. AutoCAD and solidworks will give the most power and versatility for the money. if you need complex and compound curves AutoDesk Inventor or Rhinoceros (Rino3D) are very powerful but costly. if you just want 3D without the properties then sketchup will work. good luck
  4. Dan I was using old bi-metal bandsaw blades from some local iron shops and I had some tested recently after some welding faliures. None of them had over .4% Carbon, all had above 3% Chromium, none had any Nickel. After i recieved those results I did not bother asking for the look up on what steel they were.
  5. Giovanni That is awesome, a great machine to work with!! Intrestingly enough I'll be in L'Aquila the first two weeks of February. Joe
  6. Scrap iron shop bandsaw blades are what I use layered in damascus. I've welded them to 1090 or 52100 or other mystery scap that passes the spark test or the QT and file test, but i'm only a hobby smith and don't make anyting to sell. The one piece that i had tested turned out to be S5 steel. I make a much thicker stack and draw them out maybe even folding a couple of time to make sure any fatigue cracks have been closed. good luck
  7. Sam Awesome mechination nice toggle spring set up. I see clamp screws on the column sleeve did you bronze line it? can't wait to see some video. Joe
  8. Christopher Price is correct! it is not just his opinion, rebar's main concern is tensile strength with a nice linear strain up to yield, I've designed enough of it. you can get the mill certs sometimes with the chemical composition then you can see if you can make a good blade out of it. i have from some bar from some special projects that is 150KSI threadbar (trade mark by DSI), i had the contractor submit me the certs and found that that batch had .70%C so i kept some cut offs from the field. all other bars i have found the certs for only have .2%C ,or so, with some other stuff so it can be work hardened to get the tensile strength up to spec. if you really want to make a blade out of rebar look for 150KSI post-tensioning rebar,rock anchors or micropile bars. good luck
  9. WOW!!! Those are amazing presentations. Dave awesome hosting as well. Thank you all for doing them. Joe
  10. Geoff still with the filter problems, i would still move it to the suction line between the pump and the tank, but i don't think it will solve the problem. also the return line does have pressure and it can be quite a bit. it only becomes zero (atmospheric)after it exits the port and is falling. what is the filter you are using flow and pressure rating, is it rated for the oil or fluid you are using? Joe
  11. Craig - I'd want to protect the pump but... Greg - Yeah Vickers is the reference but the complexity and safety issues on an excavator are a bit more than a single actuator and valve system. plus the expense of a high pressure filter more than frequently changing a low pressure suction side filter. that would be more on an engineer vs engineer debate on the system design the given clients use, need and budget. I'm not one to baulk my system has strainers and filters on every port but that was from an articulated bus system so like and excavator and as Greg said you want to protect the system from a cascading failure. Not sure if all this helps Geoff's original question but there is a lot of good info. Now i can't wait to get forging again and turn on my press, i have two billets sitting since the fall. PS Greg i saw Ontario and though you might be close but you are pretty far north, people think Buffalo is bad, got spring yet? Joe
  12. Craig What manual? All the Hydraulic system I've seen and design guides i have used have a filter before the pump at minimum. The cylinders(or motors)are closed and sealed and machine finished. The grit and debris come from the reservoir that is not finished and is open to the atmosphere (with air filter). The Monarch hydraulic unit I bought to run my 40 ton press has a filter at the pump inlet and a strainer at each valve port. It uses soleniod valves and has some inline check valves, so those need to be protected from grit as well hence the strainers. But as I tell young engineers as they come in, "ask yourself does it make senses?" you guys are bright think about where the debris is originating from, put a filter on every line if you like, but protect the pump. Plus if your blowing up filters that is not safe so it fails the question. good luck and be safe, especially with hydraulics. Joe
  13. Geoff i haven't posted or relied in a long time but work has been crazy busy and we got a dog from a rescue group and haven't been really reading or forging or anything, BUT this post caught my eye and I can help with this. firstly the filter should not be on the return from the valve it should be in the pump suction line. the purpose of the filter is to protect the pump (and thereby the cylinder) from debris that is in the reservoir. the line going into the pump should also be larger than the actual pumps inlet size unless it is coupled directly on the reservoir. if you are then still experiencing flow restrictions through the filter double them up in parallel, this will also reduce the pressure loss through the filters. because the system is pressurized after the pump you can see full pressure and "water hammer" anywhere after the pump, so every component after the pump should be rated for full system pressure. i.e. don't place a 100psi rated filter anywhere after the pump discharge, suction side only. please see the attached basic hydraulic circuit diagram (i hope it attached)the tank is on the right followed by the filter then into the pump. then into a 3 way 5 port valve then into the cylinder. from the valve the "pan" is the symbol for open to atmosphere return, usually back into the tank behind a baffle to protect the pump inlet from any entrained air. hope that helps, good luck Joe
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