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BeaverNZ, December 4, 2018 in Power Hammers, Treadle Hammers, Olivers
I have finally got the tooling for forging a conrod for my project motor bike. This has been a very round about journey and during researching this rekindled my interest in knife making and these things are the reason that I aquired my Massey power hammer. There is a lightening storm happening here at the moment and seems to be making internet play up in down loading pictures or the wife is on facebook or both (sigh) but anyway I am copying a conrod of an old KTM I used to have and just changing the centres I am going to use EN39B steel which is a case hardening steel and high tensile. Very excited about this part of the project of the much modified engine and just maybe in the future may turn into something I can sell
Lovely looking bit of machining on your dies!
It takes a fair bit of oomph to form the hot metal into such dies. Typically such items would be forged under much bigger hammers and/or presses than your 2cwt, but a Massey does have a great single blow.
I would try to forge the billet, with fullers or if you have rounded pallets, as close as possible to the shape. Making sure not to leave any sharp edges at the transitions, ie between shank at big end. It will take a couple of practice runs, you will want to leave just enough material to fill your dies, without too much flash.
If you are using a fancy material, check out it's specifications for forging temperatures. The hotter the metal, the easier it usually is to forge, but some alloys don't enjoy prolonged exposure to these high temperatures. Also keep in mind the chilling effect that your dies will have on the metal being forged.
Good luck and keep us posted, it is great to see you giving your idea a red hot go!
Yes what you described is what I am thinking too, I am going to use the dies as finishing tools an I am going to use EN39B steel for the rods and I have got the forging temp written down somewhere 970 deg C or something. This has been an interesting journey so far and have found out alot of info to do with conrod related things, did you know that the reason most single piece conrods are copper plated? It is used as a masking agent for case hardening to stop the carbon from being absorbed where you dont want surface hardening. This gives a hard bearing surface and tough everywhere else. I had the dies CNC machined locally and I have finished them by hand radiusing some areas and removing the tooling marks. I am really quite excited about this part of the operations hopfully I can get the metal to move under my probably border line too small hammer I can get axcess to a 3 and 500 ton pressbrakes while they are quick for a pressbrake the lack of real speed would pull the heat out of the billet. Have you had some experiance in work like this I am all ears. Cheers Beaver
The finished die with the radiuses all done, I am thinking of removing the flashing as it happens as this will use up energy from the hammer for no reason that is what the cutout around the impression is for and I have allowed 3mm clearance for the flashing gap. The small end will have a spigot for me to hold onto the forging as I work it. At the big end I have got a hole to be tapped with a 16mm thread to hold a button to help extrude the metal outwards radially but I will have to experiment with the size required and the materail will be drawn out length wise as well for grain in the req direction
How did you figure the flow for proper grain orientation?
For the correct grain flow or I believe micro inclustion direction I have a piece of the bar stock of the materail i am using that is 2" or 50mm and I will draw this out and down to size in the long direction of the rod
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