I have a couple of pins that should be replaced. I was thinking of having a couple machined from two and three sixteenth hex material. What type of steel should be used for this job. The pin would be hardened after it was machined. This machine is old enough so I think the pins may no longer be available. Any suggestions here would be appreciated. And if there is a thread already on this subject direct me to it. Thanks
Like a high carbon steel i would imagine, Case hardened? anyone clarify?
Last time I made pins I used a material called 4140 ground bar. It comes with a machine ground finish and it was available in a range of sizes. It is easy to machine and case hardens really well and is reasonably priced. Here is some technical info. http://www.interlloy.com.au/data_sheets/high_tensile_steels/4140.html It is pretty much like mild steel to work with except that if you get it hot while drilling or cutting it will start to harden. Drill with plenty of cutting fluid and only cut with a cold saw or bandsaw, an abrasive saw will harden it before you get half way through. Once machined get it heat treated and your done.
I would check the dimension and try to find a pin that can be cut to the right length from a aftermarket parts supplier, no worries choosing the right material and getting the hardening done right.
I will check around and see if I can buy it in 2 and 3/16 th hex. I need the hex for a wrench or stop and the pin has two different diameters cut into it. After it is heat treated do you have to make a final cut on the different diameters on the pin. I heard different metals will grow some or shrink some during heat treating.
I do have a couple of pins that are straight two inch those would need threads on one end, the other end would get welded to a piece of square 1/2 inch steel with a 2" inch hole drilled into it. Those pins are not bad yet.
I am not sure that I understand the hex part of the pin you are talking about. I would imagine it would be easier to get pin material that is ground to size already and weld a hex to it if you need that as part of the pin. Turning a round pin out of hex would be hard on a lathe and you would be paying for a fair bit of metal that you are going to machine off. I was also concerned that metals grow and shrink with hardening and was wondering about the bush to pin being to tight or too loose after heat treating, but I my information was that there is no change in size when heat treating and this has also been my experience.
Here is a couple of the pins that I could replace. I need a material that can be hardened because of the different diameters. The hex would be easy enough chucked up in a 3 jaw chuck. The other pin is on the boom section rod end. Could be just round , still needs to be turned to make the one different diameter. The large round could be welded to the pin.
Just a thought If your going to pay a machine shop to do all the work of machining why not just use a good hard welding rod build up the old pins and turn them back to size? Use some emry cloth after the final cut and you will be good for another thousand hours. When I was in college we would always leave .005 and grind to final size with a cylindrical grinder or use a tool post grinder after heat treat.