oscer Posted August 12, 2012 Share Posted August 12, 2012 Hi folks, I'm heating a #4 Morse taper lathe center as I type this. As a machine operator my understanding of the hot side of metal working is very limited. So if any one would like to comment on what I'm doing here i would be glad to read what you have to say. I started with a #4 dead center that had been abused to the point that, well there was no point the 60* taper was blunt to about 5/16" so I turned a new point on it and could tell that it was way harder near the O.D. than near the center. I don't know what it is made of but it is not rusty after many years of laying around (other parts that were stored with it are). It was pretty hard, I had to run the spindle between 40 and 60 RPM to cut it with Carmet 717 grade inserts. slowing down as I approached the O.D. I have no forge yet so the part was heated with a rose bud till it was glowing red from the tip about 2/3 the way back to the O.D. it was then quenched in hydraulic oil and is now in the oven set at 400* going to soak it for 2 hrs. and let air cool. I hope I end up with a wear resistant but not brittle 60* taper. Thanks for any advise or comments, oscer. Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 13, 2012 Share Posted August 13, 2012 Yeah, dead centers have a hard life, especially from newbies cranking them as tight as they can to try making up for not doing a proper set up. <sigh> Anyway, The only thing I would've done differently is use a magnet to determine if it'd reached critical temperature before quenching. Did you try a file on it before starting to temper? As quenched a sharp single cut file should skate. Worst case, you haven't hurt it and may need to anneal and re-heat treat it. Dead centers don't need much flex so a little brittle isn't a killer but if the point does chip don't burn up your inserts, grind it. I chuck them up and use a fine stone on my dremel, they come out near perfect, smooth and shiny for minimum friction in use. I think you're okay though, if anything a little soft but if not okay, you DO get a redo. <grin> Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
oscer Posted August 13, 2012 Author Share Posted August 13, 2012 Thanks Frosty, I did check it with a magnet before quench,it had no effect. Wish I would have checked with a file after quench. When checked with a file after tempering it can dig in a little and it seems to be the same from point to O.D. this center will only be used as a live center in the head stock so I'd rather be a little soft than have a brittle nose. Quote Link to comment Share on other sites More sharing options...
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