Mililani Stickman Posted February 20, 2009 Share Posted February 20, 2009 Hello everyone I'm new to this forum and need some help. I'm a welding major at the local community college in Honolulu. We have 3 projects to do in our shop and hand tools class. The first was make a cold chisel out of 1" diameter round stock, shape it harden it and temper it. That went fine for me. Now for the second one with a 1/2" diameter round stock shape a center punch the problem is after shaping it with the point on the end then heating to a bright orange and quenching it in cold water fast the using 400 grit sandpaper to make it shinny, then heating it again watching the color band move towards the point when it gets to a blue color then cooling it in oil. Then the test pound it on a 1" piece of steel the point just flattens out to a blunt point and leaves no make on the plate. What am I doing wrong? Thanks Quote Link to comment Share on other sites More sharing options...
Woody Posted February 20, 2009 Share Posted February 20, 2009 What type of steel did your start with, was it a medium or high carbon steel? Heating to bright orange is too hot for heatreating most steels, you want to heat to just above the point where they go non magnetic and then quench. If you started with mild steel, you probably won't be able to get it hard enough to function as a center punch. Perhaps start with a piece of coil spring from a car. Quote Link to comment Share on other sites More sharing options...
MLMartin Posted February 20, 2009 Share Posted February 20, 2009 did you do much shaping with a band sander? or on a grinder? did you do any of this after you had quenched and hardened it, if you did this after you quenched it you could have headed it to much just sanding it and softened it Quote Link to comment Share on other sites More sharing options...
Mililani Stickman Posted February 20, 2009 Author Share Posted February 20, 2009 Thankyou I used a 1/2" diameter round stock cold rolled steel I purchased from Lowe's it had was painted with blue on both ends for indenifacation. I guess my next question would be what kind of a magnet would I use? I have welding magnets can I use these or will it melt them? Do I just touch it or how close do I have to come to the heated steel? If I get a coil spring from the junk yard how do I straighten it? Sorry for so many newbie questions just want to learn the right way. Mahalo. Quote Link to comment Share on other sites More sharing options...
Alwin Posted February 20, 2009 Share Posted February 20, 2009 Cold rolled mild steel won't harden to the degree you need for a good center punch without a special quenching solution. I would recommend cutting a short piece of steel from a coil spring using an oxy-acetylene torch. Don't try to use an oxy-acetylene torch unless you've been taught how, are comfortable with it, and know how to use it safely. To straighten a short piece of steel, heat up the section in which it is bent-in the case of a coil spring the whole length. Then place it on a solid surface which you can hammer on so that the ends are contacting the surface and the middle rises up. Then strike the middle which is the high spot. With a little practice you'll get it straight. If I got anything wrong or explained anything badly please correct me, its been a long day. Quote Link to comment Share on other sites More sharing options...
Thomas Dean Posted February 20, 2009 Share Posted February 20, 2009 Howdy from East TEXAS!! and welcome to IFI! Use a small magnet, one you can tie a piece of string to--about 12"lg, and hang in a convienent place. Heat your part and hold close to the magnet, if it sticks, not hot enough, heat til the magnet doesn't draw to the part, then quench. This will harden the steel, next step is draw to temper, which you are doing correctly. Just make sure you harden and temper the business end, you want the striking end soft as not to shatter. Depending on the steel the heat is around 1500F. I'm sure if I missed a step someone will step in and help out. At least I hope so! Once again, welcome. BTW, did you upset the end of the chiesel before you shaped and sharpened the end? Just wondering. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 20, 2009 Share Posted February 20, 2009 Welcome aboard, glad to have you. If you have trouble with finding or straightening coil spring you can use hex rod. It's tool steel and should be available at a bearing and driveline supplier like "Bearing Engineering" and Anchorage AK outlet as an example. you can try a steel supplier or welding shop too. If you can't find it there you may have to resort to mail order. Shopping for tool steel online should give you enough suppliers to shop for a decent price and shipping. For checking magnetic use a hard magnet, metal or rare earth ceramic, NOT one of the rubber refrigerator magnets, they'' melt. My main ones are a rare earth magnet on a piece of baling wire that is stuck to the forge and a telescoping magnetic probe I can keep in my pocket. Frosty Quote Link to comment Share on other sites More sharing options...
781 Posted February 23, 2009 Share Posted February 23, 2009 Just filmed 90 minutes with Mark Aspery and a local metalurgist talking heat treating. Mark said using a magnet may not get the tool steel hot enough to get austinite which means it may not be as hard as it should or could be. He said the higher the carbon the hotter it needs to be to get hard. Not sure what I will do with this footage. Probably use it as fill with another conference footage to make a DVD. Dont have room on the Aspery DVD I will be making for UMBA as he will almost fill with what he did Sat and Sunday. It was an excellent demo by the way. He made a hot cutter, hammer eye drift, hamer, tongs. forge welded, water leaves more forge welding, a bird, told jokes and did the heat treat seminar at night If you have the chance to see Mark try your best to go. I know he is going to BAM and the guild of metalsmiths plus a couple of others or more. Quote Link to comment Share on other sites More sharing options...
larrynjr Posted February 23, 2009 Share Posted February 23, 2009 As this is part of a school project, I'm surprised you have to provide your own steel or that they didn't give more details as to what type of steel you would need to succeed in making a punch. If you used that same Lowes steel for your chisel it will probably notch and blunt as soon as you try to use it. Quote Link to comment Share on other sites More sharing options...
larrynjr Posted February 23, 2009 Share Posted February 23, 2009 Welcome to IFI! Sorry for skipping the welcome by posting my comment(s) first. Quote Link to comment Share on other sites More sharing options...
SK-Buckwheat Posted March 4, 2009 Share Posted March 4, 2009 Also what would work real good that I have had luck with it get your hands on a old McPherson strut or a shock absorber from a vehicle and use the shaft from that. It is good hard steel and I found it makes good punches and chisels. With them I temper to a straw colour. That has worked well for me so far. Welcome to the forum. Quote Link to comment Share on other sites More sharing options...
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