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		nuckolls.bob(at)aeroelect Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 9:34 am    Post subject: heat treat problem | 
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				I've got a project that hit a bit of a snag. I'm
  building a recovery parachute control system that
  uses a t-handle to deploy the parachute. I found
  a really handy size T-handle in McMaster-Carr
  and proceed with my endeavors.
 
  One of the last operations during assembly called for
  cutting the shaft of the t-handle to length and then
  drilling a 3/16" hole in the last 1/2".  The hole
  accepts a roll-pin that runs in the slot on a guide
  collar to set stroke of the handle and to restrain
  rotation.
 
  [img]cid:.0[/img]
  
  When I cut the shaft with an abrasive cut-off wheel, the
  it turned out to bet harder than the hubs-of-you-know-what.
  It's the right length but now I need to drill the hole. No
  chance with any tools I have.
 
  I think I recall that steel can be heated to some pretty
  ordinary temperatures (less than incandescent) and cooled
  slowly to remove the heat treat. Strength in this area is
  very un-critical. I can put a thermocouple on it and heat
  with a torch. I've browsed some heat-treat documents
  but the without some time consuming study, no immediate
  notions of process jumped out. I need to soften this part
  so that I can drill it with ordinary high-speed drills.
 
  Are there any folks on the list with some practical experience
  in this area? Hoping to deliver this thing tomorrow but
  it ain't gonna happen without the pin installed. Any
  suggestions from the List?
 
    Bob . . .
 
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		racerjerry
 
 
  Joined: 15 Dec 2009 Posts: 202 Location: Deer Park, NY
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				 Posted: Wed Apr 03, 2013 9:43 am    Post subject: Re: heat treat problem | 
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				EDM  aka Electrical Discharge Machining.  Google it for a machine shop that has that capability in your area.  EDM easily penetrates any conductive material.
 
 Good luck, Bob
 
 P.S.  You would need to locate a RAM type (plunge) EDM setup as opposed to a wire type EDM machine if you intend to go this route.
 
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 _________________ Jerry King
  Last edited by racerjerry on Wed Apr 03, 2013 9:57 am; edited 1 time in total | 
			 
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		klehman(at)albedo.net Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 9:43 am    Post subject: heat treat problem | 
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				I don't do a lot of this but if it is carbon steel just heat it up to a
 nice red color and air cool it. The hardening only occurs if it is shock
 cooled in oil or water or the attached heat sink is relatively massive.
 A room temperature slow cool should take out the hardness.
 
 A good carbide masonry bit running slow will sometimes go through pretty
 hard steel. A hardware store cobalt bit is dramatically better than an
 High Speed Steel bit.
 
 Ken
 
  	  | Quote: | 	 		   
 <nuckolls.bob(at)aeroelectric.com>
 | 	  
  	  | Quote: | 	 		   
  
  I've got a project that hit a bit of a snag. I'm
  building a recovery parachute control system that
  uses a t-handle to deploy the parachute. I found
  a really handy size T-handle in McMaster-Carr
  and proceed with my endeavors.
  
  One of the last operations during assembly called for
  cutting the shaft of the t-handle to length and then
  drilling a 3/16" hole in the last 1/2".  The hole
  accepts a roll-pin that runs in the slot on a guide
  collar to set stroke of the handle and to restrain
  rotation.
  
  Emacs!
  
  
  When I cut the shaft with an abrasive cut-off wheel, the
  it turned out to bet harder than the hubs-of-you-know-what.
  It's the right length but now I need to drill the hole. No
  chance with any tools I have.
  
  I think I recall that steel can be heated to some pretty
  ordinary temperatures (less than incandescent) and cooled
  slowly to remove the heat treat. Strength in this area is
  very un-critical. I can put a thermocouple on it and heat
  with a torch. I've browsed some heat-treat documents
  but the without some time consuming study, no immediate
  notions of process jumped out. I need to soften this part
  so that I can drill it with ordinary high-speed drills.
  
  Are there any folks on the list with some practical experience
  in this area? Hoping to deliver this thing tomorrow but
  it ain't gonna happen without the pin installed. Any
  suggestions from the List?
  
     Bob . . . 
  
 
 | 	 
 
 
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		csmale(at)bak.rr.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 10:02 am    Post subject: heat treat problem | 
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		rv7a.builder(at)yahoo.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 10:20 am    Post subject: heat treat problem | 
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				Is EDM an option?
  
 
     
 From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>
 To: aeroelectric-list(at)matronics.com 
 Sent: Wednesday, April 3, 2013 10:32 AM
 Subject: heat treat problem
   I've got a project that hit a bit of a snag. I'm
 building a recovery parachute control system that
 uses a t-handle to deploy the parachute. I found
 a really handy size T-handle in McMaster-Carr
 and proceed with my endeavors.
 
 One of the last operations during assembly called for
 cutting the shaft of the t-handle to length and then
 drilling a 3/16" hole in the last 1/2".  The hole
 accepts a roll-pin that runs in the slot on a guide
 collar to set stroke of the handle and to restrain
 rotation.
 
 [img]cid:1.2922996926(at)web163601.mail.gq1.yahoo.com[/img]
  When I cut the shaft with an abrasive cut-off wheel, the
 it turned out to bet harder than the hubs-of-you-know-what.
 It's the right length but now I need to drill the hole. No
 chance with any tools I have.
 
 I think I recall that steel can be heated to some pretty
 ordinary temperatures (less than incandescent) and cooled
 slowly to remove the heat treat. Strength in this area is
 very un-critical. I can put a thermocouple on it and heat
 with a torch. I've browsed some heat-treat documents
 but the without some time consuming study, no immediate
 notions of process jumped out. I need to soften this part
 so that I can drill it with ordinary high-speed drills.
 
 Are there any folks on the list with some practical experience
 in this area? Hoping to deliver this thing tomorrow but
 it ain't gonna happen without the pin installed. Any
 suggestions from the List?
 
   Bob . .  .
 
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		Mark(at)wessonair.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 10:47 am    Post subject: heat treat problem | 
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				There are many people that will say duh, but there may be a few that will
 later thank me.
 
 I have heard many complain about drilling the stainless firewall and taking
 an hour and one drill bit per hole.
 I will share what I learned the hard way.
 I am able to drill the stainless in less that one minute and not dull a bit.
 
 It is all about removing heat from the drill bit and the part you are
 drilling.
 If you use a high speed and it doesn't cut it will burn up the bit.
 In order to remove the heat you need to have chips flying.
 Aluminum is soft so the 4000rpm air drills we use work fine.
 The chips are a flying carring the heat away.
 For harder metals you need to increase the pressure and slow the bit down
 until the chips fly.
 It is as easy as that. Slow the drill speed down and increase the pressure
 until the heat is removed by flying metal chips.
 Now I have not tried anything too hard since I learned this but I sure have
 made butter out of the stainless that other people complain about.  
 Mark W
 
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		BobsV35B(at)aol.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 10:52 am    Post subject: heat treat problem | 
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				Good Afternoon Bob, 
   
  Maybe this will jog a few memories.
   
  Back when I was in High School (Seventy Years Ago) My shop teacher taught  us how to make great hunting knives out of worn out files, We heated them with  an acetylene torch to bright red then stuck them into some sort of powder to  cool. Once they had cooled they were very easy to grind to the knife shape.  
   
  We then heated them back up again and quenched them in a light oil to  harden the edge. 
   
  My thought is that the powder we slow cooled them in was ordinary baking  flour. Anyone know for sure? 
   
  I am also fuzzy on just what liquid we used for the quick cool. May have  been something other than light oil.  All very far back in my faulty  memory, but maybe that will jog some one else's memory.  Worked like a  champ to turn those files in hunting knives.
   
  Happy Skies,
   
  Old Bob
   
   In a message dated 4/3/2013 1:13:38 P.M. Central Daylight Time,  nuckolls.bob(at)aeroelectric.com writes:
   	  | Quote: | 	 		  I've got    a project that hit a bit of a snag. I'm
 building a recovery parachute    control system that
 uses a t-handle to deploy the parachute. I found
 a    really handy size T-handle in McMaster-Carr
 and proceed with my    endeavors.
 
 One of the last operations during assembly called    for
 cutting the shaft of the t-handle to length and then
 drilling a    3/16" hole in the last 1/2".  The hole
 accepts a roll-pin that runs in    the slot on a guide
 collar to set stroke of the handle and to    restrain
 rotation.
    
 When I cut the shaft with an abrasive cut-off wheel, the
 it    turned out to bet harder than the hubs-of-you-know-what.
 It's the right    length but now I need to drill the hole. No
 chance with any tools I    have.
 
 I think I recall that steel can be heated to some    pretty
 ordinary temperatures (less than incandescent) and cooled
 slowly    to remove the heat treat. Strength in this area is
 very un-critical. I can    put a thermocouple on it and heat
 with a torch. I've browsed some    heat-treat documents
 but the without some time consuming study, no    immediate
 notions of process jumped out. I need to soften this part
 so    that I can drill it with ordinary high-speed drills.
 
 Are there any    folks on the list with some practical experience
 in this area? Hoping to    deliver this thing tomorrow but
 it ain't gonna happen without the pin    installed. Any
 suggestions from the List?
 
   Bob . . .     | 	 
 
 
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		N20DG
 
 
  Joined: 02 Jan 2008 Posts: 61 Location: lancaster, texas
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				 Posted: Wed Apr 03, 2013 11:00 am    Post subject: heat treat problem | 
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				Old Bob
  Probably that far back in our high school days it was sand any how that is  what my dad taught me to use when converting the worn out file to something  useful
  Older Dick
   
   In a message dated 4/3/2013 1:54:16 P.M. Central Daylight Time,  BobsV35B(at)aol.com writes:
   	  | Quote: | 	 		     Good Afternoon Bob, 
     
    Maybe this will jog a few memories.
     
    Back when I was in High School (Seventy Years Ago) My shop teacher taught    us how to make great hunting knives out of worn out files, We heated them with    an acetylene torch to bright red then stuck them into some sort of powder to    cool. Once they had cooled they were very easy to grind to the knife shape.    
     
    We then heated them back up again and quenched them in a light oil to    harden the edge. 
     
    My thought is that the powder we slow cooled them in was ordinary baking    flour. Anyone know for sure? 
     
    I am also fuzzy on just what liquid we used for the quick cool. May have    been something other than light oil.  All very far back in my faulty    memory, but maybe that will jog some one else's memory.  Worked like a    champ to turn those files in hunting knives.
     
    Happy Skies,
     
    Old Bob
     
       In a message dated 4/3/2013 1:13:38 P.M. Central Daylight Time,    nuckolls.bob(at)aeroelectric.com writes:
     	  | Quote: | 	 		  I've      got a project that hit a bit of a snag. I'm
 building a recovery parachute      control system that
 uses a t-handle to deploy the parachute. I found
 a      really handy size T-handle in McMaster-Carr
 and proceed with my      endeavors.
 
 One of the last operations during assembly called      for
 cutting the shaft of the t-handle to length and then
 drilling a      3/16" hole in the last 1/2".  The hole
 accepts a roll-pin that runs      in the slot on a guide
 collar to set stroke of the handle and to      restrain
 rotation.
      
 When I cut the shaft with an abrasive cut-off wheel, the
 it      turned out to bet harder than the hubs-of-you-know-what.
 It's the right      length but now I need to drill the hole. No
 chance with any tools I      have.
 
 I think I recall that steel can be heated to some      pretty
 ordinary temperatures (less than incandescent) and      cooled
 slowly to remove the heat treat. Strength in this area is
 very      un-critical. I can put a thermocouple on it and heat
 with a torch. I've      browsed some heat-treat documents
 but the without some time consuming      study, no immediate
 notions of process jumped out. I need to soften this      part
 so that I can drill it with ordinary high-speed drills.
 
 Are      there any folks on the list with some practical experience
 in this area?      Hoping to deliver this thing tomorrow but
 it ain't gonna happen without      the pin installed. Any
 suggestions from the List?
 
   Bob . . .       | 	  
  | 	 
 
 
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		billp(at)wwpc.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 11:26 am    Post subject: heat treat problem | 
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		handainc(at)madisoncounty Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 11:36 am    Post subject: heat treat problem | 
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				Bob - 
 
 If the part is not critical, just heat it up red hot, hold it there for a minute or so, and let it air cool.  Here is a fair discussion of the process. http://www.efunda.com/processes/heat_treat/softening/annealing.cfm
 Alternatively, a very sharp drill bit, turned very slowly will also work with lots of cooling fluid.  I set up my drill press for that very purpose (had to drill some spring steel with out having to re-treat it) by installing a secondary motor with small pulley.  Liked it so well that way that I just left it set up.  Doesn't do well on soft metals, but is not nearly as hard on drill bits, and works for nearly any type of steel.  
 M. Haught 
 On Apr 3, 2013, at 1:51 PM, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:[quote]   Good Afternoon Bob, 
   
  Maybe this will jog a few memories.
   
  Back when I was in High School (Seventy Years Ago) My shop teacher taught  us how to make great hunting knives out of worn out files, We heated them with  an acetylene torch to bright red then stuck them into some sort of powder to  cool. Once they had cooled they were very easy to grind to the knife shape.  
   
  We then heated them back up again and quenched them in a light oil to  harden the edge. 
   
  My thought is that the powder we slow cooled them in was ordinary baking  flour. Anyone know for sure? 
   
  I am also fuzzy on just what liquid we used for the quick cool. May have  been something other than light oil.  All very far back in my faulty  memory, but maybe that will jog some one else's memory.  Worked like a  champ to turn those files in hunting knives.
   
  Happy Skies,
   
  Old Bob
   
   In a message dated 4/3/2013 1:13:38 P.M. Central Daylight Time,  nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com) writes:
   	  | Quote: | 	 		  I've got    a project that hit a bit of a snag. I'm
 building a recovery parachute    control system that
 uses a t-handle to deploy the parachute. I found
 a    really handy size T-handle in McMaster-Carr
 and proceed with my    endeavors.
 
 One of the last operations during assembly called    for
 cutting the shaft of the t-handle to length and then
 drilling a    3/16" hole in the last 1/2".  The hole
 accepts a roll-pin that runs in    the slot on a guide
 collar to set stroke of the handle and to    restrain
 rotation.
 
 <1efc966e.jpg>
 
 When I cut the shaft with an abrasive cut-off wheel, the
 it    turned out to bet harder than the hubs-of-you-know-what.
 It's the right    length but now I need to drill the hole. No
 chance with any tools I    have.
 
 I think I recall that steel can be heated to some    pretty
 ordinary temperatures (less than incandescent) and cooled
 slowly    to remove the heat treat. Strength in this area is
 very un-critical. I can    put a thermocouple on it and heat
 with a torch. I've browsed some    heat-treat documents
 but the without some time consuming study, no    immediate
 notions of process jumped out. I need to soften this part
 so    that I can drill it with ordinary high-speed drills.
 
 Are there any    folks on the list with some practical experience
 in this area? Hoping to    deliver this thing tomorrow but
 it ain't gonna happen without the pin    installed. Any
 suggestions from the List?
 
   Bob . . .     | 	  
 
 [b]
 
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		millner(at)me.com Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 1:14 pm    Post subject: heat treat problem | 
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				On 4/3/2013 11:51 AM, BobsV35B(at)aol.com (BobsV35B(at)aol.com)       wrote:
      
       	  | Quote: | 	 		  |  the         powder we slow cooled them in was ordinary baking flour. Anyone         know for sure?  | 	       
      Flour is combustible, and if you generate flour dust, explosive...     probably not a good thing to put very hot metal objects into.
      
      Paul
       [quote][b]
 
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		raymondj(at)frontiernet.n Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 2:36 pm    Post subject: heat treat problem | 
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		nuckolls.bob(at)aeroelect Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 3:08 pm    Post subject: heat treat problem | 
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				At 02:35 PM 4/3/2013, you wrote:
  
    Essentially that's what I did. 
 
   	  | Quote: | 	 		  | Alternatively, a very sharp drill bit, turned very slowly will also work with lots of cooling fluid.  I set up my drill press for that very purpose (had to drill some spring steel with out having to re-treat it) by installing a secondary motor with small pulley.  Liked it so well that way that I just left it set up.  Doesn't do well on soft metals, but is not nearly as hard on drill bits, and works for nearly any type of steel.   | 	  
    I tried that earlier but the stuff was so hard
    my center punch wouldn't even mark it! Couldn't
    get a bit to set still in one spot long enough to
    remove any material.
 
    Softening it up worked great.
 
  
    Bob . . .    [quote][b]
 
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		raymondj(at)frontiernet.n Guest
 
 
 
 
 
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				 Posted: Wed Apr 03, 2013 3:09 pm    Post subject: heat treat problem | 
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				Based on the old         articles I've read about heat             treating and tempering it could have been               sifted wood ash, or                   asbestos.  Just things I've read about people using.  It was probably oil you dipped in to quench.
                            
                                  	  | Quote: | 	 		  Raymond Julian
 Kettle River, MN.
 
 "And you know that I could have me a million more friends,
 and all I'd have to lose is my point of view." - John Prine  | 	         On 04/03/2013 01:51 PM, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:
      
       	  | Quote: | 	 		                         Good Afternoon Bob, 
           
          Maybe this will jog a few memories.
           
          Back when I was in High School (Seventy Years Ago) My shop           teacher taught us how to make great hunting knives out of worn           out files, We heated them with an acetylene torch to bright           red then stuck them into some sort of powder to cool. Once           they had cooled they were very easy to grind to the knife           shape. 
           
          We then heated them back up again and quenched them in a           light oil to harden the edge. 
           
          My thought is that the powder we slow cooled them in was           ordinary baking flour. Anyone know for sure? 
           
          I am also fuzzy on just what liquid we used for the quick           cool. May have been something other than light oil.  All very           far back in my faulty memory, but maybe that will jog some one           else's memory.  Worked like a champ to turn those files in           hunting knives.
           
          Happy Skies,
           
          Old Bob
           
                     In a message dated 4/3/2013 1:13:38 P.M. Central Daylight             Time, nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)             writes:
             	  | Quote: | 	 		  I've               got a project that hit a bit of a snag. I'm
                building a recovery parachute control system that
                uses a t-handle to deploy the parachute. I found
                a really handy size T-handle in McMaster-Carr
                and proceed with my endeavors.
                
                One of the last operations during assembly called for
                cutting the shaft of the t-handle to length and then
                drilling a 3/16" hole in the last 1/2".  The hole
                accepts a roll-pin that runs in the slot on a guide
                collar to set stroke of the handle and to restrain
                rotation.
                
               | 	           
         | 	       
      Image removed
      [quote]                     	  | Quote: | 	 		                    
 When I cut the shaft with an abrasive cut-off wheel,                   the
                    it turned out to bet harder than the                   hubs-of-you-know-what.
                    It's the right length but now I need to drill the                   hole. No
                    chance with any tools I have.
                    
                    I think I recall that steel can be heated to some                   pretty
                    ordinary temperatures (less than incandescent) and                   cooled
                    slowly to remove the heat treat. Strength in this area                   is
                    very un-critical. I can put a thermocouple on it and                   heat
                    with a torch. I've browsed some heat-treat documents
                    but the without some time consuming study, no                   immediate
                    notions of process jumped out. I need to soften this                   part
                    so that I can drill it with ordinary high-speed                   drills.
                    
                    Are there any folks on the list with some practical                   experience
                    in this area? Hoping to deliver this thing tomorrow                   but
                    it ain't gonna happen without the pin installed. Any
                    suggestions from the List?
                    
                      Bob . . .                 | 	           
         [b]
 
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