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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Dear Rebecca<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div><p class=MsoNormal><b><span lang=EN-US style='color:#1F497D;mso-fareast-language:EN-CA'>>…</span></b><span style='color:black'>But let me start with the simple STOVE INSERT called Mewar Angithi (MA). I would like to try this insert in my eco-kalan stove to see how much more improvement I can get from my stove by simply replacing the clay parilla with the metal MA. <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='color:#1F497D'>></span><span style='color:black'>Can this grate be made readily from an ordinary machine shop? What special tools will be required?<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'>Sorry for the shortage of time to answer just this question. The grate is an insert and it is expected that there will be a floor of some kind. To make a grate insert (which implies that the stove was not intended to have one, and it must support itself) I suggest the following:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p> </o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>If it is accessible, purchase perforated metal sheets. They are quite common or can be ordered from sheet metal suppliers. They look like this:<o:p></o:p></span></p></div><div><p class=MsoListParagraph><!--[if gte vml 1]><v:shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f">
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</v:shape><![endif]--><![if !vml]><span style='mso-ignore:vglayout;position:absolute;z-index:-1895825408;left:0px;margin-left:306px;margin-top:73px;width:236px;height:203px'><img width=236 height=203 src="cid:image005.jpg@01D15DF5.36F96620" v:shapes="Picture_x0020_1"></span><![endif]><span style='mso-fareast-language:EN-CA'><img width=236 height=207 id="Picture_x0020_3" src="cid:image006.jpg@01D15DF5.36F96620"></span><span style='font-size:12.0pt;font-family:"Times New Roman",serif;color:#1F497D;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>It is far easier to buy sheets to make hundreds than to punch your own holes. If you want to make a few to try, it is best to use a manual punch. There are many sources for such punches but basically they look like this:<o:p></o:p></span></p><p class=MsoListParagraph><span style='color:#1F497D;mso-fareast-language:EN-CA'>Home-made manual <a href="http://www.search.alot.com/landing?slk=manual+punch+press&nid=2&cid=10163569038&kwid=21069054402&akwd=manual%20punch%20press&dmt=b&bmt=bb&dist=s&uq=manual%20punch%20mubea&device=c&ismobile=false&msclkid=41fad85b4ad64549b4eb4246611ee150&accid=35000652&campid=61724902&agid=4082679782&vx=0">punch</a>:<o:p></o:p></span></p><p class=MsoListParagraph><span style='mso-fareast-language:EN-CA'><img border=0 width=318 height=346 id="Picture_x0020_5" src="cid:image008.jpg@01D15DF5.36F96620"></span><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoListParagraph><span style='color:#1F497D;mso-fareast-language:EN-CA'>Or you can buy similar things from multiple sources. <o:p></o:p></span></p><p class=MsoListParagraph><span style='mso-fareast-language:EN-CA'><img border=0 width=236 height=427 id="Picture_x0020_6" src="cid:image012.png@01D15DF4.430CC9D0"></span><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>There are manually pumped hydraulic ones that are far more powerful if you want to punch thicker steel.<o:p></o:p></span></p><p class=MsoListParagraph><span style='mso-fareast-language:EN-CA'><img border=0 width=303 height=310 id="Picture_x0020_4" src="cid:image013.jpg@01D15DF5.36F96620"></span><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>If you punch holes it is about 1/10<sup>th</sup> the cost of drilling them, maybe 1/20<sup>th</sup>. So for any level of production you want to be punching the holes, not drilling them<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>5.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>The function of an inserted grate is to get the fire off the floor. This can be done with a U-shaped sheet – i.e. a flat platform for the fire and two sides bent down. They do not have to be parallel sides, the grate can have some tilt. I suggest that the tilt be upwards at the back, that is, a marble will roll out of the front of the stove if placed on the grate.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>6.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>Don’t punch holes you don’t need. Punch first then bend afterwards. The holes should not be very large – maybe 8 to 10mm. Generally speaking grates for wood burning are far too coarse. People do that to save material but it wastes fuel. If you make a parallel bar grate make the gaps 4 to 5mm. Not 20.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>7.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>If you order sheets pre-cut to the size you want to punch then bend, it is much cheaper to order them pre-cut by a company that specialises in that trade. They usually charge by the kg. Supposed you wanted 2.2 tons of material pre-cut to 280 x 340. It would be produced from a coil, not sheets, and it would add something like $0.10 a kg or less to cut it perfectly to that size, which would be done by a fully automatic slitting guillotine in a few minutes. With 1.6mm material it would yield about 1500 parts.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>8.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>With the right jigging, small holes such as you want can be punched at a rate of 10-15 per minute. You need oil.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>9.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>In medium quantities the holes should also be CNC punched by a service. Then you bend them, but they can probably do that pretty cheaply too. In large quantities you have a punching tool made to do all of them at once. <o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='color:#1F497D;mso-fareast-language:EN-CA'><span style='mso-list:Ignore'>10.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D;mso-fareast-language:EN-CA'>Have a look at the sheets of punched material if you have to buy new sheets. If you are using recycled material (offcuts) you are ahead to punch them yourself using a manual machine. There are many sizes so get the smallest one that will make the biggest hole you will need. Smaller means faster because the arm is shorter.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'>I hope it goes well.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-CA'><o:p> </o:p></span></p></div></div></div></body></html>