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  • I cobbled together a sort of rocket stove at my employers behest several years ago, it works well but not exactly what he was expecting.

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    • Nice fun day.... calibrating the herd of Simpson 260s here.

      I found that both the early 260s that I have have weak magnets or other internal issues with the meter movement portion, so they read actually at 72% and 86% of full scale. There is not much to be done about that now, so those will be discarded. I narrowed it down to a basic deflection per uA problem, which can be done by using the 50 uA scale.... that is almost direct to the meter movement.

      I had gotten them specially because those have 5000 VAC and 5000VDC scales that I wanted. They also have standard banana plug connections like everything else in the lab. But they both read wrong, in a way that is not really fixable in a practical way.

      The other newer ones only read to 1000VAC and VDC, plus all but one have the super-safe reversed banana plugs (male plug down in a hole) which is unlike every other meter or test equipment here.

      Next I will go through the rest of the cased bench meters. And then find a loose meter in storage that will work for high voltages for the moment. I have one manufactured unit good to 25kVDC, but nothing between 1000VDC and 5000V, and no AC meter in that range. That is why I wanted the Simpsons. I will have to look for another.
      Last edited by J Tiers; 03-01-2021, 01:14 AM.
      2801 3147 6749 8779 4900 4900 4900

      Keep eye on ball.
      Hashim Khan


      It's just a box of rain, I don't know who put it there.

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      • Originally posted by mattthemuppet View Post
        could also be that the flue is too large for the fire in the bottom, so that it doesn't draw well enough.
        Flue, that's the chimney right? Figured they couldn't be too large really, based on my experiences with my forge that uses two 55 gallon oil drums, one is the chimney, gives a very good draw. One could experiment and try and tighten it off.

        This flue is longer too than most rocket stoves of this design, and more rectangular due to the nature of the material. Longer should help the draw though, but I guess rectangular is more troublesome than square, or ideally, round. I might try hanging a baffle above the fire and make a narrow part, a lot of stoves have a design like that, creating a constriction and then opening up, supposed to create a good draw.

        Another idea is adding air intakes just above the fire, on the side to introduce some sideways turbulence.

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        • On the flu/chimney/firebox whole system you want approximately the same cross section of flow beginning to end.
          The firebox/downdraft having wood in it can be a little bigger.
          the chimney is happier more symmetrical than rectangular and this is important; insulated.

          just looking at these, my unsolicited "things to try"

          1) (easy) stick a length of round stove pipe down there (maybe it squishes down a bit)
          stuff the corners to force exhaust up the stove pipe only.

          2) (easy) wrap. insulate the outside mostly the part above the firebox and up.

          3) fair bit more work & expense.. form flu in cut fire brick / castable refractory cement .

          basically you want to give the hot gasses in the flu an environment to keep combusting and
          packed together in an insulated space is much better than wandering around bumping
          into highly conductive walls & corners and cooling off.
          Last edited by Astronowanabe; 03-01-2021, 03:08 AM.
          --
          Tom C
          ... nice weather eh?

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          • I don't think it has to be insulated, since others have built these and they work.

            Today I added a secondary air intake, based on the studies I read on modified "kakelugnar" in sweden, using the same principle and cutting a slot on the side around the height the flames are when burning I ended up with this, I added a "louver" I think is the english word to prevent air going out instead.

            Made a big difference, now it burns really clean, only a heat haze is seen and it started doing that before the heater was even up to temp. I think that's a success for this mod. Works real well with the lid closed.

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            • Isaw something that made me laugh, a gold plated "statue".

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              • Scrapping this cnc machine. It had a problem that I could not figure out and the company wanted $4500.00 just to come out and look at it with no guarantee they could fix it. The only reason I am taking it apart is I don't have anything at this place that can lift the weight as is to junk it. I think I have it whittled down now to about 4000 lbs so I should be able to handle it. In the foreground is a 20kva transformer which weighs 197 lbs.

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                • Ridgerunner
                  Is the mechanics sound? And the motors and the screws? Could it be worth just putting modern CNC controllers on instead of scrapping it?


                  We know a cat has 9 lives. How many does a machinist get? Just asking for a "friend" *cough* who failed to tighten the bolts holding the chuck on his lathe. Went well turning some aluminium down to 8.01mm to stick a bearing on. Numbers were a slightly moving target but that was clearly just down to flex of a slim rod. Finish was good too. Parting a bit scrunchy but that was clearly down to incorrect centre height. Quick bit of steel turning for a washer and the finish was terrible - sort of like intermittent hard granules in the steel.....and that's when I found the chuck wobbled in the hand!

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                  • Originally posted by Cenedd View Post
                    Ridgerunner
                    Is the mechanics sound? And the motors and the screws? Could it be worth just putting modern CNC controllers on instead of scrapping it?


                    We know a cat has 9 lives. How many does a machinist get? Just asking for a "friend" *cough* who failed to tighten the bolts holding the chuck on his lathe. Went well turning some aluminium down to 8.01mm to stick a bearing on. Numbers were a slightly moving target but that was clearly just down to flex of a slim rod. Finish was good too. Parting a bit scrunchy but that was clearly down to incorrect centre height. Quick bit of steel turning for a washer and the finish was terrible - sort of like intermittent hard granules in the steel.....and that's when I found the chuck wobbled in the hand!
                    That was the shame of it. Everything mechanically, servos, ball screws etc were good but it would error saying the hydraulic turret was not locked, when it was. It would start up and home. The hydraulic tail stock and hydraulic chuck would work but could not get the turret to change tools or spin up the chuck with the error.
                    I talked to Centroid and they wanted me to get pictures of the motor tags. I thought about it and started looking at all the sensors etc and knew it would take months for me to try to convert it.

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                    • Got the tormach wired up temporarily last night, fixed the oiler cables (power and oil line), drawbar airline tee powered it up and played around with it a bit. Everything seems to be fine, no other issues. Spindle sounds fine, exactly like it did before the drop. Checked tram (and also squareness with a square) and I'm out 0.005" from front to back and side to side over about 8" . Not good, but honestly not as bad as I thought. When I first zeroed the indicator I had a bit pause before sweeping it as I wasn't sure I wanted to know....I had visions of 0.02-0.03"....

                      I "could" probably shim that out. And I might for now, but I'm also still entertaining the idea of tearing it down to the base casting to tig braze the crack and that would let me map it out and re machine where needed. Having access to the tools and equipment to do it right at work makes me lean in that direction. I'll wait and make the call when it's in it final home in the corner and leveled. I need to get some self leveling concrete to pour there as there's a pretty good slope in the back corner where I wan to put it.

                      I couldn't go to bed without making some chips, so I punched out a quick conversational facing program in path pilot, found some scrap aluminum and ran my first program on it. I missed having conversational as none of our mills at work have it. This was also my first go round with path pilot, and I was making chips within 5 minutes. I still need to poke around with it a bit more, but so far I like the control. It's missing some stuff, like wear comp, that I consider pretty strange, but I think I'll get along with it.

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                      • Originally posted by Ridgerunner View Post

                        That was the shame of it. Everything mechanically, servos, ball screws etc were good but it would error saying the hydraulic turret was not locked, when it was. It would start up and home. The hydraulic tail stock and hydraulic chuck would work but could not get the turret to change tools or spin up the chuck with the error.
                        I talked to Centroid and they wanted me to get pictures of the motor tags. I thought about it and started looking at all the sensors etc and knew it would take months for me to try to convert it.
                        That does sound a shame...but I also know the feeling when you realise you'll never get round to it and it'll just be a millstone round your neck.

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                        • Machined a pair of soft jaws for my 4" milling machine vise. The old one where getting pretty dinged up. I have to do little projects like this every once in a while just to keep my limited knowledge and skills pointing in the right direction. If I had just known I would live this long, I would have paid a little more attention to things while I was young,
                          _____________________________________________

                          I would rather have tools that I never use, than not have a tool I need.
                          Oregon Coast

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                          • More calibrating and fixing bench meters (old time single purpose cased meters, volts or amps) today. It seems I have a lot of them, but three of the herd are out now as readouts on a long term test, and there have been cases needing even more.

                            I may have to thin the herd a bit, even so.
                            2801 3147 6749 8779 4900 4900 4900

                            Keep eye on ball.
                            Hashim Khan


                            It's just a box of rain, I don't know who put it there.

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                            • did some grading with foster pup
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                              this is what the little rascal looked like when we got him and his brother
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                              he's heading off to his new family in Ohio on Thursday. I think we'll be getting another couple of 3-4wk olds straight after, gulp!

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                              • Tormach got it's first "paying" job yesterday as I needed a 27mm deep socket to replace an oil pressure sensor on my truck.

                                Nothing pretty, just a chunk of tube I welded an old 3/8" drive socket in the back end and cut the 27mm hex. Nothing like having your truck break down on the way into work ("lost" oil pressure) after spending all your money on a CNC mill. Fun times....

                                On a side note I'm really pleasantly surprised at how well the Tormach cut steel. I honestly wasn't expecting that. Can't wait to get it all fixed up and settled into it's new home.

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