tortron Posted December 7, 2020 Share Posted December 7, 2020 And you can make a tidy profit in the steel wool business! very rad so far 2 1 Quote Link to comment Share on other sites More sharing options...
sentra Posted December 7, 2020 Share Posted December 7, 2020 wow awesome stuff good work 1 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 8, 2020 Author Popular Post Share Posted December 8, 2020 I uploaded a video of my cat who loves to hang out with me in the shed, even when I'm making loads of noise. The video also shows my redneck contraption in action Tortron, I think about 100kg of steel wool was made lol 38 Quote Link to comment Share on other sites More sharing options...
rusty360 Posted December 8, 2020 Share Posted December 8, 2020 2 hours ago, cute wee gem said: I uploaded a video of my cat who loves to hang out with me in the shed, even when I'm making loads of noise. The video also shows my redneck contraption in action Tortron, I think about 100kg of steel wool was made lol That is farking epic! Great work. 4 1 Quote Link to comment Share on other sites More sharing options...
Truenotch Posted December 20, 2020 Share Posted December 20, 2020 @cute wee gem - this is wild. I'm super impressed at how deep you've delved into the project. Will you need to calculate the inertia of the roller so it can be factored into the power readings? If so, any idea how you'll do it? I've been following this dude's stuff for a few years now. He has an inertia-only dyno made from an old electric motor that gets used for motorbikes. It doesn't have any sort of retarder. He was lucky that the motor manufacturer had the rotor inertia specs available for him to base his figures off. He's also created some DIY dyno software called Ardyno that's available fairly cheaply (you have to get your own chips printed, but that's not the end of the world).  Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted December 20, 2020 Author Share Posted December 20, 2020 Cheers Markku, yes I will need to calculate the moment of inertia of all of the rotating assembly. The YourDyno site has some very good design stuff for both brake and inertia dynos, which include calculators for MOI - however this isn't always 100% accurate. The best thing about an eddy current dyno is you can easily figure out the moment of inertia by doing a run up to X rpm and then back down again with the engine at full load (retarder overpowering the engine to bring it back down), which will give you a graph displaying the difference in HP it takes to accelerate and decelerate the roll/rotating assembly. This video explains the process (maybe skip to 1:45) 2 stroke stuffing is excellent btw! Love his videos 2 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 20, 2020 Author Popular Post Share Posted December 20, 2020 The next step was to machine in some traction grooves. I came up with a few ideas in my head along the lines of using a small router with a carbide end mill mounted to the linear rail. But after realizing that could be quite expensive if I kept burning out end mills, I came up with a rather crude yet effective method, albeit extremely slow. I mounted a chamfer tool 90 degrees on the compound slide and ran it along the face almost like a shaper would, but slower. This seemed to work pretty well on the first test cut, so I carried on with this method, and used the same carbide tip for all 475 grooves (much cheaper than carbide end mills) When I say slow... Each groove took 7 passes to get a decent depth and a decent looking cut. One pass taking around 4 minutes, times 7 for every groove, times 475 grooves = 13,300 minutes or 220 hours. I had done well over half before the lock down in April/March - I then spent 10-11 hours a day for the first 7 days of lock down finishing it off. I tried several times to speed the process up, but that was the sweet spot with this method unfortunately. It also took some time to figure out the best quality cut. (blunt tip worked best in the end) There are a few cuts with tearing along the edges, but over all I'm happy with the outcome - it should do the job at least. 26 1 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 20, 2020 Author Popular Post Share Posted December 20, 2020 It was about this point I had a bit of a problem on my hands. For some reason one end of the shaft had almost 0.5mm run out (warpage from welding?) which I never really noticed during machining I ended up sleeving the shaft either end to 90mm until I had the whole lot within 0.1mm - which was a bit of drama in itself. I also attempted to balance it myself at home using a chinese vibration meter, a bit of trial and error and plotting the data as a spread sheet I managed to significantly improve the balance - however getting it up over 400rpm was a little scary when it wanted to take off across the workshop - so I gave up. Photo of the sleeved shaft, new 90mm bearing and balance weight. I then machined some hubs for the Telma retarder out of 200mm 1045. 50kg down to 9kg  13 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 20, 2020 Author Popular Post Share Posted December 20, 2020 I went to a local engineer who let me borrow his mill to cut the keyway into the hub, GC! - I then had to wait another 6 weeks to get him to cut the key into the 8018 chain coupling Another issue was the keyway in the shaft for the roller. Being to large to mill, I had to spend an entire day cutting it by hand. Angle grinder, die grinder then hand file finished, being careful to get it as close to perfect as I could and not over cut it. PS the sleeve was welded using a series of hot tacks to keep it from moving hence the ugly welds Sent the roll to Qualtex in Hamilton to have it properly balanced. It turns out my balance weights were actually in the correct location, just not heavy enough! Well worth the money considering the fine tolerance they balanced it to.  29 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 22, 2020 Author Popular Post Share Posted December 22, 2020 Catching up on progress now, this update is from 3 months ago.  With the chain coupling finished, I could finally mate the roller to the retarder and get an idea of the frame dimensions. Which I needed to know so I could build a pit for it to sit in. I have no room in the current workshop/house, so I'd have to build another shed, as a dedicated dyno cell. I decided to drop a day from work each week to try and get something built before the Christmas holidays. So I borrowed the digger from work and got to it. 23 Quote Link to comment Share on other sites More sharing options...
Popular Post tortron Posted December 22, 2020 Popular Post Share Posted December 22, 2020 goddam dude, this project just keeps stepping up a notch 13 1 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 22, 2020 Author Popular Post Share Posted December 22, 2020 Dyno pad poured Pit walls boxed and poured. They bowed a bit more than expected on the outside, but a little bit of extra concrete never hurt.. Except for my back due to doing it all by hand with a mixer. Molesealed the outside and used 3 layers of polythene underneath and up the walls to stop water getting in (water table gets quite high here) Finished the prep ready for concrete. The last photo was on November 26th. I let the concrete company know 6 weeks prior that it would be ready at the end of November as I know they are extremely busy, and kept mentioning it to them so they knew where I was at. Getting stressed about it not happening as December was rolling on and the Christmas rush was in full effect for the building trade. Not only that, it kept raining when we planned to pour! 18 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 22, 2020 Author Popular Post Share Posted December 22, 2020 Other concrete truck companies were booked out until 2021 so I couldn't even get the concrete to attempt it myself. Early December I started begging the concrete company boss. I told him all I needed was the concrete truck, a man with a screed and a bull float and I'll finish it myself by hand. Hoping this would persuade him as I'd only need an hour of his placer's time. December 14th. I rang him to ask if we were still on for that day. "Yeah but it'll be late in the day" - My hopes were low by this point as other jobs could have dragged on and it be too late in the day to do mine. But finally they came, and were gone in less than an hour. I spent the rest of the evening doing the door rebate, steel floating the slab by hand and drinking beer. I'm no concreter but it came out alright. 24 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 22, 2020 Author Popular Post Share Posted December 22, 2020 While I waited a few weeks for the concrete, I built a frame for the dyno.  Speed sensor bracket Load cell bracket. This is what measures the torque. Electric drum brake to lock the roller when mounting a car. Frame painted. The part sitting next to it bolts into the top to support the floor coverings (steel checker plate) 25 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 22, 2020 Author Popular Post Share Posted December 22, 2020 I then mounted a 2jz cam gear to the end of the roller, this will be used as a trigger wheel for the speed sensor. I then set to rewiring the Telma retarder. These have 16 coils wired in parallel for a 24v system on a truck - this is no good for a dyno. I wired the coils into series so it now runs on 192v, which can be wired to mains power through a power supply. With the retarder wired to a 12v car battery, the coils can be checked with a compass to make sure the wiring is correct. They should read north - south - north - south around the circle to form the eddy currents, which are transferred into the rotors to apply braking. 32 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 22, 2020 Share Posted December 22, 2020 Unbelievably cool. Might want to extend the load cell bracket so that it acts as a stop if the load cell or linkage fail to restrain things.  Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted December 23, 2020 Author Share Posted December 23, 2020 Cheers dude. There's not a huge amount of force on the load cell in relation to the hardware capacity, keep in mind it's 450mm from the center so it has a huge torque advantage. But better safe than sorry, so I've planned to add a stop to the opposite side of the retarder as it will be spun backwards for FWD applications, and for RWD if anything were to break, the bracket will actually hit the lower mount/frame. Quote Link to comment Share on other sites More sharing options...
rusty360 Posted December 25, 2020 Share Posted December 25, 2020 On 23/12/2020 at 09:36, cute wee gem said: While I waited a few weeks for the concrete, I built a frame for the dyno.  Speed sensor bracket Load cell bracket. This is what measures the torque. Electric drum brake to lock the roller when mounting a car. Frame painted. The part sitting next to it bolts into the top to support the floor coverings (steel checker plate) Epic build man! I'm picking there will be no sideways load on the roller? Ya just running a standard p series housing i see. Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted December 25, 2020 Author Share Posted December 25, 2020 Cheers man, yup just standard bearings. From the photo's I've seen of other dyno this seems to be fairly common? Unless I'm missing something critical, feel free to chime in. I would assume there would be bugger all axial load? Once again I'm no engineer so if there's anything I've overlooked feel free to set me straight. I'd much rather change some stuff than have it fly to bits! 1 Quote Link to comment Share on other sites More sharing options...
Popular Post cute wee gem Posted December 28, 2020 Author Popular Post Share Posted December 28, 2020 Stripped the boxing and bucketed all of the water out of the pit. My parents then popped around with their tractor and we managed to get all the heavy bits in the hole. 18 Quote Link to comment Share on other sites More sharing options...
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