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About athomas

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    Nova Scotia, Canada
  1. athomas

    Dewalt batteries 18v vs 20v

    Yes, I am rehashing a lot of what has already been stated. There are a few manufacturers that play with the naming convention when indicating battery voltages. Some rate the batteries using nominal voltage and some rate using maximum charge voltage. They should all be rated using nominal voltage for comparison purposes. To understand batteries: NiCd and NiMh cells are rated 1.2V nominal voltage. The max voltage of each cell fully charged is 1.4V. The discharge voltage of each cell is 1.0V. Under use, the 1.4V value quickly drops to 1.3V and then follows a fairly linear rate of discharge until it reaches 1.1V and then rolls off fairly quickly to 1.0V. A 15 Cell NiCd or NiMh cell would have a nominal voltage of 18V (15 x 1.2V) and a max voltage of 21V(15 x 1.4V). The old Dewalt NiCd batteries were rated using the nominal voltage. LiPo and LiIon cells are rated at 3.6V or 3.7V nominal voltage. They are mostly 3.6V, even though some of those are marked as 3.7. The max voltage of each cell fully charged is 4.2V, but most only charge to 4.0 for safety, so 4.0 is most often used as the max voltage value. The fully discharged voltage value is 3.0V (some are 2.8), but 3.2V is often used for safety to protect the cell from too deep of a discharge. (5S = 5 in series) A 5S LiPo battery pack would have a nominal voltage of 18V (5 x 3.6V) and a maximum voltage of 20V (5 x 4V). The new Dewalt lithium battery packs are rated using the max voltage. The batteries should use nominal voltage and watt-hours of capacity.
  2. The plastic of my tool is what I thought was the same plastic as every other tool. It isn't overmolding used for comfort grips. It is actually the tool structure itself. I was thinking about it last night, and I think I had the same problem before with another Mastercraft tool and just didn't know it at the time. The handle on my Mastercraft chop saw had gotten slightly sticky, but not as bad as this one. I happened to upgrade to a Dewalt 12" slider, so I sold the Mastercraft one. I have never seen this on any of my other tools nor on any of the tools at my workplace.
  3. Has anyone had an issue with plastic tool shells chemically breaking down? I am asking this question, because it appears I have it on one of my cheap tools that is about 10 yrs old. I have plenty of plastic cased corded and cordless tools that are perfectly fine and have been for many, many years. I do have one that is breaking down chemically. The tool in question is a Canadian Tire Mastercraft heat gun. I don't use it much, so it sits most of the time in a metal cabinet. I went to use it recently, and discovered that the handle was sticky. I thought I had accidentally transferred something from my hands or gloves to the tool. Upon inspection, the whole tool case was gummy on the surface. The front and back part are different plastic and don't have the same issue. I tried to wash it off using a soap and water solution to no avail. I could wipe the soft plastic off the surface if I used enough force. I suspect I could clean it off if I found the right cleaner as well. I left the tool to sit for a while to see what would happen, and it is getting worst as time goes by. I am wondering if anyone else has experienced any plastic tools reacting like this? I only have 2 Mastercraft tools (the dark blue ones before they went with the new lighter blue), so I can't say if it is an issue with Mastercraft tools in general, or just that one tool.