I'm still learning every day and that's part of the fun of going to the shop. Early on I had to repair a Stihl chain brake either a new handle or a brake band. The R&R procedure for the brake spring was at best, pliers, pull and hope. But as I saw it, that spring wanted an old fashioned drum brake pliers tool but lots smaller. For this tool I drilled a hole into the bolt that slides down over the anchor pin. a bit of crude grinding, filing and then a spiral is filed on the bevel. You have the spring relaxed, slide the bolt over the pin, line up the entry of the spiral into the open hook and twist then angle to tool to the spring and the spring is unhooked and controlled. To replace it the scrench with the hole in the middle again and an open tapered slide again similar to a drum brake tool and you hook the anchor, stretch the spring and its hooked, rotate and remove the tool. Band aid count ZERO so far. But on some Stihl saws the handle goes too close to the anchor pin for this tool. Next scrench got a pull hook filed into it, works good but not quite as nicely as previous tool combo.
The wood handle scrench has three sides cut off and notches to rotate those pesky Husky three leaf chain brake levers. Yes, other techniques exist for this job.
The dowel is a left over from my '97 KDP job. Pushing those tank grommets into a recess deep in a Husky can be a PITA and risks damage to the grommet. Its just shaping the reduced round tip so the grommet just hangs on not too tight but it doesn't fall off. Now a bit of favorite lubaduba smeared on the bevel, push down on the grommet into the tank hole and a little circle push motion on the tool and pop goes the grommet. It was so well rec'd at work I made one for each of the other techs.
The 3120XP's fate was not in our control. I don't remember what the ticket said but likely something like it cranks but needs a plug or something. We inspect first, assess and if the job closely matches the C.S. on the ticket we proceed, if it costs a lot we call and get approval first for estimate. This saw has a short list of needs a XYZABC stuff and then the scoring on top of the other stuff.
Gary