Hi,
Following this thread bemoaning the quality of the sash cramps that you can get for £1! I use a car jack rescued from the boot of a car that was in the middle of a pile of cars at the scrappy. If you don't want to use the jack as a jacl then you can nick the nice long thread and nut out of it. My method for restraining the action is pretty similar to those already seen. Just had to make up a bit of tube with a slot in it in order to go past the restraining post in the rear of my Supersport. I found that the rougher this bit of tube was the better since it grips the washer at the back of the spring. When I made up a fancy delrin prodder for this job it slid about all over the place. Just make sure the edges are burr free so that the inside of your action stays pristine...
Happy compressing...
Steve,
Salisbury, UK