I rebuilt my mechanical chain tensioners and they are rock hard. The problem was installing the tensioners in the chain box. No combination of clamps or other devices seemed to work. And I know there is a tool for this, but I did not have it and wanted to move forward.
So, I went to the local hardware store and bought this spring claim for $3.99.
I then took the rubber protectors off and set the tensioner in the clamp like this.
Then, the clamp and the tensioner went into the vise like this.
Cranked vise until tensioner compressed like this.
Took the compressed tensioner and clamp to engine and positioned in place.
Slid it in -- the clamp is so thin it slid right under the idler arm.
Held the tensioner in place and pulled the clamp out. Snap! into place.
Whole operation took about 90 seconds per side.