I used this tool to install hardware for 5 solid core internal doors. I found that the flexible nature of the material resulted in a slight misalignment between the front and back of the door. It didn't damage the door. Also, the device for adjusting the choice between 2 3/8 and 2 3/4 inch spines tended to slip on the longer spine. It caused a failure on one of the doors. Again, buying a bolt with a longer lock solved the problem. The jig and miniature cutter devised to install the latch were useless. The guide is made of plastic which immediately melted and became unusable (except as a gauge) after attempting to install the first latch. I would not buy or recommend. I don't know if other similar devices are better constructed!