Thank you for your reply. An update for you. I bought the jig that you used in your video and it worked perfectly. So, thank you once again. Just because it is cheaper than the others doesn’t mean it won’t do the job. If fitting an automatic chain door closer it would be best to use this jig too as the depth of hole needed for the door closer makes it very difficult to drill straight with a paddle drill bit and the risk of coming through the face of the door is quite high.
Hi. Sorry for the late response. For my porpoises that jig was perfect. I'm a handyman and I do maybe 20 doors a year. If I would do more I would buy a professional tool. But we're talking 10x the price.