It is called a "stop drill". In order for it to be effective, you will need 1/4" hole. Problem is the plastic will want splinter out on the back side. I'd use a 3/16 bit followed by a stepped reamer to the final 1/4 size.
The ebay item id given is invalid, no result has been sentI would go with the smaller hole. You can then fill the hole with this UV glue. I bought this stuff online, cheap. It's plastic and can be sanded, buffed, and painted or just let clear.
The idea of a stop drill is to provide a place where the stress at end of the crack is dissipated into the surrounding material. A smaller hole will not provide a large enough area to be effective long term.
In my 25 years of aircraft maintenance, stop drills were always 1/4"
I knew I was going to be drilling a hole.. Wanted to hear from some experience doing so,.. Lately I seem to rush into things without thinking it through.. I also ordered some Weldon3 to address the crack.. Its on the corner in a location that won't be too much of a problem aesthetically.. I'll just have to keep an eye on it,.. Its hard to believe that the windshield is as old as the boat.. Is there anyone making them??
i imagine if you can get an old classic re- manufactured, you can surely get a windshield. i think the company that makes the boats is in Canada. i had inquired a few years ago about making a twin of mine. they required all the spec's, and the hull is all they do. if i remember mine was $6,000 and you had to arrange shipping at your cost.
Nice looking work. I assume best to use the sharpest (new if possible) bit. Do you use somewhat slow rpm and little pressure? I am picturing a small continuous spiral of plastic rotating around that bit. Did you do a tiny pilot first and then also drill from both sides to prevent chipping before you chamfered? I just want to get this procedure correct should I need to do it. Thanks for thread and picture!
I used the smallest bit I had as a starter.. 1/16th I believe.. then up from there.. I used my Dewalt cordless, not too slow, don't want it to catch the edge of the crack and tear out material , but not too fast.. no pressure!! The bit will try to pull itself if you aren't careful.. used a step bit, by hand, to chamfer the hole on both sides.. My Weldon3 came today, so I used that in the crack itself.. Hopefully it will stay put..