There are cases that carriage stop in most useful.
I need one with multiple stops. Three or four stops being most often used. I put search engine on work. Most appealing was Mikes workshop model:http://mikesworkshop.weebly.com/multi-position-stop.html
And then I had good stare to pile of junk and pulled out some material. I figured I could this without drawings....I most often do some sort of drawing/sketch, but this I gave myself some slack. I'll be drawing least a sketch from now on. Learning experience.
Added ball detent.
The lever that locks the stop under the prism guide could have been more narrow. But I had same material that top piece was made extra 40 mm, hence same size. But if I need to make another, I would make the bottom piece smaller and probably use Mike's design.
Socket screw recess is nearly full depth. I did not want any stuff on the chuck hitting it.
Used jaw offset for drilling, to get them fairly straight, this is where a bit more drawing would have helped. This bolt PCD does not need to be at the middle of the material, I could have put them more out at the knurled section, now I had to sink retainer bush/screw a little deeper to keep it out of locking nut (which is going to hold the stop bolts).
Anyway. Here it is. Pretty ugly but it should work.