How to make a reliable center finder 

It is useless to show your videos if they do not help to carry out a similar project for whoever wants it if you do not give the measurements

@@lospoliti-locosdelmomento770 But he gives you the idea...do it

Even his sawdust looks neat and clean.

Nope...

take it easy

да....все работы мастерские........а Вы заметили руки мастера...........они не мужские.............это все делает мастер женщина..............какая молодец......и меня еще поражает ее мастерская с уникальными инструментами

а может быть я и ошибаюсь

@@nitnatsnok2526 Да, Вы однозначно ошибаетесь, этот Мастер мужчина. Я слежу за всеми его видео и однажды мне попалось видео, где он монтирует систему кондиционирования ( он великолепный мастер на все руки ). И там случился прокол - камера захватила его в кадр в полный рост, где я и увидел его лицо. Красивый японец, а такие умелые и КРАСИВЫЕ руки, как у девушки - ну, это , наверное, от Бога!

Tt

I don't see how making the original longer is a solution... You'd still fail on the ends

yes with a tolerance of +-0

he will probably pull out his "optical center punch" and ....

Pre punch OR stop blocks. Both doesn't make sense to me.

That would not mitigate the effect of using pencils with different diameters. Smaller diameters would ride deeper into the 'V', and that would offset the point from being centered between the two end guides. This kind of center finder will only work if the point of the pencil or scribe is exactly centered on a line between the centers of the end guides. So instead of a 'V' you would need something like an iris diaphragm that can accommodate different diameters but keep them centered to a specific point. I do not think that is really practical, but maybe someone has a clever idea how to do it.

X JWill you are absolutely right! However, the most common way to deal with this kind of error is to simply make a mark with the tool riding on one direction, then coming from the other side and if there is any noticeable difference between both passes, you simply split the difference by eye or drill in between the lines. After all... nobody needs to be “that precise” hehe. But thanks for the observation.

This work is done for punch work. It may not be necessary for woodworking as you say. However, since I have experience in iron processing, I was reluctant to drill as it was.

instead of the pencil insert a hard bush like a bearing sleeve and drill through the bush with an appropriate size drill bit.

@Land Rover Addict Your idea came up with a good idea. Just chuck the punch into the drill and push it in. As long as it uses a drill fence, it can be processed with extremely high precision.