Easy way of finding centre to drill a hole in round stock

[Jim]

Easy way of finding centre to drill a hole in round stock. I know that a lot of blokes (and gals) know this trick, but I'm sure that there's a lot that don't and it's always good to refresh an idea now and again. I know that true machinists have better and more accurate ways to find centre, but for your average backyard metal basher this is a quick and easy method.


<a href="https://www.youtube.com/watch?v=d9i3MEuhgmI" target="_blank">http://www.youtube.com/watch?v=d9i3MEuhgmI</a>

[Neil-Lickfold]

Its the same for setting a tool on centre height .
In the vise, you can use a file and draw file or mark it with marker pen, and rub a piece of metal over the area , as long as it is horizontal.
It will make  at thin line you can pick up on.
I dont use my rule, but use a piece of brass sheet strip.
It only needs to be 70 or so mm long.
It is one of the 1st things that used to be taught to apprence's in the work shop.

Neil

[Jim]

Thank you Neil.

[co2]

Neat trick but I wondered how accurate it is.
My calcs show that for a 1% (of stock diameter) deviation, the rule angle would be 1.05 degrees, using a 0.05" thick scale.
Pretty good, and 1 degree is easy to see.

[Jim]

Its always worked well for me, but the caveat being that what I build/repair doesn't have to meet NASA specifications.