Finding Center Of Hole To Drill A Pilot ?

[GordonC]

This might be a bit of a stupid question but I've got 5 16mm holes and I need to copy the exact position of the holes and drill them on another bit of metal, The problem is how can I work out the exact center of the holes so that I can drill a pilot hole to start with ? I cant just go by eye and punch what I think looks like the center I need them to be as accurate as possible.
Anyone any ideas ?
Thanks,

 

[Andy south east]

Hi gordon. Try measuring to the edge of the holes and add half the hole dimension. Do it from all sides if you can, that will give you an accurate measurement. Normally works for me.

 

[shenion]

That is what transfer punches are for. Basically they are punches the exact size of the hole.

 

[Splatterer]

Is it practicable to use a crayon and tracing paper to make a 'brass rubbing' of the original holes and transfer it to the new metal.
Then you can centre the holes by marking lines where exactly 16mm hits the circumference.
Or as Andy says, measure half the hole in from the sides.

 

[zzr1200]

Transfer Punches


http://www.ebay.co.uk/itm/like/1511...&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95

http://www.ebay.co.uk/itm/like/1310...&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95


hth

 

[doubleboost]

As has already been said make a transfer punch

 

[nickk]

the only transfer punches i have are sprung self centralising types 5-20mm & 20-35mm brilliant accurate to .3mm,got them years ago from tilgear,i heard warco do them. as has been said edge & centre marking + using dividers is accurate.

 

[500e]

http://www.nextag.com/Tools--zzhole+transfer+punchesz2700482zB6z5---html#!http:

//www.ebay.com/bhp/hole-finder

 

[GordonC]

Thats great exactly what I was looking for, Thanks guys

 

[ronan]

Who makes a quality set of transfer punches ? I had a set before and the steel in them was only slightly harder than toffee.

 

[scotty41]

I have these one but they where from RS
http://www.flexbar.com/shop/pc/TRU-CENTER-EXPANDING-TRANSFER-PUNCH-SET-79p3110.htm

before these i used just turn a bolt down to a point and transfare that way.

 

[AndyStobbs]

If all the holes are the same size, then the distance between the right hand edge of one to the right hand edge of an adjacent is the same distance as the centres.

 

[graffian]

If all the holes are the same size, then the distance between the right hand edge of one to the left hand edge of an adjacent is the same distance as the centres.

The right hand side of one hole to the right hand side of the next hole?

 

[AndyStobbs]

Sorry yes, don't know where I got the left bit from, will edit the above to correct that, well spotted.
Andy