Hello welcome to Enots engineering I'm Alan it's a day tool review
we're looking at this edge finder or centre finder for a milling machine
it's titanium coated high-speed steel and it has a spring down the middle that holds it together
what it will repeat to and whether it can find the centre of a hole
so let's go into the workshop and see how we do it
today we're looking at this edge finder from banggood
it's titanium coated has a spring up the middle and two polished faces
which run concentric to each other that part there is just a pin
to hold the spring and on the end there's a brass cap
on the website it says to run this set a 400 rpm
it's made from high speed steel and it's non-magnetic
So obviously when you're trying to find the edge of a component
if it's steel you don't want this magnetic so it just sticks to it
overall length is about 90 millimetre three and a half inches
at the end this is 4 millimetre diameter
this one is 10 millimetre diameter and it's reduced here so we won't touch the edge of something
and the shaft on this end is 10 mil so a few - 10 mil collet
so we'll put this in the milling machine and see how accurate it is
I fitted an ER 20 collet and the collet nut on the end
and I've push the edge finder body nearly to the end of the collet on the inside
I can fit this on to the spindle
tighten it up
so I've selected the speed it should be around 280 lets have a look
and I'll just position it on the edge of this block of aluminium
so what I'm going to do start it off just touch the edge and when this edge finder
indicates it's on the edge I'll set my direct readouts to zero
you can see here the edge finders just kicked out at the top here I'll back off
and rerun it
I will move it in
it's just kicked there
what's happening the top part just kicks across and that tells you you're on the edge
you can see here if you look at this part here
you can see when it touches the face
at the moment you can see it's running true the tops running true with the spindle
I'll move it in a bit
you can see there it's just kicked out to one side
0.005mm different to the last time
come down to the same depth
touch it on this side
zero the DRO
It's just kicked my 0.005 of a millimetre difference from the first one
so what I'll do now is I will put a parallel strip in the vice with the ground face
which probably will be a bit fairer to the product because this face is fairly rough
we're I've been measuring
so if I just touch it on the edge
there
there it's gone again that's within 0.005 microns of the first one
that's kicked that's within 5 microns again
I think this is a bit fairer on a ground surface rather than a a rough edge
yeah that seems to find the edge within 5 microns or 10 microns if you do 5 either side
10 microns which is probably good enough for most milling operations
I'm just going to see now whether I can find the centre of this hole
so I'll lower it down into the hole
I will move it until it touches the edge
now in a hole it could be more difficult
because normally when it kicks it runs along the edge of the workpiece
but the hole is holding it to the centreline
that's just kicked over zero my DRO
move it until it touches the other edge
so we half the X on the digital readouts move it to zero
and we do the same in the y-axis
zero
move it to the other side
that's kicked there
half the Y and move that to zero
and that puts the spindle in the centre of the bore
what I've done is just put the dial indicator in the spindle
I'll lower that into the bore
I'll set it to zero
it's nearly on zero anyway
I'll turn around
you can see there it's 0.01
this is the back of the milling machine and the reading is 0.03
this is the other side and it's 0.025
and back to the front and it's back to zero
so on the average the edge finder found the centre of the hole to within
0.015mm so I'd have to move it 0.015 to be on centre line
which is less than a thou
well I must say I'm surprised how accurate that is
and it costs less than five pounds
I couldn't even make it for that price
Oh well that's it for today hope you enjoyed it hope you found it interesting
and we'll see you next time on Enots engineering