Centre Finder Query

This topic has 16 replies, 11 voices, and was last updated 3 January 2018 at 14:24 by Howi.

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2 January 2018 at 11:43 #334894
Martin King 2
Participant
@martinking2
Hi All,

I have several centre finders, two of which I use all the time from choice and feel quite happy with using them.

However, I cannot for the life of me understand how one is suposed to use the 'needle point' accessory that some of them have.

I have tried to get it in a centre punched hole and managed to break two of them!

Clearly I am doing something wrong here and wish to be put right even at the expense of letting all know just how dozy I am at times!

Cheers, Martin
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2 January 2018 at 11:43 #9029
Martin King 2
Participant
@martinking2
2 January 2018 at 12:03 #334903
Tony Pratt 1
Participant
@tonypratt1
Get the needle point to run concentric & then use to pick up scribed lines, no need to centre punch the lines beforehand.

Tony
2 January 2018 at 12:25 #334906
I.M. OUTAHERE
Participant
@i-m-outahere
Make sure you use a piece of metal or a small rule to set it true – don't use ya finger !
2 January 2018 at 13:04 #334913
Martin King 2
Participant
@martinking2
Posted by XD 351 on 02/01/2018 12:25:56:

Make sure you use a piece of metal or a small rule to set it true – don't use ya finger !

Point taken!

Martin
2 January 2018 at 13:05 #334914
Martin King 2
Participant
@martinking2
Posted by Tony Pratt 1 on 02/01/2018 12:03:46:

Get the needle point to run concentric & then use to pick up scribed lines, no need to centre punch the lines beforehand.

Tony

By 'pick up scribed lines' do you mean just by eye? What about a centre popped point?

Cheers, Martin
2 January 2018 at 16:56 #334958
Jim Nic
Participant
@jimnic
I find accurately picking up scribed marking easy enough especially using a magnifying glass. However, unless you are already at the correct location dropping the needle point into a centre pop mark can move the needle and require re-centering it before you can have another go.

Jim
2 January 2018 at 17:39 #334963
I.M. OUTAHERE
Participant
@i-m-outahere
You bring the tip of the needle down very close to the line or centre punch mark and line it up by eye , with a mill the work is usually clamped down and not free floating like on a drill press where you can wiggle it around as you lower the centre / spotting drill down into the centre punch mark.

Not really a super precision item but with practice you can get within a few thousandths easily enough ( waiting now for someone to come along and state they get within 0.0001 – Good for them !) but if more accuracy is needed you would edge find then use X&Y co ordinates to locate the drill or use toolmakers buttons .

Where they are really useful is locating a centre punch mark down in a cavity or slot .

Ian.
2 January 2018 at 17:40 #334964
Tony Pratt 1
Participant
@tonypratt1
Posted by Martin King 2 on 02/01/2018 13:05:55:

Posted by Tony Pratt 1 on 02/01/2018 12:03:46:

Get the needle point to run concentric & then use to pick up scribed lines, no need to centre punch the lines beforehand.

Tony

By 'pick up scribed lines' do you mean just by eye? What about a centre popped point?

Cheers, Martin

Yes by eye, there is no point centre popping by eye then picking up the centre pop with the needle point again by eye, just pick up the lines with the point.

Tony
2 January 2018 at 18:21 #334967
Neil Wyatt
Moderator
@neilwyatt
It doesn't go in the hole, you true it up with the edge of a ruler (I use the back of my fingernail) and then line the crossed lines, centre pop etc. up with it by eye.

Neil
2 January 2018 at 19:51 #334997
SillyOldDuffer
Moderator
@sillyoldduffer
Just in case it's not obvious from what's been said already.

Assuming the target is the crossing point of two lines scribed at right angles to each other:
- Stabilise the needle so the point spins on the spindle's axis without wobbling
- Drop the needle as close as possible to the work without touching it
- Adjust the lighting to make the lines stand out
- With your head at the front align the needle point with the forward/back scribed line.
- Move head to the side to align the needle on the right/left scribed line.
- A magnifying glass helps
Dave
2 January 2018 at 20:04 #335001
David George 1
Participant
@davidgeorge1
I have a piece of plasticene which has a dressmaking pin embedded in it sat on the side of the mill I just stick it to the end of the cutter start the mill at a slow speed and using my nail set the point true and that never fails to pick up lines or points. I have been using this method for at least 40 years.

David
2 January 2018 at 20:07 #335002
Phil P
Participant
@philp
This YouTube video shows how to use a wiggler.

https://www.google.co.uk/search?q=how+to+use+a+wobbler&oq=how+to+use+a+wobbler&aqs=chrome..69i57j0l4.4314j0j8&sourceid=chrome&ie=UTF-8#kpvalbx=1

Phil
2 January 2018 at 21:01 #335015
Paul Lousick
Participant
@paullousick59116
Getting the needle point of the centre finder to run concentric & centre by eye ?????

Instead I just use the shank of a small drill (or any small round bar). Mount it in the chuck and file the end to a point. Then centre by eye with a magnifying glass. Just as accurate, as long as your drill chuck is concentric.

Paul.
2 January 2018 at 22:40 #335038
David Taylor
Participant
@davidtaylor63402
I'm glad someone asked that, I have one and had no idea what to do with that part!

I usually do what Paul said, just line up the centre pop with a drill point or pointed rod.

David.
3 January 2018 at 11:34 #335096
Martin King 2
Participant
@martinking2
Thanks guys, much appreciated!

Martin
3 January 2018 at 14:24 #335111
Howi
Participant
@howi
I usually put a centre pop,then use the pointer on the centre finder gently lowered onto the centre pop, then raised out of the centre pop, if the two are not concentric the pointer will describe a circular path when raised ( because it is off centre), by adjusting the x and y axis and gently raising or lowering the pointer into the centre pop you can get the pointer centred over the centre pop. Very quick and easy to do, long so fed to describe.
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