# Centering a Lathe Tool



## vederstein (Nov 8, 2015)

This is a little trick that I figured out on my own.  I don't know if  it's commonly known or even the "correct and approved" way to do  something, but here is goes.

I always find it difficult to accurately get a lathe tool centered on  the stock.  I've seen people use a lathe center in the tailstock and  align the points.

I know that there are some jigs to do it.  I don't have those jigs.

What has worked for me is taking a skim cut on a piece of scrap and measuring the diameter.

I divide the diameter by two to get the radius and lock down some calipers to the radius.

I place the depth end of the calipers on the turned stock.  I then  raise/lower the lathe tool until it just touches the calipers.

The tool is centered.


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## modelman1838 (Nov 8, 2015)

This is a new one to me, it`s simple and I like it ,well done

Hugh


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## tornitore45 (Nov 8, 2015)

If that works for you, great.
Any thin piece of material like a 6" length of a hack saw blade pinched between tool and part shows the tool is centered when it stands vertically.

The beauty of this method is that it gets more accurate as the diameter gets smaller, which is exactly what is needed.

You can make a jig with a beefy flat base a bolt a washer and 3 nuts, or a bit fancier.

If the first operation is to face the part then the tool is on center when there is no pip left.


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## doc1955 (Nov 8, 2015)

The simple way and no math is needed  hahah
[ame]https://www.youtube.com/watch?v=vpCu56O8AJ0[/ame]


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## RonGinger (Nov 9, 2015)

The thing can be  used to set a drill on center of round stock in a mill. Just place the rule over the stock and come down on it with a drill bit. Then move the Y back and forth until the scale lays flat over the work. I think this can get a drill on center of a part within a couple thousands, which is close enough for some things.


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## Edke6bnl (Nov 9, 2015)

RonGinger said:


> The thing can be  used to set a drill on center of round stock in a mill. Just place the rule over the stock and come down on it with a drill bit. Then move the Y back and forth until the scale lays flat over the work. I think this can get a drill on center of a part within a couple thousands, which is close enough for some things.



I forgot about that use for the drill press, I have a v shaped dohicky with a vertical shaft and a set of lines to get center, that helps center for the drill press


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## xpylonracer (Nov 9, 2015)

If you use the Doc's method with sintered inserts take care when approaching the rule or you can shell (chip) the insert at the cutting edge.

Emgee


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## Engineeringtech (Jul 6, 2016)

I like your caliper idea! Good job.


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## tornitore45 (Jul 6, 2016)

> If you use the Doc's method with sintered inserts take care when  approaching the rule or you can shell (chip) the insert at the cutting  edge.



When using that method, rather than using the cross slide to approach the metal strip, I rotate the QCTP with feeling.  Faster then micro-advancing the slide and eliminates the risk of tip chipping or dinging your scale.


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