Methods of finding center of a worn shaft?

[RJSakowski]

Finding the center of a worn shaft can be difficult if the wear is non-uniform. Many times the wear will result in an egg shape or flattened section. The best approach would be to try to work off an unworn section as a reference. If there is enough of an unworn section to rest on a v block and you have a second v block to support the back end of the shaft then what @mmcmdl suggested should do the trick. Otherwise mounting the shaft in a 4 jaw chuck and centering on the unworn section. Then center drill the end of the shaft.

 

[rjs44032]

The center finder I have is huge. The Dia of the part hardly shows
I would like to find one for small diameters. Are they sized for certain dia?

So I'm a bit at a loss. Is this shaft tiny? Please let us know the dimensions or approximate. There is a thing called a pin vise that you can use to grab tiny shafts. Then a v-block, lathe, or surface plate scribe can be employed to mark the end with straight lines that intersect in the center. Hope this helps.

Best Regards,
Bob

 

[tq60]

You can make a "cap" that fits over the shaft with a hole drilled in the center.

Place a chunk of round stock bigger than this worn shaft in the lathe and bore it out for perfect fit of shaft.


Test fit while in lathe, do not remove until finished.

Make it pocket.

Once the fit is finished, center drill hole in center.

Done.

This fits over the shaft, then use hole to guide a punch to mark the shaft.

Sent from my SM-G781V using Tapatalk

 

[mac1911]

So I'm a bit at a loss. Is this shaft tiny? Please let us know the dimensions or approximate. There is a thing called a pin vise that you can use to grab tiny shafts. Then a v-block, lathe, or surface plate scribe can be employed to mark the end with straight lines that intersect in the center. Hope this helps.

Best Regards,
Bob

Yes small , not tiny but small .3XX or so.
Surface plate and associated tooling is on the list.

 

[mac1911]

You can make a "cap" that fits over the shaft with a hole drilled in the center.

Place a chunk of round stock bigger than this worn shaft in the lathe and bore it out for perfect fit of shaft.


Test fit while in lathe, do not remove until finished.

Make it pocket.

Once the fit is finished, center drill hole in center.

Done.

This fits over the shaft, then use hole to guide a punch to mark the shaft.

Sent from my SM-G781V using Tapatalk

Was thinking something along that line. Looking at my cone center punch.

 

[OTmachine]

No other concentric reference surfaces? Can you post a picture of the whole part?

 

[homebrewed]

Does the shaft rotate or is it fixed?

 

[mac1911]

Does the shaft rotate or is it fixed?

Rotate.

No other concentric reference surfaces? Can you post a picture of the whole part?

Magnetic chuck project

Picked up this chuck a while back for scrape price. It worked but just not 100% I did get it apart and found its just not traveling that last bit to get the plates lined up correctly. I am not a machinist and often these small jobs can be frustrating as how to approach a repair on this...

www.hobby-machinist.com

 

[mac1911]

Does the shaft rotate or is it fixed?

Magnetic chuck project

Picked up this chuck a while back for scrape price. It worked but just not 100% I did get it apart and found its just not traveling that last bit to get the plates lined up correctly. I am not a machinist and often these small jobs can be frustrating as how to approach a repair on this...

www.hobby-machinist.com

 

[OTmachine]

Looked at your other post. Do you have a lathe with a 4 jaw chuck? Shouldn’t be too difficult to mount in the 4-jaw to indicate it in true to center off the remaining good surface, then center drill for a true center. Weld build-up and machine to size referencing center drill bore.