Wilson trimmer with concentricity gauge

[Booger68]

has any one ever mounted dial gauge to their wilson trimmer to check concentricity, I think it would work great using the shell holders, I just can’t decide what style gauge to use and mount

 

[ClassCat]

Would this give you an idea of where to start, or would this work ?

 

[Booger68]

That is the type of dial I was thinking, wondering if you could measure from the needle tip to the edge of the dovetail on the back for me, I am hoping I can use one of the mounts that come with the dial, or going with the rod mount like yours.
Thanks

 

[ClassCat]

Is that the measurement you want ?

 

[Booger68]

Almost, end of needle like you are doing to to the edge of the mounting dove tail, where the mounting pins go. Flip gauge over.

 

[ClassCat]

From the center of the pin to the end of the needle ?

 

[Booger68]

 

[Booger68]

Hope this helps, sorry for the confusion.

 

[ClassCat]

Are you Good ?

 

[Booger68]

Yes, you have helped me alot, thanks for your time, also I like your setup.

 

[ClassCat]

Yes, you have helped me alot, thanks for your time, also I like your setup.

I know what you are attempting to do, and it is admirable. I hope it works to your satisfaction. There are tools out there that will accomplish the same thing as you are attempting. Give me a minute and i will show you another idea

 

[ClassCat]

This is the easiest to use. The case spins on a mandrel and the gauge picks up the reading. You can float the case in and out of the mandrel to read different area's.

 

[SteveOak]

has any one ever mounted dial gauge to their wilson trimmer to check concentricity, I think it would work great using the shell holders, I just can’t decide what style gauge to use and mount

You would be adding several opportunities for error, the roundness of the cartridge holder, the roundness of the hole in the cartridge holder, the concentricity of those two, the end-to-end straightness of the cartridge holder outer surface, the end-to-end straightness of the hole in the cartridge hold and the alignment of the hole in the cartridge holder to the alignment of the outer diameter of the cartridge holder throughout it's length.

Many of these errors would be multiplied by the distance from the error to the measuring point.

Are you looking to measure the variation in thickness of the case neck, the run out of the case or concentricity like the bottom example here where the neck could be perfectly round and the case body also be perfectly round but they are offset as in not on the same center?

 

[Booger68]

You would be adding several opportunities for error, the roundness of the cartridge holder, the roundness of the hole in the cartridge holder, the concentricity of those two, the end-to-end straightness of the cartridge holder outer surface, the end-to-end straightness of the hole in the cartridge hold and the alignment of the hole in the cartridge holder to the alignment of the outer diameter of the cartridge holder throughout it's length.

Many of these errors wold be multiplied by the distance from the error to the measuring point.

Are you looking to measure the variation in thickness of the case neck, the run out of the case or concentricity like the bottom example here where the neck could be perfectly round and the case body also be perfectly round but they are offset as in not on the same center?

I have taken all that you have said into consideration, and plan on doing some checking, honestly whats to say that if I bought a concentricity gauge from one of the top makers would it have any of the problems you mentioned.

 

[SteveOak]

I have taken all that you have said into consideration, and plan on doing some checking, honestly whats to say that if I bought a concentricity gauge from one of the top makers would it have any of the problems you mentioned.

Because concentricity gauges from the top makers are based on very different principles than what you were suggesting in your original post and therefore do not have the inherent potential sources for error I cited as being present in your proposed method.

Concentricity gauges from the top makers such as Sinclair or 21st Century are based on a method that is well proven in the machining world, that is "V" blocks and an indicator.

Measurement uncertainty is a science unto itself.