[FoxCNC1]

I know this may not be the best place to post this question but its the forums I most frequent.
I just bought a test dial indication since I realize I am a point where I want to be more accurate with my projects and I noticed some run out of my tool today which caused it to break. - ekk. lesson learned.
Anyway:

I saw some tormach videos where the guy is using a test dial to find the center of a hole and the center of a block. However the part that doesn't make sense to me if that the dial indicator is on a pivot arm and he seems to be moving it arbitrarily. Wouldn't you want the TIP of the dial to be in line with the spindle?

I am trying to incorporate the dial to find the corner X0,Y0 of a work piece and be able to repeatedly find it a second time in case I have to etop the machine.

Any help is greatly appreciated.

[stucapco]

Center of a hole, YES, edge or corner of the part, NO! Consider a probe of one one sort or another. Lets assume a half inch solid probe. Find the corners, input the location, allow for the probes radius, IE: in this case (assuming top, right corner), add -.25 to the work offset. Then for repeatability add the radius to positioning. G54 X.25 and a safe Y position. Push the part against it and have a more effective cycle. Am i close? Test dial indication (indicOL?) not for edges.

[bhurts]

Yes I agree with stucapo. You can use a test indicator for finding the center of a circle id or od. Also to square a vise and check for parallel and perpendicular. For finding the edge of a part get a edge finder. There cheap and accurate.

Ben

[stucapco]

What bhurts just said. I have no doubt. In the event I need 50 or more of these parts we're going to need a stronger more reliable setup was my point. You will soon find a box of broken edge finders and electronic probes. Want a box? lol, bhurts knows, yeah "all them? broken, MEH!" Assumes many guy's working on this project.

I've never seen it end any other way.

[daniellyall]

you use test indicators for squiring stuff up finding center of holes is a different tool. get a center finder or a edge probe

[stucapco]

squirrel's work good too! lol, just having fun, no troll intended.

I love this place! Don't stop. We need this place or at least I do.

Thanks guy's, this is great, I have no one else to talk to about this crap.

Worth it.

Hey, how about a funny machining story thread? I have so many...

[FoxCNC1]

Guys thank you for the replies.
I am still a little confused as to how the center if found. This is the video I watched and notice how the indicator is an articulated arm. Is it me, or it is the dial offset for the center of the spindle?
Doesn't that matter?

https://www.youtube.com/watch?v=uqLT_fkiTo0

[FoxCNC1]

here is another video.

https://www.youtube.com/watch?v=PCWctxBseno

[stucapco]

Yes. That's a hole indicator sweep, finds position relative to an established hole. From this point we can relate it to other positions on the work piece. What I thought was in question was the corner or edge position coordinates to find the work piece. I'n which case this is not what you want. Please stay with us and explain as much as you can. We're here to help, If I understood what your goal was it would take seconds to explain. DON'T GIVE UP! Talk to us.

[bhurts]

The dial is offset yes. That is what you are needing to reach the edge of the hole from center. When you spin the spindle by hand anything mounted in it will spin around that center regardless of how it's offset. You want the indicator to read the same all the way around in a circle.

Ben

[FoxCNC1]

I appreciate that. I figured that I could find the corner of a work piece the same way the gentleman on the video found the center of the block.
However, it seem like in every scenario the tip of the dial indicator is offset from underneath the center of the spindle... and this is the part that is confusing me. woun't you want the dials needle to be aligned with the center of the spindle?

[FoxCNC1]

The dial is offset yes. That is what you are needing to reach the edge of the hole from center. When you spin the spindle by hand anything mounted in it will spin around that center regardless of how it's offset. You want the indicator to read the same all the way around in a circle.

Ben

I think you just answered my question. So the "amount" of offset if irrelevant because in the end when the needle is sweeping the holes or circular part, then spindle will be in the center...

okay, what about the second scenario where he is finding the center of the block. I guess it is the same thing.

[daniellyall]

the dial indicator is offset by x amount what the operator will know what it is there are better ways of doing but that works

[stucapco]

Yes, center of spindle. It's absolute relative to the spindle. Now we can move on. Well done guy's!

Side note: get an indicOL, grabs mostly any tool holder, any situation. No need for special setup, what ever's in the spindle will do, quick, easy, cheap. I depend on mine for quick tramming. Soft as butter, just nice.

Luck.

[FoxCNC1]

ekk.... okay.

[FoxCNC1]

hi everyone I bought a test dial indicator, I but I am unsure on how to find the center of A small Circle as in the picture below.

do in always need to use a swivel arm? - I just don't see how I would do that with a small 0.25 Circle . if anyone can please guide me that would be great.

I also bought an edgefinder , however the slowest speed I can run my Bosch notes (spindle) is 8,000 Rpms. It Works well, but I did notice a bit of chatter as I start To touch the edges of the workpiece. Is this normal? does spindle and collet runout affect the accuracy and repeatability of finding the same edge / 0.0 Point twice?

I want to be a able to find the same starting point in case i have a need to hit the estop Which usally makes you loose steps.

[stucapco]

Get an indicOL.(cheap) your way too rigid there. After throw a dowel in it, tram the OD, easier to see, easier to use. However, what your attempting is "doable".

Your on the right track! Keep it up.

[underthetire]

A little more money, but a co-ax indicator is quite handy for picking up holes, as long as you don't need closer than .0005.

[bhurts]

I probably wouldn't run a edge finder at those speeds. If/when it flies apart you could get hurt. As to the arm don't forget it's articulated. It can be adjusted to point straight down or moved offset from center. There are many available options if you have the z travel to use them.

shars.com - Universal Dovetail Indicator Holder

shars.com - 14quot Indicator Holder

shars.com - 14quot Indicator Holder

shars.com - Test Indicator Holder Arm Only


shars.com - Zero Set Universal Attachment

http://www.shars.com/products/view/7...sal_Attachment

Ben

[FoxCNC1]

At what speeds would you guys run your edge finders? It seems the even water cooled spindles don't run much slower.(6K rpms)

Regarding using the test indicator to find the center, if the key to have it on an articulated arm?
I am trying to grasp the concept of if I need to zero it out once I make contact with an edge.