Accurate way to "zero" work inside a vise?

[JJDennon]

I have the program set up to cut where I want. I have set 0,0 to be the lower left hand corner of the work.

How can I zero out the machine so 0,0 is at the lower left hand corner of the machine? I have tried using an edge finder but I can't seem to get it exactly right. I need a really accurate way of doing this.

Here is a drawing

[flyinchips]

Some skill is required. Don't be discouraged that the center finder didn't instantly tell you where the edges are. Go play with it some more. Good skills do not instantly happen. It might take 10 to 15 minutes to locate the edges until you get the hang of it. Here is a link from the Tormach site that might help; <http://www.youtube.com/watch?v=f0od-cp_9dg&feature=youtube_gdata>

You can always throw money at this problem and buy one of these: <probe cnc,cmm | eBay.

Your option.

[JJDennon]

I watched the Tormach video already, but probably didn't calculate the offsets correctly. Is it good practice to find center off the front and side of the vise like I've been doing?

I'll try it again and see if I can get closer.

Some skill is required. Don't be discouraged that the center finder didn't instantly tell you where the edges are. Go play with it some more. Good skills do not instantly happen. It might take 10 to 15 minutes to locate the edges until you get the hang of it. Here is a link from the Tormach site that might help; <http://www.youtube.com/watch?v=f0od-cp_9dg&feature=youtube_gdata>

You can always throw money at this problem and buy one of these: <probe cnc,cmm | eBay.

Your option.

[christinandavid]

Best practice is to come off the fixed jaw for multiple parts. A suitable DTI is my preferred choice for accurate edge-finding.

DP

[JJDennon]

DTI? What is that? The edge finder I have is the standard, non-digital type that has a spring loaded mechanism that will "snap" when the probe reaches the edge.

Looks like this:

Best practice is to come off the fixed jaw for multiple parts. A suitable DTI is my preferred choice for accurate edge-finding.

DP

[christinandavid]

Browse the UK Master Catalog

This style of DTI is extremely versatile.

DP

The edge-finder I used always claimed that the 'light-line' technique (ie bring the edgefinder to the part until you see no light between them) was more accurate than the 'run-off' point for finding an edge. In the end I found both methods to be crap . Depends how good you need it to be I suppose...how much error are we talking about?

DP

[kawazuki]

Best practice is to come off the fixed jaw for multiple parts. A suitable DTI is my preferred choice for accurate edge-finding.
DP

Can you explain the technique as I can figure using the DTI for finding an edge but not centring the spindle with it? How are you determining the DTI offset from spindle c/line? or is it similar to a co-axial indicator?

[JJDennon]

Here is a good video that explains a couple different techniques.

http://www.youtube.com/watch?v=r7-eEj_qq5M&feature=related]Crash Course in Milling: Chapter 5 - Work Locating, by Glacern Machine Tools - YouTube

Can you explain the technique as I can figure using the DTI for finding an edge but not centring the spindle with it? How are you determining the DTI offset from spindle c/line? or is it similar to a co-axial indicator?

[christinandavid]

Can you explain the technique as I can figure using the DTI for finding an edge but not centring the spindle with it? How are you determining the DTI offset from spindle c/line? or is it similar to a co-axial indicator?

The DTI can be used exactly like a coaxial indicator. The DTI offset can be found by clocking a feature of known size. If you only have an edge to go off, clock the edge and set zero. Place a parallel block against the edge and clock it the same - voila, you have found the position of the edge and the offset of your DTI.

DP

Warning, DTIs and multiple rapid moves don't mix....