Ideas? Switching collets between mill ends and edgefinders using R8

What's the brand name and model? ERS

But then he has to know the new "virtual diameter" to calculate where the edge is.

Also not so convinced that the EF likes the DinDingDingDing...

Nick

WAIT a minute, Nick! That's how my edge finder WORKS! (even if it's running "true"; don't need no stinkin' lights; just listen for the "DinDingDingDing".)

LLoyd

Greetings Nick, We must be talking about different things. I'm talking about the type of edge finder that has on the end a diameter, usually .200 in the USA, that is separate from the shank and retained by an internal spring. This .200 dia flares out to either .375 or .500 where it contacts the shank. The faces where the two pieces meet are polished. The spindle is turned on and the edge finder is brought up to the work until it touches. It will be running out. As the table is cranked toward the edge finder the .200 dia end will begin to runout less and less until it appears to have no runout. The table is stil cranked in the same direction until the edge finder once again run out. The edge finder is now about .0005" past the edge. With this type of edge finder the runout of the shank doesn't matter as long as it's not too much. The part that contacts will spin with the center of the spindle, not the center of the shank. ERS

I meant the same type.

You are right. Or ... The lower part is pushed to become coaxial with the upper part. Now when both parts are coaxial and you go that tad over the edge, it starts running out. But what does that mean if the EF made 1/2 a turn? Parts are coaxial, but the lower part is no longer in contact with the edge. You would need to go closer to the edge to be in contact again. And that's the excentricity (SP?).

Scratching my head ... Ah! Ignore the upper part and see how the lower part is aligned to the

OK. It works and runout really doesn't matter. It just has to be parallel to the spindle, that's all.

Nick

That's correct Nick. So any stepped adapter needs to be pushed against the collet face to make sure the EF is square to the spindle axis. ERS

Just do one corner on the vise and put that in perm. memory.

Is that still true if the axis if the edge finder is not parallel to the spindle axis? I recall having some problems a while back with hole location accuracy when the edge finder was used in a drill chuck on my mill. Using a collet to hold the edge finder seemed to improve the accuracy. It could have had more to do with mill tram, though.

Mike

O.K. That illustration must be of the other size. It does not look right for a 0.250" shank and a diagonal across the hex of 0.200". (Is it hex, or octagonal? It is hard to be sure, given the angle of view.)

Note that the 3/8" version of that has an ad for the collet step adaptor shown in the upper right corner -- but for 3/8" shank only. And it *will* fit into a 1/4" collet among others.

Thanks, DoN.

Greetings Mike, If the edge finder is not parallel with the spindle axis it will not be as accurate. But having the mill out of tram will make a bigger difference. If out 1 degree (and that's a lot) there will be an error of approximately .017" per inch. Since the quill is much longer than the edge finder it will add much more error than the edge finder will. If the edge finder was out 1 degree it would wobble like crazy so you would be sure to see it. ERS

The sensor end is a cylinder with one flat. It looks exactly like the three we have at school. 1/2 in. body, .200 dia sensor. ...lew...

Hmm? I use an edge finder quite often on my CNC mill. I don't use it a "lot", however. With just a little thinking ahead of time as to what to use as the reference edge for a particular setup, I can usually get away with only one installation of the edgefinder per day. Of course, if a screw-up happens, like I bump the vise out of position, then I have to reset my coordinates again. I can use the vise jaws, or a "work stop" that clamps to the table, or a tiny little one that clips onto the fixed vise jaw, and then repeatably place workpieces on the machine. So, I only need to find the edges on the first part.

The "thniking ahead" part allows me to use a reference edge that will position all the parts I'll be doing that day from the same reference.

Jon