Which edge finder?

[John HaineParticipant @johnhaine32865]

The wiggler type can be prone to 2 problems. One, the spring load on the ball and socket may not be ebough so it may have to be run very slow, which means that the approach has to be very slow too and you can easily overshoot. Two, if the chuck or the work is at all magnetic, it gets very erratic and the tip can jump on to the work and run off before it actually properly touches.

[Clive FosterParticipant @clivefoster55965]

John

I'm surprised that a wiggler can be made with too little friction. Would have thought that to little would make it impossible to true up before starting. I "milk" mine very close to true first, auto-truing by banging off the workpiece on approach is inelegant bodgery.

Certainly all the issues I've seen are due to too much drag on inexpensive ones.

I find the key is to run around 150 – 200 rpm and watch for it to start to crawl sideways.

If you can get at both sides the 1/2 function on a DRO makes high accuracy much easier. I suspect most folk don't fully exploit it.

Magnetic workpieces are an issue with any uncalibrated revolving probe system using a steel probe. Back to dowel, and fag paper or 1 thou feeler stock. On both sides followed by the 1/2 function on the DRO in my case.

Clive

[Phil PParticipant @philp]

A lot of people don't cotton on to the fact that the DRO 1/2 function is also an excellent method for centering round work under the spindle with an edge finder as well as flat sided parts.

I resisted getting a DRO for a long time thinking it was just a gimmick, but once you have one it makes a milling machine so much quicker to set up and use.
Instead of fiddling round for ages trying to locate the work accurately by other antiquated methods, you can have the job set up and finished in a lot less time.

Phil

[John HaineParticipant @johnhaine32865]

Well, at least one of the ones I bought had too little and isn't adjustable. Magnetism doesn't have nearly so much effect with the split cylinder type. Anyway my favourite approach is an electronic type. The one I have made is very robust to be (fairly) resistant to slight overtravel and the method of manufacture ensures good concentricity. Made originally for auto-zeroing the CNC mill but useful on the manual mill too using a "beeper".

I posted on Joe's CNC lathe thread a few details of the system I have on my lathe for tool calibration and stock end finding. This could be fitted to a mill too to sense contact for both height and edge setting without needing a specific probe. Not as precise as a Renishaw but much cheaper and more robust and doesn't eat daylight under the spindle.

[Dave Sawdon 1Participant @davesawdon1]

Thanks for all the replies – more than I'd expected and I now have a few less unknown unknowns . In particular, I hadn't heard of the Huffam type so will look for a good used one to buy. In the meanwhile I'll stick with using the split cylinder type (and occasional paper and pin).

[Henry BrownParticipant @henrybrown95529]

Dave, something to try if you purchase a split cylinder type and have a DRO. I go up to the edge being looked for and when it starts to "go" I zero the DRO, back off and try again a couple of times keeping an eye on the DRO as it counts down until I get a consistent zero adjusting the DRO as necessary. On the second side I do similar making a mental note of the DRO reading as I do a couple of count down checks.

[mechman48Participant @mechman48]

Having received an electronic edge finder this week I searched for any comments on their efficacy & usage hence this post. It seems that there are varying views, &, as others, I have a wiggler set & the disc set which both have seen plenty of use but I am one of those 'nice to have ' guys so went & searched on Ali express & found this one. All the others I have seen have a 20mm shank which is too large for my ER25 collet or drill chuck but this has a 16mm shank which suits fine.

On initial trial it's very sensitive, lights up & gives a 'beep' on contact, which does require a very slow 'creep' to the edge of the object. the ball at the end is 10mm, & is spring loaded should you 'push too far', so you do have a ref. for setting your spindle on edge if you have DRO's . very economical price too compared to some prices.Usual disclaimer applies.

George.

[old martParticipant @oldmart]

I bought a Vertex electronic one years ago, the drawback with it is the 20mm body diameter, ok with R8 collets but a bit big for some machines. There are plenty of cheaper copies on the market at the moment. It has been used at least half a dozen times. I really got comfused when I saw my original post which I had totally forgotten about.

Edited By old mart on 10/06/2021 20:56:29

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