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Imperial Electronic Edge Finder

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Brian H07/03/2020 14:46:18
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1960 forum posts
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I quite fancy one of these but as my mill and lathe are Imperial, I would like an edge finder to also be imperial. I cannot find any on the usual sites. Any ideas?

Brian

Martin Connelly07/03/2020 15:05:19
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1608 forum posts
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Do you have deep pockets? Edge finder

Martin C

Brian H07/03/2020 15:14:02
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1960 forum posts
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Thanks Martin; they're not that deep.

Brian

not done it yet07/03/2020 15:18:20
5378 forum posts
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deleted

Edited By not done it yet on 07/03/2020 15:19:51

Nick Hughes07/03/2020 15:44:17
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Linear Tools

DC31k07/03/2020 15:46:44
347 forum posts
1 photos

Look on Zoro for:

4200-520 Linear Electronic Edge Finder

Zoro also have imperial shank manual ones, but not details on tip diameter (and overall length is given in metric!).

For example:

https://www.zoro.co.uk/shop/hand-tools/centre-finders/double-edge-finder-0-500inch-body/p/ZT1002024X

[Edited to say that Zoro's offering is the same as Linear (Chronos) but twice the price!]

Edited By DC31k on 07/03/2020 15:49:32

Bandersnatch07/03/2020 16:35:28
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I have one (actually 2) of these which are not an arm and/or leg in price. Similar items ought to be available in the UK.

I have to say though that I'm not really enamoured of this type. I find them a bit unforgiving since there is no compliance in the tip and if (when?) you accidentally run it in hard, the accuracy becomes questionable from that point.

I much prefer the displaceable ball ended type. I got mine from China (eBay) and it seems suitably accurate. I doubt that you'd get an Imperial one there though. I too work in inches but I have a note of the ball radius converted to inches and it doesn't bother me. It's just not a whole number that's all .... does mean you need a calculator handy though.

martin perman07/03/2020 17:13:51
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1922 forum posts
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Gentlemen,

How do these probes work, does the small dia pin/ball move when it touches the job or is it just a circuit thats created to switch on a light.

Martin P

Michael Gilligan07/03/2020 18:01:51
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17018 forum posts
756 photos
Posted by Nick Hughes on 07/03/2020 15:44:17:

Linear Tools

.

Interesting to compare the specs, and prices, of the two items shown on that page dont know

MichaelG.

Martin Connelly07/03/2020 18:17:03
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1608 forum posts
176 photos

Martin P, the giveaway in the Linear tools offerings specs is that they work on electrically conductive material. No good with plastics or wood and no good if you do not have continuity between the spindle and machine bed (or a suitable cable to ensure this).

Martin C

Forgot painted surfaces also stop them from working. 

Edited By Martin Connelly on 07/03/2020 18:20:40

Roger Vane07/03/2020 18:21:55
100 forum posts
18 photos

Brian

I had an imperial edge finder with a fixed probe and which used a 12-volt battery and filament bulb. As happens with these things, a heavy over-run led to concerns about accuracy. I then searched the market for an edge finder with a ball-end which could be displaced and then return to position in the case of an over-run. They were certainly available at the time, but with body diameters of either 20mm or 32mm they were far too large for my use.

So, I started to develop my own with a ball ended probe, initially using a 12-volt battery and a filament bulb. Although it worked, I soon became frustrated with the poor response and short battery life.

The next stage was to move to using an LED with a flat cell battery, and I’ve found it very responsive in use with good repeatability.

The design has a 1/2” diameter body and a 1/4” diameter ball, although the ball diameter can be changed within reason if you can find a ball of the correct diameter.

I have written it up as an article, complete with detailed drawings and Neil has it in the queue for publication in MEW, so if you can afford to wait for a while then making your own could be an option.

Martin

The edge finder works by completing an electrical circuit when the probe touches the workpiece. That circuit goes from the probe, through the workpiece and machine back to the probe, and as long as everything in the circuit is electrically conductive then the edge finder lights up.

Bandersnatch07/03/2020 18:29:26
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1719 forum posts
60 photos
Posted by Martin Connelly on 07/03/2020 18:17:03:

Martin P, the giveaway in the Linear tools offerings specs is that they work on electrically conductive material. No good with plastics or wood and no good if you do not have continuity between the spindle and machine bed (or a suitable cable to ensure this).



... and the giveaway in this thread is in the "Electronic" of the title. wink

As far as not being able to use them on non conducting material, a little ingenuity can help. For example a jumper lead clipped to a feeler gauge and suitably connected can give an electrical path .... an appropriate positional correction then being made.

JasonB07/03/2020 18:33:34
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I've used a PEC brand one that looks a dead ringer for the cheaper linea offering for about 12years now and it does for me. MSC used to do them but can be had from the US Not had an issue using them with plastics and other non conductive materials, just needs a bit of lateral thinking.

Edit This is the PEC one I have

Edited By JasonB on 07/03/2020 19:07:33

Bandersnatch07/03/2020 18:46:34
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1719 forum posts
60 photos

Posted by Roger Vane on 07/03/2020 18:21:55:

.... I then searched the market for an edge finder with a ball-end which could be displaced and then return to position in the case of an over-run. They were certainly available at the time, but with body diameters of either 20mm or 32mm they were far too large for my use.



I found the same thing when I got mine some years ago but, since i have an ER32 setup on my mill, 20 mm wasn't a problem. I see some are showing up now at 16 mm. The body diameter may constrain the battery that can be accommodated though and it might end up being "special" (I have no knowledge of that one way or the other).

The other thing about my ball-ended edge finder is that, in addition to lighting up on contact it also audibly beeps which can be very handy in some circumstances. I wouldn't want to be without that feature now.

martin perman07/03/2020 19:30:26
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1922 forum posts
81 photos

Thank you gentlemen,

I know have an idea brewing.

Martin P

Brian H09/03/2020 15:11:42
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1960 forum posts
108 photos

Many thanks for the suggestions, now it's make your mind up time!

Brian

Andrew Johnston09/03/2020 15:17:01
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5828 forum posts
662 photos

Have you considered one of these:

haimer_zero.jpg

Although the ball is 4mm diameter one simply moves the ball until the dial reads zero, so whether the mill is metric or imperial is unimportant.

Andrew

Clive Foster09/03/2020 16:13:42
2530 forum posts
82 photos

Nice though Andrews Haimer is the price does rather take deep pockets into submarine test tank territory!

I picked mine up for about £100 some years ago and have yet to pluck up the courage to use it. Too many horror stories about the cost of and ease of breaking of the (relatively) fragile ceramic stem that (usually) protects the internals from damage if you have an oopsie moment.

I find the Huffam "probe walks off to the side" edge finder works well for me and, in conjunction with a DRO system, has a reliable errors of rather less than a thou' when used with appropriate care. The inexpensive versions that come as a set with walk to the side probes, sharp point probe and indicator holder tend to be both insensitive and rather hit and miss. Presumably down to frictional variations in the collet depending on how tightly it is adjusted or its lubrication state. The Huffam has a spring loaded nylon cylinder to locate the probe on a polished, fixed, seat so friction is both low and consistent.

My cheap set has the sharp point permanently fitted and is very useful for picking up the intersections of layout lines and similar. Well worth the fiver it cost for that job alone.

The Haimer Taster turned up on E-Bay the day after I'd struggled with a tricky set up which didn't really have room for the Huffam to walk. Bought on the rebound really as I've yet to have another job with similar Danger UXB frustration levels.

Clive

Edited By Clive Foster on 09/03/2020 16:14:02

Andrew Johnston09/03/2020 20:51:10
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5828 forum posts
662 photos
Posted by Clive Foster on 09/03/2020 16:13:42:

Too many horror stories about the cost of and ease of breaking of the (relatively) fragile ceramic stem that (usually) protects the internals from damage if you have an oopsie moment.

Been there, done that. Twice over the years. embarrassed

Lesson learnt, if I get in a tizzy go and have a cup of tea rather than keep rushing to get the job done. The client will just have to wait! Mind you one needs to wind the handle quite a long way in the wrong direction to break the stem. And I do use the Haimer most times I set something up on the manual and CNC mills.

Andrew

Brian H10/03/2020 08:10:54
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1960 forum posts
108 photos

Thanks to all for the answers but I've found the ideal thing; from Linear/Chronos, Electronic Edge Finder – Linear Code: 4200-520

Brian

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