LAzar egde finder

[ian HoldsworthParticipant @ianholdsworth27760]

Where/ who will sell me a cheap Lazar edge/ centre finder

[Tony Pratt 1Participant @tonypratt1]

Just search for ‘Laser edge finder’ to get multiple hits on various types of edge finder. I’m personally unconvinced of the practicality in using lasers for this purpose.

Tony

[Ches Green UKParticipant @chesgreenuk]

I’ve only ever used the mechanical type (Starrett) edge finder. It does fine for my small, cast model kits.

Here is a good 7 min comparision of Mechanical v Laser (ball end)  ….. Better than a mechanical edge finder? –

TLDR –

Mechanical – cheap (£25 or so), no battery, small (about 100 mm long), accuracy to about 0.025mm (one or two thou”), slightly more difficult to use but still easy enough.

Laser – 5x more expensive, much longer in the Z axis, very accurate and easy to use, less prone to finding burred edges, battery powered.

There are also finders using actual lasers but one has to eyeball where the laser beam falls. Those seem, to me, a bit more hit-or-miss (?) but I have no experience of them.

Ches

Edit: The ‘laser ball end’ I referenced may not actually use a laser…it’s more of an electronic device…but looks interesting nonetheless 😉

[bernard towersParticipant @bernardtowers37738]

you can use your starter one on non metallics but not the electronic one!

[JasonBModerator @jasonb]

Ches, that is just an electronic find. Lights up when it contacts metal and completes the circuit.

He is showing quite a large one, I have a smaller 1/2″ shank PEC brand one which is no bigger than the mechanical one he shows so no downsides. Battery tends to last 5-6 years

Electronic Edge Finders

I just hold a metal block of known size against plastic and that works fine so long as part of the block is touching teh vice jaws, etc.

[Ches Green UKParticipant @chesgreenuk]

Jason,

Yes, I realised after posting it was an electronic one….and it does look interesting at just over £40.

Good to hear the battery lasts so long.

Also, good tip on the ‘metal block’, thanks.

Ches

[HollowpointParticipant @hollowpoint]

SDA laser edge finders occasionally appear on eBay for around £30-40

[Martin ConnellyParticipant @martinconnelly55370]

There are many 3D touch probes available but often with high prices. However the MF60 is worth considering. It depends on your needs but should give an interesting comparison to the PEC one Jason suggests.

Martin C

[duncan webster 1Participant @duncanwebster1]

Unless you’re looking for super accuracy, a bit of round bar in the collet and a bright light behind gets you very close. You have to bounce the light around sometimes.

[John HaineParticipant @johnhaine32865]

This is my version of the “conductive” edge finder. It is made from a length of ground FC stainless steel from a surplus printer, 9.99 mm diameter. I faced off one end and drilled an 8 mm hole to a depth of about 25 mm; then a further 5 mm hole for another 6 mm or so. The latter then tapped M6 and a length of M6 studding screwed in long enough to be just under flush with the end of the hole, and fixed with a dab of loctite in the thread. Then the annulus between the screw and the hole filled with slow set araldite after the whole thing heated on top of the workshop storage heater, so the glue is much less viscous. Left supported in a vertical position on the heater for the bubbles to surface and glue to cure thoroughly. Then very carefully turned a groove in the OD just down to the epoxy to isolate the end 20 mm or so. Small split brass block has a clamp screw and a 4mm hole for a banana plug.

This can be used either on the CNC mill with the block connected to the probe input (active low) or on the VMB using an ohmmeter on the “bleep” resistance range. So far as I can tell it’s dead accurate though obviously limited by collet eccentricity etc. I used this approach to get the active part of the probe exactly coaxial with the shank and make it as robust as possible. Could also be made from silver steel but harder to machine.

[duncan webster 1Participant @duncanwebster1]

What a good idea. Another one for the todo list

[bernard towersParticipant @bernardtowers37738]

I like that.

[Roy VaughnParticipant @royvaughn26060]

The accuracy of the static  ball edge finder depends on its concentricity with the axis of the shank.  How do you check it and has anyone tried?

[Ches Green UKParticipant @chesgreenuk]

static ball edge finder depends on its concentricity

Good point. Maybe take a reading, then rotate edge finder 90 deg and take another reading, and repeat process two more times.

If all 4x readings match then good to go?

Ches

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