Wiggler, wobbler or something else?

What do you use for edge finding?

Edge finder

I use an electrinic PEC one rather than a wobbly one.

One of these (type (D).

Thor

I have a home made electronic one which either connects to the probe input of my CNC mill controller for auto aligning or I use it with a multimeter on the smallest ohms range which also has a buzzer function. I also have a couple of mechanical ones, which one I pick up tends to depend on what size collet is in the mill.

An old fashioned cylinder on a wiggly stick edge finder.

Jason,

What is the diameter of the shank on your PEC edge finder? I have ER25 collets and the biggest collet is 16mm.

Mike

Somewhere I've got a wiggler set, but don't use it.

For non-accurate stuff I just line the tool up on the edge by eye. For quick 'n' dirty alignment I use a fag paper, lightly trapping it between tool and work. For accurate alignment I use this:

And for centring on round features this:

Andrew

Mike, it is 1/2" shank with a 0.200" tip fits my 1/2" ER32 collet.

Thanks Jason,

It should also fit an ER 25 collet.

The part number looks like 4200-5??????.

Did you order it from a UK source? I always get hit with extra import duty when I order direct from the USA. Makes things expensive

thanks

Mike

I use one of these from Starrett

Brian

I got mine from J&L here in the UK but they now trade as MSC. They don't show that particular model now but have a couple of ball ended ones, the smaller of the two is the same size.

Will check the model No of mine but looks like 5200 = .500" shank, 0.200" tip

Edit. Quick google for PEC edge finder brings up several options in the UK such as this, bit cheaper than Andrews jobbie which they also sell  They also do the PEC in metric

Edited By JasonB on 05/08/2017 18:39:17

I used the same general type as Jason for several years. The problem (with mine at least) was that the tip had no compliance and eventually I ran it hard onto the side of a part (accidentally of course). I never quite trusted it after that.

Eventually, I bought one of the types with a spring loaded 10mm ball at the end which doesn't really care if you run it into a part. It also has an audible contact signal as well as visual which my other one didn't.

The problem with this kind in your case though, is that it has a 20mm shank and you need an ER32 collet setup to use it ... it was one of the reasons I decided to switch to ER32 (from ER25) on my mill. As far as I know they don't come any smaller.

My Soba wiggler purports to have a 0.250" ball. Mine has a 6mm! But the 0.050" cylinder is 0.050

O K once you find out but mystifying errors until you do.

Howard

Jason and Bander......

Not sure about an edge finder tip with no compliance. Maybe OK with a manual machine where you can feel some resistance. but with a CNC machine there is no such feel, so you could easily make one or two steps too many and before you know it there is a 25Kg side load applied to you shiny new probe. I think I will probably stick with my faithful old cylindrical wobbler for the time being.

Mike

Really it's the other way round. If the electronic one is linked to the CNC controller, using Mach3 there are probe routines that allow you to advance the probe slowly using small steps towards the edge with a tight loop in the software which stops the feed instantly once the probe is triggered. My edge finder is essentially a cylinder with an isolated ring at the end of known diameter and concentric with the shank (all machined at the same setting) and the ring gets grounded when it's edge touches the workpiece edge. I think the "touch" is much gentler than you can routinely achieve manually. It works extremely well.

The alternative is to have a "touch trigger" type probe for which there are a number of home-brew designs around based on the original Renishaw type. These detect the touch point very accurately but allow safe over-travel.

John,

Thanks for that information. I was hoping that Jason's PEC edge finder was based on the Renishaw style of probe.rather than a rigid probe. I will follow up your leads and look into the various DIY touch trigger probes and how they can connect into LinuxCNC

Thanks

Mike

I would expect the Starrett wiggler shown by Brian above is imperial but does anyone know if there are metric versions?

Like Andrew i have a Hamier 3D Taster for really accurate alignment but for normal duties I use the Huffam version of the Starrett wiggler set in Brian's picture. Have both metric and imperial versions which avoids conversion errors or, more correctly, forgetting to switch the DRO system back after using an imperial wiggler on a metric job or vicky versa.

The Huffam set only has ball and cylinder probes so in a sense its less versatile than the Starrett set. But the pivot bearing uses a spring loaded nylon pusher to apply constant, light, pre-load making it more sensitive than the more common Starrett and no name knock off types. Getting down towards ± a teeth of a thou or so if you are careful the machine adequately tight and the surface finish on the target decent. Since getting the Huffams the Hamier barely gets used. It needs to be pretty picky job for the Hamiers better performance to show.

Picked up a no-name version of the Starrett set with my first mill years ago. Its OK but the ball in a collet pivot isn't really reliable below ± a thou or two. Fiddling about with the collet adjustment can help matters but life is too short. I keep it for the needle point. Short of proper spindle mount optical or camera system its the bees thingies for picking up intersecting lines and centre pop marks. Pivot stiffness is an advantage there.

Clive.

Mike T, here is one example.

**LINK**

Hi Mike,

You may have already found this very similar thread from 2012 **LINK**

I have just finished making a Renishaw type touch probe that is a combination of the Shaun Wainright and Wildhorse Innovations designs (see my album):

**LINK**

**LINK**

I cheated and bought the M2 ruby stylus direct from Renishaw (about £20). If you are interested in the design I think it is possible for me make the Fusion 360 files public.

Andrew.