Metric Wiggler Set.
|609 forum posts|
As it says above, "do they exist?". They all seem to be imperial.
|Clive Foster||09/05/2022 12:50:16|
|3135 forum posts|
Huffam "wiggler style" edge finders come in both metric and imperial.
Zoro sell them, as do others.
Not cheap but by far the best due to having a lightly spring loaded nylon plunger holding the pivot ball against a narrow seat. Much lower friction than the collet used in the economy range devices.
Economy range collet is great for holding the sharp pin securely to pick up lines.
Edited By Clive Foster on 09/05/2022 12:51:33
|376 forum posts|
Starrett wiggler/center-finder set is imperial. Ball diameter 0.250", disc contact 0.100".
Edited By Weary on 09/05/2022 12:55:50
8691 forum posts
My preferred edge finder has a 10mm shank and a 4mm probe; perfect for my metric mill#s 2mm per turn. An Imperial edge-finder on this machine would be a right pain!
I own a Soba Wriggler set which has a 10mm shank and imperial diameter probes - 0.25 and 0.1". Seemed like a good idea at the time but in practice only the needle has ever been used because metric and imperial points are identical. I actually prefer a dressmaker's pin mounted on a blob of plasticine because it can be stuck on the end of the actual cutter or drill without having to faff about with a real wriggler at all. And the pin having a sharper point makes it more accurate, though my poor old eyes need a loupe.
Working in Imperial is easy once a metric mill has been zeroed with a metric end-finder; I just set the DRO into Imperial and follow it's measurements. The inverse is true too, doing metric with an imperial mill. DROs are wonderful.
I suspect most wiggler sets end up in a drawer, whether metric or imperial. Anyone disagree?
|Clive Foster||09/05/2022 14:03:35|
|3135 forum posts|
Dave is probably right in saying that most wriggler sets end up in drawers.
But most wiggler sets are the collet held style which vary from total crap at the very cheapest E-Bay, Amazon, AiBaba end to sort of OK on a good day in the case of the over-priced Starrett and similar name brand versions.
The fundamental issue is excess friction in the holding collet. This demands a relatively large step over before the wiggler walks sideways. Its also pretty much impossible to repeatably set the collet grip sufficiently closely to get the same offset each time. So you can't simply calibrate it out. Which makes them pretty much useless when used as intended to detect a single edge.
If you have a high end version, eg Starrett, they may well be long term repeatable if you don't change the tip but the lower end aren't. My Draper set became a drawer queen for that reason.
I does depend on what accuracy you need. Mr Huffam states "for work where positioning accuracy of the order of 0.001" is adequate" and means it. I can live with that. Errors of 0.005" to 0.010". Fergedditt.
With a DRO you can work off both sides to determine the centre thus cancelling out most variation. By no means "silk purse from sows ear" but maybe "coarse sandpaper to hessian sack"!
My Huffams are silly accurate when used on opposite sides to determine centre. Down in the couple of tenths of a thou variation range. I imagine DRO, scale mount and general machine errors have more to say about that than the inherent performance of the Huffam. They are accurate to maybe half a thou, or possibly a bit less when I'm on a good day, in single sided mode. Surface friction, rotation speed and general operator performance at noticing when its just starting to move rather than waiting for a full walk are important in determining exactly what the error will be.
The old Draper manages to find centre to within a couple of thou if carefully used in side to side mode. In single sided mode better than 10 thou, maybe pushing towards 5 thou error is about as good as I can reliably expect.
Been meaning to scare out a clear day or so to analyse the repeatable accuracy of the Draper, Huffam and Hamier 3D Taster as compared to the conventional cylindrical edge finder. There are a couple of Heidenhain nanometer sensitive optical probes and readouts in the cupboard which might be good enough to resolve the issue.
Best thing to do with a cheap set is to make a new body with a narrow seat and spring loaded pusher for the swivel ball. Geo. H Thomas did a design back in the day which could easily be modified or take a root through my photo album for a disassembled Huffam to use as inspiration.
Edited By Clive Foster on 09/05/2022 14:06:52
Edited By Clive Foster on 09/05/2022 14:15:28
|John MC||09/05/2022 15:40:58|
376 forum posts
I use my wigglers frequently. they live by my drilling that has an X-Y table with an old "Ortec" DRO. With this set up I rarely bother to mark out now, if I do then its with a pencil or fine felt tip pen so I know I'm in the right "ball park".
The two wigglers I use are a Starrett that has a1/4" ball and the other is a Vertex with a 4mm and 10mm cylinder. The ball and the 10mm cylinder are accurate to a thou with suitable care, the 4mm cylinder is not so good, no better then 3 - 4 thou.
22749 forum posts
I tend to use mine on the CNC as it is more forgiving to jogging errors or simply using rapid when you meant to jog The point is also handy and less hassle than using a sticky pin. I think it was Soba but had it so long I can't remember
As I mostly work with the ctr of the work as my datum I find one edge and zero then the other edge and half the reading so any error due to it flicking off late is cancelled out.
As for metric or imperial I actually use a 0.2" electronic finder all the time on the manual mill and it's no problem to enter 0.1 or 2.54 depending on what I have the DRO set in at the time if I am working to a single edge. Wobble is 1/4" ball so again easy enough to enter 0.125 or 3.175
|bernard towers||09/05/2022 17:04:17|
|618 forum posts|
I am a fan of Starrett tools but the Wiggler I got from them was definitely a tea break job, the collet closing nut was so out of spec that you could push it uo and down the threads if you didn't have a probe fitted. Just for 5he hell of it I made a new one and hardened and blacked it. Totally different tool now and nice to use.
|David-Clark 1||09/05/2022 17:44:32|
220 forum posts
I used the parrslel shank Metric ones for years. Not used a real wobbler since I helped build the ark.
|Nigel Graham 2||16/05/2022 22:44:20|
|2133 forum posts|
Do I detect a non-sequiteur above?
I use a wiggler when I want the milled features to be as accurate as I can make them from the edge, whether I use the DRO or the handwheel dials.
The wiggler is only for finding the edge, but if you've an Imperial probe and intending to work in mm, it's no trouble either to measure the probe in mm and work to that, or to set the edge imperially then switch a DRO from inch to mm.
I must admit I've never used the double-edge technique Jason describes, but this is because I normally relate the holes etc primarily to each other rather than an edge, where the distance from that is not critical within sensible limits for the purpose. However, I do take two or three "wiggles" and go by their mean value: the variation is generally within 0005" .
In some situations I locate the work against a stop or fence that prevents using the wiggler on the work-piece itself. In this case, to keep winding the table in the same direction, I clamp a small parallel to the exposed area of the fence face, above the work, and "wiggle" to that as a proxy for the work face.
|Howard Lewis||17/05/2022 09:46:05|
|6104 forum posts|
YES they do, or at least hybrids.
My Soba wiggler turned out to have a cylindrical probe, 0.100" diameter but a 6 mm ball! (Obviously a cock up )
Until I realised this, errors aplenty. Now, just have to remember whether to allow 0.050" or 0.118"
1152 forum posts
Yes metric edge finders are available, Starrett do one but not a wiggler, personally I don't like wigglers, sometimes use the pin & plasticine as Dave [SOD] says but much prefer the ones shown here. The magnetic type suit either system, mine is a Hauser but there are other brands.
Or use the age old method [ 2nd photo] of a spigot and slip gauge, this could be either imperial or metric. As with all tools if you want accuracy it will cost !
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