Where can I buy an individual Starrett 167M-1/2 Radius Gauge, 0.5mm

OK that IS embarrassing. I miss-read the direction of travel in their 01Jan message.
I am new to this game. Don't shoot me.
 

Edited By John Smith 47 on 05/01/2022 10:28:10

Back to the question.

I've thought about this and I'm not sure I'm ready to pay £30 for something that will be slightly irritating for the rest of time because it isn't metric.

Also, having never used them before, it may be that none of them turn out to be all that useful in the quite way I had anticipated. So, with the greatest respect, as per my original question I think I want to start with just buying
- just ONE gauge,
- metric,
- 0.5mm or less
- sub £15....

[Explanation: I only want it for checking the circularity of my fillets, as I now have that Insize "Digital Chamfer Gage", in my hands to measure sizes. ]

As an aside, I wondered what differences there might be between the Starrett gauge and the ArcEuro offerings.

This ArcEuro example is a tidied up stamping I think, probably made from an ordinary carbon tool-steel (hard but not rust-proof.)

The minimum radius is 1mm and there's only one form per gauge. The tool isn't particularly robust, and the radii might not be particularly accurate. (No surprise if the 7mm male leaf didn't exactly match the 7mm female leaf at all points.)

In contrast, the Starratt gauge is much more solid, goes down below R1.0mm and each has 5 radii on a handy 'L'. Though Starratt don't specify it's accuracy, I suspect the gauge is precision ground: the radii are all very similar, the edges are reliably straight, and the right angles are gauge close to 90°. I expect it's made of the hard long-lasting stainless steel used to make knives, and would resist wear and corrosion.

Of the two, the ArcEuro is exactly the sort of 'good enough' tool I'd buy if I needed a radius gauge for ordinary purposes. I'd need a special reason to cough up for a Starrett, but wouldn't hesitate to find the money it was really required.

Dave

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… and if I needed one, I would consider the expense trivial

So … it’s expensive but reasonably-priced

[ what a lovely language we are blessed-with ]

MichaelG.

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Dave

May I suggest that you look at the ARC product which Jason linked on the other thread

MichaelG.

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Have you stopped to consider

• what number of positions along each ‘fillet’ you will want to check
• what pass/fail criterion you will be using

MichaelG.

"Don't shoot me" Personally I would be disinclined to waste the shot and certainly wouldn't be willing to do the time.

Robert Butler

I would have gone with good value.

Another thing to consider when you need such a tool is how much time you spent looking for one and obsessing about its features and involving other people in the process. Anyone who has actually bought stuff for use will know that finding one in the first catalogue you looked at, for a price that's within the budget is ordered and you move onto the next piece of work. Often the hardest part of sourcing stuff is knowing what it's actually called: one of our service engineers was always asking for parts 'like that, but with a bigger flip on the other side. In green'.

With a digital measuring device that is good for +- 0.06mm I don't see why you are bothered by an imperial gauge that will only be 0.008mm out from 0.5mm

Dave, why not compare the gauges I linked to which are dead ringers for the Starret L shaped ones So have all the features the OP wants wanted

All good points.

All I will add re quality is that about year or so ago, I bought some extremely expensive callipers from Starrett and I was NOT very impressed with the quality. From memory they had some sharp edges in the hand that one wouldn't expect at that price point, but worse, I had to adapt them to make them meet correctly.
==> Despite their high prices, not everything Starrett is of premium quality. 
 

Yes. I shall be assuming that my whatever 'non-circularities' each of my deburring wheels (I have 2 to choose between) are creating, is scaling at least roughly. And then I shall use my new Insize Chamfer Gage that was the fruit of the other thread to take multiple indicative measurements.

Quite dinky. Nice piece of kit. Returns to zero perfectly so far.

In the nicest possible way, the pass/fail criteria about a balance of complex competing ergonomic issues that would be too complex to go into here.

J

Edited By John Smith 47 on 05/01/2022 11:27:02

Dear Robert, this is a free country and nobody is compelling to read this thread, so if this thread is not of interest to you personally, in the nicest possible way, please do not waste your precious life reading it.

Typical! When I looked at Arc's website rather than following your link, I missed those. Sackcloth and ashes again...

Dave

John, just be wary of the readings; as far as I can work out, it's a chamfer gauge.
i.e. it will give a consistent reading for a 45° flat chamfer.

Effectively, the chamfer is a tangent to a circle's radius.
So consider that chamfer/tangent as at a mid point spanning 0° arc of a circle.
The gauge will give the same reading from a full flat chamfer to a 90° arc of a circle, as it relies on one point of contact.

Yes it will give an indication, but only if you are sure that your radiused edge is a full 90° of arc.

Bill

All noted. It is of course a compromise.

While we are here, can anyone tell me how to convert a 45° chamfer measurement into a fillet arc (albeit one that assumes a 90° circular arc), in mm units if that's important?

I've been trying to work out if the geometry and whether there is a simple number I need to multiply the chamfer measurements by, or whether it's more complacted that that.

J

I am finding these threads awefully fascinating and am amazed by the tenacity shown by some of the contributors.

Years ago I bought a set of the Starrett radius gauges on eBay for a small sum, Small sum because the set had the 4 mm gauge missing. I have used the set quite often and frequently missed having that 4mm gauge. Michael's link has spurred me into buying a 4 mm gauge from the Starrett website. I was very pleased to find that the 4 mm size gauge was little more thah half the cost of the very small one. Thanks for the link Michael.

R od

Multiply the reading on the calliper by 1.7070789 and you will be quite close to your radius, better if you have more characters on your calculator display.

This will work with both metric or imperial readings

If you do end up buying the Starret 0.5 gage it would be interesting to know what reading the callipers show, should be 0.29mm or more accurately 0.0292893mm

Edited By JasonB on 05/01/2022 19:01:02

Yes, I did a digital sketch and multiplying by "1.7070789" does work (to within the accuracy of my drawing).
Out of interest, what is the equation for it? Where did it come from?

I just drew it out in CAD. First did the 1mm radius and then a line tangent to that at 45 degrees and took the 0.586 dimension from that. It is then just the reciprical of that (1/0.586) to get the multiplier of 1.707

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You’re welcome, Rod

May I ask a small favour in return ?

… When it arrives, could you please post some close-up images of it.

As you will see from the thread I started this evening … I am interested to know by what method they are made.

Some ‘forensic photography’ might provide the evidence.

MichaelG.

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Ref: https://www.model-engineer.co.uk/forums/postings.asp?th=176415&p=1

Edited By Michael Gilligan on 05/01/2022 21:57:32

Michael. I am not very equipped or expert at forensic photographs.

If you send me a PM with your postal address I will send you the gauge ( when it arrives) and you can analyse/ photograph/ post and tell us what you find, and then return the gauge in due course.( it's a bit cold in my workshop for doing fiddly things at the moment.)

Rod