Disk Styli

[[Ri...]]

It seems no one makes disk styli in diameters or thickness that would be beneficial for use. They are all stuck on 1990's dimensions and styles.

The last quote I got for Disk stylus (3 pcs) is quite high in my opinion.

I am looking for three sizes, Ø14mm, Ø20mm and Ø25mm.

These have to be M2 mountable. Attached is a basic sketch I saved from an online Stylus business. I use it as a generic sketch.

From one quote for the Ø25mm size, its $450 each for 3 pcs. I would need three of each size I stated, about $4,000 plus dollars if not more for 9 disk probes. I dont even want to talk about lead time.

Thats very hard to justify. I would have thought by the year 2024 (Approaching 2025) these could be made in 1mm increments easily.

In the 2000's we made Disk probes on a Swiss lathe, editing for diameter was simple.

What other places are there for Disk Styli other than:

Q-Mark, ITP and Carbide Probes?

Edited November 25, 2024

[[Ma...]]

We get ours from ITP, just one size.

In a Google search I see a site for CMM Technology (Metrology Solutions) that appears to have the sizes you are looking for.

I've never used this place before, so I can't comment on the quality, shipping or customer support, but a quick glance at their prices look decent.

[[Ri...]]

Thank you, that link has 2 of the three I could use at significantly lower costs.

[[Je...]]

I tend to agree with you on this one, Rick.  Disk stylii are often used to inspect snap ring grooves and other tight internal features that are not feasible to probe with a standard star stylus system.

This requires them to be thin.  Very thin.

[[Ri...]]

We inspect a large amount of aerospace products; they love grooves in the parts. 

Grooves can be from .080 to however wide and as deep as .400. The disk dimensions I posted are typical of what I have seen throughout my career, and they work on nearly every combination of groove size.

Ø14mm, Ø20mm and Ø25mm ODs on an M2 connector. From this I can use 2mm or 5mm extensions and maintain ample clearance.

Edited December 2, 2024
typo

[[Je...]]

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Interesting, Rick.  That sounds like a challenging task to measure grooves of those dimensions.  Great job on standardizing a set of disk stylii as a toolkit.

Is the stylus material still synthetic ruby or something else?  Would carbide or perhaps some type of thermally stable tool steel work as a disk?  I imagine ruby would be challenging to machine that thin and wide.  Reminds me of Bilbo Baggins' quote in Lord of the Rings.

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[[Mi...]]

We've gone away from discs to mini stars like this, little more compilated to program, doesn't suit every single need, but it does do most for us, also lets you properly measure groove widths and locations, which you can't truly do as correctly using the side of a disc. It also lets us have "disc-type" measurements on XXT machines without doing any sneaky stuff.

M2 thread, 0.5mm ruby, overall diameter is 27.5mm.

Going much smaller would be difficult, larger is easy. We have larger versions with 1mm and 1.5mm rubies and M3 threads. 

 

[[Ri...]]

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I can't recall the steel used, but it is typical with everyone I have purchased from for the last 15 years.

I use only steel and no ruby/steel balls for hooking inner or outer faces.