Gauge Threads (type) And Carbon Brush Sourcing

c60 said:
I want to make a couple of extended stems for my gauge (Or Gage if you prefer). It is just a bog standard Mitutoyo 0-10mm analog. As I don't have a thread gauge can anyone please confirm the cap screw is 4-48 UNF before I splash out on a tap? A longer solid stem at 6mm and 8mm collet compatible would make tramming and also finding TDC on rounds easier. Better still I guess would be a shiny new (cheap) gauge for purpose.
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Can you get your hands on any old random screw of 4-48 persuasion? That would let you verify the thread quickly and easily.

If not, you can probably be pretty safe in assuming it's 4-48 anyway. That seems to be more or less a worldwide standard. The only exception I've seen is an older Mahr Zentimess indicator I have that uses 3.5mm x 0.45mm threads. Just in case you're wondering, the OD of 4-48 threads is 0.111", and that of 3.5 x 0.45mm is 0.095" (I bought an adapter from a local dealer, so I have both handy).
 
brino said:
@c60,

Unfortunately, there are no direct "drop-in" replacements in that bunch.
However, there may three possibilities for you if you're willing to do some modifications.

View attachment 127074

View attachment 127075

View attachment 127076
those last ones are actually two thin brushes in a bundle, the two wires go thru one spring.

Let me know if you think you can make any of those work for you.

-brino
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Your effort much appreciated there Brino. I think all 3 would mean me removing the spring and wires and reattaching the ones from the original brushes. The problem I've got with the originals are twofold.
1) Uneven wear between the two , that could of course be down to just one having been replaced by previous owner. Knowing him I doubt that. Maybe a spring is catching somehow and not giving even pressure.
2) The wires coming away from the carbon. I've got the longer brush of the pair reattached to the wire by a small blob of epoxy ATM. Not down the hole enough to cause insulation of course. Wire replacement puts me right back in the same boat.

If it is alright I'll shout if I get no other option. Thanks again.
 
hman said:
Can you get your hands on any old random screw of 4-48 persuasion? That would let you verify the thread quickly and easily.

If not, you can probably be pretty safe in assuming it's 4-48 anyway. That seems to be more or less a worldwide standard. The only exception I've seen is an older Mahr Zentimess indicator I have that uses 3.5mm x 0.45mm threads. Just in case you're wondering, the OD of 4-48 threads is 0.111", and that of 3.5 x 0.45mm is 0.095" (I bought an adapter from a local dealer, so I have both handy).
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That is a thought. I may be able to see if my local unified fixings branch can do a screw measurement for me. There is always a big queue but they are usually pretty helpful once at the desk. I'll get the gauge on this too at least for OD now you've posted the numbers too.

I've just bought a heap of nuts and bolts (bought the parts boxes and the contents were obligatory takeaway!) a cwt or more I think mostly stainless and the ONLY imperial I can find are 3/8 unc nuts, rest are metrics.
 
I think I've made a massive error here, the thread is absolutely not 4-48. I was just about to order a tap when I noticed the recommended pre-drill was 2.3mm. No way can that be right for the dial thread in discussion. I've gauged the outside of the thread as best I can, it isn't that easy to angle onto, and reckon OD is near 7.23- 7.25mm . The original impression came from a reference for Mitutoyo specs on Amazon. I think maybe the original info I got is not referring to this particular screw I wish to use on the gauge. I'll add a photo later.
 
Model number is:- 2046S SYB638
Just been down to my local engineering suppliers. They have display cases full of meters and gauges in this brand. They were very helpful in trying a thread gauge. No luck as it is finer than their 42tpi gauge he thinks, though with so few turns it isn't easy. Reckons the Australian Distributors will not be any use (there isn't a service centre here) and are not good to deal with anyway. A call he did make elsewhere came up empty.

Thread size I'm after is that one that holds the dust cap in place. NOT the one for the tip. My next step is to email one of the US service centres.

_MG_5485.jpg _MG_5488.jpg _MG_5490.jpg
 
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I found a CAD drawing of the indicator, but it is the entire gage only, no components. https://www.mitutoyo.co.jp/eng/products/dialgauge/dialgauge.html. No idea on the pitch. It's going to be Metric, almost positively.

Since you have the cap off, what is the minor diameter of that thread? You might be able to make an educated guess from that. Since you can access the male thread stub, you should be able to get a over-wire reading also.

Just FYI, the tip thread is a m2.5-0.45 if it is not 4-48. Those are the only 2 options available on that model.

Ref links:

https://www.mitutoyo.co.jp/eng/products/dialgauge/dialgauge.html

https://www.mitutoyo.co.jp/eng/useful/catalog-2014/index.html#page=337

https://www.mitutoyo.co.jp/eng/products/dialgauge/pdf/dial.htm
 
Cheers Tony. I have emailed the Asia Pacific service centre. The OD I reckon is a tad over 7mm ( I got 7.23 without my glasses on and the shop got 7.15) and the cap came out at id 6.8 ish. That would suggest a 7mm. For the pitch I turned cap out by 3 turns with a 2nd Gauge above, that seems,- with a lot of inaccuracy due to push on the thread and some side slop to give around 60 tpi, - that seems way too fine to be right. Wasn't familiar with over wire reading but have now looked it up. I'm fairly confident Mitutoyo will give out the info, just a matter of email hitting the right desk.

The CAD drawings are neat. Pity they don't contain the details. That catalog is tantalizingly close to giving the info.

2046s nearly.JPG
 
Just got a reply from Mitutoyo UK.
Thread size for anyone else thinking of using this is - M7.4x0.5

No clue atm where I'd find tap and die for that.
 
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