Moore & Wright disaster

Yes indeed! Thank You!! I will check or they accept Paypal and when they do order 2 of those!

Hope, they can be recharged with the regular charger.

Hi Paul,

Given the vintage of the calipers the original cells are probably NiCad rather than NiMH.

If the charger uses some fancy end charge detection it may or may not work well and this could reduce battery life as the parameters are slightly different and NiCads are more tolerant of abuse.

In all probability in this application it's probably just a 1/10C continual trickle charge (17)mA or less. There would be no adverse effect of continually charging a 250mAH NiMH at this rate, it would just take proportionally longer to give a full charge.

Neil

I have a M&W 2000 micrometer in perfect working order apart from the battery.

Batteries are a difficult problem to solve for this device, The original size of NiCad (or NiMh) button cells are no no longer manufactured. Because of the housing construction there is no room for anything larger in diameter, its one of those cases where you can't just squeeze something even a little bit bigger in!

Off hand I don't remember the exact diameter (22.6mm maybe) or the A/h rating but using much smaller diameter button cells will probably mean the existing charger is too high a current to leave connected.

I made a replacement battery pack using four cylindrical cells that I removed from a rechargeable PP3 battery. Again I don't remember what rating the PP3 was but it does work in my micrometer. Because the PP3 I used was old (and not been kept charged up for more than 8 years!) it will only power the micrometer for about one hour. I intend to purchase a new PP3 and rebuild the pack.

You can just make out the 4 cells in the bit of plastic packaging I used to make the casing. I have no idea why the picture is head over heels (its fine on my PC and I've done this image the same as all others I upload) but I assume it this site software!

Ian

Hi Paul,
If you don't mind shorter battery life and having to modify the charger to reduce the charging current you can buy some solar powered fence lights in "Pound World" They have a cell in them that is 12 mm dia. and about 6mm thick. I bought some of these to repair some plug in timers. I would guess that these would only give about one quarter of the capacity of the originals. I bought mine at Birchwood near Warrington but I expect other branches have them. It may be worth looking at some of the other solar powered garden lights to see if they have a more suitable size cell.

Les.

Les

The charger that came with my micrometer is a sealed (13A plug type) transformer unit so would definitely not be easy to alter its constant current output. The other complication is that the charge connector is a proprietary design and moulded on the end of the cable. The cable and connector though could be salvaged and put on a more suitable charger.

Ian

.

Neil,

The link that I posted earlier gave me some confidence that NiMH would be O.K.

... but I may have misinterpreted

[if so, then even with a new charger, what I suggested looks a good bet]

MichaelG.

[quote]

Posted by Michael Gilligan on 30/07/2014 23:58:08:

Sit down and breathe deeply ... then look here

Edited By Michael Gilligan on 31/07/2014 20:57:11

I have just had a look on Ebay for "nimh button cells" I found this item which might do the job if you don't mind modifying things. You would need two as these are only 3 cells. Googling the part number I found another seller that lists the dimensions as 21mm x 45mm x 11mm. This would suggest that the cells are very close to the size of your original cells.

Les.

Les

That's a good find!

I have just measure the original NiCad and its larger than I remembered at 25.5 diameter x 26.5 Long.

I am now thinking of buying 2 of those packs to get the four cells needed, if anyone else is doing the same we should get together and make a third pack with the spare cells as its a waste otherwise. (PM's in order here)

Ian

Hi Ian,
I misread the dimensions. They are in cm not mm so I do not think they are correct. I would hold on until we can confirm the dimensions.

Les.

Hi Ian,
From your dimensions your pack looks like a single stack of 4 cells. The one Paul describes is 2 packs of 2 cells. Two of these from Farnell might do but they are about 0.4 mm thicker than the ones Paul has.

Ignore this post these are the ones Michael found earlier.

Les.

Edited By Les Jones 1 on 31/07/2014 21:51:06

Les,

Deja Vu

MichaelG.

.

Edit: Cheers, Les

Edited By Michael Gilligan on 31/07/2014 21:53:40

The width and height measurements on the Farnell site are a bit confusing. It was a battery I discounted because of the 26mm dimension although I now think that it might be it includes the PCB pins.

If the diameter is OK I think the extra 0.8mm height could be catered for so I will investigate.

Ian

Ian,

As I mentioned to Paul, earlier ... the DataSheet [linked on the Farnell page] shows the detailed dimensions of the individual cell.

MichaelG.

Edited By Michael Gilligan on 31/07/2014 22:13:45

Thanks to all of you for the overwhelming responses and help!

I think, there is enough room for the 0,8mm extra hight and the diameter of 25,2 mm was measured from the dead cell including crimp foil I took out of the micrometer, think, even 26 or 27 mm will fit in the battery compartment.

Unfortunately Farnell does not accept Paypal, so I will have to look ok Ebay to get a 3+1 stack to get the needed 4,8 Volts. What I know from experience is that not only there voltage must match, also the amount of AH must be in line to avoid an explosion of a cell. I had this problem some years a goo with a rechargeable flashlight and it exploded right in my hands when I switched it on and it did cost me over 75% of the use of my right thumb, stiff and no feel in it anymore.

Slightly off-topic, but you guys with Classic digital micrometers might apprciate these.

[of course they are only "digital" in the human interface]

MichaelG.

Stub Mandrel Neil,

Snap!

Had this happen after cleaning using molasses then paraffin. As yours, a gentle 'ping' and it fell apart.

Snap again!

My welding would do far more damage than fix.

Geoff - Feeling so much better after 40 winks in armchair. What can I say!

Hi Peter,
I think Geoff is just getting the thread back to the original topic of the broken spring. It was Neil that had this problem at the start of the thread. (Note I am not complaining about the thread meandering off topic. It can make the thread more interesting.)

Les.

Fear not Peter, I have absolutely no intention of welding it, not even with TIG.

The parts are with the other tools that went 'ping' as well.

What piping are you refereing to?

I don't need the caliper, but it would be my first attempt at making a spring of this shape.

Geoff - Need to sort out the WB on the HV20.

I was able to buy 2 of the 2,4V Varta 2XV250H cells! No answer from Farnell, so that will be a company not to do business with in the future.