Giant dial indicator

[Sonic EscapeParticipant @sonicescape38234]

I found a ridiculously large dial indicator ~11cm in diameter. I couldn’t resist buying it. In general it measures as accurately as the digital indicator. But unfortunately when it reaches 0.68mm it locks and then jumps to another position. From what I understand is not ok to lubricate dial indicators with oil? Because I have a feeling that some WD40 will fix this.

[vic neweyParticipant @vicnewey60017]

I have had some success using light watch oil on some that came in a job lot but it didn’t work on all of them.

[Peter Cook 6Participant @petercook6]

Bit of dirt in the rack?

[bernard towersParticipant @bernardtowers37738]

Im with peter on that!

[roy entwistleParticipant @royentwistle24699]

Do NOT use WD40 on brass

Roy

[Martin ConnellyParticipant @martinconnelly55370]

WD40, the WD stands for water displacement. It is not designed to be a lubricant. Once the volatile compounds have evaporated a stick waxy deposit is left. On engines (back in the pre-electronic ignition days) people used to spray it liberally in the engine bay of cars to try to keep the HT for the spark plug from leaping to earth when it was damp. After being subjected to the heat of a hot engine for a while there was a varnish like deposit left behind. Google what is WD40 meant for.

Martin C

[Neil LickfoldParticipant @neillickfold44316]

It will need to be cleaned. I used to use baby oil, unscented pure paraffin oil. Now I use the thin vacuum pump oil or ATF oil. It seems to stay for a very long time. Most people over oil things. The droplets need to be very small on the bearing areas. The rack and pinion is usually clean and dry, with the oil drop being on the pinion pin bushes. Some use full synthetic oils. A watch maker will set you onto a better track, but my indicators are still working well , the oldest was new in 1980. A very small amount of oil on the top and bottom guide bushes sometimes. If it is used in a dusty environment, then I leave the indicator shaft clean and dry. I use a pin point to apply the tiny drops of oil.

WD40, CRC, and similar products, evaporate and leave a nasty deposit that over time will ruin things.

ATF oil has additives for mixed metals to prevent corrosion. The vacuum pump oil is very low evaporating, and lasts the longest. At least for 3 years or more.

Neil

[Peter Cook 6]

On Peter Cook 6 Said:

Bit of dirt in the rack?

I don’t think so because it is a periodic problem. It gets stuck in the same position on every turn.

I had a look inside and I noticed two things. First, it is the most complex dial indicator I saw. Second, somebody flooded it with high viscosity oil.

There is also a lever that should press on a small wheel. But it is bent and was pressing in the wrong location.

There are also some adjustment screws. This is serious stuff not something to fix quickly at midnight. I’ll have a look in the next weekend.

[larry phelan 1Participant @larryphelan1]

Would it be worth while to bring it to a watch repair man ??

[larry phelan 1]

On larry phelan 1 Said:

Would it be worth while to bring it to a watch repair man ??

Where is the fun then? 😀

[Sonic Escape]

On Sonic Escape Said:

Where is the fun then? 😀

Good point !

Now:

1. Dismantle it carefully, taking notes and photos as you go
2. Clean all that filthy thick oil off every part
3. Reassemble it dry, and check that it works properly
4. … any slight lubrication can be considered after you know it works

MichaelG.

[Grindstone CowboyParticipant @grindstonecowboy]

I’ve mentioned it before, but I’ve found lighter fluid works well for cleaning mechanisms such as these and has the added bonus of leaving a very slight oily film which is adequate for lubrication.

The higher quality brands (e.g. Swan) are less oily than the “pound-shop” variants.

Rob

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