Micrometer woes

I have had a 0 - 3" Mitutoyo micrometer set in it's original box for some 40 years, the 0 - 1" mike is usually to be found on my bench or lathe but never in the box. Imagine my horror earlier when I went to use the 1" - 2" and found that the nesting foam in the box has turned to dust. Worse still is where the dust has adhered to parts of the mikes and setting bars has caused some kind of corrosion, not on the painted frames only the satin chrome and bare metal. I've managed to clean most of it off by scraping with a finger nail, cocktail stick on the knurled parts and metal polish, but there is some staining which I cannot remove fortunately not that prominent. Has anyone any idea what could cause this to happen? I can't remember when I last opened the box maybe a year or more and it was ok then.

I have just opened another Mitutoyo box that I have containing a dial caliper which has definitely not been used for many a year and the nesting foam in that is starting to turn to dust, fortunately I've caught that in time.

Need to source some hard foam to make some new nesting packs, suggestions anyone?

Phil

Hi Phil,

I get this all the time with old cased micrometers, it does not seem to matter what make they are although perhaps Mitutoyo are slightly worse than M&W.

All I do is blow the worst off and out of the cases; I use meths to clean the instrument and if really bad a gentle touch with very fine grade Garryflex block. Not much can be done about the staining.

For the case linings I have tried all sorts and latterly have settled on either the soft black padded vinyl that HALFORDS sell as boot lining OR the black non slip material that lines drawers. Both are good.

Using foam when you have a lot to do is abit of a faff as it does not cut well leaving ragged edges.

I use spray mount sparingly to stick the new linings in.

For larger cases I use adhesive backed sound proofing foam from EBay, cost very little and one lot will last me literally years and I do a LOT of cases.

Cheers, Martin

Phil ... I share your pain

Not only micrometers, but exotic microscope parts, have suffered.

The only truly stable foam that I know of is Plastzote

MichaelG.

**LINK**

https://www.zotefoams.com/product/azote/plastazote/

I have both Mitutoyo and M&W micrometers and neither of them have foam in the case and I bought them new, both about ten years old I think.

.

They learned their lesson, Vic.

MichaelG.

The curse of foam. I was given a British Thornton drawing instrument set years ago. The same thing happened. It took ages for me to clear the small particles of foam that seemed to get into everything. I do hope the mic is OK and no crap got into the thread etc.

Elmo

I had the same problem with my Thornton set. I remember the plastic hinges were on Tomorrow’s World and were supposed to be good for a million reversals. I have had the set since about 1970 and the hinges are still good but I had to replace the foam.

Mike

Thanks for all the replies and commiserations, it's good to know I'm not alone. I will investigate the potential materials suggested and report back in due course. I find it curious that some foams deteriorate and others remain fairly stable over many years, I have a set of drawing instruments that I made a ply box for and lined with some foam that came out of my mother's sewing box when I was a teenager about sixty years ago and that is still good. Ok, it's worn a bit around the edges where fingers rub but the foam is still quite resilient.

Phil

It's an issue with many plastics as the plasticisers evaporate, or migrate to the surface.

N.B I'm not a chemist, just an observer.

Rigid plastics get brittle, foam disintegrates, which might actually be the same process.

I'm guessing its more obvious with foam due to its much higher surface area. I wonder of the longer term solution is the old fashioned one and to use felt as a box liner.

The other really obvious problem with disintegrating foam, is in the compliant pars of loudspeaker cones. Rubber lasts longer, but the foam falls apart after a few years, especially if you live near the sea.

Fortunately this one is curable as kits are readily available to repair the driver units.

Whilst on the subject of HiFi, anyone with an old collection of vinyl would be well advised to check the inner sleeves. Many of those used to have a plastic liner to the paper inner, and it's now getting to the age where it's starting to break down.

The same problem that Philip has with his micrometer can also affect LPs, but in this case the damage is audible rather than just in appearance, and is harder and more expensive to cure.

Bill

Edited By peak4 on 27/01/2019 00:48:11

Beware also of polystyrene, the usually white foam more often, but not always, used as packaging material rather than as a liner. If used for longer term storage it has a nasty habit of adhering to metal and painted surfaces and may contribute to corrosion of metal.

The residue ( but not the rust ) can be removed from metal surfaces using acetone but I would welcome advice on a method for removing it from painted and lacquered surfaces without causing damage to the underlying finish.

Pero

Seems many have the same experience! I have had the same problems in a number of applications using foam - Vinyl acetate based, as well as polyethylene (cross linked and none-cross linked) as well as polyurethane. I have tried so many types and am still trying! I use the foam as packing base for small unmanned aircraft in a largish rugged case - about 1.5m x 0.8m tall x 0.6m deep. I get maybe 2 years of life out of the stuff. It starts to 'powder' and if you grab hold of a piece and squeeze tigtly, it does not return to shape. If you squish it between thumb and forefinger is becomes pasty and sticky. These cases/aircraft are in use on the west coast of Namibia and are exposed to a lot of salty humidity.

I used a 'fancy' automotive foam, closed cell type - used to pad car engine cells/bulkheads to reduce transmission of noise into the cabin, and made a storage case for my 5C collets - that reacted so badly with WD40 that I oil the collets with before storage, and started becoming sticky and staining the collets. I would have thought that an automotive foam would need to withstand car engine oils/fuel spills etc - I obtained the foam from an automotive body manufacturer in Port Elizabeth in South Africa.

The problem is however not limited to foams..My Agilent oscilloscope ( a 4 channel digital storage scope, 5GHz sample rate, ie, not 'cheap'..) has most of the control knobs made from a nice tactile feel rubbery material. These have ALL become sticky and if squeezed likewise form a sticky malleable muck between the fingers.

My Infra red handheld thermometer has a rubberised coating on the handle and this after two years has become sticky to the extent it became disgusting to hold..Cleaned off the coating with thinners and it is usable again. Ditto the handle of my 'press to extract' wine bottle cork extractor...which was fine in Johannesburg ( no sea, salt and low humidity) and which went sticky after around 18 months at the coast..

No idea what to do about this - move to drier climes???

Joe

I have some older Mitutoyo dial calipers and they are in a timber box. The calipers rest on timber blocks lined with felt. Still as good as new. A better system than using foam.

Paul

They should use the plastic that is filling our oceans, that seems most reluctant to degrade. Starrett used to just use a wooden box for larger mics but I have noticed many felt lined cases seem to hold moisture and are obviously in close contact with the item to be protected so promoting rust. It is vital that tools in cases should be kept dry and not subject to temperature changes that cause condensation. After making a wooden block to hold taper shank tooling I noticed that where the shank contacted the hole a rusty ring developed, I don’t think it was the wood but condensation would accumulate at the contact ring and the wood would absorb it and make a rusty ring. The rest of the drills stayed free of rust as they are slightly oily and dry quickly.

Mike

Edited By Mike Poole on 27/01/2019 10:36:46

Last year when I joined up with the local Menz Shed, initially just to get the Box-Ford A lathe up and running, I found that someone had taken a block of wood about 100 mm x 75 mm x 300 mm and drilled holes in it to take all the drills next to the drill press, I wanted a drill, but had a hard job getting it out of the block, the shank had rusted, as had the shanks of all the other drills. I soon got rid of the wood, and made a drill stand from steel.

Got a number of different cases for micrometres, the one for the old Starret is some old type of white plastic, mabe Casien, it's warped. Another has a steel spectacle case type container. The 1" to 2" mic has the plastic box it came in, and my ex Russian fishing boat 50 mm to 75 mm mic has a fairly large wooden box with a sliding lid. No problems with any of them.

Ian S C

You need to be aware that the plastic supermarket bags also disintegrate over time. We had some items stored in the loft in old supermarket plastic bags, when I went up to retrieve some items the bags just crumbled away in my hands, seems that the dry atmosphere in the loft caused them to disintegrate, shame the same thing doesn’t happen when immersed in salt water then perhaps our oceans may not be quite so polluted.

Dave W

The Mitutoyo foam seems to be excessively sensitive to temperature fluctuations. Back around 1995 a friend got a used Mitutoyo dial capiler. maybe 5 years or so old and clearly well looked after. After about 3 years in his unheated, but properly brick built and dry garage, the foam had pretty much crumbled away. Due to its location and alignment that garage was very cold in winter and very hot in summer. Similar Mitutoyo foam in a temperature stabilised lab environment still good after 20 years to my certain knowledge. Not bought new during my time in the lab. Probably pushing towards 30 years old when I left.

I wonder what wood Starrett used for their plain wood cases? Attractive, lasts well and clearly doesn't affect metal.

I have some micrometers in "distressed" plastic cases and really should get round to making something better. Starrett style would be pretty easy to copy and looks well if I knew what to use.

Clive

Mitutoyo tools are excellent, but their boxes are rubbish. The cream coloured boxes that their micrometers come in are extremely brittle, i have several where they have cracked or broken, leaving the tools open to damp and dirt, not good.

The felt in the micrometer boxes, is in the lid, and yes i have several that have turned to crumb rubber, leaving the mic covered in little black specks.

I also have a metric mitutoyo depth mic, that came in a nice wooden box. It was in perfect shape, but i went to use it one day and was disgusted to discover the depth rods covered in rust. I had to clean them off and some were pitted. Things like wood and felt absorb moisture and rust tools.

Someone told me mothballs in tool cases resist rust, or maybe things like vp90, as used in gunsafes and things like that.

The instruments that I have that have lasted longest are the ones that I just leave lying around on the machines. That promotes their continual use and prompt cleaning and maintenance. My 0-1" mic dates from 1976, and I've no idea how old my M&W Vernier protractor is - a friend gave it me spotted with crud and rust from being kept in a case. I ScotchBrited it off with WD40 and it's never had the opportunity to come back since. The mic is a Mitutoyo and still works pretty well to a couple of tenths on its Vernier barrel, though it lost its metric mechanical counter about a month from new.

I think the tales of woe above confirm my view that it was just well I lost the boxes!

Tools in daily use are not going to suffer from adverse storage conditions but in the home workshop it is difficult to use every tool everyday so storage that keeps tools in good condition is important. Keeping precision tools safe in a workshop that has temperature and humidity variations is a challenge so maybe bringing them indoors to keep them in a warm and dry environment is a wise if inconvenient strategy.

Mike

Edited By Mike Poole on 27/01/2019 21:23:36