Metric micrometer what t buy?

[Brian GParticipant @briang]

Perhaps worth mentioning in the context of this thread that this week Zoro have a "black friday" promotion and the 0-25mm Kennedy micrometer is reduced to £16.99. Mine arrived this morning and whilst it is still at the bottom end of the price range, it feels nice to use, has clear markings and gives repeatable results. Having said that, the £10 "Whale Brand" micrometer I was using was as accurate (using the ratchet, I couldn't get repeatable results with the thimble as it felt rubbery, unlike the Kennedy which comes to a solid stop), but I do this for pleasure, and it just didn't feel as natural in the hand as those I used in industry. The Kennedy does, so I just ordered the larger sizes to make up a set.

Brian G

[Henry BrownParticipant @henrybrown95529]

I'd noticed that Zorro had the promotion on Brian, looks a good buy. Just out of interest did you get the little adjusting spanner with your 0 – 25 mic?

[Brian GParticipant @briang]

Posted by Henry Brown on 27/11/2019 10:31:44:

I'd noticed that Zorro had the promotion on Brian, looks a good buy. Just out of interest did you get the little adjusting spanner with your 0 – 25 mic?

Yes, mine came with the double ended spanner for the barrel and ratchet. Cromwell/Zoro don't seem to be very good at descriptions as they don't mention either the spanner or the setting standard that is shown in the picture of the larger micrometers.

Brian G

Edit:  I suspect from the markings and the fact that zoro.com sell Insize in the US that Kennedy micrometers now come out of the same Chinese factory as the Insize 3203 series.

Edited By Brian G on 28/11/2019 08:59:04

[Henry BrownParticipant @henrybrown95529]

Ok, thank you Brian.

The 2nd hand 25-50 I bought recently didn't come with a spanner and, of course, the M&W one's I have don't really fit. I was using the 0-25 yesterday and it's ok but I noticed the 1mm graduations on it are on the other side of the datum line to the 25-50 Kennedy! I think I'll invest in a Kennedy 0-25 from Zoro as I could do with a 12mm end mill so that will qualify for free delivery. I've bought a few cutters from Zoro, sometimes via ebay as I find their website is slow and confusing – always cross referencing the price of course. They generally have good prices and are very good on delivery.

I've no doubt you're right about the Insize connection, Incidentally, it looks like Zoro are the mail order arm of Cromwell in the UK.

Cheers, Henry.

[Mark Gould 1Participant @markgould1]

I watched a youtube video a while ago in which a Chinese digital caliper was shown to be changing the indicated value as the battery depleted. This was an eye opener for me. Since then I have decided to buy only Mitutoyo’s (or similar) and would prefer a decent second hand quality mic to a new Chinese made one.

That being said I do buy my milling cutters from Banggood which I have found to be excellent, generally. That is more an aside just to prove I’m not a complete tool snob

Mark

[peak4Participant @peak4]

Posted by peak4 on 14/11/2019 12:41:37:

Have you considered an electronic/digital one?
This is an ebay example, though I'm not particularly advocating this individual product.

Note that, unlike some, it does also have a proper thimble, so can be used conventionally as well.

They are available with both metric and imperial thimbles, from a variety of manufacturers.
I recently bought an SPI one at a good price, Swiss made and feels good in the hand. Mine's got an imperial thimble, which is ideal as all my machines are also imperial.

Unfortunately I hadn't realised until it arrived, that the fixed anvil is ball ended, so it works well for flat surfaces and tube wall thicknesses, but since your main use for it is on the mill. that might even be advantageous.

p.s. This looks to be a similar item with a different badge if the Silverline logo offends, and also has a metric thimble. They probably all come out of the same factory.

Bill.

Edited By peak4 on 14/11/2019 12:45:41

Just a quick update, I actually made an ebay purchase recently of a cheap Chinese digital micrometer, which looks very similar to the to the one in my second link; the only difference seems to be mine's in a wooden box the same as the Silverline one in the first link.

It arrived today, very promptly, Royal Mail tracked 48 for the princely sum of £15.08 all in.
It was originally priced at about a tenner dearer, but the seller offered an auto discount, so I thought I'd try it as an experiment.

Well for the price, I'm most impressed, the paint finish is nothing special, and the wooden box is one of the normal tacky varnished ones.
Initially it didn't turn on, but that was because of a dirty battery.

The anvils are carbide tipped and nicely ground and polished; they appear to be flat as well, as I've tried measuring a ball bearing at a good number of points on the surface.

I've a couple of M&W manual, ones 0-1" and 1"-2", the latter of which has a 1" round standard with it.
I used said standard to check both manual micrometers with respect to each other, and as expected they both show 1" dead as far as my eyes can tell.

I then tried various feeler gauges, ground rods, and the 1" standard, in both the smaller M&W and the new digital.
Everything seems to concur throughout the 0-1" range. This of course is only reading the LCD display as the thimble is graduated metric. The new one is adjustable and supplied with a suitable C spanner.
The ratchet seems smooth and the results are repeatable at each of the readings I took.

I don't possess any slip gauges, but from what I can tell, the results are spot on compared to the kit I've already got.

Looks like a bargain for £15

I'd add a link to the seller, but I got the last one, though it looks very similar to the other ones out there

Bill

Edited By peak4 on 21/12/2019 20:37:14

[Ron LadenParticipant @ronladen17547]

Still some bargains out there, I picked up this 0-1" Moore & Wright for £7.50. It was pretty dirty when it arrived but a really good clean got rid of most of it though not all of it. Its very smooth with a good ratchet, the mating faces are as good as new and its spot on zero and accurate to a few slip gauges I tested. Came with a case the spanner and a clip on pointer/indicator, not bad for less than a tenner.

[SillyOldDufferModerator @sillyoldduffer]

Surely depends on what the micrometer is for?

• I don't need an Imperial Micrometer at all. (Nasty things involving lots of silly conversions!)
• If it's really got to be accurate, which is what they're for, best to buy a new one. Maybe with a certificate.
• Buying second-hand is pot-luck, anything from scrap to 'as new'. As an inaccurate micrometer is junk, why risk it.

Buying pot-luck needs more analysis. Shame on you if it was bought expecting it to be in good order. (Some have been used as G-Clamps). Top-marks if it was bought for the adventure, cheerfully expecting it might have to go straight in the bin, or collected for nostalgic reasons.)

Assuming it was bought to be used, is it logical to buy a precision measuring tool that has to be checked with slip gauges before it can be trusted? I'm glad the Moore & Wright passed, but I bought an ordinary micrometer new, nothing special about £25, that was reliable out-of-the-box.

Putting it another way, would you care to have an elderly worn-out silly old duffer in your workshop. I'm sure a quick clean and polish will have me in perfect working order, at least for any Armchair Engineering needed…

Dave

[Ron LadenParticipant @ronladen17547]

Well it obviously didnt meet with your approval Dave but it met with mine..

Silly conversions, what silly conversions..? I am quite happy working with metric or imperial and most of what I do is metric, my locos are metric. When it comes down to tight dimensions/tolerances etc I instantly see thousands in my head better than I see parts of a mm but that is just me, hence an imperial micrometer.

It didnt need to be checked against slip gauges but I thought I would and I would have done the same for a new measuring tool.

"Shame on me" and "why risk it" well having spoken to the previous owner I knew it would be good and at £7.50 what is there not to like.

Ron

[mark costello 1Participant @markcostello1]

If You buy new and do not inspect, You might not get what You expect. Sorry I'll get Me coat

[Anonymous]

Posted by SillyOldDuffer on 16/03/2020 15:04:33:

• Buying second-hand is pot-luck, anything from scrap to 'as new'. As an inaccurate micrometer is junk, why risk it.

……………..

Putting it another way, would you care to have an elderly worn-out silly old duffer in your workshop.

Wouldn't worry me, but no touching the machine tools without strict supervision!

Oh dear, I've got lots of micrometers, imperial and metric, and I've never bought a new one in my life. Only had one duffer, a 4-5" micrometer bought on Ebay that was about 15 thou under-reading. Sold it back on Ebay and got my money back.

Andrew

[Former MemberParticipant @formermember32069]

[This posting has been removed]

[SillyOldDufferModerator @sillyoldduffer]

Posted by Ron Laden on 16/03/2020 16:08:20:

Well it obviously didnt meet with your approval Dave but it met with mine..

Silly conversions, what silly conversions..? ….

Ron

Quire right too Ron, you wanted it, not me!

30 examples of silly conversions have been carefully engraved on the side of your lovely micrometer. Happens to be 16ths and 32nds, but engineers once had to deal with thirds, quarters, sixths, eighths, fourteenths, 64ths, 128ths and others. How many inches and thou in one third of 5' 5¾". How many thou in 1/6" + 3/128" ?

Thou (also known as mil & points) are a handy way of defusing one of the Imperial Systems less desirable features – fractions! Fractions may make easy calculations easy, but they also make hard calculations much harder. For that reason thou have become almost universal in Imperial engineering, but no-one else uses them.

Metric goes a step further by completely dumping the likes of fathoms, yards, feet, inches, and fractions. Doing so removes the need for many unnecessary and error prone calculations.

I suspect half an hour doing serious engineering sums would cure most Imperial Fanboys! What's the volume of a super-heater tube 40' long, 5⅛" diameter and 7 s.w.g thick? If the tube is made of steel weighing 0.283 lbs per cubic inch, how much does it weigh in cwt? If the coefficient of expansion of steel is 0.000007, how long will the tube be at operating temperature 420°F?

Each to his own, I'm only stirring the pot for fun.

Dave

[Author]

Posts