|923 forum posts|
Andrew - I like you method of working, very sound, but not all - perhaps very few, I don't know - of us have the grinding facilities to accurately grind hole plug gauges parallel and to size, we have to make do with the measuring tools we have, but as you say, you can't have too many micrometers, inside and out! I need a depth one now too.
thaiguzzi - quality verniers are very good but the problem using them you have identified, eyesight. That doesn't get any better as you get older and a lot of us here are not so young as we like to think! (Think mind making promises the body can't keep anymore. You think you are still 27 but the reality is more like 72!). That is why digital and to a slightly lesser extent dial calipers have their attraction, big figures easy to read.
|Andrew Johnston||28/10/2017 11:39:04|
5841 forum posts
A ground gauge isn't always needed. For my traction engine rear wheel hubs I simply used a piece of the stock bar I bought for the axles.
All my micrometers have either been inherited, or bought on Ebay. I've only had one complete duffer, a 4"-5" that was about 15 thou out, ie, the frame was sprung. I put it back on Ebay with a note saying it was in error; and it still sold!
6713 forum posts
And IanT said:
'Whereas I was told to always use the ratchet to ensure a repeatable torque....and I do so without any problems in use... but each to their own...'
I think you're both right. The reason being it's important to use exactly the same pressure every time you use a micrometer. That's not easy to do and some are better at it than others. The ratchet is a simple way of improving consistency, but imperfect. I reckon a skilled operator develops a 'feel' making him more consistent than the average ratchet.
Being self-taught and cack-handed I always use the ratchet. I get reasonable rather than completely repeatable results. Perhaps one day I'll take better measurements without a ratchet; it'll take a fair bit more practice though!
Edited By SillyOldDuffer on 28/10/2017 20:25:59
|997 forum posts|
Same here was given an analogue Moore and Wright micrometer (when they were good) at last place. Filed stuff up to the thou, easy to use just feel for the flat then ratchet in.
Verniers, phew i go through them like no tomorrow but still have a Mitutoyo analogue from 84 long relegated to scribing.
|Neil Wyatt||28/10/2017 22:15:22|
18425 forum posts
The National Physical Laboratory says that if your micrometer has a ratchet, you should always use it on the first click.
It's worth downloading the docuiment that link connects to.
It also says a lot of other interesting things, like don't by callipers or micrometers too accurate for your needs as you are just wasting money and time, to make sure everything has stabilised at room temperature, and to be aware that micrometers will give different readings depending onw hether you use them hand held or in a clamp or in different orientations.
|Phil H1||29/10/2017 19:06:20|
|339 forum posts|
Right or wrong, anybody caught using the ratchet would be mocked. When everyone calmed down and stopped the chimpanzee noises, the answers were actually quite reasonable.
One reason (and I have definitely come across this problem) is that over time, the ratchet 'wears' and if you try measuring slip gauges, the ratchet fails to achieve the correct 'feel' and hence the correct measurement - and that is using a properly calibrated toolroom micrometer.
The second reason hinted at by Dave's answer is the need to try and train into the apprentice the correct 'feel'. This is important because there are many situations e.g., using slip gauges to measure a precise gap where a ratchet is obviously not available.
Finally, this might not apply anymore but many of the very best mircometers simply did not have a ratchet.
703 forum posts
Well, 3 years later, just turned 60, and my Mit verniers are finally getting awkward to read on the imperial scale.
Being a Luddite, and refusing to have anything to do with digital, batteries or electronics, i am now looking at dial calipers.....metric and imperial....
|Speedy Builder5||01/12/2020 07:02:51|
|2191 forum posts|
I do like Dial callipers, but of course you would need one in metric and another in imperial - or would one? Has anyone seen a digital dial calliper where the analogue face of the dial could change between the two measurement systems. That would be a neat idea.
Its a bit like the speedo on your car, do you prefer dial or digital ?
|Clive Foster||01/12/2020 08:58:48|
|2540 forum posts|
My solution to the vernier scale reading problem was to find some with double length verniers, 2" or metric equivalent, rather than the usual 1". The markings are deeper and clearer and the more open scale is easier to read.
Mine are M&W but some other breeds around, Mauser(?). Dont have internal scale knife edges tho' so you have to subtract a correction factor for internal work.
I have apiar of Mitutoyo 8" / 200 mm dial calipers for general work. The extra lenght makes them a little cumbersome at times but is often handy. But I work 12" to the foot scale. Not models.
703 forum posts
Hate digital anything, especially tachs and speedos in cars and on motorcycles.
The big brand names and quality dial calipers don't do dual needle and dual reading, i would imagine it could get confusing and mistakes get made.
There are some cheap 30 Quid Chinese no-name brands that do.
6713 forum posts
Even dear old friends have to go when the time comes I think!
Staying inside a comfort zone is all very well but tools that don't do what you need are useless. The reason doesn't matter. Look for alternatives with an open mind.
Vernier and Dial displays have their advantages but digital displays don't require the operator to have such good eyesight! Only spare batteries...
|1750 forum posts|
Yes, stopped using Imperial on my Vernier's a while back, as I can only read them with an eye glass now - but I'm still OK on the metric scale. Don't have a problem with my Imp Mics yet - they read just fine.
I have a rather nice Metric Mic (brought it nearly 30 years ago) which rarely gets used. I keep it "For Best" - rather like my wife's expensive cooking pans, which have never been used since they were purchased some years ago
|Nicholas Wheeler 1||01/12/2020 10:13:25|
|457 forum posts|
Dials are good for approximate readings from a quick glance. Speedos and other instrumentation are excellent examples.
Digital is for when an actual, specific number is required. Good for precise, stable measurements, less so for changing ones.
Most of my work is done with a digital caliper. I bought a set of micrometers that got from 0 to 100mm and have never used the bigger two. I also have a 0 to 1" micrometer so I don't have to convert imperial into metric.
|Ronald Morrison||01/12/2020 10:37:18|
|59 forum posts|
It's time for you to join the 19th century and move to digital. The fact that your eyesight has changed enough to move you from a vernier tells me that in a few more you won't be able to read the dial caliper either. Voice of experience. Buy a cheap digital caliper and a pack of batteries as the the cheap calipers use batteries more frequently than the more expensive ones. Use that digital caliper for a month, using it's ability to switch between imperial and metric measurements and being able to reset zero to read incremental measurements instead of having to calculate how much stock is left to remove. Use it lots in that month. Then rethink whether you want a dial caliper or not. By the way, you only need one spare battery, not an entire pack. My most used digital needs the battery replace about once per year.
Edited By Ronald Morrison on 01/12/2020 10:38:32
|Howard Lewis||01/12/2020 13:27:33|
|4177 forum posts|
I have all three types.
As an Apprentice, I bought a Rabone Chesterman vernier calliper from the Chief Instructor. It stood in for several micrometers, having a 6" capacity, and was used for many years.
I was given a Mitutoyo dial calliper. A nice instrument, but once it did jump a tooth.
Then I bought a digital one from LIDL. This gets used most of the time, because I am bone idle, and the scale is more easily visible, in Imperial or Metric. But the jaws need to be cleaned, and sometimes the Zero rest to obtain repeatability. very occasionally, it plays up, but usually removing and refitting the battery cures that. If it doesn't then a careful strip down and gentle clean with solvent or a glass fibre brush fixes the problem.
For accuracy, I would choose the vernier (Along with my Shardlow Height Gauge ) The Dial is nice to use and easy to read, but the rack and pinion, and any gears inside the dial, introduce backlash, and therefore the risk of inaccuracy, when chasing microns.
I did have a Machine Mart Dial calliper, but the Inside and outside measurements differed, so it went back!
In theory, the digital will resolve to 0.0005", where a vernier, read with a magnifier will give 0.001" but CAREFUL judgement may possibly better that.
The LIDL digital is backed up by a M & W Economy calliper, as featured in Neil's comparison article. It has a nicer feel than the cheapie. Both are easy to read, given my aged eyesight.
Spare batteries are kept in stock for both.
None of them are used for bore measurements requiring any great accuracy. For that, I try to use instruments intended for measuring bores, such as a bore set, and a micrometer held in a stand.
Each of the vernier type measuring instruments has its own cheap magnifier with it, with more better and more powerful ones available if needed.
If there is any doubt, a good micrometer, such as a M & W gives a second opinion, after checking against a calibration piece.
For "Near enough is good enough" the Digital will be used. For greater accuracy, (or my belief ) a Vernier or ideally a Mic with a vernier scale.
You need to choose what best suits your needs and your budget.
Edited By Howard Lewis on 01/12/2020 13:28:19
|old mart||01/12/2020 16:43:56|
|2504 forum posts|
I have two pairs of Mitutoyo VERNIER CALIPERS, both parallex free, two Mitutoyo DIGITAL CALIPERS, 6" and 12" and two pairs of Lidl DIGITAL CALIPERS. The cheapies get used most of the time, but for tighter tolerances, I always use the Mitutoyo's. They are even good enough to measure bores to 0.001". Digital is much less likely to be missread and can be used to calculate things. For instance, set a digital to zero, open the jaws to the required size, re zero and measure the workpiece. You now know how much more metal there is to remove.
Dial calipers are nice to use, but must be kept clean, I had a 150mm Tesa, but it was so worn in the jaws that it was replaced by my first Mitutoyo digital, which has 0.0001" wear in the thin part of the jaws after 30 years.
|old mart||01/12/2020 20:56:42|
|2504 forum posts|
There's a Tesa digital caliper brand new on ebay at the moment, with a starting price of £100. I keep telling myself not to be tempted by it, I have plenty of the things. Tesa is Swiss made and as it is not as well known as Mitutoyo, very much less likely to be a far eastern copy in disguise.
|Howard Lewis||02/12/2020 11:49:59|
|4177 forum posts|
Tesa is used in industry so will be good quality.
Worth having if the budget will run to it
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