Chris. the small ratchet thumbwheel is to give a uniform pressure when measuring close tolerances, Thumb pressure on the large thimble can vary so much as to give odd readings.

Edited By Clive Hartland on 05/09/2019 14:28:36

Because when you hold the mic with 1 hand & use it you have 1 finger which is normally little finger holding the curved body you would not be able to reach the ratchet knob at the end. The large knurled part is also handy when you want to open or close the mic down some distance you run the barrel up or down your arm.

A lot of people say that the Ratchet should be turned until it has clicked three times, to give a consistent pressure.

The narrow knurled ring set into the frame of the micrometer, is used to lock a reading.

In this way, then reading can be retained when the mic is removed; or it can be used a Go/No Go gauge.

Howard

I have suggested useful reading material to Chris on more than one occasion, he has not responded.

Book 6 in the Workshop Practice series, Measuring and Marking Materials, by Ivan Law, would answer this question too.

The preferred option appears to be to bombard the forum with questions instead.

Chris,

Although quite a bit of money can spent on building up a library of books, it will be money well spent.

None of us know everything, so we need books as a source of information to which we can refer.

Some books will be opened more often than others. That will depend on:

the state of your knowledge

what you want to do

how often you wish or need to perform that task.

As an instance, if you bash on regardless, you could spend more on replacing broken Taps, and spoiled workpieces, than if you had bought a book on Taps and Dies, and how to use them. Which just happens to be No 12 in the Workshop Practice series of books.

Other than for interest, there is not much point in buying books on the vertical milling machine, if you don't have one. Some of the info MAY be useful if you use a vertical slide to do a little milling in the lathe.

L H Sparey's "The Amateur's Lathe" is often cited as a good starting point, (Although this heavily features the 7 Series Myford, because this was almost the standard machine, when the book was written ) just as is Ian Bradley's "The Amateur's Workshop" and Tubal Cain's "Model Engineer's Handbook". This latter sees a lot use by me, and I've been in Engineering since 1958!

When you find a need for a book, buy it. You will refer to it more than once, although some less than others, but it will be there when you need info on that subject.

Find your local Model Engineering Society, and join it. There will be folk there prepared to guide you on your machine, or show you how on theirs.

You ask questions, in the hope of gaining knowledge, not to be laughed at. If I need information about my eyes, I ask an Opthalmist. I am an Engineer, not a medic. Should I wreck the control board on the mini lathe, I shall consult someone with good knowledge of electronics.

Keep climbing the learning curve.

Howard

Chris,

With the greatest respect I have followed many of your question posts and the answers which seem to be perfectly valid. However the way your responses read to me seem to dispute most suggestions as not appropriate according to your answers already gained from your valued advisor. I am sure you do not really intend to come across as I interpret your responses and there is nothing wrong with questioning to properly evaluate a method or process but the way you do this perhaps does not encourage people to respond?

Paul.

That’s a new one to me Alan, I thought the second knurled grip was to provide additional functionality as a G clamp.

Photo finish Paul, let’s call it a draw

or a C spanner

No hammering Phil but the ones without the second knurled knob work better as pipe wrenches than the ones with…….

…….and a 12" caliper makes a better hammer anyway, due to leverage!

This is now getting silly and VERY unhelpful.

Brian