Anyone know where I can get hold of 'Gauge Rods'

Maybe use your favourite search engine on the term "drill blank set", essentially drills but before the flutes or cutting edges are machined. Often more expensive than a set of drill, but drill sets are often made with undersized shanks

For Example, though there are other suppliers of course

Bill

Edited By peak4 on 05/09/2019 13:00:02

As has been said you can use the topslide handwheel or a DRO if you have one.

Lets say the photo is a 0.221" dia rod. I would touch my tool against the lefthand shoulder and set the handwheel dial to 21. Then turn the smaller diameter stopping when the handwheel was on zero and just over two full turns away.

Alternative is to hold the rod or block against the left hand shoulder and bring the tool up to touch the rod where you would then set dial to zero, you then turn the smaller dia stopping at zero. You can also use a finished part as the gauge if you want one to slip onto the spigot and both ends flush.

Both these methods would be better than comparing by eye or feel.

I don't have gauge blocks so my suggested sizes may not be what comes in a set.

Edited By JasonB on 05/09/2019 13:22:42

Thanks Andrew, from what I am so far minded;

Either i should by a used set (likely) of gauge pins or make my own (not so likely). Drill blanks would be expensive to make a set and machining them tricky although possible using ceramic cutters. I appreciate you mentioning your gauge blocks are slightly rounded as this also is a factor. Regarding accuracy of lengths at this stage I am aware some dimensions are more critical than others and this will be refined as I get bearer to actually attempting to machine one.

Regards

chris

For most practical applications the internal jaws of a good digital caliper should suffice for those measurements.

Neil

The standard sets are listed in Machinery's Handbook.

Andrew

Can't imagine why you'd need to use WD40, or anything else, on brass. I always machine brass dry, with one exception. That being CNC engraving where the sole purpose of the flood coolant is to wash away the fine swarf. On something like this:

The only time I use WD40 is for manual drilling of aluminium alloy to prevent the swarf sticking to the drill.

Andrew

Never seen a 0.001" guage block, not able to handle something that thin

I have a specialised set of gauge blocks - the thickness run from 0.5 to 0.9mm in 0.05 steps the 0.91 to 1.0 mm in 0.01mm steps Not sure for what purpose they were acquired by a now defunct microelectronics company - dated 1971 made by Cary Le Locle Switzerland but marked on box "Calibration uncertified"

(difficult to photo as very reflective)

They are really clean room only use - they need cleaning (iso-propyl)  but my own usage is more admiration than use as I have a more useful standard imperial set which allows checking of mics etc

Edited By Frances IoM on 05/09/2019 16:00:27

Don't have that either

Hi guys in case anyone is interested just got reply from my horological expert he says as I suggested that block gauges are great for many applications but with the micro sizes involved with balance staff machining block gauges are arkward and have limited sizes.

Regards

Chris

I would say yes, but to be definitive consider the original post : 'What I am looking for is precision ground small round rods to use to hold against micro items being machined to assess whether it is the right length.' (A perfectly reasonable approach within limits.)

I think the keyword is assess. From the description I believe high accuracy is not needed, ie the job doesn't require an absolute measurement of a value to be made as per the formal definition of accuracy. Rather the intent is to get close to a dimension by eye and magnifying glass so that a number of tiny parts can be made close enough in size to fit together without major rework. The comparison could be relatively crude by absolute standards, say within 5%. ( ie 0.01" is acceptably anything between 0.00975" and 0.0125" )

If that interpretation is the case, pin gauges (useful to a clockmaker) would be a convenient way of assessing size as shown in Chris' picture. No need to invest in a set of costly slip-gauges, even though these would do a better job. (I don't think slip gauges are otherwise useful for clockmaking).

No reason why non-absolute pin gauges shouldn't be home-made and calibrated with a micrometer. I'd be inclined to use Silver Steel or Brass rather than mild steel because mild steel goes rusty and is a little soft. Brass is easier to turn to size than Silver Steel but not as hard wearing. However, treated with care, I'd guess Brass pins would last years.

Great things can be done by comparing magnified objects. Slip gauges and the like come into play when making many objects to specified tolerances, ie 0.015mm ±0.001mm. Mostly done so parts from different suppliers don't have to be fitted together. This is because fitters cost a fortune, take ages, and make mistakes. Working to tolerances is unlikely to be needed in most amateur workshops where our time is our own. Everything I make is fitted, not precision made.

Dave

Edited By SillyOldDuffer on 05/09/2019 16:32:14

The question in my mind is "Why assess, when you can measure and be more certain"?

I would reiterate the advice to use a Depth Micrometer, or the jaws of a digital, dial or vernier Calliper.

Using Slips is probably OTT, unless you really need to have lengths correct to within 0.0001"

Don't waste time chasing microns, needlessly. (Unless that is your hobby )

Industry will not work to microns, if 0.1 mm will suffice. The cost increases, possibly exponentially, as the tolerances decrease.

Howard

Andrew

.

On an earlier thread: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=144147&p=3

I posted a link to this page: **LINK**

http://www.learnclockrepair.com/balance-staff-critical-dimensions-variants/

... Which describes in some detail the sort of item that Chris has expressed an interest in making

[ ref. his very first post on the forum ]

This is likely to involve a very steep learning-curve, and when supporting Chris, I think we need to bear in mind that normal industrial, or hobby-engineering, methods and tolerances may not be particularly relevant to such items.

MichaelG.

"This is likely to involve a very steep learning-curve"

No kidding Michael!

For this sort of work a loupe magnifier with scale is a good option. Peak make nice ones and can often be picked up used quite cheaply. Only problen I could see is if you can't get your head close enough with the workpiece in the lathe. A little jig to keep it squae to the work and at the same distance might be useful.

Another option woud be a USB "microscope" camera in a fixed position connected to a cheap laptop or tablet with a scale stuck on the screen calibrated against a couple of slip gauges. There is also measuring oftware available see https://www.model-engineer.co.uk/forums/postings.asp?th=144331 for a similar application.

Robert G8RPI

Fascinating stuff, I can see why people take to clockmaking! Can Michael or another expert explain a little more about the technique used to size such objects? The advice given on learnclockrepair.com talks in general terms, not dimensions or tolerances, as in 'The overall length of the staff must be such that it floats with barely perceivable endshake between the top and bottom endstones, but enough that it runs with absolute freedom.'

So how is 'barely perceivable endshake' achieved? In my rough workshop, I'd attempt this by making the balance staff slightly over-length by comparison (not measurement) and then shave the ends down until it ran 'with absolute freedom.' But is that practical when the balance staff is one of several spindles all carefully sandwiched between the side-plates of a clock movement?

Talk of practicalities reminded me of my recent go at hand-graving blue pivot steel on my WM280. Big lathes aren't well suited to micro work! First problem is a 4-way tool-post gets in the way and is best removed. Second problem is turning tiny work held in a chuck is seriously scary because knuckles and graving tool are both likely to have a close encounter with whizzing jaws. Vote collets! Third problem is getting close enough to see exactly what's going on, the headstock tends to get in the way, and stooping over a lathe on a stand is uncomfortable.

Although big lathes can do tiny work, I felt a micro-lathe on a comfy table-top would be far more practical.

Dave

Edited By SillyOldDuffer on 06/09/2019 09:01:36

Dave,

First can I mention that you have revealed another useful Truth

Despite the oft-recited mantra that the best lathe is always the biggest lathe .... in truth the best lathe is the one that suits the job; and that is sometimes more about ergonomics and precision than it is about capacity and brute force.

I will append a couple of links to this brief post, if I can locate them before the 'edit' time expires

[ otherwise ... see later ]

MichaelG.

.

Saunier: https://archive.org/details/watchmakershand00tripgoog/page/n4

Hall: https://archive.org/stream/atreatiseonstaff20317gut/pg20317.txt

... and, of course:

Daniels: https://books.google.co.uk/books?id=ZWq8c0xvGxsC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

Edited By Michael Gilligan on 06/09/2019 10:15:29