Member postings for Chris TickTock

Another option to save you making a load of pins is to use the shanks of drill bits, just check the actual shank with your micrometer as they may be 0.1mm below nominal size so just use one that measures what you want. I often do this to gauge the width and depth of small grooves.

With Gauge blocks you tend to group then together known as "Wringing" so for say 0.221" you would combine 3 blocks 0.200 + 0.020 + 0.001

Edited By JasonB on 05/09/2019 12:25:03

Thanks Jason OK I am learning stuff, I think at this point I will get back to my advisor and ask why he isn't using gauge blocks with square ends?

Regards

Chris

Gauge blocks would do what you show and easier to compare the flat side with the faced shoulder and they will be more accurate than home made.

If you want to turn your own then EN1A will be fine as they are unlikely to get enough use to wear. or need callibration.

I assupe Gape pins are the same a spin gauges

Thanks Jason ...well will be gaping at them!. I agree square faces might be better can't see set with imperial range of about 200 up to 0.250 inch

Chris

I'm sure others will know better ways of measuring distances like you show, but a steel rule will be inherently better than eyeballing the edge of a cylindrical gauge.

Other than that why not just use the indexing on the lathe feedscrew dial (or a DRO or DTI) and make the part the correct length?

Ian P

If you are checking lengths, then the most accurate way is as already suggested, Slip gauges (Jo Blocks etc )

BUT DO use the protective slips at each end of the gauge block,

Would a depth mic not do the job, as a simpler and cheaper alternative??

Howard

confounded emojis!

Edited By Howard Lewis on 05/09/2019 11:13:20

I made this unit from the drawings in Model engineer
designed by H.D. Bickley
Vol 167 no 3903 16 August-5 September 1991.
It works very well for small workshop items.

John

Standardising threads , as Whitworth and Maudslay did, greatly simplified life. Others came after and made improvements that suited their particular needs. Until then, it was the whim of the local blacksmith, as to what he made.

We use a "standard" thread because it it is simpler for us to interface with others. If you want to make your product unique, (so that you have sole control of the aftermarket, you build in a unique feature, such as the need for a 7mm Allen Key to service the brakes, or a unique thread.. You could go for a 12mm x 8 tpi. with an angle of 45 degrees,for instance).

But for the rest of us, standardisation makes life much easier! Hence our need for thread gauges, to help identify the thread standard with which we are dealing.

Howard you are a gem and plainly a font of knowledge.

Regards

Chris

But "oddballs" will crop up. Such as the 1.125 inch x 12 tpi used by Myford, which over the years, has effectively become a standard. Ditto for Boxford, or Raglan with their threads. My lathe mandrel is 2.25 inch x 8 tpi Whit form, which may be described a standard, IF you happen to have one of its clones or derivatives.

The thread for a drain plunger, at least in UK, is 3/4 x 7 tpi Whit form. Try cutting one 1/2 inch long! Europe still uses BSP in the guise of Gas.

Enough of my ramblings

Howard

.

Try using the small sample that I sent you, Chris

This is top quality vintage material, purchase at auction from the estate of a watch & clockmaker in Prescot.

... You will then have your own benchmark for the [variable] quality of the modern stuff.

MichaelG.

Putting threads into context:

• Whitworth is the first standard thread, introduced about 1840, with 55° flanks. As a coarse thread Whitworth is well suited to the needs of Victorian and Heavy Engineering.
• In the USA, 25 years after Whitworth, Seller's proposed an improved thread; similar to Whitworth but simplified for manufacture, and with a stronger 60° thread form.
• On the Continent, where the metric system had almost entirely displaced local weights and measures, engineers developed coarse metric threads,
• As Light and Precision engineering developed, it was found that Whitworth, Sellers and Coarse metric were all inappropriate for small diameter fasteners and for some materials, like Brass and Steel. Fine thread versions were added to all three systems, but even they didn't satisfy all needs, notably Bicycles, Electrical, Instrumentation, and Aircraft. This led to the introduction of other thread standards, notably BA in the UK. BA is a scientifically designed thread (for electrical and other light work) and is interesting because although metric, it was carefully converted to inch measure because the engineers of the day (including Whitworth), felt that British Workmen were too thick to take kindly to metric.
• Over the same period, large numbers of other special threads were developed such as tapered threads for sealing joints on pipework, and square, buttress and ACME threads for power transmission. Some lasted, others faded away.
• Taken as a whole, by 1930 the sheer number of incompatible threads were a major obstacle to trade. This came to a head during WW2 when joint US/British military operations were compromised because American Nuts, Bolts and Spanners were incompatible with their very similar British equivalents. Supply of spares was complicated and repairs delayed. Such a mess, that the USA and British switched to a common system, the main feature of which is a 60° thread. In consequence, Whitworth faded from mainstream use since 1940 and is now rarely found. (Except on heritage machinery.)
• Since then, metrication has taken a heavy toll of Inch Threads. Dumping Whitworth fixed a compatibility problem between two close allies, but it did nothing for sales to the rest of the world. Today, apart perhaps from the USA, metric threads are almost universal in new equipment.
• Much confusion is still evident; I've owned cars which mixed all the main thread systems on the same vehicle, spent a small fortune on spanners, and never had a full stock of spare bolts. There is a lot of older equipment worth repairing that's held together by obsolescent thread systems.

Navigating this mess can be a problem for hobbyists. Trying to follow an old British or new American Project Book can be deeply confusing. What made sense in 1949 may not in 2019, and stuff easily obtained in the USA may be hard to find in Europe. I'd recommend going metric if general purpose making or repairing new equipment is your bag. Makes more sense to go Imperial if renovating old equipment, building models to Imperial Plans, or grandad gives you a fully equipped Imperial workshop. There are hobbyists who need to work with both systems, and it's certainly possible to do metric work on an imperial lathe and vice versa. Less amusing if you have to buy full sets of Imperial and Metric drills, taps, dies, spanners etc. because it soon gets expensive.

As a budding clockmaker, before tooling up, it's worth looking at a number of designs to see what threads are recommended and trying to standardise. It's unlikely any clock plans will call for Whitworth! American designs might call for UNF, British for BA, and German metric. Actually it may not matter much because designs can be tweaked to use any thread system, but it's all time and trouble. I'd be interested to hear from proper Horologists which thread system(s) they use in practice?

Dave

I got a set of insert tools from Glanze. They use CCMT inserts. The 89* included angle lets you face or turn without re-orienting the tool. It also included holders that let you use the 100* corner so you can use all the corners of the insert.

Thanks John I'm still making sure I understand the uses of the different angles so the 100 degree angle is used for smoother turning than the 80 and the 80 would be for smoother than the 55. But sharper included ange lets you get in to tighter spaces but does it allow more metal to be removed during turning. If not you would if you did not have to get in tight always chose a wider included angle?

regards

Chris

When it comes to identifying unknown threads the compilation of threads in ascending size originally done by Andy Pugh and refined by other folk is pretty much unbeatable.

Much easier than normal listings 'cos you don't have to identify the thread type first. Normal way is far better if you plan to cut threads tho'.

The essential "wot thread is it" identifier here :- **LINK** in text format which may need bit of massaging for easy reading.

A bit of web searching should find links to a pretty Excel file version, which I use. Google should find a direct download link.

A pdf version here :- **LINK**

There is also an HTML version here **LINK**.

Clive.

Edited By Clive Foster on 29/08/2019 11:03:36

What you call "waves" are the form of each thread.

In the case of Whitworth form threads, (BSW, BSF, BSP and BSB - British Standard Brass ) the angle of the thread is 55 degrees.

The Depth of the thread is related to the pitch, by a formula, which need not concern you as a user.

Thus, a 1/4 BSW is 20 tpi, with a depth of 0.0320", whereas a 3/8 BSF is 20 tpi and the depth is still 0.0320".

If it were a 1/4 BSF thread, it would be 26 tpi with a depth of 0.0246". So for a given size, the finer thread would have a shallower depth.

The 40 tpi Model Engineer series are Whit form, but have a thread depth of only 0.016"

If you do not have one, invest in a set of Zeus Charts. You will find them invaluable. I still use the ones that I bought as an Apprentice, back in 1958!

This lists the details of many sorts of threads, giving tpi, pitch, depth and core diameter, and in a separate table the correct tapping drill and clearance drill to be used.

Additionally, it includes allowances for when bending sheet metal, and Trigonometry tables, which you may also find useful

Find a Model Engineering Club near you, and join. You will then be likely to obtain actual hands on experience, with other more knowledgeable folk.

Howard

Fat Fingers strike again!

Edited By Howard Lewis on 28/08/2019 18:29:29