Metrication, screw threads in particular.

[Malc-Y]

The thread about BA threads (no pun intended) got me thinking about this thorny subject. I am old enough to have left school before the matter of metrication reared its ugly head and try as I might, I still can't get my head round it. The only concession to metrication that I have made in my workshop is a set of metric drills from 1mm to 10mm by tenth of a millimeter increments. As far as taps and dies are concerned, I may have the odd one or two picked up in job lots of secondhand tools. As most of the work I do involves old machinery (Steam traction engines) and model engineering, I have never had the need for metric screwing tackle. I still use British Standard Whitworth (BSW), British Standard Fine (BSF) British Standard Brass (BSB, a constant pitch series, 26 TPI all diameters), British Standard Pipe (BSP), British Asociation (BA) and Model Engineer (ME) for most of my work. I also have taps and dies for UNF, UNC and NPT threads.
Here in the UK it is still easy to get hold of Imperial size drills, taps, dies and reamers etc. but it is getting increasingly difficult to get fasteners in imperial sizes, especially if you only require a small quantity of a particular size, say half a dozen or so. Last week I tried to buy two 3/8" x 2 1/2" unc bolts to attach the travelling steady to my Colchester lathe, no luck so far.
Am I just a dinosaur living in the past or should I just try to carry on as I am?

Malc.

 

[richie k]

Malc
unc and unf fasteners are still readily available from any decent engineering supplier. The normal ironmonger won't bother to stock these as his customers are mostly metric nuts and bolts men. There are specialist fastener people in every major UK city.Keep up the good work on those old engines.
Richie

 

[Carl Darnell]

I am a 65 year old dinosaur I guess 'cause I still use the old ways and fractional sizes. I only get metric stuff when the drawing or project requires it.

 

[Malc-Y]

Hi Richie,
I tried all my local engineering suppliers and they are no longer willing to sell small quantities of nut, bolts screws etc., I would have to buy a box of 50 or 100 depending on the size which is a lot of money if you only want the odd one or two and don't want boxes of fasteners that will probably never be needed just lying around. This seems to be the trend among supplies here now. For sizes that I use plenty of, there isn't a problem but I can't justify the expense of buying 50 when I only need 2.

Malc.

 

[johnoder]

Try emailing these folks where you get to talk to actual people and ask them if they would send small quantities by mail provided you opened an account and had access to catalog numbers (from your yankee pals with catalogs)

[email protected]

The is the Atlanta, Georgia USA address of McMaster-Carr, that has way more "not metric" bolts than anyone will ever need.

John

 

[Limy Sami]

Cromwells UK list and stock imp threads, agricultural/ tractor dealers, (must be some in the land of the concrete cow), they usually have good stocks, - John Deere and Case esp, look for one that stocks ''BEPCO'' products, if not got fasteners they'll be able to get in small quants.
I will have a delve for your 3/8 X 21/2 unc's and email u if I'm lucky.

Take care Sami.

 

[Malc-Y]

Hi Sami,

I appreciate your efforts on my behalf, I've just had a look for Cromwells in the Yellow Pages and my nearest branch is in Bedford, about 20 miles away. I'll give them a call tomorrow.

Malc.

 

[RC99]

Even though we have been metricated since 1969 it is still easier here to purchase Whitworth bolts at the local hardware stare than metric bolts...

 

[CharlieBiler]

I am so glad I live in such a backward land. Twenty five years ago the gas pumps went metric, for about ten minutes.

They pased, in this state, a law to force milk to be sold in metric. I think they quietly strangled that enlightened boob, at the milk marketing board.

We totally went metric twenty years ago. The local hardware stores and fastener suppliers still work overtime keeping the dust off the metric bins.

In three or four generations we may even be able to even buy metric end mills without calling in a special order.

Bless those government officials and may they swing long and twist slow from every meter of good rope.

 

[Limy Sami]

Malc, sorry I had a good delve in my shop, no joy, niether at two of my mates close by, Cromwells take ''plastic '' orders and deliver FOC in my area.

Take care. Sami.

 

[JV]

Just reading about BSF, BSW, BA, ME, BSB, BSP, UNC, UNF, NPT threads, makes me so thankful for having grown up using metric threads exclusively. It makes life so much easier. The metric standard series covers far more than 90% of all applications, one tap and die set is all most people ever need.

 

[RC99]

Just reading about BSF, BSW, BA, ME, BSB, BSP, UNC, UNF, NPT threads, makes me so thankful for having grown up using metric threads exclusively. It makes life so much easier. The metric standard series covers far more than 90% of all applications, one tap and die set is all most people ever need.

Perhaps... I like the metric system as far as it's lengths and weights go but I hate it's threading system with a passion...

why oh why they decided on such a backwards way of working out threads, a system where you need change gears for the threading dial if you want to cut a metric thread on a lathe with a metric leadscrew.. A system where it seems every country has decided on what it wants to set as a metric thread standard..I have come across a vast array of weird and wild metric thread pitches(no doubt made to some obscure constant pitch ISO standard but shunned by bolt manufacturers except for OEM's), however if I work on an old US/British machine they all mostly stuck to using standard pitch bolts...

 

[Rudd]

I've noticed that an "x" sized metric bolt from Japan will have a 10mm head, and the same thread one on a VW will use a nine. Not just the one case. Seems Europe likes the odd numbers, Japan the even. Not a big deal, just a minor PITA. Something Machinery's Handbook sorted out a long time ago for Imperial, at least here.
Metric is a heck of alot easier when it comes to figuring physics of things.. as RC says. BTU's, ft/lbs, etc are alot more unweildy than joules or newtons.
Weird obscure pitches? We've got it down in the Unified National series, no need for metric to make it more confusing. 5-6 different pitches for a 3/4" fastner, on top of the 3/4-10 NC and the 3/4-16 NF. how's about a #10-56 tpi screw? or 10-64? Right there in the book. I have some on an old machine. Stripped.
Two things that boil my bottom - Ford truck made in Norfolk Va, Lincoln town car made somewhere in the US, you need both metric and imperial wrenches to work on them. Make up your mind, one or the other. Sheesh.

Lost a bolt into the spagehtti on the truck last weekend, took it off with an 8, went and got another 6mm bolt, put it back in with a 10mm wrench. ?

I think the imperial system of measurement is something not many people take the trouble to master, therefore, the people that do are more valuable. It's a trade skill. How many of you (in the US) can tell me the decimal equivilants of 32's of an inch w/o looking at a chart or your Starret mike? I'd bet most. The F-16, co-produced all over the world, but based out of Air Force Plant 5 in Texas, shipped fastners all over the world, all bolts/rivits etc. were/are imperial. Makes it just a bit harder to work on if you make us mad...

Other thing, I do some construction estimating. Anyone care to guess what "M" means as a quantity? Yup, it's 1,000, just like the Romans intended. Right there in the 2007 (AD) edition of Means.

 

[Dimitri]

Canada went "metric" but really we are a "odd" system nation. Imperial and metric are somehow "co-existing" more or less for the most part.

Mind you most things seems to still be in Imperial including machining which makes sense considering 84% of everything we export ends up in the US. Personally a good 90% of everything I do is still in Imperial.

The metric system sucks for fasteners IMO, for fasteners I'm going to stick to the UNC/UNF series thats 2 pitches for every size you can imagine with standard bolt diamentions!

Dimitri

 

[gmatov]

Dmitri,

There are not 2 standards for every size. I/2 inch can be 1/2-13, 1/2-20, 1/2-24, 1/2-28.

Most other diameters are the same, depending on the application and the Engineers desires.

Look at a comprehensive thread chart.It's 4 feet long, or more, not that one page you get from the fastener salesman. They are kinda dumb people, else they would not be salesmen.

I have been trying to buy a couple 1/2-24 bolts to make a new mandrel for my rivet press. Cnn't be had. Rarer than Unicorns, and THEY have like a one in one foot thread.

Same for tubular rivets, would like to buy some, biggest supplier of them sends me a flashy double leaf flyer. Have to register to even get THAT. No idea what they cost. I don't really give a damn, would like to buy a hundred, if I gotta buy a thou, so be it.

TELL ME HOW MUCH, AND WILL YOU EVEN SELL THEM TO ME?

I NEED about 24, might use the rest before I die, might not, BFD.

Suppliers are some of the most arrogant people there are. You GOTTA get it from us or look further.
I WILL look further, especially since I found you queried you, and you ignored me.

Cheers,

George

 

[richie k]

The Germans and Japanese realised the importance of imperial and metric threads a long time back.They both produced in the early fifties lathes with fully enclosed screwcutting boxes no need for change gears.Result a massive world market.Many US and UK makers never grasped this and only the ones that did, survive.As regards imperial sizes, trained in imperial but never want to see it again,too slow, too much head wrecking conversions and calculations.No more imperial oddball bearing sizes[US NOT UK]. Now thats an area if you want a shock [in europe], buy imperial bearings.

 

[Malc-Y]

Metric fasteners and bearings are fine for people working on modern machinery but are as much use as an ashtray on a motorbike if you are repairing old machines that were built using Imperial standards (either British or US). Many modern business men would have all old machinery (and vehicles) consigned to the scrap heap but there are a lot of old machines of all types that have plenty of working life left in them, not everyone needs or wants cnc machines. Perhaps some enterprising business man will programme his cnc machines to produce Imperial fasteners.

Malc.

 

[richie k]

Modern manufacturing in europe with extremely high labour costs dictate the use of cnc and even better still if its a lights out situation.All of their poduction will be to metric spec. if its for machinery being poduced for the EU.Bearings and fasteners in imperial size are manufactured at a higher cost because of small runs requiring more frequent changes.Nuts and bolts come in various sealed packed quantities depending on size. When they came in the hessian sacks the ironmonger sold whatever you wanted.Today he will not split a box of imperial sizes due to the inconvenience. The simple way to overcome this is for members of vintage clubs or model engineering club to share and split cost if they each only require small quantities. The ironic thing it all this is when you look at the packaging the bolts were probally made in Germany.Now for the one off repair type shops there are still plenty of old and very old good manual machines working and will continue to do so for a long while.Some of these are a unique breed and their type existed also in the days of the capstan and autocycle mill[THAT ERA]but they never entered into masss production.No cnc ,no computer,work behind closed doors,the repaired or new part handed through a small hatch,the guy the cnc people hate.
Richie

 

[johnoder]

They both produced in the early fifties lathes with fully enclosed screwcutting boxes no need for change gears.Result a massive world market.Many US and UK makers never grasped this

Lodge & Shipley Model X ( that is a USA make) was closed quick change gear box. Came out in middle of WW2

Always helps to have all the facts.

John

 

[richie k]

I never said any USA or UK manufacturer. I said many.