Metric/Imperial/MT/R8 ....... where lies the future?

[John Candy]

Machine tools continue to be offered in a variety of "standards"; Imperial has survived Metrication (probably as much to do with the US shunning Metric as for any other reason).
Since we scale our model in Metric units, it makes sense to buy Metric machines....or does it?

When it comes to chucks, etc. which is more "future proof", Morse Taper or the "R8" standard?

Machines are offered in any combination of these standards, so which makes most sense, with an eye to the future availability of tooling?

John.

[Andy B]

Well John, open questions like those are prone to stirring up big debates on buying new vs used, quality of imported machines, etc. 

My simple 2p worth to try to directly answer your points:
Imperial vs metric - primarily depends on what you're comfortable working with. If one equips the tools with a DRO, then there is no issue - just switch the display. The US is still a significant market for small chinese-built machines, so imperial will be available for many years yet.

Machine tapers - the common standards, like MT, R8 & ISO will be around for years yet. I don't forsee any of these becoming hard to obtain. If you look at companies like ARC Eurotrade, or the 'quality' chinese suppliers like CTC tools, they are bringing out new products with all these tapers.
It will also depend on the size of machine. At the 'small' end of the range of machines for doing G3 work, one will only have MT (No 1 or No2). At the 'larger' end, R8 or ISO 30 are also possible, and have their advantages over, say 3MT (ease of removal being one).
Some people like to stick with MT on a mill as it may be common with their lathe.
Some go for a particular fit as their mate down the road has the same and they can share the less-used tooling.

In summary - Horses for courses, but you're likely to come across some very polarised views......

[cabbage]

Having grown up in a metric country and emigrated to the UK... All my tools are metric but the standard for "kitchen sink engineering" is MT1 & MT2. I use this because of the large range of tools that are easily available in MT2.

Regards

Ralph

[John Candy]

Thank you Andy and Ralph.

I am considering a new milling machine which has MT3 and Imperial/Metric options while other contenders have R8 option.

My biggest concern (and what may ultimately be the deciding factor) will be weight!
The machine I would like weighs 150Kilos and would be impossible for the two of us (old and infirm) to move/assemble, although it may "knock down" into manageable components.

My existing machines are MT2 and Imperial, so ultimately I may settle for MT2 but Metric.

Regards,
John.

[IanT]

Most of my machine tools are "old" and therefore Imperial in nature. They have a mix of MT tapers - mostly MT1/2 - although my large mill is MT3.

Therefore the dials are Imperial and when machining I work in 'Thous' and use an Imperial micrometer. When 'laying-out' work - I tend to measure in mm's (which I find easier to read on a Vernier or rule) and all my CAD work is generally in mm's too. I don't find this a problem and can easily convert between the two without too much trouble (1mm = 40thou'ish / 4 thou = 0.1mm etc) - only using a calculator if I need to work with fractional numbers.

When building or repairing models I use mostly BA & ME fasteners, either because they were used originally or because they are conveniently sized and I have good stocks of them. When building tools, jigs or fixtures I use metric fasteners exclusively because they are less expensive and freely available. I have drill sets in fractional, number and letter sizes but wherever possible now use metric drills (and have sets in 0.1mm steps from 1-10mm). 

If I was starting from scratch and purchasing new equipment, I would specify metric dials and standardise on it where possible. The lathes would probably still have MT2/3 tapers but I would choose an R8 taper for the mill, simply because it is easier remove than an MT taper.

Whilst we are on the subject, I've tried various collet systems but have now standardised on ER32 & ER16, with a few C5's for special uses. I have various machines, collet blocks and rotary/work holding devices that use these fittings.

So it's quite easy to live with both systems but for anyone who's starting out - I'd just go metric and simplify things....

Regards.

IanT

PS Just seen John's latest post. Even with MT2 tapers on both my S7 & Atlas mill - I would still opt for R8 on any new mill. MT tapers get stuck when 'drawn-in' and can be hard to remove - R8 doesn't suffer from this. I don't use MT tapered "chucks" on my lathes either, always choosing a back-plate mounting (including for all my ER16/32 chucks) - as they a) can be adjusted to run absolutely true and b) will pass material through the headstock (which an MT taper mounting cannot). The choice of Imperial or Metric will largely depend on personal preference of course.

[John Candy]

Thank you Ian.

On the basis of your advice I will go for R8 since it is a bugger when I have to change chucks on my MT pillar drill. Could do with three hands...one to hold the drift, another to wallop it with the mallet and a third to catch the chuck!

Metric with R8 it shall be.

Now just have to find one with all the features I would like and which doesn't weigh a ton.

Regards,
John.

[jamiepage]

John,
I do firmly believe in the adage of buying a machine that seems too big, rather than one you could make do with.
It would be a shame if you denied yourself the option of something more substantial just because of difficulties in installation.
All my machines, both second hand ex- tech college, and new from the Far East via Warco were installed by the supplier concerned. For the secondhand machines, ( a Bridgeport and Colchester Triumph 2000) the positioning formed part of the negotiations. I'm trying to remember, but I think Warco charged something or other, although again it got wrapped up in a deal to take an old machine away as part exchange, plus bells and whistles such as DRO etc.

It might be worth thinking about, especially if you don't plan to move for the forseeable- and the railway suggests you don't.

As to the actual question asked (!), then yes, R8 for a milling machine. Imperial or metric? There may be a case for standardising, but it's simple enough to convert anyway, so look for a deal, or delivery times etc. My mid sized mill was a few quid cheaper, brand new,  because it had been returned from another customer who wanted what it wasn't. With DRO, which I thoroughly recommend for all sorts of reasons, it really doesn't matter, as Andy says.

Yours
Jamie

[John Candy]

Jamie,
Thank you for those thoughts on not selecting an inferior spec just because of weight issues ... it is the reason I have been putting off the decision for a few years now.

I will have to see whether I can arrange for the Monkton Priors team to be here on delivery day and cajole them into helping unpack!

Regards,
John.

[jamiepage]

John,
It only has to be done once, but you'll be living with the machine for a long time so it seems a shame not to 'go large' if that's where you're tempted.
If you've got the space, and a nice stable floor, put the problem to the supplier.
Certainly, in my experiences, they arrived with all the kit, slings, trucks,  and the knowledge to move the things around safely and efficiently.
All I had to do was make the coffee.
Yours
Jamie
Not sure whether you are thinking of it, or indeed whether you're already converted,  but I would strongly recommend 2 axis DRO on your mill. I need all the help I can get, and it is superb. No more squinting at dials, or adding/ subtracting compounded dimensions, or twiddling about with backlash; just look at the screen.
A pair of loco frames can be milled out of a sandwich of sheet material simply by indexing a small dia. cutter along the two axis. Spot and drill axle holes, (or mill slots),  then use the same dimension on the screen to drill coupling rods with guaranteed accuracy.

[tramcard]

Well the last influence of the imperial system on the metric system has just ended. The Johnson Mathey made kilogram standard has finally been replaced.
Technically though we are using the SI standards where the unit of force/weight is the Newton only created in the 1960s.
As real engineers in the USA are going metric there seems little point in hanging on to a previous system.

[cabbage]

I was rasied in a metric country before we emigrated to the UK... I thus was a firm Gramme Centimetre Second user!!! I don't really have any problems with differing styles of measurement. My mother bought cloth by the Metre or El or Yard. My late wife bought fabric by the "fat quarter".

My only real concern begins when the volume of liquid served to me over the bar is not "a kings measure"!!!

Regards

Ralph