Die confusion!

[Andy BrocklehurstParticipant @andybrocklehurst85292]

Ive just bought a tailstock die holder and some metric dies for some threading I wanted to do this weekend. Unfortunately the dies I’ve bought won’t fit into the die holders. When I measured the dies they all seem to be over size. Is this normal or am I missing something or bought the wrong dies????

[duncan webster 1Participant @duncanwebster1]

Common size for dies is 13/16 and 1 inch, which looks like what you have. What size is did holder?

[JasonBModerator @jasonb]

I would say you have imperial OD dies mascerading as metric or at least an inaccurate metric description.

the ones that are just over 20mm are most likely 13/16″ nominal and the ones just over 25mm are 1″ nominal

[JasonBModerator @jasonb]

This is a 1″ die

 

This a 13/16″

And this a metric 20mm OD

 

[JasonB]

On JasonB Said:

This is a 1″ die

 

This a 13/16″

And this a metric 20mm OD

 

On JasonB Said:

I would say you have imperial OD dies mascerading as metric or at least an inaccurate metric description.

the ones that are just over 20mm are most likely 13/16″ nominal and the ones just over 25mm are 1″ nominal

Thanks Jason, is this normal or should I send them back?

[JasonBModerator @jasonb]

Imperail OD dies are quite normal and can be used in imperial sized holders. However you have bought what is listed as metric OD when they are not so would have a good case for return particularly as you hove a metric holder to put them in.

An alternative would be to change the holder for an imperial one and make sure you don’t buy any more imperial OD dies. This may be the better option if you also intend to make things where imperial threads are specified as imperial thread dies tend to almost always have an imperial OD but metric dies can be had with either metric or imperial OD.

The other option is to make some imperial holders to suit your tailstock die holder and then you are covered for any future dies you buy.

[JasonB]

On JasonB Said:

Imperail OD dies are quite normal and can be used in imperial sized holders. However you have bought what is listed as metric OD when they are not so would have a good case for return particularly as you hove a metric holder to put them in.

An alternative would be to change the holder for an imperial one and make sure you don’t buy any more imperial OD dies. This may be the better option if you also intend to make things where imperial threads are specified as imperial thread dies tend to almost always have an imperial OD but metric dies can be had with either metric or imperial OD.

The other option is to make some imperial holders to suit your tailstock die holder and then you are covered for any future dies you buy.

I’ve emailed the company I bought them off so I’ll wait for their response. Many thanks.

[duncan webster 1]

On duncan webster 1 Said:

Common size for dies is 13/16 and 1 inch, which looks like what you have. What size is did holder?

All the holders are metric sizes as advertised on the box lid.

[VicParticipant @vic]

This is something to watch out for I think. Most of my Dies are metric threads and have imperial bodies to fit my Die holders.

How long have they been making metric bodies and metric holders?

[duncan webster 1Participant @duncanwebster1]

If it were me I’d just set up the 20mm and 25mm holders and bore them out yo 13/16 and 1″.

[Old SchoolParticipant @oldschool]

I have bought Volkel dies and found them to work well never realised that they were imperial OD.

My tail stock die holder came with both imperial and metric holders.

[JasonBModerator @jasonb]

Metric OD has been about for a long time

Altering the metric holders will mean having to make new holders when you have the need to hold imperial. Could make some adaptor rings to allow the larger 30 & 38mm to hold 13/16″ and 1″

Volkel make almost exclusively metric OD dies but they do make a few with imperial OD for legacy users who have imperial tools particularly the UK market as mainland Europe tend to be metric which is why I bought their imperial OD ones and why the likes of Rotagrip stock them.

Just take a look at their catalogue starting at page 174 for dies almost all metric OD and that includes the imperial threads, just a few with imperial OD. And like other makers a lot of solid dies not split

https://voelkel.com/media/4e/69/b8/1709295983/VD%2023%20DE-EN.pdf

[VicParticipant @vic]

Good info. If I need any more dies I’ll avoid Volkel like the plague! 😆

Looking at Tracey Tools Diestocks, the majority are imperial, just a few metric ones in lager sizes.

[bernard towersParticipant @bernardtowers37738]

I have some large diestocks with adaptor rings like Jason says and they look professionally made not home grown and ive had them for a good 30 years plus.

[VicParticipant @vic]

Are manufacturers really making imperial OD dies just for the UK market? I find that somewhat hard to believe?

[Vic]

On Vic Said:

Are manufacturers really making imperial OD dies just for the UK market? I find that somewhat hard to believe?

And the USA!

[Roderick Jenkins]

On Roderick Jenkins Said:

On Vic Said:

Are manufacturers really making imperial OD dies just for the UK market? I find that somewhat hard to believe?

And the USA!

They don’t seem so keen on metric cutting dies like us, but some hobbyists must be using them?
It also makes you wonder. Why when the UK started using metric cutting dies, they didn’t also use metric OD for them?
I’m sticking to imperial tap wrenches, that’s for sure! 🤣

 

[JasonBModerator @jasonb]

Dormer use imperial OD on all their dies but when I was renewing my metic coarse sizes were about 4 times the price of Volkel.

https://5wyuco84ao39w9tsgkkmnmx.blob.core.windows.net/cms/THREADING-2024-EN.pdf

As to why things did not change, too many people with old tools to put the dies in.

[DalboyParticipant @dalboy]

I took the precaution of buying a set which has both imperial and metric die holders, at least that should cover me for the sizes I use

[VicParticipant @vic]

Only a quick look on eBay but the Volkel dies I saw were imperial OD, just like the Presto ones, only a lot more expensive.

[Vic]

On Vic Said:

Only a quick look on eBay but the Volkel dies I saw were imperial OD, just like the Presto ones, only a lot more expensive.

 

 

Confirms what I said

Volkel make almost exclusively metric OD dies but they do make a few with imperial OD for legacy users who have imperial tools particularly the UK market as mainland Europe tend to be metric which is why I bought their imperial OD ones and why the likes of Rotagrip stock them.

[Vic]

On Vic Said:

On Roderick Jenkins Said:

On Vic Said:

Are manufacturers really making imperial OD dies just for the UK market? I find that somewhat hard to believe?

And the USA!

…
makes you wonder. Why when the UK started using metric cutting dies, they didn’t also use metric OD for them?

Bad decisions in the past.   British industry started by being up for anything, but rapidly degenerated into ‘old ways are the best’.  Various reasons: on the shop floor, old dogs don’t like learning new tricks and feel threatened by new ideas.  At the same time owners who’ve invested heavily in tooling are reluctant to change until they’ve got value out of it. Serious trust issues too: Victorian labour abuses led to Unionisation, with both sides unwilling to give up hard won privileges, despite the world changing around them.  All change was resisted, even good ideas. The Metric System is a considerable improvement over Imperial, yet it’s introduction was fought tooth and nail by small-c conservatives, largely for selfish reasons.

Most countries realised the advantage of metricating with a big bang and rode over the opposition. Painful for a few years, thereafter the benefits kicked in, and the old ways were forgotten.  Not here!  UK government wimped out by allowing industry to change as and when they wished.  Saved a lot of political hassle, but allowing two different engineering standards to coexist created a running sore.  Extra costs with reduced benefits and many jobs were lost.    That die holders exist in both Imperial and Metric sizes is just one example of the confusion and extra expense caused.

The USA, who have a huge local market, chose to ignore metrication, and were able to make Imperial pay.   They are why it’s still possible to buy affordable Imperial tooling in the UK.  But the rest of the world went metric, and even the US isn’t big enough to ignore the pain, and is slowly switching over.  Though Imperial is fading, the disadvantages of having two standards will be hurting the West for yonks yet.

Today, I recommend Model Engineering newcomers to standardise on metric unless:

• they live in the US, or
• intend to build models (especially steam locos) from old British plans, or
• have picked up a second-hand Imperial workshop for a bargain price,
• are British with no experience of metric.  Probably means being over 70 years of age!

Unfortunately, failing to grasp the Metric nettle in 1965 means British workshops have to cope with both systems, an an expensive nuisance 60 years later!  Sins of the fathers.   We are changing: when I first read the forum, over ten years ago, many members were Imperial Zealots, dead against Metric for non-engineering reasons, such as claiming it was unpatriotic! Metric was an unpopular minority choice.  Not so today, much less controversial, and metric model engineers might even be the majority…

Dave

[Robert Atkinson 2Participant @robertatkinson2]

For many years otherwise identical Ford Transits sold in the UK and Europe (made in Germany) had Imperial and Metric threads respectively. No end of trouble…
Commercial and military aviation still use mainly imperial fasteners. This is due to very long product development time and operational lives and the cost of certifying new parts.

Robert.

[Colin BishopModerator @colinbishop34627]

Though Imperial is fading, the disadvantages of having two standards will be hurting the West for yonks yet.

Many, many yonks. There must be millions of structures such as bridges etc. stuck together with Imperial fasteners. They could last for a hundred years or more.

I do agree than anything new should standardise on Metric but I must confess that I do find brass BA nuts and bolts are just the job for my modest model boating requirements.

But I am one of those crossover individuals who like to work in both as convenient at the time. Nothing like mm to the foot to keep the brain active.

Colin

 

 

[old martParticipant @oldmart]

I bought a tailstock diestock set and because the museum has many dies of different outside diameters we made some custom dieheads for the sizes that did not fit. Easy to make, just copy the fitting sizes that fit the holder and make the die a loose fit so that you can expand it slightly for the first pass. We made two or maybe three ends for the common sizes. We do have some bigger dies but I would prefer to singlepoint the larger threads if possible.

[Author]

Posts