Emco Compact 5 Modifications

[PeteParticipant @pete41194]

As always wonderful, well designed and thought out Gray, and certainly better than my use of a DI with an enlarged “elephants foot” tip on it. Mine works well for tools in there normal orientation, but as you pointed out yours can also work with the tools inverted. A very cleverly designed tool in my opinion.

Fwiw, I have an old book that shouldn’t be impossible to find a used copy of even in the UK that I think you’d find of great interest. It’s one in a series from the American Machinist Library titled Tool and Gage Work and written by C.L. Goodrich & F.A. Stanley. No ISBN no. of course since that was before the ISBN system was invented. It was first published in 1907 by McGraw- Hill and mines a 1923 second edition.

In it there’s a description and working drawings for a dial less but high multiplication early form of DTI. Starrett Tools at one time produced one much the same. They show using a shop built version of it, a set of shop made hardened and ground tool maker buttons, and positioning by hand with a micrometer and that DTI master gages for a typewriter manufacturer on a sleeve bearing lathes face plate to under 10ths accuracy for boring and finish grinding. All done before jig borers and grinders were even invented.

There’s also a full chapter on what must have been the very first set of Johansson gage blocks in North America, and they speculate how they might ultimately be used by industry. Quite remarkable just how accurate those predictions turned out to be.

[Graham MeekParticipant @grahammeek88282]

Hi Pete,

Thanks for the kind comments and the reference to the book. I will definitely try and search that one out. I did see the Starrett and Verdict patents in amongst the ones John sent me. It was the simplicity of the Verdict patent that started me off on this current design.

I seem to recall Ford buying out the Johansson business, but I am not that sure I am correct. At the time I seem to recall thinking it was something you would not associate the mass production techniques of Ford with. I am almost sure I have a few odd gauge blocks made by them in my small parallels tin.

Regards

Gray,

[PeteParticipant @pete41194]

You very welcome Gray.

The history of the Johansson company is a little murky. As far as I know, Johansson after introducing those gage blocks into the U.S. started out in America and had Ford as a partner. Apparently as soon as Henry Ford saw his gage blocks he was convinced they would be an instant success. I believe but don’t know for sure Ford bought Johansson’s gage block production facility some time later, but the early gage blocks were stamped with Johansson’s name as well as having the Ford logo on them. I’m pretty sure the rest of Johansson’s business in Sweden was never any part of his partnership with Ford and was always a separate entity. Another guess, Johansson likely used the sale of his share of the gage block facility and reinvested it back in Sweden. Around that time or slightly later he brought out his Mikrokator, a very high accuracy plunge indicator. I’m fairly certain his initial design was used and adopted later after the patent ran out by at least a few other manufacturer’s. I’ve read that most of Johansson’s internal design for those Mikrokators is still used in the Mitutoyo millimess indicator I have that’s actually built and labeled with the Mitutoyo logo by Mahr. Afaik the only real difference between the Mahr indicator and mine is a simple plastic bezel with that injection molded Mitutoyo’s logo on it.

I know the Johansson company also manufactured very high precision indicator test stands for use with his indicators. Beyond that, I’m not sure what else they produced. Today those indicators and test stands can usually be picked up at fairly reasonable prices since not that many are now familiar with the name or the history. Even Starrett and Mitutoyo still make indicator test stands to the same general design that Johansson used.

One often repeated story about those first gage blocks was that Johansson produced the first few sets using a converted treadle driven sewing machine to lap them flat, parallel and square to those low millionths of an inch accuracy. Since Johansson would have been trying to protect his patent and keep his methods secret, I’ve always been a bit suspicious as to just how valid that story was. But I’ve yet to figure out how he did manage that level of accuracy given the technology available at the time.

[Graham MeekParticipant @grahammeek88282]

Hi Pete,

Many thanks for the update on Johansson. I have learnt something new today, thanks for that. I seem to recall a pair of Gauge blocks wrung together with a large weight hung from the lower block.

I too wonder how they managed to achieve the finish and accuracy back in those days. Getting something flat is one thing but to get that flat parallel to another flat and to within half of nothing is quite a different matter. It is thanks to their determination to strive for something better that we have such good equipment today.

Regards

Gray,

 

 

[PeteParticipant @pete41194]

Well unfortunately I seem to have taken your thread a bit OT Gray. But I guess some of it is at least remotely related to that very clever gauge you came up with.

In that book I mentioned, they show two gauge blocks wrung together and with a weight of 11.75 lbs suspended from them. So even back in the early 1900’s, they knew and could calculate the surface area that there was much more than atmospheric air pressure holding them together. They just didn’t fully understand the exact reasons. Most today agree it’s caused by what’s known as the Van der Waals effect or force in combination with lesser effects like that air pressure and possible surface tension at the molecular level.

Two surface flat enough to wring together would be tough enough. Doing the same in all 3 dimensions, parallel and to low millionths level for those surfaces, and then to extremely accurate sizes, plus accomplishing all that for each set of blocks, is as you say quite a different matter. Afaik and from my limited information about it, manufacturer’s around that time period and prior to Johansson’s gauge blocks already manufactured there own various sized single blocks to suit there own in house gauging requirements and used as there own reference standards. Obviously and without the specialized lapping and measuring equipment, the true sizes and finished accuracy could vary a bit. It was also considered a large, ongoing, costly as well as time consuming effort by those same manufacturers.

Johansson’s invention gave them high precision size standards to use within at least known amounts of deviation, and in my opinion, that ability probably accelerated the previous ideas about interchangeable parts. Or at least made it much easier. I also think once they started being adopted as standards and if you consider a bit of manufacturing history, you also started seeing many more standards being put in place between the early 1900’s and WW II. Fully agreed to and formal standardized thread sizes and pitches world wide would be just one example. Johansson’s gage block invention may not have been the single and only reason, but to use a bit of logic, they might well have been a large part of it.

[Michael GilliganParticipant @michaelgilligan61133]

At the significant risk of creeping this topic even further:

https://www.nist.gov/system/files/documents/calibrations/mono180.pdf

… it’s long, and quite techincal.

MichaelG

[Graham MeekParticipant @grahammeek88282]

No Problem Michael,

I am always open to learning something new about Engineering. The subject was touched upon in my ONC years but I must say my memory will not recover that information.

To get us back on track here is the Mk1 version which was too big.

 

Regards

Gray,

[Graham MeekParticipant @grahammeek88282]

Twenty years of wear on the knurling of the Feed screw Handwheels on the C5 had reached the stage where I could not grip them very well any more. While new handwheels are still available from Austria. I decided to make some new ones similar to the ones I made for the Unimat 3 that I have. An example of this type can be seen on the C5 Topslide.

 

I also took the opportunity to alter the cone angle of the handle to give better access when adjusting the dials. The revolving handles were also changed. The new ones are parallel and made of steel. The tapered plastic Emco ones were also showing a lot of wear. The handles revolve on a commercial 6.5 mm diameter x 25 long Shoulder screw. This has an M5 thread and screws directly into the Delrin handwheel. A custom steel washer abuts the shoulder screw and increases the contact face with the Delrin. This washer also stops the handle from wearing into the Delrin over the years to come.

This mod was done some weeks ago, but today was the first chance I have had to get a photograph.

Regards

Gray,

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