Author Topic: Eureka-Tool.  (Read 416 times)

Offline Bruno Mueller

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Eureka-Tool.
« on: May 04, 2022, 02:23:51 PM »
While studying self-built gear hobbing machines, I came across a device with which it is possible to create a true-to-shape clearance angle on each tooth of multi-bladed form cutters.

The device is based on a patent from the USA by Stephan M. Balzer. Pat.No. 535,127. from March 1895 and a further development by Charles G. Taylor Pat.No. 817,885. from April 1906.

Prof. D.H.Chaddock and Ivan Law took up the idea and presented it in a simplified form in the magazine "Model Engeneer" in 1987.

I found the drawings in a booklet from England "Workshop Practice Series" No. 17, but the drawings and dimensions are not well visible in this booklet.

I asked in a forum if someone could provide me with better drawings, possibly still from the magazine "Model Engeneer". Fortunately I got better drawings for it.

Now the conversion from inch to millimeter started. First converted to millimeters to two decimal places and then adapted to round dimensions. The available material cross sections were of course also included.

After everything was done, the material could be ordered and started after delivery.



I have deposited the complete metric drawing set as a PDF file.
https://mueller-bruno.de/media/files/eureka-metrisch.pdf


Offline Bruno Mueller

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Re: Eureka-Tool.
« Reply #1 on: May 04, 2022, 02:31:13 PM »
Easter is over and there was time again to make chips.

Today was Part No. 1. The shaft with its two eccentrics.

Material: 42 CrMo4.

I have to explain something about the production of the main shaft. Making the shaft is not easy, because there are two eccentrics in total, which overlap each other.

First I turned the shaft to the dimension 45mm, of course with tailstock support.

Then I turned the shoulder for part no.2 38mm in the same clamping.

Now I changed the three-jaw chuck with the 125 mm four-jaw chuck with individually adjustable jaws. A miserable adjustment with the dial gauge for the eccentric whose center is 4.3mm away from the previous center began.

The dial gauge must show a full deflection of 8.6 mm at the end. At 90 degrees, the deflection must be the same.

For control I made a distance piece for the jaws. Rest on the bed and always strike the jaws at the same point. So the angularity remains.

Now turned the heel 25 mm , 16 mm and the shaft 10 mm in one clamping. Before this, a new centering hole was set and supported with the roller center punch.

After everything was ready, the shoulder for the M 8 x 0.5 mm thread was turned and adapted to Part No. 7. When the M8 x 0.5 mm nut is tightened, this part should not jam or have much play. The centering hole was then turned away with a very small infeed to make room for the centering hole of the final rotation axis.

Now the second eccentric was set. Its center point is 0.8 mm from the previous center point and 90 degrees offset from the first eccentric. It took me almost half an hour to get this right on the single adjustable jaw chuck. Now the center hole of the final rotation axis could be set. Supported by the roller center punch, the journal on the chuck side was turned a little until the shaft was round. On this surface, I could then, after reclamping with the dial gauge, adjust the clamping spigot to absolute concentricity. Centering and turning to 25mm. The turning work on the shaft was now finished.

Only a surface for the driver tension must be milled.

Offline Bruno Mueller

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Re: Eureka-Tool.
« Reply #2 on: May 04, 2022, 02:34:00 PM »
The ratchets are now also hardened. Normally, mild steel (S 235 JR) cannot be hardened.

I proceeded as follows. First heated the ratchets to cherry red heat and let them cool in nitrogen hardening powder.

Subsequently heated again and quenched in water. The file test showed that the surface was very hard. The file could not remove anything.

The retaining screws of the pawls are made of 42 CrMo4 and were also hardened and then tempered. Tempering is very important, otherwise the parts are too hard and break at the slightest load.

After all parts were cleaned, degreased and the screws with Loctite 243 inserted.

The moving parts were then oiled.
« Last Edit: May 04, 2022, 02:42:40 PM by Bruno Mueller »

Offline Bruno Mueller

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Re: Eureka-Tool.
« Reply #3 on: May 04, 2022, 02:34:47 PM »
Resume:

Making the part was a nice challenge and a demanding job. There was some headache in the production of the main shaft with its two overlapping eccentrics. Adjusting the single adjustable four-jaw chuck took what felt like hours. It was the first time I had worked with the 42 CrMo4 material. Machinability on the lathe and milling machine was good. I learned that it is important to temper the material after hardening.

The piano wire was easy to work with.

The first time I treated mild steel with the nitrogen hardening powder, the result was excellent.

Now I just have to try out how the part behaves in the production of form cutters.

Here is detailed the whole process.
https://mueller-bruno.de/eureka.html
« Last Edit: May 04, 2022, 02:45:01 PM by Bruno Mueller »

Offline crueby

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Re: Eureka-Tool.
« Reply #4 on: May 04, 2022, 02:51:37 PM »
Quite an interesting project!   Do I understand correctly that this machine will create the cutters, which are then used in normal hobbing process to cut the threads on the end parts?

Offline Bruno Mueller

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Re: Eureka-Tool.
« Reply #5 on: May 04, 2022, 03:11:16 PM »
It should actually be possible to produce hobs with it. Actually, the device is to manufacture disc mills so that they retain their contour during regrinding.
There are a few videos with this device on Youtube.
I the search bar on Youtube "Eureka Tool" enter.
https://www.youtube.com/results?search_query=Eureka+Tool

Offline RReid

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Re: Eureka-Tool.
« Reply #6 on: May 04, 2022, 03:20:06 PM »
Thank you for posting your drawings of the tool, along with your description of making it. There are some interesting and beautifully executed project shown on your website as well! The Bosch-Combi is an interesting little lathe, and part of a clever system overall. :cheers:

Regards,
Ron

Offline Dan Rowe

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Re: Eureka-Tool.
« Reply #7 on: May 04, 2022, 03:52:15 PM »
I proceeded as follows. First heated the ratchets to cherry red heat and let them cool in nitrogen hardening powder.

Interesting and I would like to give it a go but my search for 'nitrogen hardening powder' did not help as there were way to many websites with different products. A link to what was used for the process would be very helpful.

Cheers Dan
« Last Edit: May 04, 2022, 05:08:25 PM by Dan Rowe »
ShaylocoDan

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Re: Eureka-Tool.
« Reply #8 on: May 04, 2022, 05:36:08 PM »
I proceeded as follows. First heated the ratchets to cherry red heat and let them cool in nitrogen hardening powder.

Interesting and I would like to give it a go but my search for 'nitrogen hardening powder' did not help as there were way to many websites with different products. A link to what was used for the process would be very helpful.

Cheers Dan

Kasinite
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Dan Rowe

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Re: Eureka-Tool.
« Reply #9 on: May 04, 2022, 06:28:55 PM »
Kasinite

Thanks, Dave I have a can of that on the shelf.

Cheers Dan
ShaylocoDan

Offline Roger B

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Re: Eureka-Tool.
« Reply #10 on: May 04, 2022, 08:07:50 PM »
My Swiss/German version translates as 'Nitrogen Hardening Powder to Spread/Sprinkle'. it's just case hardening powder.
Best regards

Roger

Offline PJPickard

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Re: Eureka-Tool.
« Reply #11 on: May 05, 2022, 01:12:31 AM »
Thanks Bruno, this tool is on my to do list! 3D files of it are available on Grab Cad(or they used to be anyway I haven't checked recently)