Ohrndorf V12, new challange

[fumopuc]

Achim,
I am enjoying the progress and seeing your setups. I assume you're doing the crank webs in matching pairs. Keep up the good work!
Art

Hi Art, thanks for watching.

Today was the day for the little CNC mill to eat steel.
The outer contour of the webs, 15 pieces over all.
Temperature in the shop nearly 31°C.
Final marking done also.
Very fine steel swarf all over the place.
But finally all parts done.

[Vixen]

Hello Achim
À fine looking set of steel crankshaft webs.   
Did you cut them wet or dry?

Cheers

Mike

[fumopuc]

Hi Mike,
Good Morning.
I have been unsure if it is really useful, but at the end the decision was to cut it wet.
May be it was helpful for the cutter live time.
The cutting parameters have been very conservative.
Material is ETG 100
A 3 flute 5 mm VHM cutter was used with 5700 rpm (90 m/min).
A feed rate of fz 0,0305 mm should be possible, but I wanted to be gentle with my small CNC mill and I have reduced it  to fz=0,0116 mm (200 mm/min)
Radial depth of cut Ae was 0,5 mm and max axial depth Ap 4 mm, so two steps for the  7 mm thickness of these part.
The finishing operation was Ae 0,2 mm and Ap 7,2 mm.
It took around 14 minutes run time each web, but every time I have checked spindle and stepper temperature it was "hand-hot" only, so I felt confident.
The mill was running the entire afternoon.
Before will I clean the mill now, I will try to measure the out come of my MQL settings.

[Art K]

Achim,
That is a really nice set of parts, each in its own muffin tin!
Art

[Roger B]

Excellent   

I wondered where the little Proxxon vice came into the precision set ups and then I saw it was just to stamp the numbers 

[fumopuc]

Art, Roger thanks for popping in.


Time to catch up to the real build status again.
Crank webs next steps, holes, threads and a recess for the head of the bolts, followed by cutting the slot.
My circular saw blade was not the best anymore, but it survived and the webs also.
tbc

[fumopuc]

Some deburring, specially around the slot was necessary.
Also some internal stress was detected, the 9 mm holes has Not been the same after the cut.
So the 9 mm reamer was used to get it round again.


I had to find a way now, to assemble the crankshaft out of the crankcase.
So here my thoughts how to do it.
I will try to explain with some CAD pictures.
First picture, the crankshaft how it should look like complete, with the exception of all con cords, one pair only as a sample only.
Next picture, together with the main bearings and, not really visible, some axial bearing discs from bronze.
Idea is to fix this unit at a simple plate.
Some quick an dirty made 3D printed parts, the yellow ones should do it.
Last but not least, I have to find a way to bring the web units into the right angular position to each other.
Also here some 3D printed jigs should solve the problem.
tbc

[fumopuc]

The 3D printed jig here in detail.
The 3D printer was quick with this small parts.
2 of each should be enough for the final set up.

[fumopuc]

The right M4 bolts for the webs arrived and I have started to shorten the 9 mm pins with my tool grinder to the correct length.
When all these part laying on the table, I could not resist to try to joint the very first web unit with the arbor press.
All made with my extra set up parts.
First I had to measure the stack of the the con rods and the three bronze discs.
With this information, a 6 mm pin was also prepared with the tool grinder.
At the moment no pictures from all the details, but I have to make another 6 sets and pictures will follow soon.
The result can be seen below.
Also a quick movie, with the parts in my 3D printed dummy crankcase.
https://youtube.com/shorts/EnA4KVWr1c8?si=xuIzvRf9OQPS0OHw

[RReid]

Excellent progress Achim, and more beautifully made parts!

[Admiral_dk]

I like your 3D printed Jigs and how you use them 

Great progress again - but I have to ask - did you have any problems aligning the Reamer again ?

Per         

[fumopuc]

Excellent progress Achim, and more beautifully made parts!

Hi Ron, thanks for watching and the friendly words.

[fumopuc]

I like your 3D printed Jigs and how you use them 

Great progress again - but I have to ask - did you have any problems aligning the Reamer again ?

Per         

Hi Per, thanks.


The reamer was used, not turning, to center the part with the floating vice, before I switch the spindle on and pushed it in the hole again.
I hope that this will not have caused any new misalignment.

[fumopuc]

Hi everybody, I will try to show the way how the assembly has been made.
First another jig was necessary, as a stop for the press fit.
Than I have measured each stack of the con rods and web pairs.
The relevant 6 mm pin for each assemble has been made the same length as measured.
A new champfer each side was made again and the pin set the first tenth by a hammer.
Now cleaning and adding some Loctite 646.
tbc

[fumopuc]

The arbor press has finished the job to set the pin in one web.
Now the conrod assembly.
A 9 mm pin in a light slip fit as an additional guide.
tbc