Building a V12 crankshaft

[ZAPJACK]

Picture 11 & 12: Here is the first steps, the part have now 4.5kg weights and we already have 2.5 kg of chips.
Picture 13: Drilling the centers with centers drill. The four big one’s are corresponding to the axles of journal and crankpins. The small one’s are the future binding of the reductor gear. To make it easier, it is possible to program the DRO and have the right drilling postion following X &Y. As soon as the first face is finished, it is necessary to turn the part and to do the 4 centres once again. Take care at the right position of the milled flat it is very important!!!

 

[ZAPJACK]

Picture 14 : To increase the precision and the rigidity of the assembly, I totally have to unsettle the table of the milling machine.The part is thus directly fixed on the bench. The part has to be perfectly ofset square and the plate (Ph4)turned and perfectly parallel to the bench. Check with a rail of 30 cm atleast.
Picture 17: Fastening must be strong and hard.

 

[rccubed]

I hate to show my ignorance but what kind of machine is that?
Also I would like to say that this is some of the best education some of us Garage guys will ever get! Thank you for posting and explaining it! And it goes without saying, this is some awesome work!
LW

 

[canadianhorsepower]

Picture 14 : To increase the precision and the rigidity of the assembly, I totally have to unsettle the table of the milling machine.The part is thus directly fixed on the bench. The part has to be perfectly ofset square and the plate (Ph4)turned and perfectly parallel to the bench. Check with a rail of 30 cm atleast.
Picture 17: Fastening must be strong and hard.

Salut Zap tres belle ouvrage facinent a reguarde. Je reste de vant l'ecran et attand pour des photosth_wavth_confused0052

Luc

 

[ZAPJACK]

what kind of machine is that?

It's a SHAUBLIN 13 type milling machine. Swiss made.
LeZap

 

[ZAPJACK]

Pictures 26, 29, 30 and 32: Now, on the milling machine, it is necessary to debur crankpins by milling it. Mill with a 3 sizes alternated of10x100mm plate-mill. 58 r.p.m. and 17 mm/min advance. The target is to obtain more or less six squared crankpins!!!
Very visible on (Picture 32)
Picture 33: Marking of crankpins coupled by cylinders to avoid stupid error.

 

[ZAPJACK]

Picture 35 and 36: Now, place the crankshaft between centers on the versatile dividing head
The centres used are of course those of the crankpins.
The milling machine must be fitted with milling head and 10mm end-mill. Now it is necessary to make round the square crankpins. Then move laterally the mill in order to adapt to the required dimension, we are still in deburing phase. Combine the mill rotation and the spindle manual rotation of the versatile dividing head until you get 0.5mm of the definitive quotation.
Note 1: The versatile collets holder willlet go back up the end-mill inside the holder which will falsify all yourmeasures. To avoid this phenomenon, use tool holder with single diameter.
Note 2: This method of milling (using atthe same time the end mill and manually the rotation of the versatile dividinghead) gives a shape of keg to crankpins. This phenomenon decreases when youmove the mill from the centre up to 5 mm. but keep in mind this.

 

[Omnimill]

Amazing work. :bow:

 

[ZAPJACK]

Pictures 37: This is the end of the deburing. See on picture that pins in the shape of keg as well as the first pin deburred in"square".
Picture 38: mounting between centers on lathe. The centre used is the one of the trunnions 3-4. To give the good thickness to the crank's flange, keep attention to manufacture still in absolute measure. Now trunnions can be machined at size +0.2mm. Keep attention, there is approximately 40mm offset.Working condition 200r.p.m.. You can, either work with tools from the left to the right, or re-turn the crankshaft in alternation. Weight 2925gr.

 

[ZAPJACK]

Picture 57: Now it’s time to grind journal and crankpins. If you do not have any grinding machine, you can manufacture one and adapt it on the lathe. This was a former circular saw
fixed upside down under a table. I only had to modify the spindle and to adapt the wheel clamping flanges to the grinder. 3000rpm for the grinder and 200 rpm for the lathe. Both have to turn opposite. The grinder must be straightening with a diamond and must be perfectly perpendicularto the lathe’s spindle.
Remove step by step max:0.05 mm until you get the final quotation.
Think to protect your favourite lathe from abrasive dust.
Picture 66 & 60: Other view and finishing.

 

[larry1]

12 cyls,, and I feel lucky as all get to a 1 cyl to work right. A beatiful piece of art. larry

 

[ZAPJACK]

Picture 70 & 75: Now trunnions and crankpins must be drilled from one end to the other. This is a very delicate work. I choose to machine with the milling machine because the Myford is too small and not adapted forthis kind of job. To have more precision the milling table has been disassembled so that the crankshaft has directly been fixed on the milling bed.Check the symmetry of the angle of the top side of the drills (118°). The finished quotation must be X-0.1 mm. Finish after with a machine-reamer.

 

[ZAPJACK]

Pictures 79, 75 & 74: Now it’s time to machine the counterbores on both side of trunnions and crankpins (26 in total). On picture 79 you see the tool in action and on picture 65, you can see the result (testing plate). For this“blind” work, it is necessary to machine a tool as show on picture 64. The bar has exactly the internal diameter of the boring and the cutting tool must be positioned to have the good diameter on the counterbore. The "good “diameter of the bar must only be respected about 3mm before and 3mm after the cutting tool, this to guarantee an excellent guide and to avoid vibrations of the tool. The rest of the bar is a little bit thinned to avoid a possible tightening. Lubricate a lot during these various operations. This tool allows making a counterbore forward and behind, however it is necessary to unsettle the plate in every change of flanges of the crankshaft. Note: these counterbores will later help to place corks for oil flow. At this step there is"only" 2500gr of material left.

 

[ZAPJACK]

Pictures 82, 83 & 138: The crankshaft is now weakened. It is absolutely necessary to build a versatile steady for any operations on the lathe or on the milling machine (fixed and moving steadies) by working between centres on the versatile dividing head. Try not to force during working "between centres",a light tightening is enough.
In any case, this bearing must support the crankshaft without ever forcing either in vertical, or in side. This is to avoid distortion of measures.
Picture 86: At this moment, it is necessary to build small corks like a false centre, this to be able to work between centres while machining crank’s flanges. Obviously at this steps the real centres are definitively lost. But the precision of the external finishing of crankshaft’s flanges does not require a high level of precision.

 

[ZAPJACK]

Reduction and shaping of thecrank’s flanges
There is nothing complex in this work. Indeed, the precision is not very important.However by analyzing the more in-depth the problem it appears:

• 4 different standards,
• A lot of material must be machined
• The crankshaft is very weakened as far as its structure is concerned.
• Combined work on the lathe and on the mill,
• need to build a jig bearing to maintain the crankshaft,
• Work complicated for the extremities because of the nearness of spindle, chuck, Vernier etc…
• Picture 87: At first, reduce on the lathe all it is possible to reduce until quotation +0.1mm. Use of tool at 200 r.p.m. Work as close possible to the jigs
• Check your "freedom of movement" before starting to run

Pictures 107 & 106: Each crank’s flange has an important chamfer about 10 mm and under an angle of 11°. 200 r.p.m. and a maximum of 0.5 mm.

 

[Peter57]

Amazing work, Le Zap ! :bow:
Peter.

 

[ZAPJACK]

Pictures 89, 91 :
Turning between centers on the universal indexing head. The milling machine is fitted with its vertical milling head,with a sole carbide tip face mill.
Diameter : 12 mm. Speed : 1300rpm. Pulsed jet lubrication. 1.0 mm-wide passes.
Slow manual feed.
At this point, you have to rough form the flangesby removing all linear parts.
Precision is required (dimension + 0.1 mm).
The centers of the crank journals are theones to be used (center of the crankshaft).
Carefully mark the disc of the universal indexing head. Also, the crankshaft must be positioned according to the initial cut.
Mark the machining surfaces with methylene blue. This is important, as it allows you to get the right flange and roughly draw the final form.
It is extremely important to use both the dividing head and the Y-axis of the milling machine, as well as keeping your eyes on the DRO.
Zero the Z-axis on the digital readout.Place the zero on the central axis of the crankshaft, not on the work piece.This absolute zero is obviously tied to the swing of the indexing head.
By using this repository, you will be able to unmount the crankshaft or turn it over without losing your measurements.
Now perform the same operations, using the different centers of the crankpins (i.e. 3 times, with 120° intervals). Again,remove only the linear parts, and keep dimension +0.1 mm.

 

[Brian Rupnow]

Amazing work.--Perhaps I should consider flying you to Canada---I've got this single cylinder engine crankshaft thats giving me fits----

 

[ZAPJACK]

Pictures 95, 112, 120, 123 :
Go through the same operations, removing the round parts this time. In that case, you need to use the milling machine (Y-axis) and turn the indexing head at the same time. Remember to mark the disk of the indexing head. Remove 0.5 mm at a time, then 0.1 mm for the final pass.
For the finishing, using a face mill with 3 or 4 teeth (800 rpm) is recommended.
If you are careful, you can actually machine two faces and a rounding in one cut.
LeZap

 

[stevehuckss396]

That is some nice work there!!!!!