Author Topic: 1/4 scale Porsche 917 180 degree V12 Build  (Read 57502 times)

Offline Kim

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #195 on: January 02, 2022, 05:55:17 AM »
Great to see you had some shop time, Dave!

That's nice looking gear, for sure!  :ThumbsUp: :popcorn:
Kim

Offline Admiral_dk

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #196 on: January 02, 2022, 10:38:25 AM »
Holliday and shoptime  - things are improving for you or ....
Anyway nice to see that you are moving forward on this build again.

Per

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #197 on: January 02, 2022, 10:59:36 AM »
Great to see you had some shop time, Dave!

That's nice looking gear, for sure!  :ThumbsUp: :popcorn:
Kim

3 gears!     :whoohoo:
I'm looking forward to finishing the crank!   I needed the center gear before I could do the final operations to the crank.
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Offline Don1966

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #198 on: January 02, 2022, 10:03:11 PM »
Nice gears Dave….. :ThumbsUp:


 :cheers:
Don

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #199 on: January 02, 2022, 11:35:52 PM »
Great progress on the crankshaft segments.  The final operation for each segment is to turn and face the unfinished end while mounted by the finished end in a "insitu" fixture in the lathe.   I've gotten to #3 of 6 segments, and I'm calling it for tonight... One wrong move now and the parts are junk...so come back and finish it when I'm fresh.......Here's some photo;s including 2 segments bolted together!...

1   turning fixture. It stays in the lathe until all the sections are done

2   The semi finished segment mounted in the fixture

3    The bearing diameter turned and the bearing fitted

4    Two finished segments with a bearing mounted in place in the center
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Offline crueby

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #200 on: January 02, 2022, 11:59:16 PM »
Slick setup! And knowing when to walk away and rest/reset is a key workshop skill.


 :ThumbsUp:

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #201 on: January 03, 2022, 12:05:51 AM »
Slick setup! And knowing when to walk away and rest/reset is a key workshop skill.


 :ThumbsUp:

Keeping it all clean is really tough.....it doesn't take anything to make it all run out...

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

Offline Roger B

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #202 on: January 03, 2022, 11:22:02 AM »
Splendid  :ThumbsUp:  :ThumbsUp:  :wine1: Good to finally get some workshop time  :)
Best regards

Roger

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #203 on: January 03, 2022, 09:25:08 PM »
Crank is done!!!    this will be the hardest part to make, so i feel pretty good about the rest of the model!    Hardened crank pins, 8 ball bearing main bearings, and the center power take off gear just like the prototype.   The crank, a CAD model of it, and a picture the real thing with the crank case split

Interestingly enough, the best way to get the small chips off the parts while I was machining was a clean toothbrush!!.. 

« Last Edit: January 03, 2022, 09:38:19 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Craig DeShong

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #204 on: January 03, 2022, 09:31:49 PM »
Looks good Dave.   :ThumbsUp:
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline crueby

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #205 on: January 03, 2022, 09:40:20 PM »
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:

Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #206 on: January 03, 2022, 09:46:40 PM »
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:

The real engine is plain bearing, I'm using 25 x 32 x 4mm ball bearings.   Those are the parts sitting above the crank gear
The crank is composed of 6 crank sections and a center gear.   Here's a model of a crank section
« Last Edit: January 03, 2022, 09:51:09 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
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Offline crueby

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #207 on: January 03, 2022, 09:48:38 PM »
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:

The real engine is plain bearing, I'm using 25 x 32 x 4mm ball bearings.   Those are the parts sitting above the crank gear
Gotcha!

Offline Vixen

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #208 on: January 03, 2022, 10:12:48 PM »
Hello Dave,

The crankshaft came together quickly towards the end, and before the end of your holiday break. Well done, it looks fantastic.

Did you measure the run-out before each section was added? If not, you can always mount and clamp two adjacent bearings to Vee blocks and check the runout of the each section.  The whole cranksfaft looks long and flexible, so the eight equi-spaced bearings should have little difficulty in pulling out a few thou of run-out, That is, if there is any.

Fantastic work

Mike   :praise2: :praise2: :praise2:
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Offline steamer

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Re: 1/4 scale Porsche 917 180 degree V12 Build
« Reply #209 on: January 03, 2022, 10:24:43 PM »
Hello Dave,

The crankshaft came together quickly towards the end, and before the end of your holiday break. Well done, it looks fantastic.

Did you measure the run-out before each section was added? If not, you can always mount and clamp two adjacent bearings to Vee blocks and check the runout of the each section.  The whole cranksfaft looks long and flexible, so the eight equi-spaced bearings should have little difficulty in pulling out a few thou of run-out, That is, if there is any.

Fantastic work

Mike   :praise2: :praise2: :praise2:

I checked the fixture before and after each section was turned and it was consistently in the .0002-.0004" radially and axial run out range.  That said, I don't think I could do any better if I tried.     I've not measured it yet, but I will, but I think it'll be fine.   The fixture worked very well, and asl long as you were gentle, it stayed put.   A somewhat common occurance was to slightly marr the face surface, so I would take a thou off, just to clean it up after each couple of sections.     To drive the thickness, I made up a gage block stack, and set the axial distance from the face of the fixture to the tool, and then set the bed dial indicator to zero, so I knew where to go as I turn/faced the crank cheek for the bearing.    Just keep and eye on the fixture, and keep checking it with a dial indicator to make sure it stays true.

Dave
« Last Edit: January 03, 2022, 10:42:59 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

 

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