Demon V8 Slow Build

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Maxine

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I prepped a 1" diameter stressproof bar for the crank shaft today by offset center drilling both ends. But I do not own a 4 jaw chuck. A 4 jaw is the only set up I have witnessed in use for offset turning. What sort of fixturing should I be looking to make for the driven (chuck) end of the stock using my 3 jaw? I know I saw some pictures of a nice fixture on here somewhere but of course now I can't find them. Any advice would be much appreciated.

Maxi
 
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vcutajar

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If you drilled the offsets at both sides how about between centres. This is how I held it for my Kiwi.

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Maxine

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Hmmm OK. I just feared with the weight of the off center stock swinging in the lathe (and the interrupted cutting action) that holding it between centers might not hold the part secure enough. Not so with your part huh? Maybe I am over thinking this by trying to come up with a fixture. Or just being a chicken...
 

idahoan

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Same thing here; I used a piece of soft wire to tie the blank to the drive dog. The key to lessoning the intrrupted cut is to mill most of the material away before turning the throw.

Dave

 

Maxine

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OK gents thanks for the advice. I am going to mount the stock between centers tomorrow and give it a test spin to see how secure it looks.
 

e.picler

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Hi Maxine!
For my project, I`m planning to machine a round fixture that can be hold on a 3 jaw chuck than mill a hole off center with the throw of the crank, tap a hole to fix it on fixture. Use a round piee of brass to shim the screw to avoit it demage the crank shaft.
I hope it helps you.

Edi
 

Maxine

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Thanks for the advice Edi. I was making real good progress on my Demon V8 but when I got to the crank I hit a wall and have made no further progress at all in about 6 weeks. I had the blank for the crank shaft all blued and marked out and mounted between centers on the lathe. It sat there for about a week but I never worked up my confidence enough to try turning it. Finally I needed the lathe to turn and thread a piece for another project so I took the blank out and set it aside. I may just switch to making the heads, the rocker arms, the valve guides etc and come back to the crank later. I don't really know why I'm so stuck on this but it stopped me cold. I do like your idea. I might make an offset fixture for the three jaw like you are planning to do and see how that looks.
 

e.picler

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Hi Maxine!
Congratulation, you are progressing very well.
I really like your method of making almost everything using the 4th axis.
I just installed the 4th axis on my mill and plan to use it as much as can.
I`m using the Master Cam. I still don`t know how to use it well. I purchased a DVD training with a book. So far I`ve learned the basics.
I have a friend that teaches Master Cam, he is going to give some lessons on how to program the 4th axis on the Master Cam.
I`m just waiting to receive the SIEG iKC4 CNC Lathe I purchased so I can learn the lathe programming as well.
I also plan to machine the camshaft and crankshaft on the 4th axis.
For sure I will ask you some help.

Great and wonderful work!

Edi
 

Maxine

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Thanks Edi. Do ask away if you have questions. I have used Master Cam in the past but the work I am doing on this engine is all done in Alibre. I did make my camshaft completely on the 4th axis and it came out really well. I may do my crankshaft on the 4th axis as well, I'm not sure yet. For many of the parts on this engine using the 4th axis saves a lot of set ups. I just added mine to my mill a year or so ago and it has been interesting learning how to use it. I like it a lot and have used it for several projects besides the little V8.

Good luck with your build. It's a great project and the plans are really well done.
 

rrocky

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Thank you Steve, coming from you that means something! I have used Alibre for CAD work ever since it came out and then I added Alibre CAM about three years ago. Yes it is a version of VisualMill that runs inside Alibre. It is not quite as sophisticated as programs like MasterCam but 2 things I really like about it: 1) since it runs inside Alibre if I make any changes to my CAD models the CAM picks up the changes immediately and modifies the tool paths to suit. That saves me a ton of time since I tend to draw and tinker and modify my way along with things as I design them. 2) It is fairly simple to learn and use so if I don't need the very highest end sophisticated tool paths it is quicker and easier for me to get the Gcode done. This is the first part that I cut on my new 4th using full 4th motion (as opposed to just indexing). It was fairly easy to program and so far making the chips has gone well and without error.

The local sales guy for Solidworks tells me that there is now have a version of MasterCam that runs integral with Solidworks. That didn't exist when I bought Alibre CAM. If I was buying again today I would research both programs but I am definitely happy with what I have and would likely go this way again due to cost. I have been able to program almost any part I want so far with ease and success. One important point though, Alibre CAM does not support lathe tool paths. I use the MasterCam seat that we have at work for lathe stuff or just program parts directly on the lathe control. That's easy on the Haas with Intuitive Programming.

I am looking forward to getting my version of your V8 design done and running Steve. Next up once I put the finish passes on the block (10 thou left for a nice finish pass plus boring all the pockets and drilling/tapping the bolt holes) will be the camshaft and crankshaft. I have the material in hand and I want to program both of those using the 4th axis as well which should work out slick but I haven't drawn them up in CAD yet so it will be a while I guess.

Cheers and thanks for the compliments!

Maxi
 

rrocky

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Hullo would you share your files for crankshaft

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