Author Topic: 80CC OHC V8  (Read 17309 times)

Offline Coopertje

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Re: 80CC OHC V8
« Reply #30 on: December 14, 2014, 03:29:39 PM »
Thanks for the warnings, up to now I never experienced this with aluminum, I will try to remember it for the future to keep the part cool during machining. But most likely I need to hit my own nose before it stuck into my brain…. like with children, you can tell them 100 times that they should not that, one they will do it anyway and hit their nose. Then the lesson is learned. Did make quite a progress this weekend, do not have time to put a post together now, will do that beginning this week. I found also a mishap, the hole made by the boring bar is not round but oval  :rant: The diameter where the 2 pieces of aluminum are connected is exactly 42.00mm (this is the dimension I have check during boring). 90 degrees further its 42.07mm, so 0.07mm oversized! The only explanation I have is that there are 2 different types of aluminum, so most likely the boring bar had a different flexing in the both blocks. It can be fixed though, I will skim of a little of the blocks so the hole becomes undersized again and when all the machining is finished I will clean it up on the lathe with a between the centers boring bar.

Regards Jeroen

Offline Coopertje

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Re: 80CC OHC V8
« Reply #31 on: December 15, 2014, 11:35:53 AM »
Had quite a productive weekend (at least for me it was). I started with turning 2 disks having 42mm and 48mm diameter. When I mounted these in the 42mm hole I had bored for the main bearings I noticed that the boring was not round. At the line where the lower and upper block join it is the required 42.00mm, but 90 degrees rotated it is about 0.07mm oversized. It must be the result of using 2 different grades of aluminium causing the boring bar to flex differently....Lesson 1 learned.



Set-up the angle plate and put the block on a set of parallels. I wanted to clean up the outside of the block related to the boring, if it would have wandered off a little it would be corrected by this operation.







Next I drilled the 8mm water passage holes to the required depth of 154mm (they were pre-drilled 60mm deep). I used the hand drill for this, much easier  to retract and clean the drill.



Then I milled out the pockets in the bottom of the block. Started with drilling the corners and then with a 8mm end mill the pockets. This would take ages, so I swapped to a bigger end mill to remove most of the material. Later finished the pockets with the 8mm mill.









Drilled and tapped the M4 holes using my recently acquired tapping head. What a nice toy this is, torque limitation and auto reversing mechanism, such a joy to use! These M4 holes will be used to mount a bracket securing the main bearing position (should not be necessary, but just to be sure it will not hurt),


 
Tested the fit of the bearings, they can be mounted but I noticed that they would become oval due to the weak outer ring...



Then late in the evening I took the stupid decision to cut away a little material inside the boring to prevent it from being squeezed oval. The reason I did this was because on side of the bore is too big and I never managed to make a hole smaller.... During the night I woke up and realized I made a big mistake. The diameter can be reduced by skimming 0.1mm of the under or upper block and re-bore it to the correct size, but this time with a between the centers boring bar in the lathe. I will fill out the removed material in the boring with JB weld and save the new boring as last operation after the warnings about the behaviour of the aluminium during machining. Lesson 2 learned, never take such drastic decisions without taking a good night of sleep first (I knew this one already, but I seem to forget it now and then...)

Since I have a new CAM software I would like to test the code before attacking the real material. I took some piece of “flower foam”, it cuts really nice, to test the CNC code. It did exactly what I expected to do, nice to get some trust in the generated code. Roughing pass 6mm end mill, finish pass 6mm ball nose mill.







Full of confidence (I know this is the point when it is about to go wrong) I mounted the lower block and started the CNC program. Quickly after it started to make noise and I hit the stop button. The End mill came out of the collets and caused quite some damage to the part. The collets used in the speed increaser suck, they need to be tightened extremely hard to hold a mill. I will not use this anymore until I make a new ER-11 collet holder for it....





Mounted a normal tool holder and restarted the program. All went ok from here, just a little slower because the reduced feed speeds. Below some pictures of the process, rough milling, ball nose finish, Dremel, file and sand. Need to play a little but more with the CAM settings to find a optimum between finish and machining time (Rough and finish pass took about 1:30 hours).


 












Last the part had a visit to the sandblast cabinet, I must admit I like the looks. It removes  the small filing and sanding marks and gives it a casting look.





That’s it for now, regards Jeroen
 

Offline MMan

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Re: 80CC OHC V8
« Reply #32 on: December 15, 2014, 01:59:40 PM »
Hi Jeroen,

Which CAM program are you using now? I am just comparing HSMxpress (free) against CamBam (popular) and AutoDesk Fusion 360, trying to find something good for a good price.

All the best,

Mman.

Offline Roger B

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Re: 80CC OHC V8
« Reply #33 on: December 15, 2014, 02:46:58 PM »
Very nicely finished piece  :praise2:  :praise2: I'm glad you have managed to find work arounds for your problems.

I would wait until all the other machining has been done before line boring the crankcase. There may be some more movement/distortion when you shape the cylinder block and bore the holes for the cylinders.
Best regards

Roger

Offline Coopertje

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Re: 80CC OHC V8
« Reply #34 on: December 16, 2014, 08:02:35 AM »
Hello Mman. I am currently using Sprutcam V9. We used this software for an article in a model magazine and it is not perfect (does that software exists?) but it can do 4-axis milling, 3D waterline operations and has milling and turning. Sometimes it does things that I do not expect it to do, then I have to reload the part and set the operations again and it works. Do not claim this is a bug in the software, it might as well be my inexperience. I have tried other software’s (mastercam, solidcam etc) and the entrance step was just to big. I spend many evenings and never got reasonable code of the other software’s. With SprutCam I was able to have a 3D part carved out the first evening, intuitivety is very important to me because there can easily be 6 or more months between my CNC milling projects and then most what you learned is already again forgotten. I believe Sprutcam is also offered together with a Tormach milling machine. They have some nice tutorials on their website.

Thank you Roger. The part is not to bad in the end but is far from perfect. There are just to much little mistakes in it, I hope one day I can get rid of those. If you move your mill only 0.02mm too far in a pocket it already shows, as you can see clearly if you look in more detail to the part I have made. But for the moment this is the best I can do, guess that is a fact of live when you put a account manager with an electronic background behind a milling machine  :facepalm2: But as long as I am having fun and step by step improve I am happy!
What you suggested is exactly what I will do, save the line boring until the other operations are finished.

Regards Jeroen

Offline Coopertje

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Re: 80CC OHC V8
« Reply #35 on: January 06, 2015, 11:39:44 AM »
First of all a very happy new year to you all! That it may bring a lot of shop time and successful projects.

Time for an update, made some progress (and more mishaps) on the V8 block. Got a little slowed down, got myself a nice Deckel SON tool grinder and that needed to be refurbished. All parts of the Deckel are now in the ground layer of painting waiting to dry well and then receive their final finish painting.

Created the G-code to mill out the bottom of the cylinder block to a V-shape. The block is too big for my vice on the small PC mill so I had to make me a set of bed clamps first. Next I could not reach the outer edges to indicate the block in the milling machine so I mounted the lower block in order to be to indicate the part in the machine



Roughed out the pockets with a 8mm end mill and ran the finish pass with a 6mm ball nose



After cleaning up with files and emery paper, sandblasted the pockets. Below the result





While the CNC was busy I started to turn the crank disks from C45 steel. I cannot get a good finish on this material, no matter what I try. The disks are well oversized, 36mm in diameter, final diameter will be around 35.1mm.





Next I brought the height of the block to its final dimension. It needed to be reduced more them 10mm so I tried to use the bandsaw to cut off most of the material.



Bandsaw is too small (or block too big....) so off to the mill and take of the material. Paid attention to the temperature, cooled the block with air in-between the cuts.



Unbelievable how much swarf is created....



With the block at its correct height the next operation was to mill a V-shaped pocked in the top of the block with the PCMILL. The nice thing about CNC machine is that they do exactly what you tell them to do. The bad thing about CNC machines is that they do exactly what you tell them to do!
I had a soft limit warning because I loaded the G-code and did not indicated the part yet in the machine so it was out of range. After indicating the part I still had the message, so I reloaded the code and the message was gone. All good so far. Hit the start button and the 8mm end mill went in 3mm deep and started to make some serious cuts. W.t.f. @#^. Before I realized what happened and hit the stop button it already cutted a nice pocked. When reloading the G-Code I selected the program for the bottom instead of the top of the block :Doh: Loaded the correct program and milled the pocked. When the engine is assembled this part will not be visible, so in the end its only my emotional damage and the knowledge that this is quite a stable machine and that I program it way below its mechanical limits. 


 


Good that we have JBWeld available (Did they invent this especially for me? My first name is Jeroen, last name is Broek, in short JB).



Off to the bandsaw again and cut away most of the material to get the 90 degree flats. Had to cut from both directions. Set-up was weak but good enough to have the material removed.







To mill the flats I could not use the swivel table of the mill, this is limited to 30 degrees. Luckily I have a very large travel in the Z-axis and bought a angle sub table some time ago over internet. It became quite a tower but it worked out fine





In the same set-up I milled the side of the block to size. The angle came out to exactly 90 degrees, finally a operation that went without any mistakes!



That’s it for now, next is to drill the holes for the cylinder liners.

Regards Jeroen
 

Offline Roger B

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Re: 80CC OHC V8
« Reply #36 on: January 06, 2015, 11:52:33 AM »
Good progress  :ThumbsUp:  :ThumbsUp: That's a lot of metal to remove  ::)  I think that Jason B already has the rights to JB weld  :mischief:
Best regards

Roger

Offline vcutajar

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Re: 80CC OHC V8
« Reply #37 on: January 06, 2015, 12:55:29 PM »
That is a lot of progress there Jeroen.  Keep it up.

Vince

Offline fumopuc

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Re: 80CC OHC V8
« Reply #38 on: January 06, 2015, 01:03:15 PM »
Hi Jeroen, a lot of swarf to feed the work shop gnomes. A big step you have done there in the meantime. Still following along.
Kind Regards
Achim

Offline Coopertje

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Re: 80CC OHC V8
« Reply #39 on: January 07, 2015, 11:38:01 AM »
Thank you for checking in Roger, Vince and Achim!

Regards Jeroen

Offline gbritnell

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Re: 80CC OHC V8
« Reply #40 on: January 07, 2015, 12:04:02 PM »
Hi Jeroen,
Even though your setup looks like it wouldn't be that rigid with everything stacked up the cut on the head deck sure looks nice and smooth.
gbritnell
Talent unshared is talent wasted.

Offline Coopertje

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Re: 80CC OHC V8
« Reply #41 on: January 08, 2015, 11:44:58 AM »
Hi George,

Thanks for passing by. Guess you are right, it might look instable on the picture but it was in fact rock solid. The sub table is a heavy one, it weights about 30kg. Its well designed and accurate made. All adjustable parts are locked with big M10 bolds. Glad I have it, easy to mill a part under a specific angle without having to tramp the milling table to zero afterwards.

Regards Jeroen

Offline metalmad

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Re: 80CC OHC V8
« Reply #42 on: January 10, 2015, 10:25:43 PM »
Hi Jeroen
That Block is really starting to come up nice  :ThumbsUp:
Pete
A little bit every day, sometimes the same little bit