Solid Axle Pro4 SCT
 

I posted this on RCShortcourse also but i figured the peeps here would be interested also.

Lets start with some simple math.

(1) MBX6 Eco 1/8 Buggy
http://sphotos.ak.fbcdn.net/hphotos-..._3291918_n.jpg
Plus
(1) Kyosho Mad Force Axle
http://www.rocousa.com/kyosho/31225-4.jpg
Divided by:
(1) Epilog 75 Watt Laser CNC
http://farm8.staticflickr.com/7017/6...5ae1bc9a_z.jpg[/URL]
IMAG0265[/URL] by phukyr[/URL], on Flickr


Oh dear, This might be fun.

So lets start with the axle first. Its a plain old kyosho Mad force Axle. I shortened the long side so it now uses a short side bone in both sides. This makes it exactly the width of the buggy and moves the pumpkin to dead center. All you need is a short side bone and chop off the long diff tube to the same length as the short side. This has been covered plenty of times on RCCrawler so im not going to clutter it up with pics of how to do it.

One really interesting thing that may be useful is that the Mugen diff and pinion sit almost perfectly in the kyosho housing. The only thing required is some shims. The outer bearing faces on the kyosho diff are 1-1.25mm narrower. Just drop some diff shims into the pockets on the tubes and you are ready to go. The pinion drops right in and you now have helical gears and identical gear ratios front and rear and a nice 5mm output on the pinion. Mugen rear center CVD now bolts right up!
http://farm8.staticflickr.com/7163/6...ebf50462_z.jpg[/URL]
IMAG0260[/URL] by phukyr[/URL], on Flickr

Not much left of the rear end of the mugen, lol. Its not all bad, not one thing on the mugen was modified so it could go back together eventually if i felt like it.
http://farm8.staticflickr.com/7173/6...57949104_z.jpg[/URL]
IMAG0257[/URL] by phukyr[/URL], on Flickr

Now that the axle is all built it needed some mounts. This is where my new toy comes in. The Epilog is a 75watt Laser CNC. It will cut delrin like butter up to a half inch on a single pass as well as raster in images, etc. So I hopped on corel12 and drew up some lower link mounts and an upper cross brace for the upper link mounts.
http://farm8.staticflickr.com/7029/6...a2436d1a_z.jpg[/URL]
IMAG0256[/URL] by phukyr[/URL], on Flickr

The lower link mounts are 1/4 inch Delrin and the upper cross is 3/16 inch delrin. Plenty of adjustment. I want to eventually race this so i wanted to make sure i had plenty of options.
http://farm8.staticflickr.com/7013/6...10705515_z.jpg[/URL]
IMAG0258[/URL] by phukyr[/URL], on Flickr

Also plenty of options on the wheel angles. I clocked the axle up some and then clocked the hubs around even more. I can now adjust this and add toe in and camber on the rear wheels. If i need one more than the other the inner tube is drilled so the end can be rotated as needed. The link is just a traxxas spare i had from something but it will be replaced by titanium once i finish the final layout. You can also see the clamp screw towards the lower rear of the mount.
http://farm8.staticflickr.com/7173/6...2bb54e97_z.jpg[/URL]
IMAG0259[/URL] by phukyr[/URL], on Flickr

Plenty of upper link adjustments also. Just to be sure. The link mounts JUST touch the washers i put on the tube screws. This is just an easy way to make sure its centered.
http://farm8.staticflickr.com/7142/6...54faa158_z.jpg[/URL]
IMAG0261[/URL] by phukyr[/URL], on Flickr

And some random shots of the axle with wheels mounted.
http://farm8.staticflickr.com/7165/6...cd623212_z.jpg[/URL]
IMAG0262[/URL] by phukyr[/URL], on Flickr
http://farm8.staticflickr.com/7008/6...8112a617_z.jpg[/URL]
IMAG0263[/URL] by phukyr[/URL], on Flickr

Also while i was out in the shop i took a first pass as the main chassis. I scanned in the original mugen chassis to make sure all the holes lined up for what i needed on the front end and steering and also changed the motor orientation. The motor mount is actually a little to the right on the stock mugen. I rotated the mount holes around so the motor is on the left now and put the center diff right on the centerline of the chassis. I also moved it back about 10mm to make sure the motor had clearance. This meant i had to use one of the rear CVD bones for the front center CVD. This is one of the reasons i chose the mugen for this project, everything is so modular. The other reason is its pretty easy to narrow the front end 10mm without having to fab up arms, etc. I didnt think to grab any pics before i bolted stuff up so ill just throw all these out there.

http://farm8.staticflickr.com/7154/6...6a62974c_z.jpg[/URL]
IMAG0267[/URL] by phukyr[/URL], on Flickr
http://farm8.staticflickr.com/7157/6...88ac3707_z.jpg[/URL]
IMAG0266[/URL] by phukyr[/URL], on Flickr
http://farm8.staticflickr.com/7003/6...cbec5049_z.jpg[/URL]
IMAG0264[/URL] by phukyr[/URL], on Flickr
http://farm8.staticflickr.com/7148/6...f2636ea8_z.jpg[/URL]
IMAG0268[/URL] by phukyr[/URL], on Flickr

lookin good man!

awesome! subscribed!!

Hope to see some trailing arms.

Was planning on sorta scale delrin lower links with the shock mounts pocketed into them below the pivot point between the ball ends. That what you mean? Its wide open so im open to suggestions.

RC4wd wak a really nice pair. Look up Hardcore link

Yup thats pretty much whats going on it. Great minds think alike i guess, lol.

hey man just posted on the other place too.

check out my build in my signature. you might save some headaches if you take a look and read and do some things better or easier than me. :)

can't wait to see this thing done!

Nice work!"thumbsup"

i am doing same thing to a 1/10 drift chassis, putting a solid axel in the back"thumbsup" great job

Thanks for all the feedback! Its appreciated.

SO where are we at now. Well i put together a couple temporary vertical mounts to check link and shock mount positions. Amazing how much crawler stuff i still had in a box so plenty of revo ends and allthread to mock up some temporary links.
http://farm8.staticflickr.com/7141/6...b12d5bd9_z.jpg
DSC_1006 by phukyr, on Flickr


Im pretty happy with the link locations except for the chassis side upper mount holes. They need to move down to take out the squat but it turned out pretty square. Took about 4 tries tho, lot of material. For some reason i just couldnt get my head around the upper shock mounting positions and kept pushing them way back but eventually after blowing through 4 feet of 2x1/4 delrin i got it right, lol.
http://farm8.staticflickr.com/7142/6...96cfcb9e_z.jpg
DSC_1007 by phukyr, on Flickr


One of the things that kept holding me back from starting this build was what to do about the rear driveshaft. Revo shafts, maxx shafts, adapter this, reduce that, drill out this, etc. I thought i had it all worked out with revo shafts and adapters from monster RC but once i got the Mugen diff in the Kyosho axle i knew what the plan was, just use the mugen rear center CVD.
http://farm8.staticflickr.com/7017/6...e26ece2e_z.jpg
DSC_1008 by phukyr, on Flickr

Fully Compressed
http://farm8.staticflickr.com/7173/6...0d152b0e_z.jpg
DSC_1009 by phukyr, on Flickr

Fully Extended
http://farm8.staticflickr.com/7145/6...a0a62a55_z.jpg
DSC_1010 by phukyr, on Flickr

Just need to lower the chassis side upper link mount holes and im going to lay the upper shock mount down so i get more dampening adjustment rather than height adjustment.

Next up: MONSTER TRAILING ARMS (TM)! Stay Tuned!

I almost forgot the obligatory flex shot! LOL

Since it doesnt have any sway bars yet its pretty flexy
http://farm8.staticflickr.com/7015/6...66d72aa8_z.jpg
DSC_1011 by phukyr, on Flickr

that thing is going to be a beast! looks awesome man!

MONSTER Trailing Arms, LOL.

So these turned out a little extra beefy. 3/16 delrin sheet, cut 3 pieces and stacked together with 8 screws and M4x20mm setscrews. The idea was to make SURE the lower shock mount was below the link mounts so it was self centering and didnt wobble. The first one caught fire in the laser, whoops. To anyone following along from home dont go less than 20% speed at 100% power on a multi pass raster, it gets ...... HOT :shock:

Being that the setscrews for the revo ends were m4 i was concerned about them breaking out the sides of the center piece which is why it ended up so thick towards the front an rear. I wanted to put a screw on both the top and bottom of the setscrew to keep it clamped tight.

So anyhow i got a prototype knocked out this afternoon. Be warned, its beefy!
http://farm8.staticflickr.com/7169/6...a12b1e36_z.jpg
DSC_1003 by phukyr, on Flickr
http://farm8.staticflickr.com/7027/6...32140b77_z.jpg
DSC_1001 by phukyr, on Flickr
http://farm8.staticflickr.com/7151/6...beeb476f_z.jpg
DSC_1004 by phukyr, on Flickr
http://farm8.staticflickr.com/7164/6...387e45bf_z.jpg
DSC_1005 by phukyr, on Flickr


So then it was out to the rc shop to mount them up and check the fit (this is why i only made one, just in case).

So as seen below i had to make some adjustments to the second prototype. I measured the depth of the ball on the end of the shock but i forgot about how low the spring perch hung and how the lower shock end got wider as it went up. No worries tho, i can adjust it easily in the system tomorrow for the final cuts.
http://farm8.staticflickr.com/7150/6...6e2be0e4_z.jpg
DSC_0005 by phukyr, on Flickr

Its a little thicker than the allthread, LOL.
http://farm8.staticflickr.com/7150/6...61d857be_z.jpg
DSC_0004 by phukyr, on Flickr

http://farm8.staticflickr.com/7159/6...a45eca3f_z.jpg
DSC_0003 by phukyr, on Flickr
http://farm8.staticflickr.com/7154/6...8289cf26_z.jpg
DSC_0001 by phukyr, on Flickr
http://farm8.staticflickr.com/7160/6...24960602_z.jpg
DSC_0002 by phukyr, on Flickr

I think on the final version i may take out the fancy rastering and just go with something thinner for the outside pieces. But damn i think it looks cool like this, LOL. "thumbsup"

Another great use of the amazing twin force axles. Nice build"thumbsup"

Some nice parts being built! Those trailing arms are cool.

On the rear trailing arms, you could always space up the shock springs, so you don't have to notch the arms. That was my cheap-o solution. But you've probably already figured out another solution with hole depth.

Some longer shock ends would work too
http://c0456141.cdn.cloudfiles.racks...n/ofn40056.jpg
OFNA Plastic Shock Parts Set (4) [OFN40056] | RC Cars & Trucks - A Main Hobbies

Got some time to remake the trailing arms today. Decided to pass on the engraved sections between the screws and just cut clean through them and switch to flat head screws. This takes out quite a bit of weight as well as making them look a bit more svelte, LOL.

Did learn something interesting today. The laser wont cut carbon fiber, period. Technically it would with a couple passes but the resin burns off the edges where you are cutting and weakens the parts. Not a big deal really since i wanted to get a cnc router anyway but now i cant make the side plates out of CF.

Anyway, on to some pics. I painted the center spar red just so it shows up better on camera. Looks pretty cool. I may order some white delrin and dye it for the final version.

http://farm8.staticflickr.com/7027/6...f872d56f_z.jpg
DSC_0014 by phukyr, on Flickr
http://farm8.staticflickr.com/7009/6...5d1a5f0d_z.jpg
DSC_0013 by phukyr, on Flickr

You can also see where i pulled the big Tekin T8 2650kv and popped in the Pro4 4000kv 4pole. Aside from the weight this will let me move the diff back to its more forward position. I test fit a bunch of bodies today and its coming in a bit longer than i would like. By going back to the stock front center CVD i can shave 15mm out of it pretty easily and not have to change anything else. So tomorrow, hopefully, new chassis cut and ill start working on the vertical rails. "thumbsup"

Oh i almost forgot. You can also see where the lower link on the shock is different. Its a steering link from an rc8 buggy. I went to my LHS today and was talking to them about the project and they had the perfect piece. They have a slight bend in them to keep the wheels from rubbing the link in its normal use. Works perfect and looks good without having to add spacers (thanks for the spacer idea though. I almost went with it) "thumbsup"