poor judgement

a little grease works fine for me, more hassle than its worth imo

BootMachine

Hey Guys

Sorry for not getting this done sooner.

I almost got the front diff finished and then I left to go home because of the stupid teachers strike here.

I will be back at my work station in a few days...then exams...then I can work on the drawings more.

Dr. Honda....start on the rear diff case...I will finish the front!

Dr Honda

My Feedback: (4)

Hey Bootmachine...

dustin7837 is sending me his front case... so, if you could, please work on the rear case.

BootMachine

ok with a few mods I can make the rear case out of the front case....

BootMachine

What is the screw callout for the countersunk machine screws that hold the engine mount to the chassis?

I'm going to use these to hold the diff cases to the chassis.

I need the thread ID so I can draw the holes in their correct positions!

Tnkx

LA

azzman

They are 3x8 screws

BootMachine

What is the thread pitch?

BootMachine

I did a little work on the rear diff drawing tonight since I broke all my spurs and have nothing to do!

Check out what I have so far!

Any suggestions?

P.S. I'm leaving extra material where is wont harm anything so when these get made they will be SO STRONG!

dustin7837

My Feedback: (1)

Dude, thats pretty sweet! Are you imputting all measurements manually?

If you Git R done send it over to DR Honda and he can try it. I sent him all the internals from my diff too so he can make sure everything fits.

poor judgement

looking good, i can see it being expensive tho! we will see...

the original 3x8mm screws are self tappers, better to use 3x8mm metric, M3 threaded screws imo - but then im in the uk... can US owners get the M3 screws ok over there?

azzman

Yea they can get metric, but what pitch are they PJ!!!!!!!!!!!!!!!!!!!!!!!!

poor judgement

u asked for it... according to my good old Zeus bible, i mean book...

ISO Metric Coarse Threads (only ones it lists at 3mm)
Overall Dia - 3mm
Core - 2.3866
PITCH - 0.5 (i always thought they were 0.25 tho... best check... lol)
Depth - 0.3067
Flat - 0.06250
Effective Dia - 2.675
Tapping Drill - 2.50
Clearance Drill - 3.10

All dims in mm.


is that ok for yers?

BootMachine

Yes...I'm drawing this all from manual measuring. I could not get a CMM so I'm using good old vernier calipers. Brand new set of Mitutoyo...I checked them with gauge blocks before I started also.

This is partly why everything is taking so long...I need to be as acurate as I can!

And there will be quite a bit of milling to do on these bad boys....could get pricy...I hope I'm at least getting a deal for all this drawing. [8D]

STRONG though....I dont think these will break...all the material that was relieved I left in so these are going to be super strong.

We will be the only guys with this mod!

Dr Honda

My Feedback: (4)

Bootmachine…

VERY nice work!! If these get done… I will hook you up. You are saving me a lot of time by drawing it. And, since the wife is towards the end of her pregnancy… it’s time I don’t really have. (thanks) Even though I’m getting a front one sent to me… if you want to do a front case also… go for it. The originals will be good for doing my set up, and checking the fit of the parts.

Poorjudgment…

Unfortunately… you are right… these won’t be cheap… but I’ll do my best to keep the costs down. Depending on how many tooling fixtures need to be built… and how long the machine has to run for… they still may be reasonable. I may even offer a special price for my loyal followers.

OK… this is for every one…

What would you be willing to pay for one case? (front or rear) Also… can you guys can live with a “rough” finish? That would help keep the cost down. A fine finish on the machine will take almost as long to run as doing the rough, and intermediate cuts.

dustin7837

My Feedback: (1)

A rough finish is fine with me. If anyone cares about how smooth and shiny, we can always do a bit of sanding and get ou thte mag polish ourselves. As for price, I really have no idea what to say, could you give us a ballpark figure? I don't know how hard it is to machine something like that. Whether a set of cases will be 50$ or 500$ i have no clue.
I do know that i have spent a bunch on my MT2 already and the only things left stock currently are the diff cases, A arms, lower chassis, and battery box.
So I would be very interested in buying these diff cases!

alvinl

The finish doesn't matter to me either. Sturdy aluminum cases is all I care about. But you can count me in for atleast 1 set (front and rear). I would like to buy 2 sets, but will have to see. I just bought 2 new motors, so my hobbies are getting more funding than the Electric company right now.

BootMachine

Not including proto's and machine set up......1/2 a day's labour to do each section.

2 sections per part so......100 bucks for front and 100 for rear...if 10 people buy them...150 USD for both.

Thats $1500 in your pocket Dr.Honda....so....with all the set up and building your milling strategy (if you can get it done in 2 days) you can profit 1/2 of that!

The only parts that need a good finish are where the bearings sit and the hinge pins go through...

I have the ARO shock towers so I'm going to size my holes for mounting to those...

The bottom holes and locating pins will be sized according to the stock FF chassis. I dont have the JT racing chassis.....YET!

I want to take my time with some of the measurements so Dr. Honda wont have to make too many proto's.

To cut down on machining time I can remove a bunch of chamfers and fillits I added just to make things look good.

I will only chamfer the pieces that need it.

Dr. Honda...Hook me up and I can draw the front for you also.

Feel free to use my drawings to make as many as you like and set your own price. Feel free to put your "ARO" mark aswell!

poor judgement

DrH - do u have any pics of the rough vs polished finish? im not too fussy myself either, just curious...

and btw - i have a set of metric taps and dies here that i could use to save u a little time and me a little money! in fact id be happy to drill and tap all the holes to be honest. all depends on the price tho, im willing to pay up to around 50GBP for a full set, im thinking thats not going to be enough... its not a simple job for sure.

congrats on the due Little One mate - best get a move on before life as u know it ends!

BootMachine

I would prefer to have the CNC machine do the holes for me.

All DR.H has to do is get the right tapp.

In the cad tool I can program the hole dia. and thread pitch....so when Dr.H's mill asks for a tool change, it will even tell him what tapp to load!

Plus some of the holes are blind...and would you really want to snap off a tapp in one!


and I dont mind about the rough milling....

For those that dont know what roughing and finishing passes look like....






To make the outside of the diff case look like the bottom pic would double (EASY) milling times.

poor judgement

DRH - what grade aluminium (aluminum ) are u going to use?

Dr Honda

My Feedback: (4)

Hi Guys,

Bootmachine…

Don’t remove any of the fillets. When I work on the CAM program, I will just omit them… or I may still use them… but at a roughing speed. I can always make a rough cut with a large tool, and then do a semi-finish cut with a ball nose to get the fillets. (probably not exactly the size you drew them at)

To all…

I will drill and tap all the holes in the case via the CNC machine to make sure they are in the right spot. And anything like a bearing support, or hinge point will be a fine finish because they must hold a tolerance.

Basically the picture posted by bootmachine is the idea of a rough cut… but because we are dealing with smaller parts, and cutting tools… it will still be a semi smooth finish. In a part that I would call a rough finish… you will still see all the tooling marks. And cut lines. (think more like an industrial finish) To get it to a high gloss… you would have to sand and polish it.

My Maxx Gasser braces have a semi-finished pass to make the design in the pockets. So the cases will probably look like that all over. (it’s a faster cut)

Dr Honda

My Feedback: (4)

Poorjudgment…

These will be made out of 6061 like every thing else I make. I really like that grade. It’s relatively inexpensive to buy, easy to get, and it machines very well. And… for hobby use… it’s strong but not brittle.

If you would like them made from something else… let me know.

Cityhunt3R

Just to let you know the New magnum shares alot of the same parts at the MT2 I sugest you pick up the new DIFF CUPS FF232 to replace your GX12. They are BEEFY-ER then the GX12

alvinl

Cityhunter, have you used these replacement diff cups? Or do you sell them? I am debating trying them or waiting for a review. But my modded cups have held up very well. I really can't see them being any stronger than a modded diff cup.

azzman

Still I can see them being helpful if they are stronger but just dont break so easily, but will still break instead of the driveshaft if need be!