Where to get a tool steel revo primary gearbox shaft?

[TK5310]

My picco .28 turbo powered revo has been chewing up the driveline piece by piece, I've now got to the point that every single component in the driveline is steel (Hardened 1/8 buggy bell with 4 shoe progressive alloy clutch, RR steel slipper conversion, RR full metal gear set, TRX steel driveshafts, steel CV 1/2 shafts, billet alloy diff cups).
I thought I had finally managed to build a bulletproof driveline - then I snapped the primary shaft in the trans.

Maybe my fault - running big joe tyres with a tight slipper on concrete.

I've got a new trx primary shaft on the way, I'll loosen up the slipper & switch to my badlands tyres for higher traction surfaces - that should reduce the load on the shaft.

But methinks it's just a matter of time before I break another one & they are not the cheapest 'consumable' item.

So, anyone know where I can buy or get made a tool steel primary shaft that'll cop bulk abuse?

 

[EXTREME1]

maybe a machinest shop?don't know hade the same problem w/k-rocks.but ,i did go with the 3.8 badlands and they are :whhooo:

 

[TK5310]

I own a machine shop!

I can make a shaft no problem, but only from softer steels.
The shaft needs 2x holes drilled for drive pins, so if I use tool steel to get a hard enough surface for the 1 way bearing I won't be able to drill it, if I use steel soft enough to drill the 1 way bearing will chew it up.
I made a new shaft from bright steel bar & case hardened it in the 1 way area, but I couldn't get it hard enough & the 1 way started to eat it, it also started to twist along it's length.

So it does actually need to be tool steel or another grade of steel that can be drilled & case hardened properly.

Whenever the shaft dies it takes out the rear bearing for 2nd gear & hurts the 1-2 dog clutch, so I don't feel like experimenting with other grades of steel - each failed experiment costs me a bash session, a bearing & a dog clutch!

I'd rather fork out the $$ for a proven shaft.

 

[moe7404]

"Maybe my fault - running big joe tyres with a tight slipper on concrete." i wont say its your fault. you just mixed the wrong parts. some times a little less traction and/or a looser slipper clutch works better. see you have all ready experimented, and you have learned a lot. that is good info. just remember what you have learned. see how smart you are. i think your doing good.

 

[TK5310]

Yeah, I learned that big joes look tuff - but that's about it!
They don't handle for sh|t, they balloon like crazy at high speed & they have too much traction so you traction roll or backflip too easy & break driveline parts.

Before the shaft I made let go I ran it with the badlands on - much more fun, didn't have to run after the dang thing & flip it back over all the time, powerslides on demand but enough traction to get up & boogie when need be.
The big joes can go in the cupboard, useless bloody things.

Maybe I'll just stick the new trx shaft in & see how it goes, worry about a tool steel shaft if/when it lets go.

 

[SchrodeMode]

I see a set of Big Joes being added to the FS thread. lol

 

[joshman1204]

I know nothing about the difference hardness/strengths of metals but could you not make it out of something other than steel? Would titanium or some other metal not make a better shaft?

 

[Racer 1966]

I can make a hardened shaft with no problem. What's it worth? Also I would need a stocker to copy dimensions from.

 

[TK5310]

You done em before?

I can draw you up a blueprint for it (detailed thumbnail anyway LOL), I'm in Australia so sending a stocker over would be a bit of a problem.

Needs to be accurate to within -.0005" on the OD for the 1 way to grab it properly, needs to be case hardened spring steel or solid tool steel to be any better than stock, methinks 4340 steel would work nice.

If you reckon you can do it PM me a price - remembering it'll need to be posted to Australia.
A friend that's building an LRP .28 powered revo may need one as well.

---------- Post added at 9:54 PM ---------- Previous post was at 9:52 PM ----------

I know nothing about the difference hardness/strengths of metals but could you not make it out of something other than steel? Would titanium or some other metal not make a better shaft?

Titanium is far too soft, 1 way would eat it in about 3 seconds.

Nothing short of a steel alloy will cope.

 

[olds97_lss]

I run t-maxx 3.3 tires on my revo with an LRP28S3 in it. I shelled the trans gears a few times before upgrading to all RRP gears in there using standard offset 2 speed gears. I also run 1/8 clutch/flywheel/bell with alloy 3-shoe clutch to get the power to the ground.

I run plastic axles front/rear/center and have yet to break one. I keep a set on hand just in case or as the little eyelets where out at the pivot. I replace pieces of them about once a year (about 5 gallons of running).

These are my wheels/tires:

They aren't quite as big as 40's, but are fairly close.

Wish I had a set of 40's for comparison:

left to right: tmaxx 3.3, revo standard, savage 21, pro-line road rage standard MT (3.2" bead), traxxas t-maxx chevrons (3.2" bead).

I run the ones on the far left on both my savage and revo. Really good basher tire for me. Soft enough to work well in teh winter, hard enough to handle running at a skatepark without wearing out fast, decent grip on grass/sand.

 

[TK5310]

The tmaxx wheels/tyres look tiny compared to the big joes:

The result:

I'm gonna blame the big joes, I may use them on loose dirt, but I won't everuse them on a hard surface again.

 

[Racer 1966]

You done em before?

No I haven't made that exact part but I am a toolmaker by trade and I can easily make one with a print or something to copy.

 

[TK5310]

Looking again - I've got a set of those tmax tyres, I hated them! No grip at all, car was uncontrollable - that was on a hard surface with a covering of loose crap tho.

---------- Post added at 11:28 PM ---------- Previous post was at 11:27 PM ----------

No I haven't made that exact part but I am a toolmaker by trade and I can easily make one with a print or something to copy.

How would you drill it? - edm? - boron drill won't do it!

 

[Racer 1966]

EDM will work but that's not cost effective for this type of part. How I'm going to do it is a toolmaker's secret.

 

[TK5310]

LOL fairy muff.

I'm a machinist - but engine machining, I build competition engines, so I lack the tooling to machine this sort of stuff.

 

[olds97_lss]

I sheared that shaft in my t-maxx when I ran a BB in it many years ago and it was a weak OS21RG!. I've only done that once in any of my rigs.

Considering the torque of electric... I wonder what shaft the e-revo uses. Electric has far more torque than nitro.

 

[TK5310]

Turns out 8740 steel case hardens quite well with a basic oil quench, unhardened it is *just* soft enough to be drilled.
I got a whole bunch of 8740 laying around - that's what ARP head & main studs for 1:1 engines are made from, got a big box of old ARP studs.

So I made a new shaft from an old ARP chev head stud, drilled it & case hardened it.
Should be tough as nails & with the case hardening a file can barely touch it.

Win!

I'll report back on how it holds up to abject abuse!

 

[2revo1maxx]

I wouldn't blame any set of wheels or tires, I'd blame the clutch bell and spur ratio.

 

[WoodiE]

EDM will work but that's not cost effective for this type of part. How I'm going to do it is a toolmaker's secret.

This made me chuckle!

 

[chickenman242]

If anyone is going to put these into production can we have some for maxxes
Big block +standard output shaft = trip to hobby shop