Isuzu MSA Gearbox to LT230

In an earlier post my thoughts on fabricating a housing now to machining .The recess for the bearings and circlips machined .010" deeper to allow facing the mounting surface.With this done the mill head is checked for square with a dual digital indicator gauge .A steel plug the size of the bearing is now bolted to the mill table and with a dial gauge in the boring bar the table is positioned and locked.The housing is then bolted over the centralising plug and the TC end bored Then faced .A plug is now made to fit the whatever size you bored on one end and the TC seal size on the other.I now machine two short dowels with a .125" hole thru the middle to fit the TC . With the dowels fitted I then drill thru the TC.The TC is then fitted over the adaptor housing plug and clamped in position The mounting holes then drilled and the dowel holes drilled with a .125" drill, the smaller one from inside the TC with a RA drill.The TC then removed and the dowel holes bored to the correct size.The adapter should now be in perfect alignment :o

AM

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Originally Posted by Vern

We're alive again😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😆😊😊.
Now i'm just going to take easy until i get home, the holiday continues

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Congratulations, Not a bad effort to be back on the road after the weather, no facilities, the depths of disappointment and a thread going knowhere sic. This sure is a sign of your perseverance, tenacity and rat cunning. Let's see if the wife lets you live it down.

I was ready to go buy a new landcruiser, only took 5 min of driving down the road to think i really should just through more money at, i do like driving it😆

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Originally Posted by Bearman

Sorry to hear of your troubles Damien, but great to see how people have jumped in and helped with spares etc. Hope the rest of the trip goes OK. If you have any more problems I can send down a tried and tested LT95 to get you back on the road again :D

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Brian, i would have kept and used that lt95, but it wouldn't fit due it being a soft dash

Bugger, just lost all my typing - cursor 'jumped' out of text box. So I then got stuck in some sort of blue selection process that I could not click out of. Then this thread just froze. Could go to other tabs. Have to restart the thread.

So...

Ancient, some questions if its ok, about your two piece adapter shaft and drive flange. Given I have the Outcast shaft I can determine many of the measurements, but the mystery to me is how to turn the design into two pieces (although less of a mystery to poor Damien). I feel the main difficulty is designing the drive flange - I think the floating shaft will 'just follow'. I'm not talking about breaking up my Outcast for this exercise, to be clear.

Regarding your two piece adapter do you have any drafting plans tucked away?

What alloy did you use?

Heat treated to what hardness?

Cryogenically treated as well?

I examined the MSA drive flange today and got the impression it is an SAE20 spline (if such a beast). Is there any rational in making the adapter kit drive flange splines stronger - my initial thought is just to duplicate the MSA drive flange splines into the adapter kit drive flange and keep the strengths the same. I got the impression after some reading today that the SAE spine is favoured because it is easier to machine, when compared to involute splines which have the advantage of self centering and spreading any misalignment load more uniformly.

The MSA drive flange has a 'witness' ring machined into its face, the face to which the NPR drive shaft would normally attach. The 'witness' ring is 0.1mm larger in diameter than the 'female' recess machined in the Outcast unit to take it. Therefore the Outcast shaft is tight fit. Is this a good thing to emulate in a copy of your adapter kit drive flange. After removing bolts, I've never found a LRover drive shaft so tightly attached to a LRover drive flange.

My reading told me that splines should not stop dead at the next riser, but be chamfered up to it. Do you know if the chamfer is simply a reflection of the hob cutter diameter, bought to a holt at the end of a run? Or is there some other process involved ie lifting the cutting tool toward the end? Or did you use a shaped tooth cutter or shaper machine with planer tooth? You have a well equipped shop?

How many miles on your kit have you clocked?

Cheers.

Workingonit,

The tables I have seen for splines have three levels of tolerance, interference fit, transition fit and clearance fit. The last two allow different amounts of movement while transmitting torque. I think that could explain the differences in tightness of fit. The involuted splines are stronger for a given diameter.

Thanks slug. The tightness I was referring to was in relation to bringing together the mating face of the MSA drive flange and the mating face of the Outcast drive flange (opposite end to the SAE10) - much like when you mount a drive shaft to the drive flange on your transfer case there are two mating faces involved, just the LRover is never so tight in my experience. I've seen similar references to levels of tolerance in splines before, so it is good to be reminded.

AM.

Just had another look at your kit on page 51 of this thread. I now realise you did not take the splines up to the oil seal ring. Outcast did for the SAE10. Not much either way you think?

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Originally Posted by the_grubb

Durability as in strength or wear?

Don't believe strength is going to be an issue here. Unlike axle halfshafts your not getting any torque multiplication when in low range. Hence I believe the material strength is sufficient - which I meant to be 4140 (not 4130 as I miss typed...)

Can see some benefit in wear reduction by flame hardening to Rc 50 from Rc30.

How about I get them hardened and provide a warranty - if you break it I replace it? Uh oh sounds like a challenge to me.... Obvisouly price will go up.



Material? Design? Dimensions? Stress raisers? Internal spline to NP box or flange mount? Alignment? Tolerances? Surface finish? LT230 transfer case or series? May not necessarily be that the breakage occured due to un(heat)treated shafts.

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Wonder if this still stands😊

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Originally Posted by Vern

Wonder if this still stands😊

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Maybe... If you can find him...

I would have thought 4340 would be preferable. Do we know what Outcast use?

I think the difference is down to heat treating though. You can see from the colour of the shafts the processes have been quite different. The Outcast shaft looks like it has had an oil quench?

Some discussion on 4140 vs 4340 here:
4140 vs 4340 - Material engineering other topics - Eng-Tips

Also some specs for 4140. It would be fine for the application if properly heat treated.

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Heat Treatment

AISI 4140 alloy steel is heated at 845?C (1550?F) followed by quenching in oil. Before hardening, it can be normalized by heating at 913?C (1675?F) for a long period of time followed by air cooling.

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