Intermediate shaft machining

I have decided to go ahead and give the 555 "Honda bearing mod" a try. I've been fishing around the local machine shops and have gotten an overall cool reception to machining the intermediate shaft.

Only shop I found that was willing to try to machine the intermediate shaft says he would "grind" it. I would have assumed it would be better to just turn it on a lathe with a ceramic insert given it only needs about 6 thou removed.

Just looking for thoughts on this from those have a better grasp of machining case hardened parts as I am no expert. These shafts aren't overly plentiful so I would prefer it be done right.

I would look into having it re hardened. or at least bake it a while and drop it in some oil a few times.

I agree...look into having it re-hardened (induction hardening...like a cam maybe?) or having DLC applied to it, which I've been considering for a while now.

what about nitriding it ?

it ALL you have to do to make the 75# 460 cast crank good for 800 hp-8 second door slammers...and that was the new thing 35 years ago

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Originally Posted by Dr. Johny Dodge

what about nitriding it ?

it ALL you have to do to make the 75# 460 cast crank good for 800 hp-8 second door slammers...and that was the new thing 35 years ago

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I would think it would be harder to find a company to throw a single part into their nitride furnace than to get it induction hardened or coated.

- just a thought - really depends on what's doable locally & how

I've seen "the cabinet" .. somewhat larger than a blasting cabinet but not much

I'd think they probably do things in little batches so there would probably be a wait

a crank , couple of somethin shafts , someone's gear parts , a handful of ford oil pump hex-drive shafts (junk) maybe someone's shortened distributor shaft .. Idono

im just saying.. you can harden it yourself.
https://sciencing.com/how-4579248-ha...motor-oil.html
https://www.wikihow.com/Harden-Steel
https://www.paulo.com/basics-oil-que...heat-treating/

Ok so I talked to a couple shops about hardening.

First shop said that all the previous hardening would need to be machined off before they would harden it and said if the shaft hadn't been hardened by nitriding originally it cant be now. I asked how he felt it had probably been hardened at the factory and he offered nothing but a laugh. Moving on...

Next shop seemed more helpful. He wants to check the hardness before and after machining but feels that it will probably still be about the same given we really aren't removing much material. He also said he knew a few shops that could easily handle the machine work. If the hardness wasn't good enough to just induction harden the bearing surface, not the whole shaft (which he could not do, but could recommend a shop that could). He felt if the entire shaft were done it may become brittle. and also no longer straight. I will stop by with the shaft next week and he can have a look at it.

that sounds positive - please keep us in the loop

Latest update,

Had the heat treat guy look at the shaft. He figures there isnt much that can be done with it. It would be very difficult to just heat treat the bearing surface without affecting the gear beside it in a negative way. He felt the shaft would get brittle in the heat affected zone of the gear.

He did a test and found the shaft to be 55-63 rockwell hardness depending on the location of the bearing surface on the shaft.

Finally found someone willing to machine it. Older guy in a small machine shop. He has a friend with a "cylindical grinder" and as long as I wasn't in a big hurry, he could get it done for me. Other shops said they would do it but I had to buy the tooling, which apparently would be $300 plus the shop time to turn it.

Heat treat guy said bring it back once it was done and he would check hardness again.

WOW! 55-63RW is SOFT for steel! No wonder it galls so easily!

I wonder if we could have sleeves machined, then hardened to press on like the 523/543/568?

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Originally Posted by Reaper1

WOW! 55-63RW is SOFT for steel! No wonder it galls so easily!

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Can you explain this? I looked up bearing race hardness, and the mighty Google says 60 RC is about right. Also keep in mind this was with a small handheld tester.

Im thinking about sleeving also. Not sure if I should bother turning it down 60 thou and checking the hardness, or just bite the bullet and see if it can have a sleeve installed.

And then there is the modification Gaboon did......used the internal race of the bearing he bought. don't really want to get into welding up the case though.:yuck:

what's the trans again ?

re welding the case .. 555's have a heat treated case , 520's do not

then there's actually welding the case , how good is "the guy" , how badly saturated is the case with oil etc = last resort (imo)

a welded hardened sleeve sounds like a plan .. or a parts transmission collection

Quote:

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Originally Posted by Dr. Johny Dodge

what's the trans again ?

re welding the case .. 555's have a heat treated case , 520's do not

then there's actually welding the case , how good is "the guy" , how badly saturated is the case with oil etc = last resort (imo)

a welded hardened sleeve sounds like a plan .. or a parts transmission collection

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....yep.

I have a 555. Here is the thread about the welded tranny case...I assume it was a 555. PMed him the other day and he said he ran the tranny a few years with no problems
http://www.turbo-mopar.com/forums/sh...-shaft-bearing

The only way to fix it so it lasts is to have a race made and attached to the shaft. People have tried cutting, grinding, welding etc. It does not hold up and fails in a short amount of time.

Post by moparracer 35.

Thanks
Randy


https://www.turbododge.com/forums/f4...mission-2.html

https://www.turbododge.com/forums/f4...-repaired.html



Here is a thread on how to repair worn intermediate shafts.
!. Shaft has to be turned to bushing size 1.190 by either grinding or using ceramic tooling on lathe. Shaft is hardened.
2. Press fit bearing sleeve with Locktite.
3.Tig weld onto shaft end ( 3 spots).
4. Turn to size 1.400 by either grinding or using ceramic tooling. Bearing sleeves are 65 rockwell (bearing steel) which is very hard.
5.Finish polish with 2000 paper.

I have repaired 4 of these and run tested with no problems. On the original shaft the hard surface is thin and uneven. The sleeve I used .105 thick after turning and hardened all the way through. It could be replaced again if ever needed. This is not an involved process but it is time consuming. Maybe this will save some of transaxles that are becoming harder and harder to find. This process does a beautiful job and is very durable and you can keep your original shaft from your transaxle.

Since I made these pictures I invested in ceramic tooling that makes the job faster and easier. When you use ceramic tooling you get a red string of metal off the hardened material. This eliminated the grinding process. I don't like grinding on the lathe because of the grit on the lathe ways. The pictures are on another post I made 9-10-15

That’s the way to fix them. Good write up. Do you have a source or part number for the sleeve?

Sorry, no, I just remembered this thread from a while back.

I was hoping someone knew more than me.

Thanks
Randy

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Originally Posted by ajakeski

That’s the way to fix them. Good write up. Do you have a source or part number for the sleeve?

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Hey Randy, thanks for posting that info. Ill have to resurrect my TD account as I haven't been on that site in a while and I cant view it as a guest anymore.

Hope your recovery I going well.:D



That is very good info, and since I have pretty much decided to get the shaft sleeved, I have better direction now.

I have found bearing sleeves that are 30mm ID (1.181) but not as wide as I would like so Ill have to keep looking.

I would still like to do this in conjunction with the Honda bearing. Boring the case the extra .035 to accept the bearing doesn't bother me at all.

So here is the rub: The shaft would need to be 1.340" (as opposed to the stock 1.400"). That would mean the sleeve would be .075-.080" thick, instead of the .105" the OP did.

What would be too thin? Maybe I could find a slightly smaller ID insert, but "off the shelf" sizes seem very limited.

Hi Rob:

Appreciate the kind words, recovery is slow but steady.

Moparracer 35 made some good posts and seems to be a competent machinist but I don't know him.

I want to thank you for the great nose cone you supplied to me!!

Its very nice and I finally got the rebar etc so I hope to get the nose completed soon.

Stephen delivered it to Red Deer and Lawrence drove me down to pick it up at the SDAC meet.

Hopefully I can provide you with something in the future.

Best of luck with the shaft repair, I'll probably need it myself some day.

Thanks
Randy

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Originally Posted by 83rampage

Can you explain this? I looked up bearing race hardness, and the mighty Google says 60 RC is about right.

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I expected to see numbers in the higher 60's. Based on your research, it looks like my expectations were a bit high!

Quote:

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Originally Posted by Dr. Johny Dodge

what's the trans again ?

re welding the case .. 555's have a heat treated case , 520's do not

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I know this has been debated for a long time. Is there any actual indication of this?

Quote:

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Originally Posted by Reaper1

I expected to see numbers in the higher 60's. Based on your research, it looks like my expectations were a bit high!



I know this has been debated for a long time. Is there any actual indication of this?

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none whats so ever, the case part numbers back in the day were the same between the 2 transmissions and were cast at the same place.

Decided to post an update of sorts. Nothing really new at this point. All my summer obligations have completely de-railed any momentum I had to get this done, but I plan to bring this to a resolution.

I did email a member on here that had offered to get these repaired few years ago, but his feedback was that he had a few with problems so he stopped providing the service. I asked him for some specific info on how he did the modification and how they failed but he hasnt responded. I will try to get hold of the member on TD and see if he has any helpful info.:thumb:

Last update. After a lot of consideration I have decided to abandon this method in favour of the modification using the NUP 2206E bearing. This has been successfully done by another member, and although it requires more substantial modification to the case, it is more practical than trying to get the Honda bearing to work.

The ultimate problem I found with the Honda bearing is the inner race on the shaft. There isnt enough hardened material left on the shaft if machined to size, so a sleeve is the only option. There in lies the problem. The only "off the shelf" sleeve I found would require removing a considerable amount of material from the snout of the shaft due to the thickness of the sleeve, and in my estimation, would not leave enough strength in the shaft to have a reliable transmission... unless someone can run the engineering numbers and tell me the shaft would still be strong enough at 25 mm diameter.

That leaves getting a custom sleeve made and machined to size to balance sleeve thickness with inner bore size. This gets into metallurgy and trying to source the proper material, and getting it heat treated.....way too far out of my comfort zone. At least with an off the shelf bearing race you know that engineering has been done and it should work as expected.

Doing the alternate mod gives a physically bigger bearing which should have a better load rated capacity. Welding up the case to support the bearing is the only sticky point that I dont really love, however the concept has been proven, so I need to find a good aluminum welder.:)