Hardening half-shafts

[Mr Spigot]

I have been fortunate enough to obtain a pair of NOS half-shafts and wanted to get them hardened before fitting. Does anyone know who can do this? Preferably in the South East as I live in East Sussex, but may have to send away if further afield.

[King Kenny]

Hi. It was my understanding that half-shafts are already hardened. I know that you should not swop them over from left to right as they get work hardened to whichever way they are turning.
We used to case harden components in the factory that I worked in many years ago. I would think it would be costly and not represent value for your money. My Traveller's half-shaft napped in the 1990's.I replaced them with a second hand pair and I am still running with them.
Remember...a half-shaft is not for life.

[philthehill]

Minor half-shafts can be additionally heat treated to increase their strength.
I had a pair of NOS Minor half-shafts heat treated by a firm in Northampton way back about 25 plus years ago - guaranteed to transmit 178bhp without snapping. Still in use after many hard full power standing starts.
Unfortunately I have not retained the address for the company in Northampton but do have a spare set on the shelf which are not for sale.
There has been some previous correspondence/threads about hardening Minor half-shafts and it may be that using the search facility throws up some details.

[Mr Spigot]

Thanks for the replies. I have done a search of the forum, but nothing came up with any great details. A web search did come up with this firm who I may contact and may be the one mentioned:
Heat Treatments Ltd,
Sheaf Close,
Lodge Farm Industrial Estate,
Northampton,
NN5 7UL

[simmitc]

You can buy new tough shafts from at least David Manners and ESM, and probably the other suppliers too. I think that would be better value rather than hardening existing shafts.

[Mr Spigot]

You can buy new tough shafts from at least David Manners and ESM, and probably the other suppliers too. I think that would be better value rather than hardening existing shafts.

Yes, the ESM ones are £623 and David Manners lists them at £344 but unavailable, which is why I am looking at this option! I would be very surprised if the cost of hardening exceeds this, but I will have to find out.

[philthehill]

You can get uprated half-shafts for the Morris Minor with banjo axle from Peter May Engineering
https://www.petermayengineering.com/pro ... a-a-653mm/

[Mr Spigot]

Thanks, yes but they are still over £550! My pocket won’t stretch to that which is why I’m looking to get my set hardened. I picked them up for £30 so there is scope for a much cheaper route.

[philthehill]

If you only paid £30 for a pair of NOS half-shafts you had an absolute bargain.

[ManyMinors]

I know halfshafts CAN break, but how often do people think it actually happens on Morris Minors? Certainly I have never had one break in more than 50 years of driving these cars - and that includes competing in sprints and autotests in the past with a 1340cc engined Minor with standard halfshafts. I for one wouldn't even consider spending such a sum on a precautionary measure unless I was putting much more power through than most of us will
As somebody has already mentioned - if you do have to replace one, it is always advised to use one from the same side of the car.

[Mr Spigot]

If you only paid £30 for a pair of NOS half-shafts you had an absolute bargain.

yes, I could not quite believe my luck!
I know some people have never had a half-shaft break, but I have once and it is not something I would wish to repeat. I have a 1275 midget engine, 1.75" carb and LCB 1.5" exhaust. It is not raced or thrashed but does put out more power than a standard engine. I'm probably safe with the existing standard shafts, but having picked up some new ones so cheaply, if I need to spend just a little more to have them hardened, I will feel confident that they will last me out without any worries about breakage. I don't want to spend several hundred pounds on this by buying the hardened ones available, but if it can be done cheaply I will be happy, if not I can live with it and probably just fit the new ones anyway as they are.

[jaekl]

I agree with you ManyMinors and different Minors with the same driver, some will and some won't. It's not driver style. I'm leaning towards a structural problem such as the differential is slightly clocked causing stress concentrations on the spline. But that doesn't explain why the passenger side typically is the one that breaks. I'm running a test on my Minor that breaks shafts but putting in a used one that had been on the other side to see how long that lasts. I thinking it may be prudent to change entire axle assembly instead of just the half shaft.

[simmitc]

I've been driving Minors for around 45 years over many 100s of 1000s of miles. 1 car has never had a broken shaft, three different cars have all broken the passenger side. All standard engines with normal road use; 1 x 948cc and 2 x 1098. No car has ever broken two shafts. I can see no pattern other than all nearside.

[philthehill]

The majority of times the cause of the half-shaft breaking is the (nearly always the) N/S wheel loosing contact with the ground and then coming back down and the sudden contact shock breaks the half-shaft.
I never had a standard half-shaft break under hard straight acceleration.
The last time I had an axle failure was when the diff planet gears came apart whilst going round a corner at Prescott and the N/S wheel lifted momentarily and slammed back down.
Having additional strength half-shafts is horses for courses. With my 1380cc, 140bhp engine I could not run without the stronger half-shafts.

[jaekl]

Bear in mind the when, how, where of when it breaks is only the last straw on the camels back. The interesting observation is whether RHD or LHD, overwhelmingly it's passenger side half shaft that breaks. Also I've learned that early Sprites had a very high frequency while the Nash Metropolitan with the same rear axle width as the Sprite did not. Some say the quarter elliptical springs cause too much shock to the shaft.

[philthehill]

The Mk 1 Sprite with the quarter elliptic springs also had torque control arms which held the axle from rotating. I am not aware that the Nash Metropolitan had the torque control arms.
The Sprite axle would be subject to more traction shocks because the quarter elliptic springs had little chance of flexing unlike the Nash Metropolitan springs which when flexing would absorb some of the traction shocks.

[moggiethouable]

I wonder if you can get a good second hand pair, perhaps from Tom Roy ?

[ManyMinors]

I don't think there is any shortage of secondhand halfshafts. The OP already has a NEW pair which he was able to purchase at a bargain price. His question is regarding heat treating them

[Blaketon]

I had some made, by Quaife, for my Midget 1500. I had previously had a pair of "Heat shrunk" shafts, that didn't last more than a few months and that was without any quick starts. The Quaife ones are splined together and have lasted over thirty years, with numerous hillclimb starts to their credit, between 1992 and 1997.

[stuffedpike20]

I broke one pulling off my drive. Passenger side.
My friend broke one driving off a curb, with his Traveller loaded full of wood. The axle casing slipped on the U bolts too. Drivers side.

Are you MORE or LESS likely to snap a half shaft with a 3.9 diff and 1098 engine, than with a 4.2 diff?