Rear axle shaft identification

[losmorob]

How can I tell if the set I have here on the bench are of the later hardened type? There's a series of number and letters on the end, what's the "secret code?"

 

[Spridget64SC]

BTA806 was the latest part number assigned to axles. The material used was EN17 steel and I don't believe they were every hardened.

Any part "Tufftrided" by the factory usually carried the suffix 'T'. 1968 to 1974 Spridget crankshafts carried the EN16T code, with the T standing for the "tufftriding" process.

While the BTA806 axles were the latest part provided for factory use, a racing version of the axle was produced in EN19 steel. This axle carried the part number BTA940.

FWIW, there were axles made by independent aftermarket producers which may have been hardened. The most popular aftermarket supplier was a West German company and usually they marked their axles on the shaft itself and sometime there is still a sticker on the shaft that denotes the manufacture.

Whatever part number you have, it is worthwhile to crack check the hub end and inspect the splined end. Significantly twisted splines and cracked hub ends are to be avoided. Often you can tap the axles with a hammer while holding it with a coat hanger and listen for a long high pitched ring. It the ring is short and dull, it most likely has a crack in it.

HTH,
Mike Miller

 

[Sarastro]

Figure below illustrates what you <span style="font-style: italic">don't</span> want!

This was a cheapo replacement axle (Borg Warner). 'Course, that tells you something about the original one.

I replaced both of mine with BTA806s. No problems so far.

 

[twas_brillig]

Per Mike and Steve: with luck you've got the 806s. I've copied an earlier post (of mine) below; the Horler info might be of interest, and if anyone has any idea what my codes mean, I'd appreacite it!

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I've got the following identification on my rear axles:

Right: BTA501S MOWOG BH ONES EN17
2A7242

The first line is all cast into the axle; the 2A7242 is stamped (irregular in alignment; handstamped?). The 'ONES' is cast in smaller letters and not real clear.

Left: 2A70 85 EN17C MOWOG ONES
All cast; no stamped alphanumberic; the 'ONES' is also cast in smaller letters but pretty clear.

She's a 1960 model, and has never had anything other than the 948 cc engine. I replaced the right axle (unknown donor model) some time in the 70s/maybe 80s when the splined end twisted off (using a 'puller' 'fabricated' from a piece of 1/2" plywood).

According to Horler's "Original Sprite & Midget", the Sprite Mk IV and Midget Mk III got stronger half shafts. "The steel wheel shafts could be recognised by the new part number BTA 806 in raised letters on the end face. As the new shaft was interchangeable with the earlier type, it is now quite common to find one fittted to an earlier axle."

He doesn't indicate the chassis number at which the axle changed occurred (or my skim reading missed it); however,he also shows under Special Tuning that "axle shaft, heavy duty, disc wheels only, C-BTA 1226; axle shaft, heavy dty, wire wheels only, C-BTA 939", and that production of these models began Oct. 1966 and ended Oct. 1974.

Anyone got suggestions as to what I do have? I'm assuming I DON'T have the 'stronger half shafts."

Doug

 

[Spridget64SC]

I don't have my British steel codes "cheat sheet" here at the office, but in the codes above, here is the way I would decipher what you have.

Right:
BTA501S- BMC Part number. Sequentially before BTA806 and therefore not of the stronger material. Likely an early square body Spridget part from 1962-1965ish.
MOWOG- Morris Wolesly Group. Normal marking of manufacture. On Many parts.
BH- Don't know. Maybe a date code or location.
ONES- Actually OMES. Most likely a sub-contractore.
EN17- British steel type. Not quite as good as EN19

Left:
2A7085- Most likely a very early Sprite part number. Could also be a Morris Minor part number
EN17C- British Steel Type. The 'C' indicates sub-type of EN17 steel. Much like the EN40B cranks of Mini and 1967 Spridget fame.
MOWOG- Same comment as for the Right.
ONES- Same comment as for the Right again. Look closer. Should be OMES.

C-BTA939 is the EN19 steel version for the wire wheeled cars.

For the best "Factory" part for street application, find a set of BTA806 axles with good splines and no cracks at the hub end.

HTH,
Mike Miller