Gearbox Mainshaft Woodruff Key..

[brackenfel]

Dear All,
Still on the painfully slow rebuild of the A10... Back wheel now in again with a slightly non-standard brake plate & brand new tyre.. Managed to thread the chain through the front section of the FERC unit (what a bl**dy job that was!!). After a lot of fiddling got the nut on the bolt & washer that secures the rear of the primary inner to the frame - yes, that bl**dy FERC section was in the way again...

Now the next gremlin has surfaced...
When I rebuilt the gearbox I used a different mainshaft as it was slightly better than the original. Now I can't get the original / only woodruff key I have to fit.. Am getting bored with filing and the key is now sloppy in the old shaft but too tight in the new. It does appear to almost fit but the upper surface seems higher than that of the shaft.

Before I start trying to file the top or get a new one I was wondering if there is more than one key to use here, maybe the slot was cut deeper on some shafts than others..  Any ideas as this stupid little bit of metal is holding things up....

I'll happily buy another but don't want two that won't fit!!  Preferred supplier for these things??

Thanks as always,

Adrian

[brackenfel]

Sorry - forgot to mention - 1961 A10, 4 Spring Clutch. Can't get clutch centre to fit all the way over the key, only part way (but it does over the old shaft with key!!)

Thanks
Adrian

[bsa-bill]

Draganfly list about five different mainshafts but I would perhaps wrongly assume they would all have the same taper/keyway except perhaps the plunger one.
Mostly they are different because they are for differing ratios internally or  are RRT
However there is a lot of plunger stuff around ( I have my share of it )

[Beezageezauk]

Hi Adrian,

I've checked out my parts lists and it appears that all swinging arm A and B (pre-unit) models use the same part number (2-433) for the gearbox mainshaft key.  For what they cost I would get a replacement key.  This way if you can't get your original one to fit then at least you'll have a spare to play about with.

Beezageezauk. 

[brackenfel]

Thanks Bill & Beezageeza,
I'll get a new one asap, as you say they'll not be dear & weigh nothing for postage..!! It'll save file file, fingers & patience too - hopefully!!

Cheers,
Adrian

[chaterlea25]

Hi Adrian,
Fettling is all part of "assembling" your "A"
MAKE SURE the key is a perfect fit in the shaft and clutch adaptor
Sometimes it is necessary to make the key stepped to ensure a perfect fit
Also it may be necessary to reduce the height/depth of the key to ensure that it does not hold the centre off the taper
It may also be neccessary to ease the edge corners of the key so as it sits to the bottom of the shaft keyway
Clean any burrs from the keyway in the adaptor!!
Hope this makes sence ???? ???? ????

HTH
JOhn O R

[brackenfel]

Hi John,
That's most helpful - many thanks... I guess I'll try a new key & failing that carry on with the file until it all fits !!!

Cheers,
Adrian

[dpaddock]

It's the taper that matters here; the key is essentially superfluous. I once had a key that  sheared in half because the mainshaft nut was not tight.
If you wish, fit a close fitting key or none at all, but get the taper surfaces to match by lapping them to each other using valve grinding paste, and tighten the nut to 75 ft-lb. Do not let the key interfere with a full taper fit.

David