Had a similar issue a few Raleigh sports .... and cringed / thought of the worst case at first ...
In both instances , the result was a much simpler fix than I was sterelong myself for
- excess play was due to too loose adjustable side cup adjustment ... that’s all !
- play due to a crushed / disintegrated bearing (s) caused appearance of chainring wobble when viewed from top down and hand pedaled in stand
- play due to too loose / misshaped cotton pins that could not be further snugged / tightened
In all cases it’s was not as bad as I thought .
my limited experience observations/ thoughts :
- looked for 26 tpi cup set with lock ring on June 22 and found listing on eBay for $9.90
( ended up Finding in my own stash) ( someone here surely has what u need )
- found it very helpful to note the “ o ‘ clock position of the cranks .... hand pedaled on stand , as well as under pedal actually riding , and match that up to a pronounced shift in the chainwheel , and or a sound , or a skip feeling ,
Under actual pedal resulted in diagnosis of shift I could not see / feel feel on stand .
- cotter pins : I have a pile of NOS cotter pins from an old bike shop stock . The ones marked and labeled 9.5 mm , I found in one case were too loose for Raleigh sports crank arms I attempted to install on .... I believe these were meant for road bikes / stronglight ?
I am now learning above from Sir Mike ... so , yeah , don’t be surprised if you find nominally “ right sized “ pins that don’t quite fit , after wards I checked using own cheap digital caliper read the old ones reading closer to 10.5 .... now I’m reusing old pins when possible
- in the case of alloy cranks , an apparent bent chainring situation is sometimes due to misshapen bevel on the crank where the spindle is received , but in this case , given both are steel , I doubt the Raleigh crank would be deformed where the spindle is inserted .... however , you might want to look for odd wear pattern in that area
G L
Hope you find it’s a relatively easy solution !