Bobbin / spindle sander advice

Raymond UK · 5 Jan 2020

I have a Clarke COBS1 bobbin sander (same as the Triton, Scheppach, Vonhaus and Draper)

The oscillating has stopped but the spindle is still spinning. I've taken it apart and it looks that one of the drive belts has stretched and skips teeth resulting in both plastic cogs (the ones with the arrows) spinning at the same rpm.

I've ordered both drive belts so they should be here soon.

I have cleaned both cogs as it had some build up of dust etc on. My question is, do I need to put any grease on these or do they just run plastic on plastic?

Thanks in advance

MikeJhn · 6 Jan 2020

I would hazard a guess at plastic on plastic as any grease would attract sawdust?

Raymond UK · 6 Jan 2020

Good point about the dust. It's enclosed pretty well and has good extraction but somehow dust always seems to get anywhere.

Belts should be here tomorrow so I'll see how it goes. In worse case scenario I could always replace the cogs as they're quite cheap.

graduate_owner · 7 Jan 2020

Would something like a ptfe spray help?

AndyT · 7 Jan 2020

I'm pretty sure that plastic cogs and a ribbed belt are designed as a maintenance free combination.
I wouldn't add anything at all. If you lubricate it you could help the teeth of the belt ride up over the teeth on the cogs. There does need to be grip on the side surfaces of those teeth.

Raymond UK · 7 Jan 2020

I have fitted the new belts just now and not lubricated the cogs and all is running/sounding like it has always done so all seems good.

Andy,

I didn't mean to lub the teeth on the cogs but the bits that separate the cogs to create the oscillating action. The bit with the red arrows. I think it will be fine without any lubrication though.

On the label attached to the sander it has a number 15E which MachineMart used to identify the year and month of manufacturer for warranty purposes. Looks like I bought this March 2015 so it's not done bad 8)

AndyT · 7 Jan 2020

Ah yes, that makes more sense, sorry for the confusion. I'd go with dry shiny plastic myself, but I am only speculating here. If they don't provide a port or something that says 'oil here' it probably doesn't need anything.