I've replaced my old chain and chain ring with a new 1/8 chain and 1/8 chainring - kept the old cog - also 1/8 and in good shape. (riding it fixed with a good chainline.)

I get a really loud grinding noise when cranking hard but nothing with soft pedaling.

I have had this before where it was a new chain and it only made the sound for the first ride or so then slowly went away.

This one seems more pronounced - and doesn't appear to be going away.

Tried: Lubing & re-lubing, re-adjusted the wheel in the drop-outs several times, etc...

it was really quiet before the new chain and ring.

Has anyone ever had this griding noise issue before? could it be just a matter of getting the chainring "ground" down to a perfect fit with the chain (the chainring was from eighthinch.com - cheaper than most - wondering if this is what a cheaper chainring does if it is not machined perfectly...

Thanks