spoke to soon! By the third grind there was a whole portafilters worth of coffee stuck inside, including whole beans :S Had a bit of a fiddle but ended up putting the old burrs back. Think the mod has potential, but i dont have the time or skills to perfect it

did it today, was really easy and the grind does look ALOT better. Just need to dial it in again now

ill try it with some thin plastic sheet i have then, dont have access to any sheet metal to make a shim from. Theres a great site in the uk, {link}. Sells stainless steel bolts and nuts etc with no minimum order and cheap postage and packing. Makes it easy to get just 6 good quality bolts the

Ordered the burrs and found somewhere to get a tap and stainless steel bolts when i find out what size i need. Was thinking i could use stainless steel washers on the bolts between the stationary burr and the body of the grinder to shim it out? How sharp were the burrs you got? they looked quite old?

Heard about someone helping the clumping on a doserless macap m4 by polishing the aluminium spout, think i might have a go at polishing the interior of the grinder. Was also thinking about reducing the size of the hole letting the beans into the auger, maybe less beans in the burrs at once would imp...

Found some mazzer burrs for £30 so think ill give it a go once you put up how you did it in more detail

Certainly couldn't ever say the proline suffered from clumping. Amazing how smooth the grind is

Sounds good, have you noticed if theres a lot of coffee grounds getting stuck inside?

Surprised they are that much thinner, they look roughly the same in your photos

The anticipation is killing me! Whats the grind like?