Flat lap plate--grooved or not?

[techoff2]

I need to replace my old hand made vibrating flat lap 22" machine.The one I am looking at is made in Qld by Lapidary Slab supplies.The current plate  has concentric grooved lathed into the surface.The new one is smooth no grooves.What are the pros and cons of a smooth plate.I have looked at a couple of videos from Highland Park and all of the machines that they use are smooth.Comments please.

[Faceting Frank]

I would imagine for a vibrating lap you would want a flat surface. Don’t see any point in having grooves in it, since it would be covered in grit.

[mehoose]

Maybe the grooves help hold grit across the surface a little longer instead of being pushed to the sides quickly?

[techoff2]

Raytech, Covington, Lortone and Diamond Pacific all produce grooved plates on their retail vibrating flat laps.Highland Park used to produce grooved plates but their latest machine uses a smooth plate.I have spoken to Woodies at Mildura who have a commercial setup and they used to use smooth plate but they no longer do much flat lapping as it is cheaper to buy them in already done. Their supplier however uses a grooved plate!!

[Greenmachine]

I have the same question. I bought an old machine today that had grooves but were so warn toward the centre they have warn flat. I have another plate that is flat and wondered the same thing why don't HP Lapidary have no grooves? and can I just use flat plate?

[Faceting Frank]

It's been decades since I was into polishing flat slabs of agates etc. But from memory you start off with a course grit and you don't want bits of it sitting in the grooves, to come out later. So, I don't see what advantage grooves have.