Copal 1 Lens Board Hole Size

I recently acquired a 210mm Schneider lens in a Copal 1 shutter without a lens board. I picked up a Linhoff style Copal 1 board on eBay but the hole seems excessively large compared to the shutter's threaded diameter. I didn't measure but there's probably 1.5mm of play all the way around and this seems like far more slop than there ought to be. I was able to get it tightened down and centered (well enough) but I have no context for how it should be as I've only one other lens for my 4x5 that's never been removed from it's board.

What should fit closely in the lensboard hole isn't the lens barrel, but a shoulder of the tightening ring.
You can see a retaining ring at Grimes; see the narrow shoulder sticking out? That should fit in the hole, so your 1mm+ clearance round the lens barrel itself is right.

I should admit that, before I knew this, I have made a couple of holes in lensboards for myself, and sized them to fit the lens-barrel, and the sky didn't fall on me, so I haven't gone back and corrected them.

Ahhh... so the ring was wound on backwards and I repeated this error. Thanks!