5mm to 7.8mm shaft coupling?

I didn't notice till today that the acme screws I got from openbuilds are actually 7.8mm in diameter, not 8mm. I have 5mm to 8mm shaft adapters for turning these screws as the Z drive on the printer I'm building, but tightening the screw on the adapter won't grab the 7.8 mm shaft. The adapter I have is a clamping style that has a screw which draws the sides of a slit together. Is there another style adapter that would work better? I've looked on Misumi and didn't find 7.8mm as an option, but there are lots of other style adapters. (Or I could get McMaster to make a couple to order for $300 or so :-). Would wrapping some aluminum foil around the end of the screw work? Or I just thought - maybe wrap some wire in the threads to make the end larger?

Edited 1 time(s). Last edit at 03/09/2021 02:11PM by Claghorn.

... get some 0,1mm steel-sheet and cut pieces to wrap them around the 7,8mm to get 8,0

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Or cut shims from a beer can....

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I finally got back to this, and some strips from a can rolled around the screw thread worked great (sorry, it was a soda can, not a beer can :-).

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]