Work Sharp Professional Precision Adjust, Replacement Handles

Two different handles for the "Work Sharp Professional Precision Adjust" knife sharpener. 

-"Standard" for using the regular abrasives that comes with the sharpener.

-"Universal" for using generic ~160mm long abrasives (the ones with wedges on each end), but also the abrasives that comes with the sharpener.

Since the newer version of the “Work Sharp Professional Precision Adjust” handles are glued together, you can't replace the bushings inside of it. So when those bushings wear out you have to buy a completely new handle.. 
So I made these new handles that will accept regular 6x10x10mm bushings that the older handles used. 

You can use bronze replacement bushings (probably the best option), or print some plastic ones yourself. I've added some printable ones with slightly different internal diameters. Depending on your printers tolerance.

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The “standard” handle requires one standard grip and one standard base part to be printed.
For hardware you will need:

-8x M3x8mm screws with matching nuts.
-1-4x 8x2mm magnets (depends on how strong your magnets are). These will have to be glued   in place.

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The “universal” handle requires one universal grip, one universal base and one universal endpart to be printed.
For hardware you will need:

-8x M3x8mm screws with matching nuts.
-4x M3x6mm screws for attaching springs (or longer screws if you want to use  rubber bands instead).
-2x extension springs or rubberbands.
-Some electrical tape or other material with some grip to it.

I had some “5.16x20.6” extension springs in my spring assortment box which I used since those where the strongest. But I made another set of holes on the side for longer springs if those fit better for you. (Those extra holes are roughly 55mm apart from each other when the endpart is all the way in).
 

I would also recommend wrapping the contact surfaces on the universal handle with some electrical tape or something which adds a bit of grip. 
Generic abrasives normally have a plastic backing which can be pretty slippery against the printed parts.
I added  some thin grooves on each end where the tape can be cut and ever so slightly pushed in. 
I would also suggest to add some superglue to the ends of the tape to lock it into place and keep it from peeling off. 

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Vertical vs Horizontal versions.

Each handle are made in two versions, "Vertical" and "Horizontal".
That simply depends on how you want to print them.

-Vertical needs to be standing up and will require a brim + supports. If you have a bedslinger you will most likely also need to slow down the print speed a lot. 
I painted on organic supports on each side of the parts here and there, just to keep them from falling over. 
So you will need supports to be painted on, but there aren't actually any surface or overhang that requires it from a structural/tolerance standpoint.
Personally I think the finish of the prints looks better when printing vertical, but with a MK4s/bedslinger it's very slow. And those tall supports waste plastic. The base part is also more fragile (not really an issue unless you try to bend it).

-Horizontal can be printed laying down flat on the bed, which ofcourse is much more stable and faster.
Though here you will need supports for all the overhangs, which can cause issues with the tolerances between parts. It's naturally also more annoying to remove the supports, especially from the tight gaps.