Knife Sharpening Tool V2.1 (with video)

by CNCKitchen Jan 17, 2016
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What US measurements should the rods be? Unfortunately the superior metric system isn’t used here.

I used 1/4 for the handle and 3/8 for the rest. the 3/8 is just a bit too small and the 1/4 is just a bit too big. I drilled out the handle till the 1/4 pipe fit snuggly and wrapped the 3/8 pipe with tape where it needed to fit tightly with the feet and base.
Been using it for a few weeks and sharpened about 10 knives of various sizes - it works great! Very happy. Made one for a friend who loves it too.
If you have pairing knives with narrow blades you might want to print the Guide_15mm_longer.stl by Baggi0 here: https://www.thingiverse.com/thing:3738397/files

Knife Sharpening Tool for whetstone
by Baggi0

Not sure if this has been answered before, but how can the bolt hole be printed without supports? Is bridge mode used?
Please see attached image.

PS. Thanks for this design, it is really a great idea and implementation.

For the bolts and fasteners, does anyone know where you can get them all in one place? Like a Lowes or a Home Depot, even? It's hard finding the right fasteners for U.S. based suppliers and I'd like to get them all in one shot if I could. They seem pretty standard fasteners, honestly.

Try a True Value, Ace or your local (non-chain) hardware store. Lowes and Home Depot suck for actual hardware - at least the ones around where I live. Our local hw store also caries pretty much the entire line of K&S Precision Metals products - I used their stainless tubes for this project.

Is it possible to change the 6mm rod in a 10mm rod? I do have 10mm rods, but no 6mm rods

Can anyone tell me if 7/16th inch round aluminum stock would work in place of the 10mm round stock? I would like to make this and it's hard finding metric stock in the U.S. to the right diameter.

Might be a little too big, but just drill the wholes a little open. 3/8th might be more suitable.

Follow up question: do I have to do any other modifications to the design in assembly when using the 3/8th inch versus the 10mm stock? I want to do this quickly and the stock is available but I'm not sure if it's a straight switch in terms of design modifications. Would I need to widen the holes? Shim the gaps? Any information here would be greatly appreciated.

Great Design! Thanks for the work!
I modified the handle to be compliant with my sharpening stones by adding long threads.

The fit of the stabilising end peaces was a bit lose. If I need to print another I would make the hole 10 -0.05mm
Kind Regards

I have corrected the Materials List:

1x M3x12 cylindrical head bolt (X, spherical housing)
1x M3 nut (X, spherical housing)
1x M4x16 hex head bolt (Z, adj knob)
1x M4x16 cylindrical head bolt (Y, file handle)
2x M4 nuts (Z&Y)
2x M5x20 cylindrical head bolt (Z, bottom stay)
1x M5x20 hex head bolt (bed, blade stay)
1x M5 washer (bed, blade stay)
2x M5 nut (Z, bottom stay)
1x M5 thumb nut (bed, blade stay)

Hi, It would help things immensely if the BOM was updated and the older version files were deleted. I am mostly assembled and don't have much metric hardware so i've been to the hardware store about 3 times. Also if anyone is trying to make this with imperial rod then 1/4 in works for the smaller rod but 3/8's is too small for the bigger rod..

Hello i have a Problem with your newest 2.1 Version.
I cant figure out what Parts i really need to print.
Do i need them all or can you exclude some Files like the Assembly.stl
Id like to have Folders like " to Print" or so.
Please help me.

Also i like your Youtube Channel so much, subscribed and liked most of your Work.
I have an Filabot V1 Green and Filawinder but not enough space to make my own Filament.
In the next flat (I´m moving into bigger Flat with my Wife) i´ll have that space.
I can help you with making Filament or test Samples.
I´m from Austria so you can write in german if you like, but others here like too see whats my Problem and a Solution from you in English.

best Regards,


Please correct the bill of materials.
Thumb nut and washer should be M5
Missing M5 hex head bolt
Missing M3 nut
Missing two M5 nuts

Thank you, changed it!

Still incorrect.

Still incorrect.

How many hex head bolts are necessary? The BoM lists 2 m4*16 hex head bolts but gblades mentioned an M5 as well.

What should be the length of the stones? I ordered stones from u link and they dosn't fit. They have 158,5 mm lenght.

Mine are also the same length (159mm). If yours don't fit just scale the handle up or down to get the proper length.

Ok thx for u reply and really good job with this project! :)

Comments deleted.

Got everything printed, but the outrigger legs want to twist with the added "frog eyes", do you glue the 300mm x 10mm rod/tube so it doesn't twist, or are my tolerances just so slightly off?

Just glue it into place.

Thanks! I hot glued a dab and gave it a slight twist to draw some glue in between the parts. Works like a champ!
I didn't care for the "frog eyes, I found a piece of grippy cabinet liner to work wonders. I will post a make soon.

  • Posted with 3D Geeks Thingiverse Browser App

I am slightly confused as to which files are the most recent version. My guess is that the ones with no V1 in the prefix, right ? V1's are the old version and V2's are the files with no prefix. Correct ?

You are correct. There is unfortunately no way to add folders so I had to do it that way.

  • Posted with 3D Geeks Thingiverse Browser App

I was unable to get ahold of the stones you posted in the link locally, (ie amazon), and I was able to prototype an adapter for ones available on amazon if you are interested in including this in your next revision. I also remixed the feet a tiny bit to accept (and not be so sloppy really) on the locally available round stock here in the US at 3/8 inch. Luckily metric screws and bolts arent so hard to come by here.

link to amazon item: https://www.amazon.com/gp/product/B0796SW8LV

link to the adapter: https://www.thingiverse.com/thing:3681202

Sharpening Stone Adapter for CNC Kitchen's 3D Printed Knife Sharpener

Direct link to captainslooose's adapter: https://www.thingiverse.com/thing:3681202

Sharpening Stone Adapter for CNC Kitchen's 3D Printed Knife Sharpener

Fantastic design, I have printed all the parts in PETG and am waiting for the rods and stones to arrive. One observation I'd make, if you re-visit this, is that stick on rubber feet tend to be more secure when secured within a moulded/printed recess.

It tends to reduce the risk of them getting peeled off; if you look at commercial designs they almost always recess the feet slightly. It also gives the advantage of locating them consistently during the attachment process and tends to improve adhesive performance in terms of impact absorption and shear strength. It also provides a neater appearance.

It's a tiny detail in what is otherwise a really well thought out design - thanks for providing the F360 files, I made a longer guide to allow the support and sharpening of smaller pocket knives.

Hi Stefan, thanks for that great Design. Just finished the littel weekend projekt and it came out perfect! :-) One thing though: there is a mistake in the BOM: the Guide needs a set of M5 hex bolt, washer, thumbscree. Best, Björn :-)

You should make the clamp to hold the stones adjustable. This way you dont need tape, and it is more secure.

hello, how about adding a function to also support planes and chisels ? also a 35° piece

Cool design. Thanks for adding the Fusion360 file to the project! I just opened up the Fusion file. Shouldn't the Guide > Body1 have a hole in it for the bolt that holds the swivel guide together?

If you'd put a hole in there supports would be necessary. This is a trick that the hole can be bridged with one layer that you can easily remove with a knife or a drill bit. Take a look at the part in your slicer.

Hi, is it 8mm or 10mm magnets now? It says 10mm in the parts list and 8mm in the post make section. Cheers for the great design!

The 8mm magnets are actually the ones used in the V1 design. Forgot to delete that part.

Dankeschön :)

Hi Stefan, nice and super usefull idea .. inspires me to build a similar holder tool for finish-refaceing/sanding my 3d printed mouthpieces for sax/clarinet .. you mentioned Fusion 360 as a CAD tool .. could you share also a Fusion file .. in particular this cute flex-rodholder could be my key feature ...

Fusion file can be found under the downloads (f3d).

How are the stones attached to the handles?

They are just slit in from the side.

And how are they fixed? Glued? Clamped? Screwed? Magical air anchors?

I was curious about this as well, and I looked up the stones on Ebay, and found that they're affixed to a base that has a dovetail on the ends, which this model is designed to retain.

In the handle there is a slot to put in an M4 nut. There indeed is a dovetail and in combination with this nut and a screw, you can fix the stones.

Comments deleted.

Hello awesome design! could you please upload cource files, to modify stand for base fixing, like screws. and to adapt it to my magnets?

The STEP file is available for download.

Hey, great design. I would like to adjust the rod and screw sizes, mind uploading and stp?

Just uploaded it. Have fun with it and please share your results.

Great, thanks.

Btw I just found this https://www.youtube.com/watch?v=6W7hUEa_NDE looks very similar to this system as well.

Nice design! Nearly done with printing. But I noticed a hole in the stone holder, with another hole at the side. Probably for a nut. What is/was the purpose of this hole? A screw to secure the stone?
Stones and magnets are on their way, so I hope to post a "Made" soon...

Hello!!! This is wet stones you using on video! Do you hear the sound! You should wet them! Before and During! You are welcome.

Well, hello!!! Thank you for you positive comment! I'm glad you're not overreacting. Did you make one? I guess not... But you're welcome indeed.

What length rod do you recommend for the "foot" and the "Upright"? Also, it seems to be difficult to locate 10mm aluminum rods here in the U.S. I am using 3/8" rod instead. It fits a little loose but I think it will work. Any chance you might release a version using SAE fasteners and round stock?
Great design by the way! Thanks for sharing it!!

Thank you for this beautiful design!

Yes, they look like the ones I use. Should be suitable.

Just made this. I will post a "Made" soon. Looks nice and thought through. Some minor comment though to others who want to make it to print the angle guides a bit smaller - they don't really fit below the stone if you align the knives to the edge of the base (and if you want to set the angle without a knife). The set angle will also be off by the angle of the non-cutting part of the knife blade, but I think that's simply part of that concept of a knife sharpener.

@cocoknight: what did you use fix the screw of the alignment part? Also your knob?

Now the next step for me is to insert some magnets. Not sure yet which size fits in well, but I ordered some 8mm diameter, 5mm height ones - I hope they are strong enough although the hole is deeper.

I used a simple wing nut for the alignment part. That keeps it well in place.

Try to press fit the magnets into place and even use some glue to hold them even better. Push them a little bit further in than the level of the surface is. This will avoid scratches on the knifes blade.

What size magnets please?

Disregard: 5 8mm neodymium magnets in the holes to hold the knifes
I ordered 100 8mm x 1mm magnets for #3.80 from dealextreme

I used 8x10mm magnets. They fit snug in the holes and if you push them all the way in then there is some play so they do not scratch the knifes.

Where do you use the angle gauges?

Take a look at the third image in the gallery. You place them between the stand and the back of the knife.

Bought stones today! Waiting for them before print!
Do the jig need to be strong, such to use polycarbonate or is normal ABS enough?

The tool does not really see any high structural loads which is why you don't need any special plastics. When using the device you really don't apply a lot of pressure on the blade you try to sharpen. Use more or less only the weight of the stone itself.
I would recommend using PLA since otherwise you might get problems with warpage of the stand and the stone holder.

Sorry I dont get that option.
When trying to download it gets all the files. Also the ones with zero bytes.

After downloading some files are 0 bytes!!!

This seems to be a problem with Thingiverse. If you download the files on their own they are working fine.

Great desing, thank you for sharing.
Could you please also provide a link to the stones?