Custom Built MDF Wheel Sharpener

[GruffaloGriff 1,858]

Heard a while back mention of sharpening with MDF wheels but never really paid much attention. I recently thought i would give it a go and turned up a quick MDF wheel on the face-plate of my wood-working lathe. I clamped a makeshift guide to the back of the lathe and worked with the wheel turning away from me. I was blown away by the results! Super sharp paper slicey edge straight off the wheel.

 

Decided a dedicated MDF wheel sharpener was high on the list of must haves so started gathering bits. I was lucky enough to pick up an old 8" Makita bench grinder on ebay for £25. Everything else is made from scrap bits so that was all the outlay for the build.

 

I took the guards off the grinder, swapped the switch and the power cable around so the on/off switch is effectively now on the back so the grinder can be operated with the wheels running away from you.

 

The knife clamp is made from an old door hinge welded to a bit of rod off of some other power tool, hence the nice grippy knob on the end. A 6mm hex bolt through the hinge clamps the knife in place. A cutting of hex bar slides up and down to alter the angle of grind and locks in place with another allan bolt.

 

Once set up to the desired angle the blade can be sharpened on both sides and both wheels quickly without altering anything.

 

The MDF wheels are loaded with grey polishing compound and jewelers rouge respectively.

 

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[smithie 2,443]

I watched a video on youtube yesterday doing this. Chap used ply instead of MDF and turned the grinder around so it would not grip..

Looks good

[Caravan Monster 323]

Wheels made from glued together leather discs are good too. Make your own or you can get them ready made with a spindle to go in a drill chuck. Load them up with linishing compound or whatever. You don't need to be very precise with the angle of the knife to the wheel because they are just polishing the burrs off the edge. I use the top of the wheel, obviously with the edge away from the direction of rotation. Never been able to get the hang of sharpening with a flat stone but get stupid sharp edge with the leather wheel.

Also bodged up an axle for an 8" carborundum grinder wheel. I run it in water (cut the side out of a plastic milk bottle to make a trough) at slow speed so that it isn't flinging water about. Knives are held across the top like the leather wheel. It's really good for sorting out chipped edges and there's no way you can blue the steel. Suppose it works like an old school hand cranked water stone.

[socks 32,253]

Ive heard about using mdf and ply wood as sharpening wheels but bed paid much attention to it. How does it compare to sharpening using a belt grinder ??? 

[shovel leaner 7,650]

I’ve been using one for a while . I bought the cheapest bench grinder from screwfix £19.99 and watched a YouTube video . I made the MDF Wheel by drilling the centre and jigsawing the circle and then finishing with a chisel . I just use the green honing compound and you can shave the hairs off your arm . By far the quickest and best sharpening method I have ever used . 

[GruffaloGriff 1,858]

6 hours ago, socks said:

Ive heard about using mdf and ply wood as sharpening wheels but bed paid much attention to it. How does it compare to sharpening using a belt grinder ??? 

Not realy for grinding just putting a wicked sharp polished edge on. Saying that it is surprising how much removal it will do.

[Tyla 3,179]

I saw Griffs version on another thread, I knew there would be a how to thread somewhere and here it is. Cheers Griff 

[socks 32,253]

Built myself one today and it’s shit blunted every knife I tried on it .....

 

[GruffaloGriff 1,858]

I found you need the jig to keep the blade in a consistent position on the wheel. Free hand it wanders all over the place  and is impossible to get a decent edge.

As Balaur says try a smaller wheel to slow the surface speed down. The faster speeds i found don't work quite as well. Tip: Frequently flip the blade toward the end of the sharpen and give light passes.

[Greyman 28,198]

On 20/09/2020 at 22:08, socks said:

Built myself one today and it’s shit blunted every knife I tried on it .....

 

Feck me ken that’s the London eye

[socks 32,253]

Go big or go home mate .....

[johnbaz 363]

I have an  old 1hp Wolf buffing machine, I made a leather wheel from a pile of old leather aprons at work!!, I noticed that when I buffed blades up, It edged them up better than I could on my Arkansas stone!! 

It's the right one and is switched on in the pic as it just flops over when turned off due to not being stitched!!

John