Disc Sander / Grinder Hack




About: Just a fellow who want's to learn new tricks and skills.


If you have visited here before, you might noticed that i like to modificate machines.

This instructable is again another modification.

It shows how i made my grinder / sander, but it has some parts that can be used with other kind of modifications too.

One improvement that i have planned for this, is to make alternative door for it.

Door includes needed accessory to turns this grinder, > to bowl turning lathe...

I bought used woodshredder couple years ago, paid 30 € from it.

It was a cutting model, after little use i noticed that it didn't work at all like i expected.

It was too slow, and got stucked too easily... So i stored it for further use.

Machine has 2000w motor and it runs 4000rpm, so it was somewhat obvious that i will re-purpose it sooner or later.

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Step 1: Video About Making..

Video shows the making and using of the grinder.

Shredder has a built in safety system, it can't be turned on if door was opened.

This is a good feature for the grinder too, so i keeped it

Tools that i used:

Angle grinder for cutting and grinding metals.

M14 threading insert.





Surplus nuts and spacers from the old / broken angle grinder

Some steel plates and sheets.

Nuts and bolts.

Feets and handle is from the shredder itself.

Diy bending tools.

Step 2: Taking It Apart..

Taking shredder apart was very easy task.

I just lifted the front door out, removed the blade and feets.

That was enough at this stage..

Funny thing was that it started to look new tool allready on this stage.

Step 3: Re-shaping Axle..

Because i wanted to use grinder / sander with angle grinder wheels & discs.

I had to re-shape original M22 axle to suitable M14.

I did shaping, by turning shredder on, and grinded axle smaller with angle grinder equipped with 40 grit flap wheel.

Time after time, i measured diameter with vernier caliber.

When diameter started to be close, i continued with the file. I succest to move file at the same time, if hold still it easily happens that file wears out from the used area.

Its important that you keep pressure even at the very start when you grind the axle, otherwise it goes easily oval shaped.

If that happens, then your hand keeps following the axles oval shape, and it stays oval.

That is somewhat tricky to fix without real lathe.

When axle was on the right diameter, i grinded slots for the axle, fitted to 17mm wrench.

I used 17mm wrench to lock axle on its place while threading it.

Making this slot has another, important reason too, it can be seen on the last step.

Finally finished the shape with file and dremel.

Step 4: Making Stand for the Grinder..

I made a new stand for the grinder from 3mm plate.

Originally shredder had no stand at all, but.. anyway, i made a stand.

Designed it so, that i could use it also as an tray, to store powercord, keys and stuff, under the grinder.

Used my diy press for bending plates that i had cut to right size with angle grinder.

I skipped those parts from the video, beacause there's no matter what tool is used for cutting.

Stand is made from four simple pieces, and weld together with stick.

"Fifth part" is under the stand and connects third leg to it, two others are bolted to the sides of the stand.

I used original feets from the shredder, did some fixes for the bends and lenght to get them symmetrical.

Step 5: Axle Locking System...

This is somewhat most important thing on this build..

It makes using the grinder easier, faster and it would be little too tricky to change wheels without it.

I did three "feets" from 20 x 20 x 3mm L-profile.

Cut the ends so that i could make 90 degree bends to them, weld and drilled holes for connecting them to the body.

Marked the locations, and drilled holes trought. Used M8 bolts and locking nuts to secure connection.

Step 6: Axle Locking System Continued..

This step shows the actual idea of the axle locking.

I made a "wrench" from 8mm thick steel plate. Used angle grinder for cutting the shape, and finished the slot with file.

Slot is made 17mm wide, and 22mm deep.

Then i locked the axle using the 17mm wrench, same way that i did when threaded the axle.

Filed slot for the axle, then removed material from the opposite site with file, until slot was symmetrical and same sized with the locking wrench.

I made a framing from 3mm plate, to hold and guide locking wrench to the slot on the axle.

Used M6 bolt as a hinge, and equipped locking wrench with strong spring that keeps it away from the axle, when its unlocked.

Step 7: Improving Cooling..

Because locking system that i did, is blocking some of the original airflow, and also..

beacause i wanted to make smaller casing for the motor..

I decided to improve cooling of it.

Originally fan blades took ait for the center, and pushed it out from the ends, with smaller casing, airflow wouldn't be very well if keeped with that stage.

So, i heated the blades and bend them so that now fan pushes air directly trought the motor.

Simple airguide, made from 1.5mm sheet metal ensures that. ( I have instructable about roller bender coming, making those parts can be seen then)

Step 8: Re-shaping the Front Door..

Started re-shaping of the front door, by cutting out the cone from it.

Used angle grinder with 1mm cut off wheel.

  • Cut the cone out roughly, leaving enough working allowance.
  • Cut tack welds and remove rest of the cone
  • Clean welds with the flap wheel.

Made a disc guard from 4mm plate and 3mm flat bar.

Bend the upper edge so that i can use it as a workplane. ( making this can be seen in my next instructable )

Marked the location of the guard to the door, and drilled 6mm holes to it, for the tack welds that connects

disc guard to the door.

Made couple holes with the holesaw, to ease shaping of the door to follow shape of the disc guard.

Connected parts with plug welds.

Re-shaped the door and removed old paint with the 3M rubber brush.

Step 9: New Casing..

Made a new casing for the motor from 1.5mm thick mild steel.

Cut parts to the shape with angle grinder.

Made bends with my diy bending brake, using 5mm bending radius.

Made a slot for the axle locking handle, and then fitted parts on their place with the help of alumine tape.

Alumine tape is stronger than masking tape, also its good when welding parts together.

Its not so sensitive to heat, and even when heated, it doesn't leave glue to the surface, as masking tape does.

Marked the locations of the mounting screws and made M5 threads to the "feets" that supports the axle locking system.

Finally made the back plate. Drilled a set of holes to it for the cooling airflow.

"clamped" it on its place with alumine tape, and weld it to the upper part of the casing.

Finally smoothened welds by sanding.

Step 10: Closer Look About the Idea.

And here is the idea.

Axle is shaped so that i could use washer and locking nut from the angle grinder with it.

When grinding metals, i can use 180mm flap wheels or fiber discs with it.

There's fiber discs available from 25 grit to 120 grit. That gives nice scale for rougher metal shaping.

When doing woodworks, i can equip sander with 205mm " velcro " sanding pad, this gives me possibility

to use papers from 40 grit to 1000. And allows use of the central area too.

Papers can be used with metals too, obviously.

But when you can use same paper again and again, to sand wood, that doesn't apply with metals.

That was the reason to make possible to use rougher options too, flap wheels and fiber discs lasts much longer with metals than papers.

Step 11: Finished..

And here is the finished product.

Its a very powerfull sander / grinder, that can be used fast material removal.

And also for finer finishing too.

Axle lock makes disc changing easy and fast. Safety lock on the door makes it safe.

Most of the dust is guided under the sander, when i can place a bucket or bag where dust is collected.

You can find more sanders, and those tools that i used for bending from my instuctables page here.

Next builds that are coming..

  • Roller bender
  • Stainless spider
  • Dagger
  • Big angle grinder stand with slide...

So, stay tuned!


Tuomas Soikkeli

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    15 Discussions


    11 months ago

    Your fabrication techniques are amazing!

    1 reply
    The other Finnish guycnludwig

    Reply 11 months ago

    Thank you.
    Stick is easy to use, so i'm not a wizard with it.
    Its Light weighted to carry. That's why i use it on my homeshop. Splatters are biggest minus.. Mostly i weld with Mig & Tig

    Alex in NZ

    11 months ago

    I wish you'd posted this two years ago, before I threw away my previous shredder.

    Great re-use of the machine, and the new grinder looks amazing. Thank you for sharing this :-)

    2 replies
    raphanAlex in NZ

    Reply 11 months ago

    Never throw away working motors.
    Raph (not in NZ)

    owlmooseAlex in NZ

    Reply 11 months ago

    Man, I was thinking the same thing, Alex! Thomas has some serious skills. That 'brake' to switch discs? incredible.

    Adrian (also in NZ)


    11 months ago

    Outstanding repurposing and construction!

    King Ripord

    11 months ago

    Absolutely fantastic build, looks like a store bought machine. You're a genius, I look forward to see what you're next project will be.

    1 reply

    Thank you... Next project should be roller bender / ring roller.. but i also started to build my version about Seamster's height adjustable vise..


    11 months ago

    that is truly awsome. you have some serious skills


    Question 11 months ago on Step 11

    Thanks Tuomas.

    Personally, I had never heard of a wood shredder. From my own experience, it's not something you'd find here in Canada. Wood chippers are available for outdoor use, and they're usually large bulky items that are gas powered or a powered by a PTO on a vehicle that take large pieces of wood and reduce them to mulch size. I've even seen yard waste chippers that can handle small trees. But. I've never seen a residential use wood shredder. That's why I found teh article so interesting.

    1 answer
    The other Finnish guytercero

    Answer 11 months ago

    Here those are very usual. Nearly every house has one, to keep garden tidy.

    We have big trees around our garden, and time after time i need to cut branches from them, to keep them tidy. Those are too small for to be used as a firewood.. so we chip them and use different ways. Composting.. fire starters.. under the berry bushes or flowers to keep unwanted plants away...