Quick Mounted Angle Grinder Power File / Belt Sander.

Introduction: Quick Mounted Angle Grinder Power File / Belt Sander.

About: Ews & qualified welder/metalworker since 1998


There is a lot of power file angle grinder hacks on youtube.

I haven't actually searched them, but youtube suggest them sometimes.. and when you have watched one, it suggest you to watch another one..

Seems that most of them that i have seen, are based to that same "Mother of all grinder ..." -video made some years ago.

Little different ways to make it, but mostly result is somewhat same.... Why to change working consept, i know..

One reason is, that i have four Bosch angle grinders, all of them use different way to attach disc breaking guard, none of them uses that old method, tightening guard around the grinders neck with screw.

That same method has been very popular in power file hack videos that i have seen... None of them fits to my needs. And buying one grinder more..?

Second reason to think alternative way is, that when you need to use many tools for connecting attachment to the grinder. It usually happens, that attachment stays mounted, and you buy another grinder for the task where you need angle grinder as it is...?

Therefore, i desided to think alternative connection. Easy to use, no need for separate tools...

I used Bosch AdvancedGrind 18 cordless angle grinder.

Wich i found to be best option for my use. It makes this consept also portable, and it has variable speed.

Short preview of the features.

This version can be mounted / unmounted with in 10 seconds.

It can be tilted, and mounted to saddle to be used as a belt sander.

Also, its designed for to be easy to open and maintain.

Frame and stand is made from 3mm mild steel.

Plate and 25 x 3mm flat.

Guard is 1.5mm stainless.

130mm long piece C-track, with 24mm x 6mm inner dimensions.

30mm x 30mm x 3mm L-profile 30mm long piece.

Tools used:

Angle grinder

Stick welder

Drill, threading tools, files, sanding drums

Diy press

Step 1: Frame

Frame is made from 3mm mild steel.

Piece size is 150 mm x 50 mm, these are to outer dimensions too.

Shorter end is 30mm wide, narrowing starts 55mm from the wider end.

Bend lid is 20 mm x 90 mm from the shorter end.

Made cuts with the angle grinder using 1mm thick cut of wheel.

Then rounded the edges and corners with 40 grit flap wheel.

Made 90 degree bend for the lid with my diy press. ( 3mm can be bend in vise too )

This bend is to give strenght to the body, also it guides C-track straight and makes assembling easier,

its somewhat optional.

Continued with drilling hole with 38mm holesaw. Diameter between locking fingers is about 39mm.

Using little smaller hole saw gives little working allowance for filing.

Centerpoint of the hole is located to the center of the 55mm x 50mm area. ( height of the piece is 50mm, 55mm to the point where narrowing starts. )

Cleaned edges with file..

Connection to the grinder is made similar way with my earlier pipe sander.

Step 2: Mounting Slot..

This attachment replaces original disc brake guard of the grinder.

I traced the places of the slots to the plate, and removed material with rotary tool and file.

Its better to make several test fittings to get firm fit.

When plate locked on its place, i weld 6mm wide ring, cut from the 44.5 x 2mm tube. ( outer dimensions )

This leans to the locking spring on the grinder.

Also slots for tilting adjustment will be carved to this ring.

Just little tack welds, its better to let it cool down between welds.

After welding i smoothened joints.

Step 3: Slide..


Is made from 130mm long C-section, and 25mm x 3mm flat bar.

Internal measures of the C-section is 24mm wide and 6mm high.

C-section is weld to the body from all four corners. Tack welds are enough, bigger welds makes unnecessary disortion.

Actual slide is made from two peces of flat bar.

Both of them has 7mm holes on the centerline, 20mm from the end.

One of them is bend to "chair" shape. Measures are taken from the width of the bearings.

I used 8mm wide bearings, two of them comes between the flar bars. Between the bearings and the flat bars i placed 0.5mm thick washers. This gives 20mm wide slot needed.

Third bearing is "outside" of this structure.

After bending, i weld flat bars together from the sides. Before welding i placed bearings, and lined them straight.

Then i pressed flat bars together and weld them from the both sides.

Because flat bars have rounded edges, its not necessary to chamfer the edges for welds.

Smoothened the edges, and at the same time, i grind the widht of the slide to 24mm.

Now it fits inside the C-track.

Manufacturing this stage, can be seen from this video:

Slide is locked on its place with M6 bolt. Inside the bolt is a spring. Tension of the spring keeps screw on its set tightness.

Step 4: Plans for the Body

Here is the plans for the body.

Note that holes for the table mount and dust guard needs to be similar with the objects that will be mounted to it.

I personally liked easier to make holes to the stand and guard first, then i traced location to the body.

Smallest radius at the mounting slot is 19mm ( made with 38mm hole saw )

Second one is 21.5mm ( this curve is made with files )

Third radius is 27.5mm. ( Rounded corners at the bottom section, of the mounting area.)

Step 5: Tilting

To be able to adjust tilting.

I made a new latch for the grinder.

I removed the old one, and traced lines from it to 3mm thick plate.

I just added a little finger to it, where i can press latch open.

Hole in the latch is 5.2mm dia.

Then i searched suitable angles that i want to use.

Marked locations to the ring, and carved slots with dremel and tungsten carbide cutter.

Latch is spring loaded, it presses against the ring and when it drops to the slot, it locks the sander to set angle.

Even that the new latch is little bigger than old one, it doesn't come on the way when using grinder as i is.

Actually, new latch allows to turn original guard in both, counter clockwise and clockwise, when it originally moved only clockwise.

That was annoying when you accidentally turned it too far, you needed to turn it whole new round again.

Step 6: Front Wheel, Bearings

"Front wheel" is made from bearings.

35mm outer dia, 8mm wide and 7mm hole.

On the video i usen two bearings, but when i choosed to use 30mm wide belts instead of 20mm, i added one more bearing.

To connect the bearings, i used M5 rivet nuts. These has M5 thread inside and outer dia is 7mm wich is similar with the hole in the bearings.

( M6 rivet nut has 8mm outer dia, and there is many different sizes. You can easily find suitable pair. )

So, axle is made from M5 screw, and two M5 rivet nuts at the both ends.

Third rivet nut is shortened to the right lenght and placed between the rivet nuts.

I use drill and dremel with cut of wheel in this kind of tasks. Easy way to get straight cut.

Clean and nice looking result. I used a drop of locktite to secure connection. But still ist easy to open and remove bearings for maintenance.

Step 7: Pulley

On the video is used skateboard wheel.

It was the same wheel that i also used with my pipe sander.

It works well, but i wanted to remove all possible driftings or belt drops.

So i turned this new pulley from the nylon.

Skateboard wheel with the rounded edges works nicely too.

( 52mm dia, 32mm wide, M14 nut pressed on it )

Step 8: Guard

Guard is made from two pieces of stainless steel.

Curve is made by pressing it around the 50mm pipe.

Then i made the bend with brake, traced the curve from the sander attachment and grinded with sanding drum.

Then i traced the shape of the guard to another plate.

Cut and grinded internal shape first.. Weld parts together and smoothened joints. ( with couple tack welds )

Then i cut the outer shapes of the guard.

This makes welding much easier, wider plate doesn't melt away so easily.

All welds with this project are made with 1.6mm stick using 40-45A

Guard is connected to the body with M3 screw, and M6 screw wich also works as a stopper.

Stopper prevents attachment to scratch body of the angle grinder, so its not very important issue.

This screw is also locked on its position with spring.

Step 9: Platen


Is filled with 12mm holes.

These are for reducing friction between the platen and belt.

Three holes at the center line, four 15mm to both sides of the center line.

Distance between holes is about 30mm.

Platen is connected to sander with two M3 screws.

I drilled 3mm holes to the platen, traced the placements to the sander, made 2.5mm hole and threaded with M3 tap.

To connect sander to the table saddle.

I used two M6 screws. Both are threaded and countersunk to the platen.

Longer one is for connecting, shorter works as a guide and support.

Step 10: Stand

Stand is made from one piece of 3mm steel.

Before bending i filed square slot for the c-clamp.

Then i bend edges together and weld.

C-clamp is made from 12mm x 12 mm bar.

M8 thread, and screw that i found somewhere.

Step 11: Finished

And here is the finished product..

Sander uses 30mm x 533mm belts.

I like 70's muscle cars.

Tried to get something similar look to the attachment..

But, anyway.. it works nicely. And has now become my favourite diy tool.

Idea was to make simple to use attachment for portable use.

Overall weight of the sander with stand and the pulley is less than 1kg, not much when compared to the weight of the one battery of the grinder. 0.65 kg

This was a part of my experimental consept for mobile sander.

You can see the preview from this video:

Thanks for watching!

Stay tuned..


Tuomas Soikkeli

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    17 Discussions

    Alex 2Q
    Alex 2Q

    1 year ago

    Nice work! Very interesting project indeed! You got my vote!

    Alex 2Q
    Alex 2Q

    Reply 1 year ago

    Thanks a lot for your vote! I do have the problems with the comments and messages as well from time to time.


    1 year ago

    Fantastic. You could possibly sell the concepts and drawings for the attachments to one of the tool companies and get Royalties.

    The other Finnish guy
    The other Finnish guy

    Reply 1 year ago

    Thanks. This consept continues.. Same connection can be used with cutting stands and guides too. Maybem after those i try to show it somewhere.


    Reply 1 year ago

    Tuomas. Believe me when I tell you that this is something that is ready as it stands at this very moment to be presented to whomever you might pitch it to. The rest can be easily built later. It's that good man. You know many people can build things like this if they set their minds to it. Tools of this measure in utility and function are only designed and built by the USERS of said tools. The mind that can visualize this attachment and put it together from things laying around the shop which can be acquired easly and inexpensively is extraordinarily rare.

    Don't sell yourself short. I fully expect to see your name credited towards some wonderful things in the future. Not blowing smoke buddy. Just encouraging you to seek the sky and beyond You were born for this.


    1 year ago on Step 11

    Wow Tuomas. Hard to imagine anyone improving the best damned angle grinder available in the world, but you have done it. Your work is sheer genius my friend. Methinks perhaps these tool companies could use a mind like yours in their R&D Department. Very nice work buddy. Superlative!


    1 year ago

    How long does the cordless grinder last with it?

    The other Finnish guy
    The other Finnish guy

    Reply 1 year ago

    I have 6 and 4A batteries.
    So far 6A battery haven't run out before i have quit using it.
    I guess: About 30min when using with higher speeds.


    Question 1 year ago

    I've got several speeds of angle grinders. What's the best speed range for a tool like this ?

    The other Finnish guy
    The other Finnish guy

    Answer 1 year ago

    This has max 11k rpm. This gives belt speed 1650 m/min = 27 m/ sec with that nylon pulley.
    I have set of 3M metal grinding belts that are recommended to be used with speed 25 m/sec. And some wood sanding belts with max 15 m/sec speed.

    I haven't noticed any big difference in use,
    when using speeds between 8k -11k rpm.

    So. My opinion is that higher than 11k /rpm is unnecessary.

    8-11k/rpm is suitable.


    1 year ago

    hi, great, it looks like a dealer tool !

    The other Finnish guy
    The other Finnish guy

    Reply 1 year ago


    I made edge sander saddle for it too.

    I'll update this instructable within couple days.


    1 year ago

    I can say Is wow... And well Done... Been wo dering how to do something like this but never have had the equipment or time... Nice build
    Btw I voted for u in the metal working competion

    The other Finnish guy
    The other Finnish guy

    Reply 1 year ago


    I tried to answer earlier, but "something went wrong".. Thank you!