DIY Bench Grinder to Belt Sander Conversion With Templates

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Introduction: DIY Bench Grinder to Belt Sander Conversion With Templates

About: We're Laura and Louis. Laura is an educator and Louis is an engineer. With our powers combined, we make things and try to show everyone how we tackle projects in hopes to inspire others to get up and create!

This Instructable will show you how we turned a bench grinder into a belt sander!

You can check out the entire build video on Youtube linked above. (We would also appreciate a like and sharing if you think it's worth it :))

This bench grinder has served us well over the years, but we needed a sanding configuration that allows us to quickly remove more material when working with metal and the stone discs just don’t cut it.

We decided to retrofit this guy instead of buying a proper 2x72 belt sander because 1) 2x72 belt sanders are way out of our budget and 2) we don’t have the shop real estate to accommodate the footprint.

Supplies

Here is the list of supplies we used: (These are affiliate links where we earn a small commission at no extra cost to you, Thank you!)

2 x 42 inch Sanding Belt Assortment: https://amzn.to/3d6KKLG

2 x 72 inch pulley set: https://amzn.to/2FXNxeU

5/8 – ½ Reducing bushing: https://amzn.to/3bVLgfu

Extension spring: https://amzn.to/3bVLgfu

3/16” steel plate: https://amzn.to/2EowCl

Spray Adhesive: https://amzn.to/3mlqvPU

Metric hardware set: https://amzn.to/3mm1jsx

Step 1: Disassembling the Bench Grinder

In order fit the retrofitted components, we removed the guards and the wheel from one side of the grinder. This process is a little different from grinder to grinder, but just a few phillips bolts to take off the guard and a locking nut to remove the grinding wheel. The locking nut on the shaft is left handed threads so the saying is backwards " righty loosey, lefty tighty"

It doesn't matter which side you choose to retrofit, we wanted to keep the wire wheel and it worked well for our shop.

Step 2: Templates

We modeled everything on Fusion 360 and printed the sketches to scale, so we can use as templates.

There is a PDF of the templates if you want to try the retrofit your own! The only modification is the mounting hole locations vary from grinder to grinder, so use your old shield to transfer the hole locations.

Step 3: Cutting Out the Shapes

Using spray adhesive, we stuck the templates onto 3/16” steel plate and roughly cut them out with our angle grinder and cut off wheel as well as our bandsaw for the finer cuts.

Step 4: Drilling All the Holes

Moving over to the drill press, we drilled out all the mounting holes using a small bit as a pilot, then drilling them to size with a step bit. The remaining material for the slots were removed with the band saw.

We removed the sticky paper and did the final shaping for all the pieces with a flap disc.

Step 5: Tracking Roller Hinge

To make the mounting bracket for the top pulley, we cut out a small square and drilled a hole in the center. Using a bolt to align the hole from the bracket with the pivot arm and a nut as a spacer in between we welded a make-shift hinge. Just two small tacks on either side is enough.

Step 6: Dry Fitting All the Pieces

With everything prepped, we can dry fit all the pieces.

The first thing is securing the main body by the three bolts…. Unfortunately I didn’t measure the hole spacing correctly when modeling, so we were off a bit. Using the guard that we removed earlier as a template, we marked where we needed to elongate the holes and filed them out.

Step 7: Backing Plate and Rest.

After bolting everything up, we cut a few square pieces to use as the backing for the sander as well as the rest. We first aligned the backing and tacked it into place then positioned the rest making sure it's perpendicular to the backing plate and tacked that in place. Once we were happy with the position, we removed it from the assembly and welded them completely.

Step 8: Final Assembly

After everything cooled down, we sprayed a quick coat of paint and assembled everything onto the bench grinder.

Following the anticipation of turning the grinder on with all the components, we were thoroughly disappointed.

One major item we didn't account for in the beginning was the power of our bench grinder. It was news to us, but our Craftsman is rated at 1/6hp and with all the added rotational mass, it never got up to full speed let along grind anything.

Luckily after searching through Offerup we found someone down the street selling a 1hp grinder with a super heavy duty stand for a steal, so we scooped that up!

Step 9: Disassembly!

The only modification we had to do was re-drill the mounting holes since the 1hp grinder had a larger hole spacing.. Similar to before, we used the guard as a template to get the correct spacing.

Step 10: Final Assembly

This time around, we took paid extra attention to the spacing of the pulleys making sure to use extra washers where needed so that they're all on the same plane. We just used a straight edge against the faces of the pulley to check this.

Step 11: A Functional Belt Sander!

After tightening everything down, we had a functional belt sander!

What a difference a 1hp unit makes, it eats through steel like it's butter.

Thank you for reading our Instructable!

If you liked the project, don't forget to share it. Comments and feedback are always welcome.

You can check out our other projects here on Instructables as well as our Youtube channel IMEE MADE.

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    31 Comments

    0
    Jeffrey1970
    Jeffrey1970

    Question 3 months ago on Step 6

    What type welder did you use. Looks like a Plasma Arc or Laser? I need to purchase some type of "cheap" welding system.

    0
    volvorod
    volvorod

    9 months ago on Step 11

    WAY to expensive to build using included links (as others have pointed out).
    Why build something that cost way more than buying it - and isn't any better?
    If you already own a bench-grinder, and have some scrap plywood (or can get it cheap) then this is a nice build. Otherwise - not really.
    I can buy this for about 45 USD here in Sweden (Included picture).
    With that said - nice build though. 🙂
    AND - it's ALWAYS FUN to build stuff! 👍 🙂

    Lidl.png
    1
    Justlearning4now
    Justlearning4now

    Question 9 months ago on Introduction

    Hello, I enjoyed your video and seeing how you do things. Please tell me a bit about that amazing little welder you used. Where could I get one like that? Thank you.

    0
    imee made
    imee made

    Answer 9 months ago

    Thank you! It's a budget TIG welder from Harbor freight, which unfortunately they don't sell anymore. but here's a machine that's similar to what I'm using: https://amzn.to/3i59So2

    0
    Justlearning4now
    Justlearning4now

    Reply 9 months ago

    Did you use inert gas when you welded in the video? Obviously I don’t know much about it but I’m trying to learn. Thank you.

    0
    imee made
    imee made

    Reply 9 months ago

    Yes, for this I use 100% Argon gas when welding. No worries! Feel free to ask away, I honestly don't mind and love to help. learning is always encouraged!!

    0
    BakerBoy7
    BakerBoy7

    9 months ago

    Looks like a much simpler conversion than others I've seen. Thankyou!
    I did felt that the instruction seemed to miss the assembly of the backing plate and rest plate, (once I saw the downloadable template this made a little more sense but this could be improved). Also not sure why the tracking roller hinge is required.

    0
    imee made
    imee made

    Reply 9 months ago

    Thank you! I agree, I could have went into more details for the backing and rest plate.

    The hinge is just a solution to adjust the tracking of the belt. Since the whole assembly can be a little off plane, using a bolt to dial in the pitch of the tracking roller helps keep the belt centered in relation to the pulleys.

    0
    kmpres
    kmpres

    9 months ago

    Nice instructible! Very sturdy looking tool that should provide years of good use. I want to do the same as I need a belt sander to help me sharpen chisels and the like. I bought one from Harbor Fright some years ago but, not surprisingly, it turned out to be junk. I need to solve these problems first:
    1. How to make the band move upwards rather than downwards;
    2. How to reduce the speed of the motor;
    3. How to make the parts without requiring a welder and other exotic tools.
    I don't have the budget, nor space for the added tools (welder, angle-grinder, bandsaw, etc.) that I'd need to make your metal one. I figure the first problem can be handled by moving the grinding platform to the rear - essentially assembling the parts in mirror image. The second problem will require a Variable Frequency Drive which can get expensive. The last problem will require the most thought, but I thank you for the inspiration.

    0
    rhyspsmith007
    rhyspsmith007

    Reply 9 months ago

    I would caution heavily against making the belt travel upwards. The reason bench grinders & sanders rotate towards the ground is so that if they catch or snag on the belt, the workpiece will be thrown towards the floor, not up towards your face, as will any filings or ground off material.

    0
    kmpres
    kmpres

    Reply 9 months ago

    I use the belt sander to sharpen lathe and woodworking chisels. The problem with downward travel is that the belt is traveling towards the workpiece's sharpening edge often catching it and shoving it into the table. That can ruin a fine chisel blade and/or send it flying into your hands, feet or elsewhere. There is also no easy way to hold the chisel at the proper angle. With upward travel the table is angled downward so the blade points up making the belt travel away from the chisel edge, not towards it. It's important to wear a face-shield anyway and stand slightly to one side to keep sparks from flying into your face, but in my mind that has to be safer than downward travel. When I need the belt sander to sand wooden or metal parts I will use it in the "normal" fashion so the belt travels downward.

    0
    imee made
    imee made

    Reply 9 months ago

    Thank you! Just my 2 cents on your list of constraints:
    1. Yes, assembling in a mirror image would solve the problem - essentially working from the back side of the grinder so the belt direction is upwards.
    2. Harbor freight has an inexpensive router speed controller like this: https://amzn.to/3iTVIHz which might work, but I don't have first hand experience with that
    3. You can build everything with plywood using the templates provided. Some dimensions may need to be adjusted to account for the added thickness. Another solution would be to mark all the welded joints and ask a local muffler repair shop to weld the pieces for you. I've asked a few shops throughout the years before getting my own welder and most of the time they are more than happy to help if they're not super busy.

    Good luck on your build!

    0
    solargroovy
    solargroovy

    Reply 9 months ago

    The build looks great and I'm going to add it to the list. I'm not sure if the speed controller is going to work because I believe that type of speed controller also reduces the torque. I'm not positive and I refer back to https://youtu.be/gMVIdDKgG5A.

    0
    kmpres
    kmpres

    Reply 9 months ago

    VFDs work with induction motors which is the type used here. They apply full voltage to the motor as they vary the frequency, which in turn, varies the speed. Torque is maintained more evenly than using SCR/Triac type speed controllers, like the Harbor Freight device mentioned above, which achieve variable speed by chopping the 60 Hz line frequency every cycle or half cycle depending on whether an SCR or Triac is used. This reduces the power you can get from each cycle which reduces speed but also the torque.

    I bought the Harbor Freight device some years ago but it didn't work at all. Very poor quality control so I don't recommend it. I ended up designing my own circuit and fitting it inside the HF box. Works for incandescent lights and corded electric drills but not much of anything else.

    Thanks for the link. Mr. Fielding is very knowledgeable and gives good, clear overviews of motor and speed controller types in his videos.

    0
    rhyspsmith007
    rhyspsmith007

    9 months ago

    Firstly, great effort & great instructable. It’s good to see people making stuff out of other stuff that ends up being cool!
    That said, I have a couple of safety issues.
    Please mention that the back plate & tool rest are as close as possible to the belt, as it minimizes deflection & the risk of snatching. Also mention that when using any power tools, clamps are much better than hands at securing the workpiece- I have scars to prove it!
    Well done though

    1
    robbied
    robbied

    9 months ago on Step 11

    I like the simplicty of your design. There's a commercial kit available here in Australia, but it uses two wheels and a gas strut for tension. Your design looks more simple to maintain, and change belts.
    For those looking to build a variable speed one, find a second hand 3 phase motor, and get a cheap VFD from ebay. Any motor from 1.5hp to 3 hp will work.

    1
    christhomaskinnell
    christhomaskinnell

    Question 9 months ago

    Hi if you don't mind I'm sure it's on everyone's minds, how much was the final bill for it all, just started knife making so really interesting

    0
    imee made
    imee made

    Answer 9 months ago

    Don't mind at all! Not including the cost of the grinder (which I only paid $80 second hand on Offerup), the cost of the materials added up to just under $150. The pulley set is the bulk of the cost which has risen in price since I purchased them, but there are a few alternatives since billet aluminum pulleys aren't necessary for this build.

    0
    christhomaskinnell
    christhomaskinnell

    9 months ago

    Loved it, need one but vs buying one the juice doesn't seem worth the squeeze, but got my vote, impressive

    2
    mkfairfield
    mkfairfield

    9 months ago

    First great job on the video. Finally someone who builds something WITHOUT cnc machine or 3d printer. I don't have a 3d printer or cnc machine. (to expensive). I will be building one of these. Thanks again great video.