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I've lost count of the times when I have been mid project and thought, what I really want now is a nice big fat disk sander. With them you can make precise angles in wood and metal. You can produce brilliant outer edge curves, and very accurate circles. You can quickly remove material and flatten off stock that's too small to be safely planed, or thicknessed. You can sharpen tools, tidy up rough edges, deburr and square up, and do extreme toenail manicure (just in case you're insane, I'm not really recommending that last one).

In short, a disk sander is an awesomely useful machine to have in the shop!

Like most of my instructables, this one is mainly made from reclaimed materials.

Where is the bill of materials and tools used?? For this 'able it didn't make so much sense. a) because I'm using lots of strange materials that I have fished out of skips, and b) because I was experimenting with tools and techniques quite a lot. And c) if you're planning to build one you're going to read this all through and get an idea of what you need anyway based on what you already have available, right? I'll give tips on what might be useful reclaimed sources along the way.

If you're still not convinced you neeeed a disk sander, fly on ahead to the various steps on 'Use' to give you ideas and tips on what cool things you could do with one.


What makes a good disk sander?

OK so lets say you're thinking of buying one - what would you be looking for?

I'd say you'd want: a very strong solid base, good quiet, smooth and vibration free running, along with a perfectly flat and accurate work table with a parallel mitre slot. A tilting table seems like it would be a nice feature - but not at the expense of solidity. Something user friendly and safe - safety is obviously important.

Personally I'd want it BIG too. 500mm (20") abrasive disks are about the biggest economically available here in the UK, so that seems a good size to aim for. Having a nice big disk doesn't just mean you can sand bigger stuff, it also means you have a bigger range of abrasive speeds. That is, you can vary the material removal rate by choosing how far out from the centre of the disk you present the workpiece: towards the outer edge will be exceptionally aggressive, with the abrasive moving many times faster than say half way out.

When we look at fulfilling all those requirements in a bought machine, the cost is over £1.5k - which is quite a bit (eeeek!) - so lets make one from some rubbish!

Step 1: Mounting the motor

I started with a 1kw single phase induction motor that I rescued from a broken floor scrubber/polisher we found in the skip. I was well pleased when I got it home, dried it out, and tested it. It went really well with very little vibration or noise, running at 1450rpm. At that speed, at the edge of a 20" disk, the abrasive will be travelling at roughly 38 meters per second - which is very fast!. But not too fast :D

This motor had a face mount, the design would have varied quite a bit if I was basing it round a foot mount motor.

I did some modification and used the housing/flange mount that came with the motor. To sit the motor horizontal I needed to support the rear end of the motor with something. For this, I glued two ply pieces together and routed a circle in them. Follow along with the notes on the photos for the whole story.

<p>Hey everyone! It won! Totally thrilled to bits! Thanks so much everyone who voted and commented, and the judges who took the time to look it over! The prize looks like it will be really very useful, :) </p>
<p>WHAT A GREAT HOME BUILD , But I don&rsquo;t have to skills or equipment <br>to do the metal work so the one I<br>am building has 2 x12&rsquo; Discs and<br>all my work is with plywood &amp; MDF</p><p>1 hp Bench Grinder 1,000<br>x 400mm base, Centre Block to raise the grinder </p><p>Left and Right blocks for<br>tables. Table 400mm x 400mm made from three pieces of Board the 20mm <br>MDF has a Triangle routed 4mm deep 305 bottom <br>on side facing sander the triangle <br>is to the centre of the<br>board 25.4mm hole drilled inside top of<br>triangle with a 25mm pvc pipe glued<br>in. </p><p>The bottom board which is also top of block is 400mm w 300<br>deep has a 25mm w slot that is 90mm long and each side slot <br>for the fastening bolt on each side also allows table to be slid back to<br>change discs . on top has 12mm MDF 400x<br>400 glued to top and lid for <br>the routed dust port #1 </p><p>Then the bottom of the sanding<br>wheel is boxed in base slot across directly under sanding disc with PVC conduit<br>glued I place then a slot routed across top opening conduit the area below<br>table is boxed in with front and back sides angled and starting near the edge<br>of conduit (blocked off one end and connector for vacuum cleaner.</p><p>The wheels are made from <br>2x 350mm Sq pieces of ply glued and screwed together hole drilled in centre and then wheel created by cutting circle<br>using table saw . </p><p>One wheel had 40 grit disc and the<br>other has 180grit </p><p>Don&rsquo;t have photos ready as have only<br>cut all the pieces waiting for new brad gun to arrive to assemble (brads hold<br>in place while glue sets saves having to have a lot of expensive clamps)</p><p>Also making mounting frame for<br>hand belt sander so can be used as a fixed vertical and horizontal belt<br>sander and still easily removed to use<br>as hand power tool. </p><p>Building most of woodworking<br>machinery in my work shop thanks to the inspiration and guidance by all these<br>wonderful people in INSTRUCTABLES &amp; YOUTUBE </p>
<p>Hi Ronald. Sounds like you have your hands full. Looking forward to seeing a photo of it when you have it all glued up. Having 2 discs will really be useful. I have wanted to have 40 or 60 grit for quick stock removal a number of times, but am usually set up with 80 as a kinda compromise between surface finish and removal rate. I could change the disc, but who wants to bother with that when they are mid project!? </p>
<p>man <br>this was awesome <br>i am surely making this *-*</p>
Thanks :)
<p>Great work, Bongodrummer! Yet another recognition on Instructables!</p><p>I have not yet read all 36 steps, but will; there seems much good info here. I got caught up on your chisel sharpening jig. Nicely done. I believe a disk sander for sharpening is underutilized. I made a couple of jigs for my little 150 mm sander, photos attached. The first is for chisel sharpening; magnets hold the blade in position. The other is for conventional grind woodturning gouges.</p>
<p>Hi Bill.Those look like some very useful jigs! Interesting idea with the magnets to simplify the holding method. Out of curiosity, what grit paper do you use for sharpening? </p>
The grit I was using in these two photos was 320. But it depends on the condition of the chisel; maybe start with 120 grit in some cases, then end up with 400 grit.<br> Woodworking chisels are not made from high speed steel, so we need to take care not to overheat the blade, which is easy to do with any powered sharpener. <br>Thanks for your interest!<br>Bill
<p>I don't know if this has been asked of you and I couldn't find the info, maybe I skipped over it while drooling over your machine.....how did you balance the disk? I know you cut a groove etc..but how do you find out where to put the weights?</p>
<p>Hi Bricabracwizard, Check out step 27 on balancing... </p>
<p>I've balance ceiling fans by trial and error.<br>Basically, you glue a weight on, and move it around noting whether each new position is improving the smoothness. Eventually you find the best position for the weight. Then you just experiment with how much weight gives the smoothest running. You usually have to iterate between adjusting position and adjusting the mass a couple of times.<br>It's not as hard as you'd think.<br>Also, google the words &quot;balance disk sander&quot; - there are probably better ways.<br>You could put a shaft through the disk and lay the shaft on two rails made of angle iron (the rails need to be leveled) to get a static balance.</p>
<p>Nice job, I need one of these! I did have a chuckle at this:</p><p>&quot;Next I chamfered the edges - this gives you a release angle - vertical edges would be impossible to remove from the casting sand.&quot;</p><p>Adding draft to ensure release from the <em><strong>sand</strong></em>, you are a funny guy!</p>
<p>My dear fellow! I'm not too sure what you mean? Have you spotted a blunder, that even now, I am ignorant of??? Maybe I should have said green sand? What else? What's so funny!?!? </p>
<p>Sand casting is a one shot process - you just break the mold apart after the casting becomes solid.</p>
<p>True but it was the original wooden pattern that I needed to get out of the sand, without damaging the mould. That's what I was chamfering - the wooden part. </p>
<p>Very professional project. The stability seems excellent. Congratulations!!</p>
<p>Wow. I am absolutely amazed with the amount of repurposed materials that have been used in this Instructable. Talk about upcycling! </p>
<p>Thanks for sharing. I learn something ingenious from most of these projects. I'm currently making a CNC machine that will take 4x8 sheet goods...and fold up in half (like a ping pong table) and work for 4x4... Its figuring out the issues and working some solution thats the fun in it...Thanks again.</p>
<p>Thanks Kwdavis. Foldable CNC sounds like a cool project! </p>
<p>Fantastic job - abrasive and gritty... yet, delicious!</p><p>Mmm... trunnions!</p>
<p>Thanks Rwinscot! trunntastic!</p>
<p>Beautiful build! I can not imagine the hours you put into this project. I am intrigued with the &quot;epoxy granite&quot; Could you share the product you used? I don't imagine it machines very well with the rock aggregate, but it seems ideal for a structural reinforcement. Thanks!</p>
<p>Thanks Brett, your instincts on epoxy granite are spot on - it doesn't machine at all well, and cannot be threaded. To make threads you have to strategically place nuts in the mold before casting.</p><p>On the plus side it is very good at vibrational damping - roughly 10 times better than cast iron, and 30 times better than steel...</p><p>I can't remember the epoxy name off the top of my head (will look next time I'm at the shop), but I can tell you it was about a month out of date, and therefore very cheap (but still worked well - possibly slightly slower cure time).</p><p>When choosing the epoxy - it wants to be low viscosity (the lower the better), slow cure is good, because it gives you more time to tamp/vibrate everything into place in your mold. Also, you always want zero solvent epoxy, which will not then shrink upon cure.</p>
<p>Thanks for an incredibly ambitious tool build bongodrummer! congrats.</p><p>About Epoxy: I've found that most epoxies last a very looooong time and still work impressively fine. I have used some more than 20 year old ones without ANY discernible degradation! About yout use of an angle grinder to roughen up the aluminum for a better adhesi&oacute;n of the epoxy: I have done this kind of roughening, and the very best results are (as tested in a simple but effective home test) by using very coarse NEW wetordry sandpaper with a high pressure applied and in a cross hatch pattern, so as to produce &quot;V&quot; shaped grooves to provide good anchoring... </p><p>But using an angle grinder only roughens a fraction of the entire Surface, therefore lessening the anchoring. (or at least I humbly suggest you to improve your excellent instructable on this minor point).</p><p>On general comments, I have found that I tend to use about 90% of the time the belt and only 10% the disc on my quite smallish bench sander (which worked OK for the first couple of years, and then started to play foul by failing miserably to maintain the proper belt alignment...) So, when I read your instructable, I wondered about a large Disc AND belt sander...</p><p> Regards, Amclaussen.</p>
<p>Hi Amclaussen. Cool, actual science style tests on the epoxy subject! Will mention you point in the instructable. I did start by hand sanding, and got impatient - the angle grinder seemed to work so much quicker ;)</p><p>Did you try power sanding, with a belt sander or an angle grinder with flap disks in your tests? I imagine an angle grinder with a flap disk would work quite well. The main problem with all the power methods, as is see it, is that you risk inadvertently un-flattening the piece. </p><p>In terms of which is used most on belt&amp;disk combos, I agree it tends to be the belt, but I think that's because the disks are a bit of an afterthought on those machines. They are usually small, as is the table, which rarely has a mitre slot. </p><p>In terms of making a large belt and disk sander, I like the idea, but I think it may become a bit unmanageable. I can just about move the disk sander about at the moment - a Belt and disk would definitely be a BIG static machine. The main advantage is obviously the shared motor... but that's a sorta disadvantage too because it uses more energy - why drive that big belt when not in use?</p>
<p>Hi bongodrummer! Before anything, just seeing all your capabilities and tools makes me a little jealous, I must admit! I build a lot of things, but admitedly, I've never learned to weld, much less to cast aluminum, both abilities that I have a need for several projects.</p><p>On your idea of power sanding: I'd say Nope...</p><p>As you can clearly see, almost any power sander (unless it is so small as a palm sander!) passes the sandpaper so many times that the grooves cut by the grain are very close to each other, thus the final effect is that the sander polishes more than creating more distinct grooves (separated from each other). I did many tests because I was helping some friends to assemble an Ultralight aircraft, and the wings needed to be joined at the center through a &quot;joiner&quot; made from an aluminum alloy, and it needed to be joined with an epoxy to the spar box securely. Researching on the subject, I found a lot of knowledge, as there are quite a few methods to properly join aluminum with epoxy type adhesives. One thing is clear: polished aluminum oxidizes in air and forms a smooth passive aluminum oxide barrier that prevents further corrosion but has a very low surface energy that limits adhesion a lot. By sanding, one removes the oxide layer and produces what is known as an &quot;Anchoring Profile&quot;, which is best when it reaches several thousands of an inch deep. Therefore, I perfomed many tests at home, to be able to really be sure the sanding action produced the strongest joint. It was achieved with No. 60 wet-or-dry sandpaper, followed by acetone cleaning. the epoxy was a professional grade from &quot;West System&quot;. Even when West recommends 80 -grit sandpaper, I found that 60 produces better gripping surfaces when I used new sandpaper sheets and applied strong vertical load, so that the grooves looked like fine thread on a fine thread small screw like an &quot;0-80&quot; but in a crossed pattern. The secret was to do a few straight line strokes, cleaning the paper after each,so as not to clog or re-deposit the sanded paticles again on the roughened surface. Before sanding, a first acetone cleaning is needed to avoid sanding the contaminants into the surface. After many flights, the aluminum wing spar joiner epoxy jouint has not loosened not even the slightest bit. And my test samples broke the hard wood well before the epoxy was remotely close to fail.</p><p>I'll keep an eye on your future Instructables, congratulations again. Amclaussen, Mexico City.</p>
<p>Check with the manufacturer of the epoxy, and also check many manufacturers. We used to use (20-30 years ago) several types, depending on whether or not we needed high peel strength, could use heat curing of the epoxy, needed moisture resistance, needed it to be hard on the surface (some are silica-filled, for example), were merely bonding or actually casting, and whether-or-not the metal surface was already treated with something that made good adhesion difficult. An example of that would be black oxide coated steels or aluminum that have an oil or acetate sealing material.</p>
<p>LOL, don't be jealous you can pick up a decent mig welder for very little, and I knocked up the gas bottle furnace in an afternoon for a very low cost (learning about the green sand mixing and casting, not so quick - still lots to do there).</p><p>Anyway, to your point on epoxy. First thanks for the detailed info- plane making = very exciting! I didn't mention it in the instructable but I also used acetone to clean the surface and lots of vacuuming with a brush as I went. So yeah , I should recommend that too.</p><p> Did you actually test with a grinder, because you get very defined groves and a fully shiny surface? The other thing that occurred to me was power wire brushing - any tests?</p><p>One thing to consider is that you get very different results with different sanders - random orbit= a surface as you described, more polished. But a belt sander on the other hand, with a fresh 40 grit on slow speed will leave very distinct grooves. A belt sander also has the advantage that a high powered vacuum can be connected so you're not rubbing in removed aluminium particles/don't need to clean the paper so often.</p><p>So are you sensing my reluctance to join you and say nope to power sanding?</p><p>Last thing, the epoxy I used was very similar to west systems, which is a touch more expensive per liter (and in my case WAY more expensive because I never did see a WS out-of-date-bargain).</p><p> . </p>
<p>I recall when 20 or more years ago the so-called epoxy granite hit the market, and may folk made their own machine bases from the stuff. Something to remember is that despite the fact that it contains rock chips or aggregate, the material that binds all of the sand and rock chips together is still resin, and tends to be a resin that permits abrasive materials to embed easily. This makes it harder to clean, too. To clean it, that is, remove abrasive materials from the surface, a technique I used on this and on semi-steel bases, as well, was to take a hard paper (I usually used hard drafting paper, in the day), wet it with kerosene or another solvent that was not too hazardous, place a flat steel block on the opposite side of that hard paper, and pull the abrasive materials out of the surface of the plate into the paper, which could be discarded after getting loaded with abrasives. You can make very flat slide surfaces of so-called cast granite with epoxy grades that are loaded with graphite in addition to the stone materials, but I cannot vouch for the claim that that graphite would protect your other hardware from the abrasive characteristics of your stone - sand fillers. You apply a release coating, just as in casting other precision surfaces with resin, to a reference surface, build your form that gets place on that precision surface to contain your composite materials, and just pour it on. Try to get a maximum amount of stone materials in it if you want to minimize the coefficient of expansion, for the casting resin would have a much thermal coefficient of expansion than would steel or aluminum structural members.</p>
<p>@BrettHacks - I was 'Gurit Ampreg20' Resin and slow hardner. Looking at the packet now I can see it was actually about a year out of date.</p>
<p>Thanks! Now I just need a project to try it on.</p>
<p>In keeping with the spirit of spend little or no money, keep an eye out at boot sales, etc. for a cheap pair of used boater's shoes, the kind with crepe rubber soles, they make serviceable disk cleaners that will greatly extend abrasive life.</p><p><a href="http://www.shopsmith.com/ownersite/catalog/images/01_AbrasiveCleaningStick.jpg" rel="nofollow">http://www.shopsmith.com/ownersite/catalog/images/...</a></p><p>Nice job too, by the way.</p>
<p>Top tip thanks! Will keep a look out for that, as I have just about used up the off-cut of a proper one a friend gave me... Anyone know exactly what that stuff is made from? </p>
<p>For cleaning the disc, I use old silicon sealer after it has gone off in the tube. Simply remove it from the outer plastic &amp; voila. Works well for me.</p>
<p>oooo, interesting idea.</p>
<p>Gum rubber or natural rubber... if you want to buy one, look at </p><p>http://www.supergrit.com/products/products_accessories-beltcleaning.asp</p>
<p>Cool thanks for the info... Now I feel like I should do some editing. I'm sure in one of the videos I call it &quot;a plastic-stick-like-thing&quot;... </p>
<p>What about using a flywheel from a discarded spin bike. They're already balanced and flat and the extra mass would help prevent the motor from slowing under a heavy load. In addition, the ones I've picked up had heavy duty bearings, a nice chain or belt drive and plenty of square steel tubing that could be reused. </p>
<p>Hay Shawn, I had the same though when I was just starting, and I was sure I would see one somewhere, being thrown or even at a garage sale or something. But nay, nothing turned up... Ill still keep a look out for one now of course, they sound really useful! </p>
<p>Great instructable, thanks!</p>
<p>So, having access to a machine shop is not something that would be considered excessive? Anyone with a machine shop would not only have a disc sander, but one that was attached to their belt sander.</p><p>If everyone had a machine shop it would be great, but I thought these &quot;instructables&quot; were a resource for those of us who do not have access to a full blown machine shop!</p><p>I have a MIG welder, drill press, a band saw, a home made router table, and a table saw and an assortment of hand tools. I would consider a lot of these common to most home shops out there, but not all of it.</p><p>I need to make a 6 inch wide belt sander with a disc on it and have to build it without a machine shop.</p>
<p>Every instructable has some tool that somebody doesn't have acsess to or doesn't know how to use... 3D printer, welder, soldering iron, whatever. </p>
<p>Agreed. A while ago someone asked me how to shorten a screw. I told him to to put it in a vise and cut it with a hacksaw. He told me &quot;Whaaat?? I don't have a full workshop like yours, just tell me how to cut the bloody screw!&quot;.</p><p>So for some, a vise and a hacksaw are a complete machine shop... Different instructables for different makers! ;-)</p>
<p>Hi Michael, you raise an interesting point, and you remind me that I still need to make a router table!</p><p>I wonder at what point a regular shop becomes a machine shop? I never really though of my shop as a machine shop (and trust me it doesn't come close to a 'fully blown' machine shop). But maybe it is part way there now. It only really has a decent lathe and a small hobby mill. Even with those, there were many things I couldn't do that I wanted to (eg. surface grind flat the table and machine a perfectly parallel t-slot, turn a 20&quot; metal disk, roll sheet metal into a circular form for a guard, effortlessly cut a disk break in half, etc). In some ways the fun is in finding ways round those limitations... I actual made the little gas bottle furnace specifically to cast parts for this disk sander &ndash; that was one of my wacky work arounds &ndash; a long cut. But I learned a lot. </p><p>One way of doing it would be to pay some one to make those parts, nothing wrong with that. I didn't make the threaded rod or high tensile bolts I used... Most people don't. But then most people don't make expensive tools either. So I guess it's a trade off. </p><p>Where am I going with this? When I look at instructables where makers are using awesome cool 3d printers, lasers and waterjet cutters, and CNC mills, I'm not thinking &ldquo;grrr they shouldn't be on instructables, the flashy gits&rdquo; - well ok, sometimes a little jealous bit of me is thinking that. But mainly I'm just excited by the possibilities and the little things they did that I could nick and fit into this project or that. Or how I could combine a cutting edge technique of theirs with some old school method and come up with something completely new. So yeah, take what you can, leave the rest. Get thrilled to learn about lasers n jazz, even if you don't have access to them right now...</p><p>Anyway, good luck with your 6&rdquo; belt and disk sander. Have you seen this one?<a href="https://www.youtube.com/watch?v=hf82bd2AV44" rel="nofollow"> https://www.youtube.com/watch?v=hf82bd2AV44</a>.Looks pretty cool.</p>
<p>A belt sander is next on my tool list as I'm killing my hands sanding and filing for hours that I could do in a few minutes with the right equipment. I wish I had a lathe and milling machine but never had the space, time, oppportunity, and the money all at the same time.</p>
nice work, and like you I like enjoy the conversion of junk into useful things.
<p>muito bom parabens</p><p><br></p><p><br></p><p><br></p><p><br></p>
<p>Awesome! Last month I posted my 15&quot; sander/lathe mod and thought that was overkill... now, not so much.</p><p>Nicely done.</p>
Wow, you have skill. Good instructable as well.
<p>At first I was disappointed that I missed the deadline for the tool contest... then I saw this... Honestly, there is kill then there is overkill! You awesomely covered all aspects of making your own tools. Casting and machining, your home shop is to die for... If this is a contest entry you definitely have my vote!</p>

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Bio: BongoDrummer is co-founder and member of Flowering Elbow. He loves to learn about, invent, and make things, particularly from waste materials.
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