Kevthefire

Low cost DIY 2x72 belt grinder

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I want a belt grinder but I can't afford one....

i know I'll make one with the stuff I have laying around, I have an old hoover electric motor and some bits of metal to start the frame, and some skateboard wheels.

i turned the skateboard wheels down on the lathe to fit into some plumbing waste pipe, 2 skate wheels into each wheel, then for a bigger wheel I got some sewer pipe, I turned down 2 disks to fit inside the pipe from some oak floorboards and drilled them to fit some wheel bearings in...

I've ordered some belts from China and I just need to make a drive wheel to fit the motor and loads of other stuff but I'll keep updating as I go ...

 

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Kev: Are you building to plans or winging it completely? 

What's the HP of the motor you have? I have a strong 1/2 Hp on my home build and it's a little weak but weak is good to learn on. Once I get proficient running a 2x72 grinder I'll maybe hook up a stronger faster motor. Till then I can screw projects up fast enough with this one. ;)

Frosty The Lucky.

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Hi Frosty, I'm completely winging it, I think the motor is 3/4 hp, what diameter wheel do you have on your motor?, I'm waiting for some more steel before I can carry on ..

cheers Kevin

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Hi Frosty, I'm completely winging it, I think the motor is 3/4 hp, what diameter wheel do you have on your motor?, I'm waiting for some more steel before I can carry on ..

cheers Kevin

I don't know, it's the same drive wheel that was on it when it was my 2" x 48" Rockwell belt grinder. Unless you build a lot of machinery I'd recommend finding a set of plans. Take a look at the problems being had making the no weld grinder. There are things you have to get right or they just won't work properly, tracking has to be precise.

Frosty The Lucky.

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Thanks for your thoughts, I have looked at plans to get ideas and see how to adjust belt alignment but I want to build my own grinder not copy someone else's .. and I enjoy making things for myself :-)

"Far better it is to dare mighty things, to win glorious triumphs even though chequered by failures, than to take rank with those poor spirits who neither  enjoy  much or suffer much, because they live in a grey twilight that knows not victory or defeats"

 

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Yeah, making is good. Draw up your plans once you get it tweaked if you will please. 

The plans we used are different and simpler than most and it's a sound design. Our club put 13 together using a group of guys with little or no proper shop experience. Mine isn't QUITE right but it adjusts to run straight so it's all good. The guys who bought 1.5 - 3 HP motors to run theirs have metal eating beasts. 

It's a good thing.

Frosty The Lucky.

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yup. mine's a 2 hp and it has quite the appetite! 

What size is your motor wheel?

Did a bit more today, started to make the platen and plate assembly, from 3mm plate, I hope it doesn't flex ( I'm thinking that when the platen and plate are bolted together it won't have any flex)

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I had a bit of a delay due to waiting for some 2x72 belts to come from China, 6 assorted belts for £7.09 including shipping..

they’ve arrived so now onwards again, I converted the 4” waste pipe pulley to a fixed wheel for the motor buy turning a shaft up on the lathe with a hole to fit the motors output shaft. I drilled and tapped the shaft and put in a grub screw to hold it onto the motor shaft

 

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I then welded up the frame parts that I could now cut to size with the belt roughly in place. 

I had a pulley wheel off a Land Rover belt tensioner that I was going to use for the adjuster wheel but a quick search revealed that I had no tubes to fit it, so I cut and glued some 4” pipe to fit.

I also needed some box section to fit inside the box section I had built the frame from, another bodge required... 2 bits of angle iron ground to make a touch fit and then welded together...

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Tomorrow i’ll Get on with the tension wheel adjuster for belt alignment but i’m Please so for and it’s only cost the price of the belts from China :-)

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can we see a picture of the belt tracking adjuster?

So tonight I roughed out the tracking adjuster, I hope the pictures tell the story...

 

 

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Ok.. did a test run tonight.

1/ the platen needs to be thicker or reinforced to prevent flex

2/ the box sections that slide into the frame on both platen and belt alignment pulley both need grub screws to prevent any movement...

onwards and upwards :-)

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You need to crown the drive or the next pully or it'll be the dickens keeping belts tracking. Not a lot maybe but it needs some.

Frosty The Lucky.

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23 hours ago, Frosty said:

You need to crown the drive or the next pully or it'll be the dickens keeping belts tracking. Not a lot maybe but it needs some.

Frosty The Lucky.

Cheers Frosty, I’ll use contact adhesive to stick another layer of pipe on then turn a crown to it on the lathe :-)

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Today crowned the adjuster arm and made a lever to pull the tension arm in for easier belt replacement.

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Test run.. a little noisy but I’ll replace the skateboard bearings with something a bit better.

I’m happy with the grinder that has only cost me £8:00 ( for the 6 belts  from China incl postage)

video below :-)

cheers Kevin

69E3BED9-23EC-407A-80F5-291155FA821D.MOV

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I found having the second pivot in the tension spring compression lever was pretty essential or it wants to rack the telescoping sections. Did crowning the wheel help tracking for you?

I don't know what kind of bearings skateboard wheels have but you definitely want permanently lubricated sealed bearings they're going to be living in an environment of metal and abrasive dust. 

Do you know what's causing the rhythmic chatter sound? 

It's looking good Kev, I'm a bit jealous over how much you have into it though. <sniff sniff>

Frosty The Lucky.

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Hi Frosty, yes the crowning has helped I think, the rhythmic sound could be a duff bearing or the joint in the belt going over the wheels, i’m Going to order some sealed bearings tomorrow after measuring the sizes. 

I ran a couple of old knives on it and they shaped/sharpened up well 

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I like mine too, I had to stop working on the collaboration seax from Theo, I sprained my heal and can't stand on it long. However I've sharpened a couple axes and a shovel. It's sweet. Your's appears to track more smoothly than mine does but that rhythmic rumble worries me.

A bad bearing should rumble, rattle, squeal, etc. pretty steadily and the bad one will be hotter than the others. It's had me thinking though. Do the roller skate wheels have two bearings, inner and outer, or are they single bearing wheels?  If they're singles or both bearings are close together then it MIGHT be that the forces are aligned closely enough to how the balls track in the race to run smoothly then a vibration builds and they go out of track, sync, whatever and the whole wheel starts to rattle, wobble, . . . ?

Whatever is causing the rumble it's not a little thing. It's shedding energy the motor has to produce, it's stressing everything in the power train and causing unnecessary heat. Its exactly the kind of sound I listen for to tell me there's a problem. 

Having this kind of problem right off with a home built machine isn't a surprise. Mine has alignment problems in the spring tensioner component or maybe the wheel train. It works but not like it should. We're just enjoying normal trouble shooting exercises with our new machines.

Frosty The Lucky.

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A couple of comments that might help, or might confuse you..
It is a bit lengthy, but, lots of info that might help..
I typed this while I was on hold, waiting to talk with someone, went back, wrote more and went back again to finish, if it seems choppy.. I went back and posted some things up to..
Here you go.. Hope tis helps...

You might have fun with this.. I built it back in November of 2014 using Skate board trucks and a Wooden drive wheel.. I had never seen anything using either of these combos before, but, but can't say they didn't exist..
Here is a quick video I shot for a friend Immediately after..
https://www.youtube.com/watch?v=RsTc3c7upSE

Then a more detailed video about the build later when I had time to make and upload it after lots and lots of questions about how I built it..
https://www.youtube.com/watch?v=gtFQt4k1kA8&t=207s

The Skateboard wheels work just fine..
I have a grinder I built November 2014 that gets used pretty regularly..
I hear some people have trouble with bearings, wheels, etc.. I have not..
One thing to note.. The ABEC rating is about manufacturing tollerances.. The higher you get, the tighter the tollerances, the tighter the bearing,, the less metal dust that gets in..
I used the ABEC9 bearings and the wheels and bearings are something I just use and never think about..
My wheels are 2-3/4" tall and 2" wide..
You can get longboard wheels that are taller and wider.. I have seen 3" diameter and 2-1/4 wide..
All use bearings that are 5/16, or 1mm larger if you can find the odd ball ones..
I actually used the Trucks that came with the wheels, instead of using just 5/16" bolts..
I am still on my first set of bushings for the trucks, but, I have loosened them, flipped them around and put them back on to get the trucks/wheels tracking straight again..
I just looked at them.. No wear on any of the wheels, except when I let something catch one of the wheels and cut it, but, it is the same as it was when I damaged it.. No further wear..
I only crowned my Drive wheel,, and,, Yes,, It is just two pieces of 5/4 deck boards cut in a circle, glued and screwed together, put on the motor shaft and crowned with a Farriers file..
It is still doing exactly what it is supposed to do.. Just the wood only..
So, keep your eyes out for a skateboard in case you need more bearings and wheels...
I am pretty sure yours are ABEC3 from the looks, so, will probably get metal dust in them..
Mine are sealed with the Rubber seals.. The sides of them have black shiny vinyl look, like other high speed bearings.. You can change them quickly..

I noticed you are interested in Motor sizes..
Mine is a 1/3rd Hp from a washing machine.. An old motor I had a 1/8" x 8" cut off disk on that I sharpen drill bits with.. The Drive pully is 5 inches. I primarily slack grind metal parts that I cut/weld, etc.. I have not started grinding knives, but, I have not bogged the grinder down eating the metal I have to eat.. I would imagine I could, but, it would be a heavy grind for me..


I'm not sure what size belts you ordered.. I might have missed it..

Your wheels look pretty wide.. It won't hurt anything. I prefer 2-1/4" wide wheels for 2" wide belts.
I usually like the same width belt and wheel on the platten wheels.. Sometimes I use them to profile the inside edges of pipe for saddles, etc.. Also to round an inside edge, etc.. Personal Preference..

Your platten will wear over time.. you may consider a second sacrificial layer of steel the width of the belt when you can.. If you can get some High Heat Glass (from an old oven or Fireplace), it is very hard and what some upgrade to down the road. The belt will slide easier on it and create less heat/friction.. You might also enjoy a little sharper edge on each side of the belt, if you are grinding plunge lines on knives, etc.. Just a thought..

Ok.. I just now see the 2" x 72" belts arrived and the motor looks plenty strong to me.. I don't know, but, older motors seem pretty tough compared to some new ones I have played with. I think you will be happy,, and if you build another, you can use it to do that too.. Ha..

Looking at your setup now, with the belt installed...
If you have trouble with tracking because of your verticle (home made box steel) wabbling around, you can pull it and lay it vertical and pull down on the back with a spring (about 30 pound spring is minimum, but, a good spring weight), or you can get a compression spring, like you have below the box and rig it up on a piece of pipe welded to your top square tube and let the arm rest on it..
If you drill through the vertical square to put a bolt, go ahead and drill out some water or gas pipe to fit snug to your bolt when you run it through.. Remove as much wiggle there as you can..
Think about it like this.. The more solid the grinder parts are, the more solid and consistent your belt tracking will be.. You can see when you adjust the belt for tracking. It does not take much movement of the wheels to change everything..

Ha.. Ok.. I see the tracking setup you have.. The Hex bolt looks pretty snug to me..
If not, pry the two sides of the larger box and slip a washer in one one side,, better if you get two sides.. It should stiffen it up if you have a problem there..
You want it snug, but, not super tight.. A Nylox nut on the other side would be good if you have trouble with it getting loose, or you an take a punch and ding the threads and then back off on the bolt just a bit to solve that problem the quick way.. Not too much, in case you want to take it off later..

Just found the .MOV you posted.. The 1/2" nut under your top Platten wheel is/was loose..
Looks like you have it tracking very well.. The rythmic sound you hear is the motor is my guess. My old motor sounds the same when I put pressure on the belt, but, it has been that way for 3 years now.. Ha..
I know you realized you didn't compensate for the extra thickness of the Idle/tracking wheel thickness being further out from the rest of the wheels.. All of the wheels are riding on the right side, but the tracking wheel rides to the left..
The only time that will bother you is if you want to grind on the left side of the belt edge on the platten and need to move the belt over...
Red the above comment about putting a second layer of thicker material on your platten to get a sharper edge,, but, I can't see the left side of the platten, and you may not be able to adjust your platen back if you welded it, rather than bolting it, but, I am betting you bolted it, so, you can add some thicker steel and/or High Temp Ceramic Glass and get it stiffer and give it something to wear out you can replace easily.. If this is your first grinder, you will find it will become one of the most used tools in your shop..

I built the Grinder I built as a prototype to see if I could build a cheap $3000 Belt grinder, because the first time I ever saw one was at a "Hammer Inn" I was invited to, and there were 15 families sharing one Club Grinder.. I figured I could build one cheap and with simple tools, since that was about what all of the families would be dealing with.. One night in the shop and I had a working prototype.. Ha.. All the while, I was saying,, If this works,, I am going to weld up a nice one..
3 years later, and I am finally getting around to making my plans up to build mine..
I have looked at hundreds of them since then, and they have evolved quite a bit in the last 3 years..
It is going to be an Interesting project for sure..

I really hate to go with the All Aluminum Wheels though.. The Softer Skateboard wheels are great in my opinion.. When you look at the hard core Kinfe grinders,,, they love their Rubber Contact wheels, and I have even seen some cover those wheels with Felt, when they want to get a good polish using the Grinder. You hardly feel the belt seam with a softer wheel.. Somewhere in the 60-70 hardness area..
I am going to try to get some larger Skateboard wheels.. I have seen some 3.5" in diameter and 2-1/4 wide.. But, they still have the 5/16" bolts and bearings.. Seems to me that they are going to be flexing when you really start hogging metal off and putting a higher tension on the belts when you have a bit heavier spring tension, etc,, on a more professional machine..
I am going to try to Freeze the One soft wheel that I have left,, and stiffen it up a bit and get polish sharpen a HSS lathe bit and see if I can cut a larger hole for some larger bearings..
The Bearings are already 7/8" OD, and all I have to do is get to 1-1/8" to get some good bearings with a 1/2" ID..
The most popular 2"x72" grinder bearing is the 1616 bearings.. They are 1.125"OD x .5"ID(bearing)x .375" width.. The Skate board wheels are 22mm(0.866")OD x 8mm(.315")ID(bearing) x 7mm(.276")..
So,, as you can see,, you don't have too far to go to get from one bearing to the other..
Thought I would give you a few ideas for now or down the road, if you want some options.. Options are always good things..Ha..Ha..
Here is the right kind of Skate board bearings to replace what you have.
http://www.ebay.com/itm/182497741900
Here is a set of the larger bearings that are used on most main brands of 2x72" grinders.. I just bought 2 sets of these a day or two ago to use on my new grinder with lots of accessories.. :)
http://www.ebay.com/itm/391801829448

One more thing.. BELTS...
Depending on what you want to do.. I hear knives are in the picture, so, here goes..
Here is a good article to bookmark to get you started..
http://usaknifemaker.com/abrasive-belt-basics-what-kind-should-i-buy.html

There are a couple of main/popular types of abrasive belts for grinding..
Cheaper to More Expensive..
AO Belts = Aluminum Oxide
They are the Medium Duty Belts.. Also the best belts to use in grits above the agressive belts..
They are much cheaper, but, wear out faster too, but, you can use them for other things when they wear out. Handles, etc..
So,, Belt Prices are very close to each other when you consider life expectance and intended use..
Use these belts in the Higher ranges.. 120 to 800 grit.. You can get J-Flex belts in this range too..
ZO=Zirconium Oxide
A little more aggresive and a little more expensive.
Ceramic can be 3x more expensive than AO, but, usually lasts 3 to 4 times longer.
These are for heavy metal grinding and tool steels.. Use lower grits on these belts.. 36-60 grit.

Actually, you will be starting with Ceramic and moving up..
Then, there are leather, felt, film and several other types of finishing belts..
You will most likely use more of the lower grit ceramic belts, becuase you do most of the heavy grinding and then, you are working your scratches out and fine tuning your blades, so, won't use as many of the other belts..
Then, you will hear all sorts of belts out there, gator, Blaze, Trizac, etc.. You are on your own there.. Start basic and get the feel and then pick up a belt or two here and there and you will know the difference and see if it is of more value to you..

Hope the grinder works out.. I'll try to keep up with the post if you have any questions.

 

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Hi Frosty, yes the crowning has helped I think, the rhythmic sound could be a duff bearing or the joint in the belt going over the wheels, i’m Going to order some sealed bearings tomorrow after measuring the sizes. 

I ran a couple of old knives on it and they shaped/sharpened up well 

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Cheers for the ...well interesting reply Mark Thomas lol, I think part of the noise was one of the small rollers was catching on the platen plate every revolution. Thanks for the information on bearings, the new ones i’m Looking at are abec9.

so I ran the grinder for half an hour sharpening everything I could :-) and here’s what I found:

1/ the heat generated softens the contact adhesive I glued the wheels together with..

2/ the cheap Chinese belts don’t last long and have thick joints that bump the work piece every revolution

3/ I platen wheel shafts are too short, causing the nuts to back off.

solutions are:

redo wheels with epoxy resin and new abec9 bearings (£4.99 for 8) or take the plunge and buy a set of nylon wheels from Poland (£70 posted)

buy better belts :-(

replace the wheel shafts..

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