2x72 Grinder Build

Fross

Fross

Joined
Jan 28, 2008
Messages
133
Well, here she is in all her green glory lol. I wanted to share what I have done for all the guys here thinking of partaking in building their own grinder(and to show off of-course :D). I used Tracy's NWG plans to get the basic machine built, I used 1.5" x 1/8" thick steel tube for most of the structure and tool bar holders, I had to buy two pieces of steel I didnt have at the farm, they were 1-1/4" tube steel for the tool arm and for the work rest arm which I haven't finished yet, it fits perfectly inside the tool bar holders, and the 5/8" round bar for the drive shaft. This build took about 22 hours of work to complete from all the tinkering I did with various set ups, I conjured up a few wild ideas and some of em actually worked!

One thing I did was design myself a multi use platen. I looked at several designs before I started, I had some 3/8" thick solid flat iron pieces so I decided to have at it(I used nothing but a 4.5" angle grinder and cut off wheels to cut the shape out, then used a grinding wheel to round the corners), I have a flat platen in between a 2" and 8" contact wheel, I bolted everything together then welded the bolts DEEP to the plate(hence the mess on the back side of the platen attachment, this was a last minute realization) I am going to grind the bolt heads down flush with the steel(I may even paint it again, lol)I can then get full rotation clearance to access all 4 positions of the platen without having to remove it... the platen serves the purpose of the 2" contact wheel, flat platen, 8" contact wheel, and slack belt. Something I did notice though, I think this has been mentioned before, when you have a tool bar that is the exact size of your tool bar holders opening, the weld inside that piece of tubing is going to get in the way, I just took a 12" bastard file and filed it down til it was flush with the rest of the inside, it now works perfectly.

I used 2 drive shafts, the reason for this is the motor I acquired from craigs list has a 1-1/8" bore and I couldn't find a 4 step pulley for it so I used the 6" pulley that was on it, being unrestricted on the bore diameter really opens up your possibilities for a motor. The secondary shaft is driven by the motor, it has 4" pulley and a 4 step pulley that in turn drives the grinders shaft with the other 4 step pulley and drive wheel on it. I placed the pillow blocks on a few pieces of 2x4s and hinged that to the work table(using a commercial heavy duty door hinge) for my secondary shaft, I then through bolted a 3/8" bolt to the table to hold the secondary drive shaft block down using the attached piece of angle iron, this makes for a quick speed change.

The motor is a New single phase 110/220v 3hp 1740 rpm Dayton take off from craigs list. I got the green linked drive belt from harbor freight when I bought my drill press and band saw(knew I would need it for this), the misc bolts and stuff came from the local hardware store, the 4 pillow block bearings are from bearingson, and all of the wheels(the wheels are the poly wheels), pulleys, and grinding belts are from Tracy at USAKnifemaker. Something can be said about Tracy and his business, I have never ran across anyone that had such great customer service, ever, the NWG plans are seriously idiot proof(heck, I did it), he has done a great thing offering these plans for us broke folk and any support he can give throughout the process.

A few things I think are worth mentioning, first the bolts you use for all of your adjustments, if you aren't going to put knobs on em(I prob will later) then make sure they are all the same size so you can use 1 wrench or socket for all the adjustments, also the drive wheel here seemed to be slipping when I applied pressure to the platen at first, 3 things can be the problem here, the first thing I noticed is after running the grinder for about 10 minutes the drive belts stretched and were slipping, I had to remove 2 links from each of them to tighten them back up to where they would not slip. Then I noticed the sanding belt itself was stopping while the drive wheel continued to spin, this was due to the tension arm not having enough tension and the drive wheel needing some more "grab", so I shortened the spring considerably to put a good bit of tension on it then I put some electrical tape around the very center of the drive wheel to give it some more grab, I can now push as hard as I can against the platen and the belt may slow down a little(this is on the slowest speed) but it is still throwing a LOT of sparks and running like a champ, and I def cant bog down that motor.... its a beast. Oh yeah and its been said a thousand times... watch where you put your hands, and make sure you dont have any baggy clothing near the machine, with all the spinning parts, you could lose a limb very fast, I wasn't paying attention and just barely touched the drive belt with my finger whiel looking at something and now Im missing about 3 layers of skin there lol...

Here is a break down of what I spent.

Motor - $120
Wheels, Pulleys, Drive Belts, Pillow Blocks - $370
Misc Bolts and Nuts - $15
Steel - $20(I had most of it)

For a total of $525

Now, I had all of the electrical components and most of the steel so that would prob add to the cost, but not by much if you get the steel from a scrap yard.

If anyone has some advice on dampening the vibration from the motor Id be much obliged, its not a major problem, but less noise is always better and as you can see I have a steel framed shop...so the vibration transfers a lot more.. I also am trying to figure out the tool rest deal, I like Tracy's design in the NWG plans but would like something that pivots on the x axis to give me the option of setting it at a certain angle... any ideas again...hit me.

And as we all know, pics or it didn't happen:)

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Noise-dampening is my thing, oddly enough.

Most of your noise is coming from transference of vibration to the metal components of your building and the grinder itself. This can be greatly minimized by adding spray-in foam to the hollows of your tubing. Those cavities are nothing more than an acoustic chamber similar to that of a guitar. Plug them full of insulation and you hamper their ability to vibrate. Because the tubes are facing your when grinding, you're actually focusing a portion of those waves right into your body/ears (don't forget bone-conduction....) while the other portion is being fired right into the thin walls of your shop.

A standard belt, as opposed to that link belt, will also do wonders to reduce noise. Every link causes a bump as it passes over the pulley and those bumps are transfered to the machine and the bench top.

As for the bench, the earliest drums were nothing more than a hollow log, which is all your bench really is. Add sheet insulation to the underside (sofa cushion foam will also work) to thicken the bench while eating up unwanted resonance. Adding another layer of plywood to the top (always a good idea for a sturdy bench) will also deaden the vibratory quality of the structure.

I also note that you're bench top wraps around the metal studs. The close proximity of the vibrating wood to those hollow metal studs is going to create a racket even if they aren't touching. Open those gaps a bit more and try to isolate you're bench from the walls as much as possible.

Finally, think about some rubber sheeting between the motor and the bench. Tractor Supply sells conveyor belt material by the foot (at least, it does at mine) and that would make a great isolation material to soak up some of the vibration being generated by the motor.

In the end, reducing noise is all about stopping vibrations from being generated, or, if that's not possible, killing them with insulation so that the sound waves are softer when they reach the ear. You're kinda behind the eight-ball because your gear is already assembled and running, but you can do a lot with the simple application of insulating materials that thicken the resonating factors, thereby reducing the rate at which they vibrate, and filling cavities that amplify or direct the vibrations.

Hope that helps.
 
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Wow, thanks very much, It just so happens I have some 1.5" thick polystyrene insulation just sitting, I will be using that and filling the tubes as you mentioned with the great stuff(where I can anyway). I have some rubber membrane used on commercial roofing systems lying around here as well so I will use a few layers of that as my noise dampening mat below my motor. Again, thanks a million.
 
Glad I could help, FB.

Using that spray-in foam sucks because you can never get it all the way through a long tube. What I've done in the past is to stuff the middle section of a length with regular pink insulation and then cap off both ends with the spray foam. Just capping the ends with foam will work, but you're still leaving a big empty space in the middle to vibrate as it likes. It will be quieter, but not as much as if the entire thing is packed.

Also, when/if you attach insulation to the underside of the bench, be sure to get it as securely fastened as possible. Using only a few staples will set up a failure very quickly because you're fighting gravity as well as the vibrations of the grinder. I like 3M's spray-on adhesive for a job like that, the staples just act as holders till the glue cures.
 
Looks like a job well done. Now let's see it in action running a full flat on a 15 inch bowie.
 
Nice build frossbyte, nicer than mine. Questions:
Did you powder coat or just paint?
Why the extra pulley setup instead of just using the 2 3-steps as shown in plans?
Thanks for posting. It helped me visualize how my flat platen needs to be.
Ross.
 
3 coats of just regular rustoleum and I used the 4 step because it seemed like a good idea at the time(4 speeds instead of 3). I can tell you this, the fastest speed is NOT ever used, its just too fast even for hogging steel, I used the fast speed once and wont be doing it again, I found myself dipping the steel more than I was grinding due to the heat build up in the steel and my inability to hold on to it when its lava hot lol. It may be useful when I start this combat machete thingamajig I got in my sketch book, but I doubt it, I like to be precise... I can deal with 10 extra minutes of profiling, also I know you didnt ask but... BLAZE BELTS are your friend... I wont be ordering anything else for actual stock removal, Im spoiled...
 
Oh yeah, here are some pics of the platen completely finished, I ground the bolt heads and all so it will now rotate 360 degrees without having to take it off. I also stuffed all the cavities with pink polystyrene insulation, then capped em off with great stuff. I added a 2" piece of polystyrene to the underside of the bench too, it eliminated the vibration from this grinder and my 4x36.... now I can talk on the phone standing next to either one of em running, although its prob not a good idea :p

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Excellent shop built grinder FrossByte!!!!
I hope mine comes out as good as yours!!!
 
Rosscoinc said:
Did the foam help with the noise and vibration???
Click to expand...

Absolutely, the only noise I get now is the actual belt going over the platen, the motor running and the bearings... its super quiet with no vibration, I recommend doing it.
 
I agree with VaughnT on all his suggestions except the segmented belts. Segemented belts do not take a set as do solid belts, unless the solid belts have been running for some extended period of time. They start out smoothly and run that way. They sure quieted my mill.
Nice build!
 
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