Thread: Mid-Budget Grinder project

I thought I'd start a thread regarding a mid-budget grinder project that I have begun. I know a lot of guys have commercial knife grinders, and some other members have built some really awesome contraptions capable of doing the same thing for little to no money.

I, however, not being particularly handy with a welder or very good at machining things, have decided that the ultra low-budget just wasn't an option (for me anyway)... and the commercial ones are just too much money.

So, I've been slowly researching and putting together parts and pieces in preperation for building a not-quite-commercial but not quite totally DIY 2x72 belt sander/grinder.

THE GOAL:

- 2x72 grinder with interchangeable tooling arm
- 8", 4" grinding wheels, and a flat-platen to start
- Variable speed
- 1.5HP+ Motor

MY BUDGET:

- $800.00

I wanted to not completely cheap out, but, I just cannot justify spending $2500+ on this setup.

Update soon to follow!

Can't wait to see what you're up to.

Keep us posted Brad, I'm interested to see the end result.

I am waiting to see what you do, it sounds like a fun project.

Charlie

to make the $$ stretch i think you might ahve ot go pullys and not a VFD to start

but other then that i think you can get real close

tracy mickley has all kinds of polly wheels that work jsut fine and cost less then rubber

Hmmm.... I am going to watch this thread!

OK, Lets get started here! First up is a motor!!!!


MOTOR
----------
I had read in several places that the minimum HP rating I would want for any respectable grinder is about 1.5HP. I originally was looking for a 2HP motor, but, then one fell in my lap -- and the best part about it is, all it cost me was buying a friend lunch. This made me very psyched about the project, because I knew a few bucks would be able to go to something else.

The only downside..that I quickly learned...was that the motor was 3-phase. For those who don't know about this stuff (which was me only a few weeks ago too) -- normal power that most of us have in our houses is 1 phase power. 3 phase motors will not run at all on 1 phase power. So, I was going to have to get a 3 phase power converter.

As I started reading about 3 phase motors, I found out a few things about them that made me feel like maybe it wasn't such a bad idea.


- 3 Phase motors last longer, and have less vibration
- 3 Phase motors are more efficient overall.

The motor that I ended up getting is a 3490rpm, 220V, 3 Phase, on a 143T Frame. The final cost was $8.00, including tip

For those of you thinking "OMG HE IS SO LUCKY...FREE MOTOR!!!!"... I found out that 3 phase motors commonly come up for sale on local classifieds and craigslist for little to no money -- because the majority of people out there have no way of running them. So, I've read all sorts of posts on forums out there that say they were able to get their motors for $20, 30, etc.

Pictures of my motor:







BUDGET REMAINING: $792.00

Hmmm...it will be interesting to see if anyone posts a practical solution to running this motor off a single phase input.

Next up...!!!


POWER
-----------

I immediately noticed that the new motor was 220/230V. Plus, I didn't want it on the other circuits in my garage (lots of other power tools).

So, I ran a dedicated circuit to my garage, and installed a 220V 30 Amp breaker with some help from an electrician friend. the wire and supplies ran me about $35.00. while I was at it I ran a second wire into a box for some future plans (back up generator when power goes out in my house. I'm not including the cost of that wire in the 35 bucks. heh).

Some pics!






However... I still had a problem... how to Generate 3 phase 220V power from a 1 phase 220V source? (coming up next....)


BUDGET REMAINING: $757

Next up....


MAKING 3 PHASE POWER
-------------------------------

As I started researching how to convert 1 phase power into 3 phase, I quickly ran into the fact that it is EXPENSIVE to do. However -- one thing I immediately noticed was that the straight converters (1 phase -> 3 phase) were just as much money if not more than a VFD, which can also convert 1 phase -> 3 phase.

Now...what is a VFD you ask?

VFD stands for Variable Frequency Drive.

Check out the WIKI for more information, but, to sum it up, it allows you to control the frequency (or speed) of the AC current that you are supplying to a device (a motor in this case). In turn, the motor will run at a varying speed. I.e., Variable speed motor!

Using a VFD, not only can I create 3 phase power, but, I can also variably control the speed of my 2x72" belt!

The sticker shock was a lot to overcome -- however, after a bunch of research, I decided on a budget VFD from "Dealer's Industrial Equipment, LLC". They had a great price, and very speedy shipment of a TECO FM50 VFD. The TECO FM50 that I ordered is rated at 2HP maximum motor. If for some reason in the future I want to upgrade my 1.5HP to a 2HP, I can. (unlikely).

So... I bit the bullet and put in the order. $160.00. ZING! hopefully I don't go over my budget in this little project...

PICS OF MY NEW VFD!








Soooooo... now all I have to do is figure out all of this mumbo jumbo!!!!






Time to call back the electrician friend?

(more updates soon to come)

BUDGET REMAINING: $597.00 (ouch!)