Plans for 2"x72" Knife Grinder/Sander No welding required

[Matt Walker]

Tracy, Great job.
Andy, Good luck.
Andy, If you are interested in using a VFD. Check this place http://www.factorymation.com/ They have the best prices I have found on VFDs.
It is possible, if you could scrounge a 3ph motor (ebay,maintenace at work etc.) that you could set up a vfd about the same as a new 1ph set up with the pulleys. Here is one of their FM50s I just fixed with plugs to move between machines, in a box with air filers to exclude the dust. Forward, reverse, emergency stop and speed control are mounted on the outside of the box.
http://img505.imageshack.us/img505/4991/vfdopenbi1.jpg
http://img515.imageshack.us/img515/5977/vfdboxct2.jpg
Matt

[tmickley]

that enclosure is great! It must be a NEMA 20 rated!
I've poked around for years looking at VFD's. I only stumbled onto factorymation recently. They are the cheapest i've found other than the occasional ebay auction.

[Matt Walker]

Thanks Tracy. Just an old standard Craftsman tool box. Put a 1/4" thick piece of aluminum in bottom to mount to for extra heat sinc. Thought about a small muffin fan but Darren Ellis looked at and said he didn't think it would be necessary. Really like the FM50. A little simpler set up than some others I've seen. But still has more features than we would ever use.
Matt

[Andrew Garrett]

Well, here's the deal on steel:

I visited three steel dealers here in Wichita and no one will sell me less than 20 feet lengths of new stock. That ain't happenin'!

I did find what I need (I think) in rusty ol' used stuff at a scrap yard. That was fun--dude had the big magnet claw hanging over me while I scrounged, stuff droppin' all around. It was pretty cool if not the picture of safety.
Th problem was that I wasn't counting on buying scrap, so I didn't bring my tape measure. I think they have it all, but I'll go back properly equipped and actually buy it next week (I didn't want to guess).

The good news is that I get it all for 25 cents a pound! The bad news is that I get a few hours on the wire brush!

Matt, Thanks for the heads up on the VFD. The wiring scares the crap out of me, because electrical work is not my strength, but if it's that cheap, it would be hard to say no!

[Matt Walker]

Andy, You have hundreds of friends here. Some of them know a lot about electricity. I read the manual then e-mail Darren to find out what I just read.
Matt

[tmickley]

That's insane they wouldn't cut it and sell you pieces. It's hard to even understand that a business would operate that way. I've lived in 3 different places and bought pieces of metal and they all cut to length.
I'll get some steel cut and listed on my supply site for those that run into the same problem. If you just can't find some in the mean time, let me know. We'll work something out.

On the other hand, poking around the junk yard is some seriously fun stuff. 25cents/lb is great price. Don't be afraid to modify the plans a little here and there. That's what they are all about.

[Don Robinson]

Originally Posted by Matt Walker

Tracy, Great job.
Andy, Good luck.
Andy, If you are interested in using a VFD. Check this place http://www.factorymation.com/ They have the best prices I have found on VFDs.
It is possible, if you could scrounge a 3ph motor (ebay,maintenace at work etc.) that you could set up a vfd about the same as a new 1ph set up with the pulleys. Here is one of their FM50s I just fixed with plugs to move between machines, in a box with air filers to exclude the dust. Forward, reverse, emergency stop and speed control are mounted on the outside of the box.
http://img505.imageshack.us/img505/4991/vfdopenbi1.jpg
http://img515.imageshack.us/img515/5977/vfdboxct2.jpg
Matt

Matt, you caught my interest. Which one of the drives would be suitable using 220 i ph input and up to 2hp 3 ph output?

As if I know what I'm talking about!

Tracy, i've been watching this whole thing with interest. Good job, my friend.

[Matt Walker]

Hi Don,
Hope Tracy don't mind us getting of the subject of his great grinder design.
Honestly I don't know that much about them either. But: TECO FM50 AC Drive, 2 HP, 230V 1 / 3 PH Input, 230V 3 PH Output, 7.5FLA, IP20
? 200-230VAC 1 / 3 PH Input, 50/60Hz (Voltage +10% to -15%, Frequency ?5%) Input
? 0-230V, 3 PH Output $145
http://www.factorymation.com/s.nl/it...j0?category=32

Would seem to fit your requirements. The one for 3HP is $40 more and seemed like the best deal to me for future flexibility. A higher rated unit will run a smaller motor fine in my experience. Looks to me like checking the amp requirement of the motor and the amp output of the VFD is a more accurate way of determining suitability than looking at HP.
My plan is to put plugs on several machines and just move the box. I use my lathe, surface Grinder and vertical band-saw infrequently enough that I don't see moving it as much trouble. Been using it on grinder with 2 hp motor. It has some braking ability. I think there is some part that can be added (braking resistor) that would improve this. Not real necessary but when you cut the grinder off and the belt dead stops in about three seconds instead of coasting to a stop is just cool.
The key to coming out cheaper than a NEW 1ph motor for someone building Tracy's grinder would be a little luck scrounging a deal on a motor. Around here 3ph motors can sometimes be found real reasonable because most people can't use them. And willingness to put it in a protective box. The VFDs I've seen that come protected are very expensive. My other one cracked exactly like a 22 pistol once from the metallic dust. It kept working but I'm sure that wasn't good for it. So the best way to use the cheaper units is to protect them.
Matt

[Don Robinson]

Thanks, Matt.

[tmickley]

This is all relevant...
I use a Teco100 on my disc grinder. I have a Teco50 in a box around here some where as a back up that I bought on ebay fairly cheap. I have a standing search on ebay for a Teco100 and Teco50 VFD in case one comes up dirt cheap.

I would HIGHLY recommend a VFD and frequency drive motor for their grinder. They are a the only way to go. I currently have a Baldor 1.5hp DC variable on my KMG. It works very well but when it goes down, I will replace it with a VFD and 2hp motor.

[Andrew Garrett]

I think I'll take this opportunity to try an extra tool arm when this project is up and running.

In the spirit of Tracy's ingenuity, I invite all to join me in attempting to put together a tool arm for 3-wheel style grinders (KMG, Bader, and this one, which I'm calling my 'McGrinder') that incorporates disc sanding ability!

My idea involves using the regular 2" x 72" belt to drive a 2" contact wheel on an axle, connected to a 90* gearbox, with a quality disc and work rest.

Is this workable, or ridiculous? Be honest.

[tmickley]

Originally Posted by Andrew Garrett

I think I'll take this opportunity to try an extra tool arm when this project is up and running.

In the spirit of Tracy's ingenuity, I invite all to join me in attempting to put together a tool arm for 3-wheel style grinders (KMG, Bader, and this one, which I'm calling my 'McGrinder') that incorporates disc sanding ability!

My idea involves using the regular 2" x 72" belt to drive a 2" contact wheel on an axle, connected to a 90* gearbox, with a quality disc and work rest.

Is this workable, or ridiculous? Be honest.

I keep thinking on that one myself. I wonder if a 90 degree box woudn't drain a lot of power from the machine? I think a 2nd power drive wheel where the contact wheel would be with a disc attachment connected to the side.

I'd also like to see a buffer attachment.

[NJStricker]

Originally Posted by Andrew Garrett

I think I'll take this opportunity to try an extra tool arm when this project is up and running.

In the spirit of Tracy's ingenuity, I invite all to join me in attempting to put together a tool arm for 3-wheel style grinders (KMG, Bader, and this one, which I'm calling my 'McGrinder') that incorporates disc sanding ability!

My idea involves using the regular 2" x 72" belt to drive a 2" contact wheel on an axle, connected to a 90* gearbox, with a quality disc and work rest.

Is this workable, or ridiculous? Be honest.

Andy,

I suppose that would work if you really needed the disc to be facing you as you are standing looking at the machine. Is there anything wrong with having the disc running parallel to the belt instead of perpendicular to it? In that case you would just need the drive wheel, the shaft, possibly another pillow bearing, and one of Beaumont's beveled discs. I'm imagining one with a disc on both sides so you don't need to reverse directions, but that could make it difficult to switch belts without having to take on/off one of the discs. . .

[Andrew Garrett]

Yea, I have a Multitool II that has a disc plate that screws on to the drive wheel. The problem is the placement on the work bench. It's just awkward. I never use it.

That's why I wanted to come up with an efficient way to turn the power 90*.

I liken it to motorcycle drive trains. Some are chains and belts, but others use a drive shaft with not one, but two 90* angles in the drive train. Granted, these aren't electric motors, but I think it's a valid comparison.

I dunno. I'll kick it around. There are a number of rotary tools out there that tranfer energy 90* with a variety of attachments. These operate at high RPM without drastic power loss. Maybe I can canibalize one of these for a good gearbox.

It's all a curiousity at this point.

[Andrew Garrett]

Here's an example of something that might work from Rotozip. It looks real heavy duty (unlike the 90* attachment from Dremel).