Grinder in a box! DIY grinder kit

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Hey Justin,

I've been hanging out at KnifeDogs, because I've met a number of people in person that hang out there. I just checked and my outlets are split on two 20 amp breakers, so I should be ok. I will have to forgo a 220v setup unless I run an extension cord and unplug my oven or dryer!!!:D:D:D I was thinking that having a one speed grinder might bump up my failure rate, because of the high speed. Now, is the 8" wheel for heavy metal removal and smaller wheel for detail work? I see some setups without the big wheel, so I was wondering what it was used mainly for? Would you recommend the multi-platen setup or the standard platen version? What rpm should I get on the single phase motor, would 1800rpm be enough, or do I need more?

Thanks,

Jeff

Justin King said:
Haven't seen you post lately, Jeff. Good to see you're still knockin' around on here. This grinder kit is not ideal for a multi-speed pulley set-up. It could be done but you would have to mount the motor off the base and add pillow block bearings and an additional shaft. If you want variable speed with this unit your best bet is to get a 3 phase motor and a VFD to drive it. If you do go this route I would personally suggest you go to a 1-1/2hp motor, from what I understand you lose some power to the VFD. For a single speed setup you can get by pretty well with 1hp. At least until you can upgrade.
FWIW mine is set up with a 1hp single phase, so it is single speed. Having a single speed grinder is better than having no grinder. If you want to get set up as cheap as possible I would suggest scavenging a used 1hp single phase motor if possible, or get one on Ebay. They can be had pretty cheap. As finances allow you can swap this out for a bigger 3-phase and add a VFD.
The beauty of this kit is that you can mix and match parts/motors easily, so you can go cheap to get it running and upgrade as you go.
Before you decide on a motor you might check into your circuits to be sure you get one that won't pop your breakers when you turn it on. A 2hp motor usually requires 220v so this is something to consider too. This is why both of my grinders are 1hp.
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Just thinking out loud here, but couldn't you also buy multiple drive wheels of varying diameters and switch them on and off to change belt speed?
 
polarbearforge said:
Switching the direction of the motor (as pointed out, usually is just done with a switch/swapping wires) wouldn't be the issue.

I don't think that it would track correctly run backwards, since it would be running with the spring instead of against it. Adding another spring may take care of that (on the opposite side). It could be attached when run in reverse.

Jamie
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The grinder I use now is a modification of an industrial grinder (change 0f motor to 115 v, adding an extra tool arm etc). I put a reversing drum switch on it without adding any extra springs. When run in reverse the tracking changes, but once it is adjusted it runs through. When switching back to the original direction you need to re-adjust the tracking back to the original position. I find the reversing of rotation very useful because this one has tool arms in both directions (which helps me using different length belts on the same machine).
 
HowellCutlery said:
Just thinking out loud here, but couldn't you also buy multiple drive wheels of varying diameters and switch them on and off to change belt speed?
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You sure can, but it is time consuming. Once you put a different drive wheel you need to re-position the tooling arm too (for the same belt).
 
I don't know if I should start my own thread or if I can ask this question here, but I need some education on this motor thing. I'm looking at single and 3 phase 1.5-2.0 hp electric motors on ebay. I see here that the recommended frame is 56C. How about 56H? Basically, what different frames can I get away with that are compatible with this grinder? When talking single phase, what is the recommended rpm's? 1800? 3450? I'm not much of a fabricator, so the frame compatibility is important. I just want to know how much leeway I have and what the differences of each frame type really are. Thank you in advance for your time.

Jeff
 
KB1SYV said:
I don't know if I should start my own thread or if I can ask this question here, but I need some education on this motor thing. I'm looking at single and 3 phase 1.5-2.0 hp electric motors on ebay. I see here that the recommended frame is 56C. How about 56H? Basically, what different frames can I get away with that are compatible with this grinder? When talking single phase, what is the recommended rpm's? 1800? 3450? I'm not much of a fabricator, so the frame compatibility is important. I just want to know how much leeway I have and what the differences of each frame type really are. Thank you in advance for your time.

Jeff
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Details on the motor frame sizes and types can be found here. You will get a general idea.
http://wiki.owwm.com/Default.aspx?Page=Motor Frame Size&AspxAutoDetectCookieSupport=1

I guess a 56-H frame will work instead of a 56-C, but I am not 100% certain about it.

Regarding speed, it depends on your skill level and personal preferences. My present grinder is a 1740 rpm fixed speed with a 6" drive wheel. I find it rather slow at tiimes. For the kit I jjust bought from Jamie I already bought a 3400 rpm motor. Like another member mentioned before you can always change the belt speed by changing the size of the drive wheel.
 
I could be wrong but I believe that any 56-frame motor will bolt up. If you can get specs on the motors you are looking at, compare the spacing of the bolt holes vs. a 56-C.
You can probably do well with a 1750/1800rpm motor and a 6" drive wheel. For a 3450rpm you will want to go with a 4" drive wheel. You might do a little math and see how close the speeds come out with these two options. The 4" drive with a 3450 rpm motor is a little fast for me, it might not hurt to slow it down a hair, going with a 1750 rpm motor and a 6" wheel might have this effect.
Contact wheel sizes are important if you are hollow grinding, if this is the case, the bigger the better IMO. Otherwise I find a smaller wheel to usually be more versatile than a large one. The multi-platen setup is probaby more useful overall than the standard one but will cost more to get wheels for due to the large contact wheel.
 
Thanks Guy's,

I wasn't sure what the different sized wheels function really was, for instance I've seen someone who has an 8" and a 14" wheel, I don't know what benefit a 14" wheel would have. Then again I've never hollow ground anything! Will it be feasible, within my means, to make a pulley system work with this kit as opposed to spending the extra money to make it truly variable?

Thanks Everyone,

Jeff
 
KB1SYV said:
Thanks Guy's,

I wasn't sure what the different sized wheels function really was, for instance I've seen someone who has an 8" and a 14" wheel, I don't know what benefit a 14" wheel would have. Then again I've never hollow ground anything! Will it be feasible, within my means, to make a pulley system work with this kit as opposed to spending the extra money to make it truly variable?

Thanks Everyone,

Jeff
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I think the extra cost of the pulleys and the shaft and pillow block bearings, plus the extra work getting that extra stuff mounted up makes it pretty much not worthwhile. Your cost to go to a VFD drive would not be much more, I think, if you shop right, and your result would be much more user friendly.

My suggestion about going with single speed to start out was based on my experience scavenging motors-if you know where to look you can get them for free or close to it. One could even make a hobby out of collecting them.
1hp single phase motors are especially common. The one powering my Coote came from a salvaged lumber/junk store for 25$, it is a Baldor and lists for over 300$ new. The one running my GIB is one of 5 that I picked up for free from the scrap metal pile at the landfill, also a Baldor and TEFC to boot.

Junkyards, small engine/tool repair shops, old factories, the list of possible sources is literally endless. Ideally you want a TEFC motor but to get you going temporarily you can use a washing machine motor. I have seen guys on here use motors from treadmills (or just use the whole treadmill to make their own uber-funky grinder). Table saws often have motors that will work perfectly.
 
Justin King said:
I think the extra cost of the pulleys and the shaft and pillow block bearings, plus the extra work getting that extra stuff mounted up makes it pretty much not worthwhile. Your cost to go to a VFD drive would not be much more, I think, if you shop right, and your result would be much more user friendly.

My suggestion about going with single speed to start out was based on my experience scavenging motors-if you know where to look you can get them for free or close to it. One could even make a hobby out of collecting them.
1hp single phase motors are especially common. The one powering my Coote came from a salvaged lumber/junk store for 25$, it is a Baldor and lists for over 300$ new. The one running my GIB is one of 5 that I picked up for free from the scrap metal pile at the landfill, also a Baldor and TEFC to boot.

Junkyards, small engine/tool repair shops, old factories, the list of possible sources is literally endless. Ideally you want a TEFC motor but to get you going temporarily you can use a washing machine motor. I have seen guys on here use motors from treadmills (or just use the whole treadmill to make their own uber-funky grinder). Table saws often have motors that will work perfectly.
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Justin, do you think a 1hp single phase would be strong enough for my uses? I think I foun one for $50 http://newhaven.craigslist.org/for/1703463727.html.

Then there is this one: http://hartford.craigslist.org/tls/1715792500.html
But I don't have a 220v connection. I can't run this without that right?

http://hartford.craigslist.org/tls/1678174125.html

http://newlondon.craigslist.org/tls/1676291897.html

Jeff
 
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KB1SYV said:
Justin, do you think a 1hp single phase would be strong enough for my uses? I think I foun one for $50 http://newhaven.craigslist.org/for/1703463727.html.

Then there is this one: http://hartford.craigslist.org/tls/1715792500.html
But I don't have a 220v connection. I can't run this without that right?

http://hartford.craigslist.org/tls/1678174125.html

http://newlondon.craigslist.org/tls/1676291897.html

Jeff
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1 HP is not bad, but it would be nice to have the power of a 1.5 or even 2hp motor. In my opinion 3hp and above is kind of over kill for a grinder.
Your best bet would be the Baldor 1HP. Good motor for a good price. If you feel it is underpowered you can always upgrade to a 2 hp later.
Remember, energy consumption is more for the bigger motors.
 
Thanks OB, if you noticed, that motor was put up April 21! I hope it's still available. If so, then it's mine!!!

thanks

Jeff
 
1 hp will get you going. Both of my grinders run on 1 hp, and they are powerful enough to do what I need. 2 hp would get me there faster but is not necessary. Those who tell you otherwise are fortunate enough to have been spoiled by an over-abundance of electricity.
That Baldor motor is a dime a dozen item, if that one is gone another one will appear soon. I should start a used motor business, I think there are several likely sources for salvage motors around here. Too bad I have more ideas than time to make them go!
The 5 hp unit you linked requires 220v. This is typical of motors rated over 1-1/2 hp.
 
Good discussion on motors. My main grinder is a 1 1/2hp motor at 3450 rpm with a 4" contact wheel(flat platen only). My next grinder is a 1 hp motor at 2800 rpm with a 4" contact wheel(wheel grinding). I had a 1/2 hp motor at 1725 rpm setup for a while for finishing, but never really used it.

Wloch248 posted that he got his vfd from dealerselectric.com and I've been looking through it. I used to have a number of 3 phase motors that I traded off since I couldn't easily use them. I might have to dig some up again.

Jamie
 
Actually I ended up getting it from factorymation.com because it was $6 less than dealerselectric.com shipped. :D

It was the exact same drive (teco fm 50) that nathan (silver_pilate) recommended. And if you look back to page 5 at airbalancer's post about his eerf build you can see his sweet setup with a nema 4 box he got from ebay to mount his VFD right next to his grinder. He has some great ideas like cutting a little hole in the box and gluing in a piece of plexiglass so he can see the display on the VFD. I'm not going to lie, I will probably copy that :thumbup: He also has a similar setup to Nathan Burgess with the remote on/off and speed pot. I was initially thinking of getting a vfd with a knob on it to control the speed but was swayed not to. I think that is def the way to go so you aren't messing with the vfd to change speed. Airbalancer's video really inspired me to commit to the remote controls even though the idea was put in my head by Nathan B. I also just saw a grinder build on another forum that had the teco fm50 just mounted next the the grinder in no box at all but I don't want to have to buy another one at any point in the future if I fry it with metal dust.

BTW if Nathan or airbalancer (mike) are reading this I thought I read that you went to some place like radio shack to get the on/off and speed pot but is there a certain tolerance that you would look for when buying these? (part #'s would be awesome if you have them on hand). That will be my next trip to pick these up.

I just got my drill press in full working order again and will be hopefully drilling and tapping my kit soon. I have the parts list of bolts from jamie's website. What is the recommendation from anyone who has finish their build be as far as getting fasteners for the grinder be? I see a lot of the hex head (allen) bolts. I was initially thinking just regular bolts but the allen head fasteners make it look a little more "professional". It seems like I would have a hard time finding them and they would cost quite a bit more. Any opinions????

And as long as my post is rambling on and getting longer by the second does anyone have any thoughts on the different types of countersinks available? I am looking to buy one or maybe a set and only want to have to buy one set that will work the best. I seem to be finding 2 types (hard to describe the differences).

Thanks,
Nathan W
 
BTW if Nathan or airbalancer (mike) are reading this I thought I read that you went to some place like radio shack to get the on/off and speed pot but is there a certain tolerance that you would look for when buying these? (part #'s would be awesome if you have them on hand).
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The wiring diagram that came with my drive (ABB) called for a 10K potentiometer. They are only 4 or 5 bucks at radio shack. I would check your manual first. As for the switch you can use just about anything. I just used a simple toggle switch.
Mike
 
91251A553 1 Pack Black-oxide Alloy Steel Socket Head Cap Screw, 1/4"-20 Thread, 2-3/4" Length
91251A555 1 Pack Black-oxide Alloy Steel Socket Head Cap Screw, 1/4"-20 Thread, 3-1/4" Length
91875A130 1 Pack Zinc-plated Steel Acorn Nut, 1/4"-20 Thread Size, 7/16" Width, 15/32" Height
6271K31 2 Each Die Cast Zinc Adjustable Handle, 3/8"-16 Thread X 3/4" L Stud, 3-1/8" L Handle
6042K86 1 Each Cast Iron Knob, Knurled Rim, 1/4"-20 X 3" L Stud, 1-3/8" Diameter
64425K76 1 Each Aluminum Tapered Handle With Stud, 1/2"-13 Thread Stud, 1-1/4" Dia, 3-1/4"l Handle

Here's a list of the hardware and bolts I used from McMaster Carr.
I also used 1/2-13 Helicoil inserts for mounting the wheels.
Mike
 
Hi Jamie,
Got my box last week, but was too busy to even open it until this morning.
The plywood box in the flat rate box sure is clever!:thumbup:. I was wondering how the box held up with all this weight inside.
Now, if I can find the time to get the other things and put it all together....
 
ob1 said:
Hi Jamie,
Got my box last week, but was too busy to even open it until this morning.
The plywood box in the flat rate box sure is clever!:thumbup:. I was wondering how the box held up with all this weight inside.
Now, if I can find the time to get the other things and put it all together....
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Thanks! So far I haven't lost a single bit in transit. Although there seems to be this near constant ringing in my ears, probable from the postal carriers that have to deliver them!

Jamie
 
Wloch248 said:
FYI, While I was looking at prices I couldn't find the 8x2 poly contact wheel on the usaknifemaker.com website which worries me a little. The other option is to get them from sunray-inc.com They supply the poly contact wheels and drive wheel for a little cheaper than usaknifemaker.com but I think their turnaround time is longer and you need to be VERY specific when ordering. SO if you went that way you are looking at less than $800 maybe around $750 or so.
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Wloch248,
They have them back in stock at $104 plus shipping. I got mine yesterday. That is a heavy beast.

The motor has been the biggest pain for me. Don't know which way to go. Finally just bought a 3450 2hp 220v single phase for $221/free shipping and wouldn't you know it the next day found a new Dayton 2hp 1750 220v single phase for $125 on Craigs List. I think I'll keep both or sell them and buy a 3phase with a vfd. Ahh my head hurts again!
Bill
 
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