2x72 vs 2x48 Grinder

[Fire plus Bird]

Hi all, first time poster and novice smith with a grinder buying conundrum. I've got a 4x36 benchtop wood sander, but that doesn't cut it for what I want to do (pun intended). I've got a little cash burning a hole in my bank account so I figure it might be time to pull the trigger on something better. 

I thought about building a grinder, but that could take me a while to find the right round-to-it, plus I'm not an experienced metalworker. I figure the time I could spend kludging one together and making it work right would be better spent learning to do what I actually want to do, making blades and other neat, sharp things. I want to spend south of $2,000 at the moment, which isn't a ton where grinders are concerned. 

I happen to have a few 2x48 belts (they may be 2 1/2 x 48, actually) that I picked up with a whole mess randon of Klingspor paper, most of it in small rolls, from a salvage building supply place that folks donate unused or still usable stuff to. So that had me thinking about 2x48 grinders, which led me to the 2x48 Steele Grinder, which is ~$1,600 for the non-tilting model with a 2 horse motor wired for 1.5 horse with a VFD for 115 v house power. The flat platen on the Steele grinder has a neat design with a 2" contact wheel on top and a 4" contact wheel on the bottom. I figure buildind a tilting base similar to the one they sell wouldn't be too hard and I probably have all the steel I need for it laying around.

Alternatively, I could get a Brodbeck 2X72 with a single speed 1.5 horse motor, flat platten, a small wheel attachment and a 6-inch contact wheel for ~$1,840. I like that the Brodbeck tilts, but I'd have to paint, assemble and wire it while the Steele maching is pretty much plug and play.

I know most folks prefer the bigger grinder, but becuase I'm looking to do this for fun and not income, maybe the difference won't matter, at least in the next few years.

Some considerations: At some point I could probably get a VFD for the 1.5 horse single phase motor that comes with the Brodbeck at this price, or even upgrade to a 2 or 3 horse motor and VFD down the line. But I'm pretty clueless about anything electronic. I figure it might be possible to turn the 48 inch Steele Grinder down the line as well and it's motor can be reqired to get the full 2 horses off of a 220 circuit if I decide to get one put in my shop.

So, what it boils down to is this question. Will I be happier right now and for, say the next 2-3 years, with a smaller variable speed grinder or a larger single speed unit? From what I've picked up 1.5 horses is the bare minimum for a 2x72 inch machine, so that power might feel better with smaller belts. I know the 42-inchers will wear faster and there's not as wide an array of selections, but they are cheaper, right?

Oh, and one more conundrum. The VFD on the Steele (A KBAC model like a lot of other grinders use) apparently doesn't play nice with GFCI/GFI outlets. And, of course, my shop is wired with GFCI outlets. If I use a spike bar, would that short circuit the problem (there's one of them there puns again...)? I guess I could always run a power cord out of the shop into the hall to a normal outlet... that would be stupid fun, or just stupid.

Love to here what folks think. Thanks in advance.

[JHCC]

Couple of things:

1. Welcome to IFI!!
2. Adding a VFD to the existing motor on the Brodbeck probably won't work. To quote IFI member rockstar.esq, "Single phase VFD's do not work with motors that have a centrifugal switch.  The centrifugal switches function is tied to RPM's so anything that slows the rotation significantly, will bring the start windings online.  The start windings can't handle continuous operation without overheating." (Full quote HERE.) In other words, upgrading the Brodbeck with a VFD would also require purchasing a new motor.
3. Belts are a consumable, so buying a grinder to match your present supply is putting the cart before the horse. Buy the right grinder for you. If it turns out to be a 2x48, great. If you end up with a 2x72, you can either sell your existing stock of 2x48 belts to someone else, or you can splice three of them together to make two 2x72s.
4. Given how many knifemakers are using 2x72 grinders, there are a LOT of options available for belts in that size, and I suspect that not all of these are available in 2x48. As the proud user of a 2x90, I can tell you that not having to spend time hunting for a particular belt in a size that will fit your machine is A Good Thing.

Since the Brodbeck would cost you around $1840, why not go a bit more and get the Steele 2x72? That would give you all the advantages of the 2x48, plus a bigger motor and a wider range of available belts. The only major disadvantage of the 2x72 would be if you don't have a 220/240v NEMA 6-15 outlet, but that's an easy job for your electrician (although it would add to the total cost).

In general, remember that this purchase is going to make a HUGE difference in your shop capability. Going from "no grinder" to "yes grinder" is a much bigger jump than going from 2x48 to 2x72, and I suspect that you will probably be happy whichever way you go. If money really is an issue, I would probably recommend the Steele 2x48, as the variable speed is a real winner in my book.

That's my two cents; make of it what you will.

[Irondragon Forge ClayWorks]

You might take a look at the KMG 2x72 ours is a 3 speed by changing the belt position an there is a better selection of 2x72 belts than 2x48. If I remember the KMG with the accessories we bought ran around $1700 U.S.

[Frosty]

I have a 2" x 36" and have used it for decades. Built a 2" x 72 grinder in a club grinder build clinic. I didn't have a strong enough motor so it's under powered right now but it still moves WAY more than the smaller belt grinder and doesn't heat the project as much. 

I started looking for stronger motors and before I knew it I have a collection of 1ph, 240v motors ranging from 1.5hp up to 5hp. Only one of them is out of the hot tub we tossed off the upper back deck and it's a nice 4hp. I haven't paid for any of them, the 5hp. is from a hot tub at a garage sale. They were asking$2,000 but hadn't gotten a single hit in two weeks. I opened the access door, saw the motor and started hemming and hawing. 

Finally I leveled with the lady and gentleman about my intent to strip the motor out and junk the rest. The wife pipes right up and says it's been two weeks and not one offer, she'll pay for the dump run if I'd take it away. She just wants it gone! I declined the money and said I'd have to find help loading it. One shout in the front door and her son and a friend come out, the neighbor and gentleman and I loaded it right up. 

I unloaded it at the dump by pushing it out with my legs with my back against the cab, the next day. 

I found a couple motors in treadmills but they're not as strong and can be more hassle stripping out. The speed controls on a treadmill were tempting but I couldn't figure out how to mount a treadmill control panel on the 2 x 72 grinder and have it look cool. No more treadmills.

Oh, and folks I know started giving me hot tub motors. I think I have 7or8 now. I'll be upgrading my 50lb. Little Giant from .75hp to 1.5 or better once I get the shop wired better.

So many projects. <sigh>

Frosty The Lucky. 

[Fire plus Bird]

16 hours ago, JHCC said:

Couple of things:

1. Welcome to IFI!!
2. Adding a VFD to the existing motor on the Brodbeck probably won't work. To quote IFI member rockstar.esq, "Single phase VFD's do not work with motors that have a centrifugal switch.  The centrifugal switches function is tied to RPM's so anything that slows the rotation significantly, will bring the start windings online.  The start windings can't handle continuous operation without overheating." (Full quote HERE.) In other words, upgrading the Brodbeck with a VFD would also require purchasing a new motor.
3. Belts are a consumable, so buying a grinder to match your present supply is putting the cart before the horse. Buy the right grinder for you. If it turns out to be a 2x48, great. If you end up with a 2x72, you can either sell your existing stock of 2x48 belts to someone else, or you can splice three of them together to make two 2x72s.
4. Given how many knifemakers are using 2x72 grinders, there are a LOT of options available for belts in that size, and I suspect that not all of these are available in 2x48. As the proud user of a 2x90, I can tell you that not having to spend time hunting for a particular belt in a size that will fit your machine is A Good Thing.

Since the Brodbeck would cost you around $1840, why not go a bit more and get the Steele 2x72? That would give you all the advantages of the 2x48, plus a bigger motor and a wider range of available belts. The only major disadvantage of the 2x72 would be if you don't have a 220/240v NEMA 6-15 outlet, but that's an easy job for your electrician (although it would add to the total cost).

In general, remember that this purchase is going to make a HUGE difference in your shop capability. Going from "no grinder" to "yes grinder" is a much bigger jump than going from 2x48 to 2x72, and I suspect that you will probably be happy whichever way you go. If money really is an issue, I would probably recommend the Steele 2x48, as the variable speed is a real winner in my book.

That's my two cents; make of it what you will.

Thanks for the feedback, everyone. And especially thank you JHCC for pointing out the issue with using a VFD on the motor that comes with the Brodebeck. It's much more helpful that the stock "you can't use a VFD with a single phase motor" that lots of people give. Apparently you can use them with some motors, but figuring out which is above my pay grade. 

And you're right, it'd be silly to key my purchase of a tool to a handful of consumables I bought in a grab bag us stuff years ago (sunk cost). I only brought the belts I have up in explaining what made me start looking at 48" models. Good point about the 72" Steele. I coudl get the shop wired for 220 eventually, but besides the cost there might be a complication with slots on my breaker box. All the slots are currently filled, but a couple are for old in ceiling heat that doesn't work in a few rooms. It's possible we can figure out which breakers power those circuits and change them out.

I was thinking that, if I got the 72" route with the Steele I should be able to by a regular three-prong plug and rewire the VFD to 115V for now. Right? The key would be finding easy to understand directions, or, better yet, a visual tutorial. I suck at learning technical things unless I can see them demonstrated, then it's easy to pick it up.