1hp Motor

E

Erdbeereis

Well-Known Member
Would a 1hp motor on a variable speed 2x72 be adequate for most grinding applications? i wouldn't be doing much profiling, just bevels, handles, and stuff. I know the Grizzly 2x72 has a 1hp motor and tons of people use that. I'm using a 1x30 with a less than 1/3 hp motor right now so any upgrade will be amazing. :p
 
The reason a 1hp works on a grizzly is that it is a direct drive 2 wheel grinder.

What type of grinder are you using? If it's set up with belts and pulleys, or have a 3 to 4 wheel set up (drive wheel, contact wheel and idler wheel, or drive, idler, and 2 wheels on each side of a platen) then I would say 1hp is not quite enough. 1.5 hp would be the bare minimum, 2 being better yet, and 3 being a little more than enough.

Even for just doing bevels, you don't realize how much torque is need to grind a full flat on a 2" wide blade, or even to flatten the face of a 6" long piece of 1.5" wide stock.

You'll never be sorry for having too much power. ;)
 
As someone who purchased a 1 hp for my kmg, trust me it's not enough. I could only do 3/32 stock if I used 1/8 or above and really leaned in I would bog the motor down and or trip the breaker.

Get a 1.5hp if your setup for 110 if you have 220 in your garage get a 2hp. It's like a $30 difference and will pay dividends later
 
I was thinking about getting a Pheer grinder.

The price difference would be about 150-200 to upgrade the motor.
 
I can not say enough good things about the 427 pheer grinders. I just bought one myself with a 1.5hp direct drive motor, 10inch rubber contact wheel, and a flat platen. The machine purr's like a kitten and has more than enough power. Jose is a great guy, has ton's of knowledge and is willing to make any modifications you want to your machine.
 
The cost difference between 1 and 1.5 hp should not be 200. Keep looking for better pricing.
 
I have use that same grinder with a 1hp for 2 years now. If you can I would get a 2hp. Remember that you need to upgrade the VFD also.

I work with both 3/16 and 1/4" with no problems. I want the larger motor for other stuff I do. I have the basic unit with a couple of mods. Consider a second tool bar and add Boss Dog's small wheel adapter with a 3/4" wheel.

1376689878976.jpg
 
A 1hp would work "ok" if you're not doing any profiling and on smaller blades - "IF" you would use a pulley setup so you could gear the belt down to around 1,000 to 1200 SFM. This speed works good for better control while doing bevels - unless you're really good. Fine grit belts like slower speeds also - too fast and they burn metal FAST!!

"IF" you wish to profile turning up around 3,000 SFM, you'll find that 1hp motor bogs down really easy. If using a VFD, then a 2hp motor would be MUCH better. When using a VFD and slowing down, you'll find it bogs pretty easy. A 2hp motor using a VFD will have waaay less than 2hp output at 25% speed. A 1hp motor using pulleys to gear down to 25% speed will have well over 2hp equivalent power.

The only reason to use a 1hp motor is because you've got it on hand, or can pick up for little of nothing. If buying new, there will be little difference in price between 1hp and 2 hp. The VFD will most likely be one that will cover 2hp for same price.

Good luck, Ken H>
 
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Hmmm.... Once again, I offer a slightly dissenting opinion. For me, knife making is about finesse more than power and speed. I have 2 variable speed grinders and both are 1 HP.

Having said that, I agree, you'll rarely be upset that you bought too much machine.

Rob!
 
If you use step pulleys you want to put the motor on a hinged plate to keep the tension on some link belt.
Bossdog sells Link Belt. If you are a part time maker or make little bird, trout & hunters you can get by with a 1hp. I have done it before.

If you really want to grind every day for a few hours and make some large Bowie or culinary knives for instance you want at least a 1/1/2 HP A 2hp TEFC motor with a VDF is most desired. Thats what I have on my Hardcore products variable speed. If you go the route of step pulleys. Get any cheap used motor of 1hp or larger enclosed or not.
On a 6 x 48 belt sander I have a old WWII 2 era 2 hp 110 thats open and has the oil spouts on it.
I haven't been able to burn it out over 10 years of fairly regular use.DSCN1089.jpgDSCN1090.jpg
I think I paid $50.00 for it I call it Frankenstein.
 
Step pulley on a hinged plate is what I did. I used a 1750 RPM, 1hp motor for a while. Grinding with finesse (slower speeds) on small blades or bevels the 1hp has all the power needed. Once the speed is stepped up over 3,000 SFM and trying hog metal, the 1hp will bog very quickly, especially when using a platen. A big contact wheel uses less hp, but still can be bogged at high belt speeds very easy.

All depends on the mounting method for the 1.5 motor - if direct drive and it bolts up direct to grinder (typical for VFD), same mounting as the 1 hp or 2 hp - as long as the motor has the required mounting holes. If using to drive step pulleys on a hinged plate, again - no difference as long as the motors have the same footprint to bolt down. It's also very easy to switch from 1hp to 2 hp - depending on mounting method. On my hinged plate changing from 1hp to 2 hp was a simple matter of unbolting 1 hp, and bolting up 2 hp.

My 2 hp motor is not a TEFC motor, and I expect "someday" the grinding dust will ruin the motor, but since it was a freebie - nothing lost and I'll look for another really cheap motor then. If paying very much money, I'd for sure use a TEFC motor.

Ken H>
 
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