First Grinder Build Q's

One Armed said:
Can't use a rheostat with these type of motors. Single phase motor, you need pulleys. Three phase motor you can go VFD.

I had my mind set on this style of belt grinder for a couple years. But so much happened in that time...my understanding, my skill level & my tool gathering. So when the time finally arrived, I built mine using cold rolled 1018 bar stock, and 2024-t3 Billet. And it's one stout piece!

The dcknives design looks like decent setup. I wouldn't go crazy with the tensioning system on a square tube build though. The compression spring is so simple and it works! Going pneumatic just seems like a fix for non existent problem, imho. But good luck with it my friend! :)
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My treadmill motor has been great. It's not sealed so I do have some foam at either end to keep the junk out it though. It's small and being DC has great torque at low RPM. This place has all kinds for cheap. I must disclose that I have never used another grinder though so it may suck and I just don't realize it. I can really lay into it though and not stall it.

https://www.surpluscenter.com/Electrical/DC-Motors/Special-Purpose-DC-Motors/
 
Randydb said:
When it comes to static electricity a lot of people just spray the underside of the belt with laundry static remover.
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And some of us use Nathans platens and dont have to worry with getting shocked at all.
 
Also the only motor I would consider using would be a TEFC motor. There are many threads here where treadmill motors last only a couple knives.
 
Spalted said:
Also the only motor I would consider using would be a TEFC motor. There are many threads here where treadmill motors last only a couple knives.
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Yep, there was a thread going just yesterday. I started off with one and used it for 3 knives, haven't looked back.
 
KnuckleDownKnives said:
Yep, there was a thread going just yesterday. I started off with one and used it for 3 knives, haven't looked back.
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interesting, I've been beating mine including running her full speed for hours working on other projects. That being said, I would still recommend at TEFC for a new build. Why risk half assing it. I only used a treadmill motor because I had one but then upgraded.

Time will tell. Hopefully I can keep the smoke from leaking out.
 
scott kozub said:
interesting, I've been beating mine including running her full speed for hours working on other projects. That being said, I would still recommend at TEFC for a new build. Why risk half assing it. I only used a treadmill motor because I had one but then upgraded.

Time will tell. Hopefully I can keep the smoke from leaking out.
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That was the only reason I used one, someone gave it to me. I didn't have much luck with it, granted it was better than the 1x30 hf grinder. I still have the grinder, it's awaiting a plate to mount a motor to and a motor, just haven't found the need to spend the cash yet as I built a new grinder and made a few changes to the design. I put a 3hp on it running off a kbac-29. I've already have a switching box built so when I do put a new motor on it all I need to do is plug it in and I can flip the switch between it, my other grinder and my drill press I modified to run off a 1.5hp 3ph motor I had laying around. I would have used it on the grinder, but it's not a face mount and not a tefc, but works great on my small drill press. I have it set up to where I can run 6 machines off the same VFD up to 3hp without needing to buy more parts so eventually when I build a disk grinder or 2 all I need to do is plug them is as well.
 
kuraki said:
I've thought about using these since I have a pile of them. Why DA? This is just spring return. Air on - extended, air off - retract.

View attachment 908132
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I’m just used to DA setups with the equipment I’m normally working on. You’re right though, a SA would work just fine and be more simplified and probably cheaper as well.
 
What do you guys think if the speed ranges? Should I go with the 730-4500 sfpm setup with the 2-3-4-5 step pulleys and 4" drive wheel or the 1100-6800 sfpm with the 2-3-4-5 and 6" drive? I've heard 1000-5000 is the general rule of thumb but as you see I have the option of going either slightly slower or slightly faster.

I'm leaning towards the slower option unless you think I'll get better results using the middle speeds (2000 and 3600) on the faster option for my bevel grinding with ceramic belts than the slower options (1400, 2400 and 4500 top)
 
boy&hisdogs said:
730-4500 sfpm setup with the 2-3-4-5 step pulleys and 4" drive wheel
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For sure the slower setup. How much do you think you'll be spending for the 2 step pulleys, jack shaft, bearings, belts..... all the parts required to build the step pulley? Do I remember you said you already have the 1 ph motor? If not, a 1 hp to 1.5 hp 3 ph motor is around $150 shipped, a NEMA 1 Chinese VFD is another $100 - that's only $250 for a variable speed setup. You can put filters over the VFD enclosure inlets to prevent metal dust from entering and use that for several years without a problem in a hobby situation. For a commercial setup where that grinder would be running several hr/day 5 and 6 day/wk, no question I'd spend the extra $250 or so for the NEMA 4 setup.
 
For me personally, I’d always rather be too slow than too fast.

For what it’s worth, I’ve never heard of anyone regretting the money spent on a vfd/variable speed setup.
If you don’t already have a motor, the cost difference may not be as bad as you think. $100 for a Chinese vfd, and anywhere from $50-$175 for the motor. You will need 220vac for the cheaper vfds, and a way to keep dust out.
 
Ken H> said:
For sure the slower setup. How much do you think you'll be spending for the 2 step pulleys, jack shaft, bearings, belts..... all the parts required to build the step pulley? Do I remember you said you already have the 1 ph motor? If not, a 1 hp to 1.5 hp 3 ph motor is around $150 shipped, a NEMA 1 Chinese VFD is another $100 - that's only $250 for a variable speed setup. You can put filters over the VFD enclosure inlets to prevent metal dust from entering and use that for several years without a problem in a hobby situation. For a commercial setup where that grinder would be running several hr/day 5 and 6 day/wk, no question I'd spend the extra $250 or so for the NEMA 4 setup.
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Beat me too it. First time I used my VFD setup, I kicked myself for not spending the money sooner.
 
The 1ph motor is in the mail. I could send it back if I found something better.

I would like a vfd if it wasn't going to cost too much more. The pulleys, bearings, extra shaft, belt, and all that will likely get close to $100 all said and done. For me the limiting factor was the price of the motor itself. I just don't know where people are finding these cheap 3ph motors. I know some people get lucky on classifieds but so far I haven't had any luck.

I only have 110 outlets, which seems to limit my choices of 3ph motors. Though I could be missing something. This is my first time building with this kind of motor/electronics.
 
scott kozub said:
My treadmill motor has been great. It's not sealed so I do have some foam at either end to keep the junk out it though. It's small and being DC has great torque at low RPM. This place has all kinds for cheap. I must disclose that I have never used another grinder though so it may suck and I just don't realize it. I can really lay into it though and not stall it.

https://www.surpluscenter.com/Electrical/DC-Motors/Special-Purpose-DC-Motors/
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Oh yes....I think everyone here is quite familiar with surplus center.:D When I designed my grinder, I would visit surpluscenter.com almost daily, LOL! I too was eyeing a D.C. motor. But the more I researched and mulled it over, the more I was drawn to doing right! And I am very glad I went with a TEFC 1.5hp 3phase motor with a VFD. It's really not bad when you search. While they are very nice, it's not necessary that you have a $600 Baldor motor. I chose a new Dayton 1.5hp that I got for a song & dance! Like $140 shipped to my door. And while I would have loved a Kbac-27d, I had to install a 220v outlet in my work room anyway. So with paying for that, on top of everything else, I just did not want to shell out the $350+ for the KB. So I went with a Lapond VFD for $97. Now here's the nutty thing. The Lapond VFD started getting goofy in me. I emailed the company and was given the best customer service I have ever received! They immediately apologized & offered a replacement, or the new version(which wasn't available when I first purchaed), for an additional $40. And it was all arranged through Amazon so I had the replacement 2 days later. Along with this, they told me not to concern myself with sending the defective unit back. Well, me being me...I just had to disassemble the old one. I found a gouge in the aluminum heat sink, under the module which was not allowing the module to sit flat against the heat sink. And both it and the bridge rectifier were drenched in cheap white grease. I sanded the gouge smooth, cleaned everything and applied a thin even coating of my super-dee-duper $$$ thermal compound to both parts. Everything together and it is working just fine now! So I actually now have two VFD's for less than $140. And although it is NEMA 1, I used breathable material taped over all entry points. So I'm not worried about material entering the unit in the least.
 
Here ya' go for decent priced 3 ph motors. Look down toward bottom of page for lager motors. The 3600 rpm motors are a tad less expensive - and that's what I went with to save cost and save weight. There's a lot of discussion about which is best with most folks touting the more expensive 1800 rpm motor and running 120 hz on the VFD drive to get 3600 out of it. The 3600 rpm motor will have a VERY small amount less torque at low RPMs vs the 1800 rpm, but you'll never know the difference in use because you're not hogging at low RPM, only using a light touch. https://goo.gl/7jcYu9

Link direct to a 1hp, 3600 rpm for $125 shipped: https://goo.gl/7ugzRN
 
Here's a link to surpluscenter.com with a 2hp, 3500 rpm (same as 3600 rpm) motor TEFC rated for $125
https://goo.gl/mouzAc Ooops, that's $27 shipping so is about same as a new Ironhorse motor from my first links.
 
So... if I'm understanding this correctly, I can safely run a 230v motor via VFD out of a 110v outlet? Assuming I have the correct VFD. I'd just have to double the 230v amp draw of the motor to find the 110v draw, correct?
 
Any VFD for our purposes will be putting out 230vac, whether 110 or 220 input voltage. The problem for many makers is having 220 available in their garage or tool shed. A kbac 27 will give you up to 1.5hp and run off of 110vac, but it is a tad high on price. The cheapest Chinese vfds, 1.5-3hp run on 220vac. I believe TECO has some that run 110 or 220, but they only go to 1hp, which, honestly, for direct drive, you could probably get by fine with.

That said, the best option if you could have anything, would be a 2-3hp vfd and motor on a 220vac circuit.

Cheapest option for 110 vac, however, is step pulleys OR, a 1hp vfd and motor. Next best option (but more money) is 1.5hp with a kbac 27 running on 110vac.
 
And to answer the amperage question, 15amp circuit should run your setup ok if there’s nothing else on it. 20 amps would be better though.
 
knife to a gunfight said:
Any VFD for our purposes will be putting out 230vac, whether 110 or 220 input voltage. The problem for many makers is having 220 available in their garage or tool shed. A kbac 27 will give you up to 1.5hp and run off of 110vac, but it is a tad high on price. The cheapest Chinese vfds, 1.5-3hp run on 220vac. I believe TECO has some that run 110 or 220, but they only go to 1hp, which, honestly, for direct drive, you could probably get by fine with.

That said, the best option if you could have anything, would be a 2-3hp vfd and motor on a 220vac circuit.

Cheapest option for 110 vac, however, is step pulleys OR, a 1hp vfd and motor. Next best option (but more money) is 1.5hp with a kbac 27 running on 110vac.
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Thanks for the straightforward explanation.

A 220v socket is out of the question, so there goes the cheapest VFDs. Although I am seeing some around $150 that are 115 in and 230 out, 1hp. I'm looking at a TECO right now with the following specs in the description:
---------------------------------------------------------------------------------------------------------------------------------
  • Cost effective drive solution with wide range of programming capabilities
  • 115V 1-Phase Input, 230V 3-Phase Output
  • 1 HP Constant Torque (4.3 Amps)
  • V/F mode or Sensorless Vector Operation
  • Simple to program with parameters grouped by function type and purpose

FACTORY NEW TECO VARIABLE FREQUENCY DRIVE

*USE THIS DEVICE TO START/STOP & CONTROL THE SPEED OF A THREE PHASE MOTOR*

1 HP INPUT VOLTS: 115V 1PH OUTPUT VOLTS: 230V 3PH OUTPUT AMPS: 4.3 ENCLOSURE: IP 20

TECO CAT#: L510-101-H1 (Replacement for the JNEV-101-H1)

Dimensions: Height: 5.67" Width: 4.65" Depth: 5.8" Weight: 5 LBS.

Applications: - Mixing - Fans - Pumps - Small Conveyors - Treadmills - AC Contactor Replacement - Packaging - HVAC - Machine and Tooling

Features: - Speed Potentiometer (speed pot) - Compact Design: the L510 has a small footprint and accommodates DIN rail mounting as an option - Simple to program with parameters grouped by function type and purpose - 150%25 overload - 0-650Hz - Digital Operator: 5 digit bright LED readout - Diagnostics and parameter configurations - Leakage current prevention via capacitor switch - Sensorless Vector , auto-torque boost, V/F control - Power loss ride-through - Teco-Link configuration software for on-line monitoring, programming, and operation via built-in RS485 - UL, cUL, and CE approved

-------------------------------------------------------------------------------------------------------------------------------------

If this would work, then that price is fine with me. 3ph/1hp motors aren't all that much more expensive than the 1ph/1hp that I bought anyway, and if I have to spend an extra $50 to get a full speed range and a simpler build on a machine that will last me decades to come then that's money well spent.

The outlet in my shed is 15a but there are 20a outlets within reach of a short extension cord if need be.
 
15A will be plenty for 1hp. You won’t be able to hog battle axes or anything, but I think you’ll have plenty of power for most appliacations. If it bogs down, just ease up on the pressure.
 
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