Horse Power Requirements For 6X26 Mill

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ptsmith

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Hi everyone. Complete machinist newbie and first post.

I recently bought a Harbor Freight 6X26 vertical mill. It arrived with a damaged motor. HF refunded $315 (their price for a replacement motor). I couldn't be happier about this, as it gives me an excuse to install a 3ph motor and VFD. This would also spare me from having to run 220V to a spare bedroom where the mill will reside.

I can get a 110V 1hp Teco VFD for $152 shipped form Amazon. And an inverter duty motor for less than $200. A 1 1/2hp motor and VFD (the max for 110V) would cost considerably more, maybe as much as double.

I see that some Bridgeports came/come with 1hp motors, so this leads me to believe that 1hp should be more than enough for my mill. Reading up on this I find there's no consensus on this.

I would like have as much power as the mill can handle and will go with a 1 1/2hp setup if that makes sense. Any thoughts on this?

PS: The miil came with a 2hp 220V motor. Other 6X26 sellers such as Grizzly come with 1 1/2hp motors. I don't think any of them come with a 1hp motor.
 
My thought would be 1 1/2 or more. Thinking you may need a little extra HP if you are going the variable speed route. Hopefully someone else with more VFD experience will see this and give a better answer.
 
I have a Enco vertical mill that is very similar to the H-F. It came with a 1 1/2 hp that did just fine. I just finished adding a
2 hp and VFD that works real well. It did not seem under powered with 1 1/2 hp but I went back with 2 hp because I found a good deal on a TECO motor on Amazon and a Delta VFD on eBay.
 
I just looked back. The motor was $270 and the drive was $80
 
I just realized there were responses to this thread. Thanks!

I also found a good deal this morning, Z2V. Whather it was a good choice I don't know.

I also posted this on the yahoo 6X26 group earlier today:

I've been considering everyone's responses (thanks!) and wasting a lot of time googling and searching ebay.

The whole reason I went with this mill is I hoped it would have more hogging ability than a bench mill in the same price range. I realized that downgrading the motor power kind of defeats that goal. Whether I need it or not, I'd like to have as much power as possible.

So considering the lack of 220V in my room, a 1 1/2HP motor with a 110V VFD seemed like the best practical option. But looking at the specs for a Lenze 1 1/2HP VFD, I found that it requires a 20A circuit. I obviously don't have that in my bedroom, so that's not going to work without adding a circuit.

So as long as I have to add a circuit, I might as well add a 220V one. And that's when the wheels start to come off! I found a new motor on Amazon this morning. It's not what I need. It's 3HP, 3600RPM, 182T frame, 1 1/8" shaft. Everything I read say 1800RPM is much better. The mount on the mill is 145T and 182T will require an adapter. The shaft on the mill is 7/8" so I'll need a new pulley.

But I bought it anyway, because it was $116.76 shipped. And it's a good motor. For that price I'll make it work.

https://www.amazon.com/gp/product/B00A8FR4WO/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

And I ordered this VFD:

https://www.wolfautomation.com/inde...7Oy_3IGlGl2k3g7wHZhBS4JFCkQCZ9_BoCzPsQAvD_BwE

Hopefully I didn't screw up too bad!
 
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I hope you don’t regret the 3600 rpm. There are several listings for 2 hp 1750 145T TEFC on eBay today. Ranging from $170- $270
 
My thinking was to overcome the lack of low speed torque with gearing (pulleying) and the extra 1 HP. Supposedly you can safely run a 3600 motor at 125% RPM. That would be 4500. What's the highest RPM I could run my mill at? 3000? So if yes, I could gear it down 1.5 to 1 and still hit 3000 max RPM. And that would give me 50% more torque thoughout the entire range. It's a 3 HP motor, so I would think I would end up with a good amount of torque. AND, at low speed the motor would be running faster, which would mean the fan is running faster, which should make it run cooler. Add to it that it was dirt cheap and at the moment it all made sense to me.

But I did have regrets, and I canceled the order. Now that exact motor cost $511.69 (click the link above). It was originally a listing error. Now I have regrets of a different kind. I should have kept it and sold for a profit.

I had to look up TEFC as I didn't know about that aspect of a motor. I think I'm going to go with an ODP though. I can get the motor in the link cheaper than I could find a TEFC and ODP is suppose to cool better. I'm not going to be using enough to be concerned about it getting internally dirty. I use to be a trim carpenter in the '80s. We would spray the ODP motors on the table saws with saw dust all day long. Never cleaned one out and never had one burn up. We gave those motors more abuse in a day than I'll give this motor in my lifetime.

https://www.ebay.com/itm/122704157883
 
The motor in the link above was originally about $130 plus shipping. About $170 total. There were 6 available.

I bought a motor off ebay a couple of weeks ago that was suppose to new. When I received it was obvious it was a repainted used motor. I don't want to go through that again, so last night I messaged the seller of the motor above:

Hi, is this motor unquestionably new? I purchased a supposedly new motor off ebay a couple of weeks ago and it was obviously a repainted used motor. Don't want to go through that again. Thanks.

I never hear from them. Now the price has been raised to $626.32 and it shows to be sold out. If you look at purchase history the last one to sell was May 1st. Not hard to put 2 and 2 together hear. I won't be doing any business with these people.
 
ptsmith said:
The motor in the link above was originally about $130 plus shipping. About $170 total. There were 6 available.

I bought a motor off ebay a couple of weeks ago that was suppose to new. When I received it was obvious it was a repainted used motor. I don't want to go through that again, so last night I messaged the seller of the motor above:

Hi, is this motor unquestionably new? I purchased a supposedly new motor off ebay a couple of weeks ago and it was obviously a repainted used motor. Don't want to go through that again. Thanks.

I never hear from them. Now the price has been raised to $626.32 and it shows to be sold out. If you look at purchase history the last one to sell was May 1st. Not hard to put 2 and 2 together hear. I won't be doing any business with these people.
Click to expand...

Wow, I hate to hear that. I’ve bought two motors from them in the last year and had no problems. In fact the 2hp I just put on my mill was bought from them thru Amazon and was drop shipped to me from Teco-Westinghouse which if four miles from my home. It came UPS the day after I ordered it. It’s been free shipping on both. The other was a 5 hp for a great price also.
I hope you have better luck moving forward in your search.
 
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