1 H.P. G0704 mill vs 3/4 H.P. Bridgeport

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Wino1442

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Hi all....I was looking to get your opinions on something.
There is a Bridgeport in my area for sale that has a 220v 3/4 H.P. motor on it. I currently have a Grizzly G0704 which has a 120v 1H.P. motor(stock). My question is: is there or what would be the difference between the two in terms of performance, like the depth of cut or ability to handle a higher feed rate etc. Thanks
 
That is a small motor for a BP that I have read was an option. I would look at the BP for it's condition, and the size of the table. Then it may possibly be a candidate for a motor swap(the gurus would know), and depending on the condition it would be a better machine, that is just my personal opinion.
 
No comparison.

The Bridgeport wins, hands down in rigidity, table size and work envelope.

I have a g0704 CNC conversion and a PM935, which is similar in capability to a Bridgeport.

But comparing a manual Bridgeport to a manual g0704, the Bridgeport is far more capable, regardless of the motor hp.

The Bridgeport motor can easily be upgraded to as much as 3hp, and still
not tax it's rigidity and the stock g0704s 1hp rating is pretty optimistic anyway. 3/4hp is more realistic for that little 90v brushed dc motor. The 3hp motor on my pm935 has never taxed it's rigidity, not even while taking 1/4" deep cuts in steel, with a 2.5" face mill.
I switchedy g0704 to a 2hp bldc motor years aago, and easily run into it's rigidity limitations. 2000lbd vs 400lbs puts them in different categories altogether!
 
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In agreement with @benmychree:
I have a G0757Z Grizzly mill. The motor dataplate claims to be 3HP, but it also claims 5.8 FLA (3 phase), 220V. So 5.8 * sqrt(3) * 220 = 2.21KW. If you divide that by 746 watts/HP you get 2.96 HP @ 100% efficiency. But if it is 100% efficient, no need for that horribly loud independent cooling fan. Something fishy in that HP rating.
 
Completely different animals; the motor HP is not a big concern and can be changed anyhow if desired
 
Motors (both 1-P and 3-P) are rated in input power not in output power.

1-P motors are never better than 87% efficient when looking at input power.
 
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