Help choose between two mills

Ben17484

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Hi All,

As those of you who follow this part of the forum will have seen from my other posts, I'm looking in to getting a new Milling machine.

I've narrowed it down to two:



Screenshot 2024-11-21 at 15.28.05.png

And the VMC Turret Mill:


Screenshot 2024-11-21 at 15.28.45.png

These are the two largest milling machines that I'll be able to fit through to my workshop.

Considerations: The GH Universal is a bit cheaper, but also a bit lighter.

The GH Universal is a gear head with 6 speeds. It's single phase and 320kg.

The VMC is a knee mill, 420kg, comes with the stand but is 3 phase (the single phase model is nearly £600 more as they don't do it without a DRO. £600 for a fitted DRO is more than I'm willing to spend).

I only have the very basic knowledge of the phase inverter that would be needed here. Looking on eBay, an inverter can be bought for around £100 I think, but I have no idea what else I'd need.

I guess the question is, is the extra 100 kg and the fact that it's a knee mill make it worth the extra effort and money needed to get a phase inverter and fit it?
 
So you are forced to buy the dro on the single phase knee mill? Sounds like highway robbery to me
Anyway, buying an inverter should be fairly straightforward- does require a few settings initially
 
from what i know there are several ways of wiring a three phase motor (star delta etc) one of the ways is to run it off a single phase (domestic supply). Far as i know no need for an inverter. however there is limitations i think you cant have variable speed which i guess in this instance you want.

If you spring for an inverter i think it does all the magic for you it basically takes in single phase and chops itup into any frequency and voltage you want so once it is set to a particular voltage etc you leave it alone. and dont have the tail off of torque etc

have you considered getting the mill and buying a dc motor that way you can off set the costof the motor against the 600 quid and sell the 3 phase one.
 
You will appreciate having a knee.

I've never owned a square column like the first unit shown but I now have a baby Bridgeport and find the versatility of having both the knee and spindle for Z-Axis operations.

John
 
Three phase is definitely preferred, also the motor on the VMC is likely a standard frame size if you ever need to replace it vs. the probably proprietary unit on the GH. Wiring up a VFD is simple for this machine since it really only requires on/off, you can run the variable speed from the knob on the VFD unit itself.

Yes, the extra mass will be appreciated as well.

John
 
@Ben17484
Just a note on Z-axis clearance. The knee mill has 328mm distance between table and spindle nose whereas the square column mill has 450mm.
328mm is not a tremendous amount of space. A vise is going to take up ~116mm to the top of the vise leaving only ~212mm for tooling which is not a lot. A drill chuck will eat a fair amount of that space.
I have seen folks make riser blocks to increase the spindle to table distance but this is something to consider in your decision making.
 
Hi All,

As those of you who follow this part of the forum will have seen from my other posts, I'm looking in to getting a new Milling machine.

I've narrowed it down to two:



View attachment 510509

And the VMC Turret Mill:


View attachment 510510

These are the two largest milling machines that I'll be able to fit through to my workshop.

Considerations: The GH Universal is a bit cheaper, but also a bit lighter.

The GH Universal is a gear head with 6 speeds. It's single phase and 320kg.

The VMC is a knee mill, 420kg, comes with the stand but is 3 phase (the single phase model is nearly £600 more as they don't do it without a DRO. £600 for a fitted DRO is more than I'm willing to spend).

I only have the very basic knowledge of the phase inverter that would be needed here. Looking on eBay, an inverter can be bought for around £100 I think, but I have no idea what else I'd need.

I guess the question is, is the extra 100 kg and the fact that it's a knee mill make it worth the extra effort and money needed to get a phase inverter and fit it?
Mass and work envelope is what it comes down to, the mass of the knee mill and its knee are nice but the work envelope is too small. If the knee mill is setup for an R8 collet you can take a little bit back by using R8 Collets and tooling but I would vote for the work envelope of the square column machine and if it comes with a DRO that is a plus.
 
Thank you for all of your input.

I was all ready to buy the knee mill when the work envelop was brought up. I hadn’t considered that. The difference in Z height is quite a lot between the two mills.

I’ll have to put some thought in to that.
 
not sure where in kent you are but i would be tempted to go to the axminster shop in sittingbourne and look at them. they are basicly the same machine just different sundries bolted to them
 
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