Acra mill

Charlie Mike

Charlie Mike

Sober since 1-7-14 (still a Paranoid Nutjob)
Knifemaker / Craftsman / Service Provider
Joined
Nov 1, 2000
Messages
28,365
I'm going to be buying my own home soon. I'll have a 2 car garage that will be entirely dedicated to shop. A couple years ago, I was told (here) to buy the biggest mill I could afford. Now I can afford a proper mill.

The heavy machinery moving company that moved my Grizzly 0705 from my ex's place also deals in Acra machines. I'm buying new, from them because they will put it in my garage and set it up for me. I also like being under warranty. I will also be getting a 3 axis DRO.

I'm looking at the AM2AC:
http://acramachinery.com/Manual_Machines/AM2.htm

Reese Weiland told me these are a journeyman grade machine if Grizzly is a beginner's.

AM2.jpg
 
The variable speed is usually $1,000 more than the pulley drive.


If I had to choose betwen DRO and variable speed, I'd go dro.

How often do you really have to change speeds ?



plus I'd choose the vfd variable speed over the snowmobile pulley variable speed.
apparently those variable pitch pulley mechanisms wear faster.
 
I'm waiting for my dealer to call back.

(Should be used to that, LOL)
 
Charlie, I can't say I know you, but I do remember a few of the struggles I've read about you facing this year... And I'm truly glad to see you doing so well.

Congrats on the new house and the new mill...

-Eric
 
12345678910 said:
The variable speed is usually $1,000 more than the pulley drive.


If I had to choose betwen DRO and variable speed, I'd go dro.

How often do you really have to change speeds ?



plus I'd choose the vfd variable speed over the snowmobile pulley variable speed.
apparently those variable pitch pulley mechanisms wear faster.
Click to expand...

I agree. You probably won't have to change speeds often enough to realize a significant amount of time savings / convenience with the variable. I seriously doubt that changing a belt location will take you more than a few seconds when you get used to it.

Another thing to consider: You can by a heck of a nice VFD for less than half of what the variable "upgrade" costs, and with a VFD, you won't need to spend big money on a rotary phase converter.

Whichever route you decide to go, DO NOT go with a static phase converter.
 
Why no static?
 
A static phase converter really isn't a "phase converter". It's really just a 3 phase motor starter. You'll then essentially be running a 3 phase motor on single phase power, which not only cuts your power (torque) significantly, but it's really not good for the motor, especially if you're gonna be running close to your full load on the motor.

A rotary phase converter will give you true 3 phase power.

A VFD will give you "simulated" 3 phase power, as well as the ability to easily change speeds (well, really it changes frequency, which affects speed).
 
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I absolutely agree that a DRO should take priority over variable speed. The only thing that comes close to the usefulness of a DRO is maybe a vise. I also agree that a static phase converter is not a good idea. I do however feel that investing in a good rotary phase converter is worthwhile. One RPC can be setup to provide power for the whole shop and opens up a lot of options for future machine purchases like a lathe and surface grinder. I even ran a VMC with a pallet changer on my 10hp RPC. I would go so far as to say, if it were me, I would get the step pulley speed control and a good RPC over a variable speed with a static PC or a VFD. Food for thought.

Bob
 
FWIW, a VFD can also be set up to run multiple machines, albeit not at the same time. You just need plugs and outlets, or a switch box.

Personally, I run a surface grinder and a mill from one 2HP VFD. That said, I don't ever change speeds from the VFD, as it's just as easy to change the belt position, as it is to remember to go back to 60Hz when I switch over to the SG.

Now for me, a RPC would be just as good, if not better, as it would alllow me to surface grind while I'm milling. I opted for the VFD solely for cost savings.
 
RangerBobTX said:
I absolutely agree that a DRO should take priority over variable speed. The only thing that comes close to the usefulness of a DRO is maybe a vise. I also agree that a static phase converter is not a good idea. I do however feel that investing in a good rotary phase converter is worthwhile. One RPC can be setup to provide power for the whole shop and opens up a lot of options for future machine purchases like a lathe and surface grinder. I even ran a VMC with a pallet changer on my 10hp RPC. I would go so far as to say, if it were me, I would get the step pulley speed control and a good RPC over a variable speed with a static PC or a VFD. Food for thought.

Bob
Click to expand...

If Matt is buying this new, he can probably just order the single phase 220v with step pulleys and dro

Then it's plug plug and play in his residential power.

No phase converters needed.
 
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