Need Help: Choosing a mill

You seem to be on the right track. I would recommend a belt-change mill rather a vari-drive due to lower pricing and greater simplicity. Vari-drive is a very nice feature and important in a commercial shop, but it adds complexity and expense in case of repair. I have a Kent 9x42 belt-change machine. It is a BP clone in every respect except it has a 2-speed motor, which is a very nice upgrade and common on many clones. If at all possible, avoid round-ram machines, get a dovetail ram, which allows adjustment without losing tram.
 
Don't let finding a 3-Phase stop you. If you have a 220 input, a torque controlled VFD with 3-phase output from a 220V single phase input making a 311V bus can be the fix, and you get high torque slow speed as well.
 
MrWhoopee said:
You seem to be on the right track. I would recommend a belt-change mill rather a vari-drive due to lower pricing and greater simplicity. Vari-drive is a very nice feature and important in a commercial shop, but it adds complexity and expense in case of repair. I have a Kent 9x42 belt-change machine. It is a BP clone in every respect except it has a 2-speed motor, which is a very nice upgrade and common on many clones. If at all possible, avoid round-ram machines, get a dovetail ram, which allows adjustment without losing tram.
Click to expand...

I'm in the opposite camp as far as vari-drive versus step pulley. I've had a 1974 Series I Bridgeport with the vari-drive for nearly 20 years. I do a lot of different materials and find the vari-drive much more convenient that a step pulley machine. Granted they are a bit more complex, and probably a bit more expensive to repair should they fail. However mine is now over 46 years old, it's used on a daily basis, and still is completely original.

As for 3 phase I wouldn't avoid it. My machine has been running on a Phase A Matic static phase converter ever since I put it in the shop. As mentioned I run it on an almost daily basis. Some weeks as much as 40 to 60 hours. Static converters are cheap and easy to install. The only caveat is that the motor will only produce about 2/3 its rated hp. With a static converter a set of capacitors provides the third leg until the motor comes up to speed. Then it drops out and essentially the motor is running on single phase. In 20+ years of running my mill on a static converter I have never had a lack of power or problem with overheating.

I have 4 machines in the shop running on static converters. They include the Bridgeport mill, Sheldon, lathe Racine power hacksaw, and Black Diamond drill grinder. I have no problem with a VFD. In the case of my machines I thought the static converters were a better choice. They allow all functions including speed changes to be done with the original control panels, and without rewiring any machine components. It takes all of 15 minutes to install a static converter, and they are all but bullet proof.
 
Can't go wrong with a Bridgeport style mill for a home shop. The only downsides to me are size and price. If those work for you, they are great. I can only personally speak for the Bridgeport brand, but I haven't heard anything bad for the clones. https://www.machinerypartsdepot.com/parts_for_bridgeport is a great source for parts and they will often provide advice as well. The repair manual they sell for the BP Series 1 is also quite nice. Most parts are even still available new. There are a LOT of these mills out there. So long as the ways are in decent shape, you can fix anything else.

Just about anything this size will be 3 phase, unless someone already swapped the motor out. For my step pulley machine, I use an import VFD. <$100. It works great and I can run anywhere from 20%-200% speed without issues. With that and the back gear, I don't have to change the belt position. I just keep it in the 2nd fastest speed 90% of the time. My mill actually has 2 of them, one for the power feed as it's the old style with a small 3 phase motor and a gearbox on X. The only complication was the control setup, but that's just a little wiring and a few switches. If you would prefer to stick to the stock switches/controls, a static or rotary converter is a good choice.
 
projectnut said:
I'm in the opposite camp as far as vari-drive versus step pulley. I've had a 1974 Series I Bridgeport with the vari-drive for nearly 20 years. I do a lot of different materials and find the vari-drive much more convenient that a step pulley machine. Granted they are a bit more complex, and probably a bit more expensive to repair should they fail. However mine is now over 46 years old, it's used on a daily basis, and still is completely original.

As for 3 phase I wouldn't avoid it. My machine has been running on a Phase A Matic static phase converter ever since I put it in the shop. As mentioned I run it on an almost daily basis. Some weeks as much as 40 to 60 hours. Static converters are cheap and easy to install. The only caveat is that the motor will only produce about 2/3 its rated hp. With a static converter a set of capacitors provides the third leg until the motor comes up to speed. Then it drops out and essentially the motor is running on single phase. In 20+ years of running my mill on a static converter I have never had a lack of power or problem with overheating.

I have 4 machines in the shop running on static converters. They include the Bridgeport mill, Sheldon, lathe Racine power hacksaw, and Black Diamond drill grinder. I have no problem with a VFD. In the case of my machines I thought the static converters were a better choice. They allow all functions including speed changes to be done with the original control panels, and without rewiring any machine components. It takes all of 15 minutes to install a static converter, and they are all but bullet proof.
Click to expand...

I also would prefer to USE a vari-drive, but I would prefer to REPAIR a belt-change.

Do not shy away from 3 phase machines. They produce more power and tend to cost less due to reduced demand in the hobbyist market.
I am also using a static phase converter. This one:
phaseconverterusa.com

MAC05-3/4 - 5Hp HD MAC Static phase converter

phaseconverterusa.com

I am entirely happy with it, though the fact that my mill is 2hp and lathe is 1hp complicates matters somewhat. I will probably get a second one to dedicate to the lathe. I also have a 7.5hp rotary phase converter. I HATE IT! It consumes more power than all of 3 of my 3 phase machines combined and WHINES INCESSANTLY! It was retired after my wife saw the first month's electric bill. It's for sale if anyone is interested.
 
To be precise, I am NOT against 3 phase, at all.

That being cleared up :)

Are there specific BP model numbers (types?) that I would want to gravitate toward, i.e. how could I tell if it was vari-drive or has a dovetail ram by the model name or number? Or do I just need to look at pictures - those are hard to search on.

Are there BP clones out there that just suck for parts? That part is important to me, as I wouldn't shy away from a mill that was broken, but just needed some parts.

Or should I play it safe and stay BP brand only?
 
Here's an example of one that I found online. But I can't tell anything about it. Is there a serial number database?

20210120113600420_L.JPG


Here's another. What's the downside of the ram vs dovetail for the head?

20201216141523251_L.JPG
 
MyLilMule said:
Here's an example of one that I found online. But I can't tell anything about it. Is there a serial number database?

20210120113600420_L.JPG
Click to expand...
This is a vari-drive machine, indicated by the circular speed dial and small adjusting wheel on the front of the head. By the time the vari-drive appeared, they were all dovetail rams.
I can't speak to serial numbers, nor parts availability for clones.

Unless you are in a particularly machine rich area, your decision will likely be determined by what is available within range.
 
MrWhoopee said:
This is a vari-drive machine, indicated by the circular speed dial and small adjusting wheel on the front of the head. By the time the vari-drive appeared, they were all dovetail rams.
I can't speak to serial numbers, nor parts availability for clones.

Unless you are in a particularly machine rich area, your decision will likely be determined by what is available within range.
Click to expand...
I'm just outside of Cleveland, OH. Very machine rich. Most of the machines I have been looking at are in the $1500-$2500 range. But they come with nothing but the mill.
 
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