[jhsmith]

Bored during COVID and running out of other projects, so .... Looking for a small milling machine to learn about machining. Grizzly, LittleMachineShop, etc. What is my definition of small? Small enough so I can move it into my garage without renting a forklift. Yes, that rules out a Bridgeport. Perhaps, one of the 350W desktop minimills all the way up to a 400 lb./1 HP machine. DRO would be nice. Included tooling wood be nice. Anybody seen a used one for sale at a good value?

[BillC]

Originally Posted by jhsmith

Bored during COVID and running out of other projects, so .... Looking for a small milling machine to learn about machining. Grizzly, LittleMachineShop, etc. What is my definition of small? Small enough so I can move it into my garage without renting a forklift. Yes, that rules out a Bridgeport. Perhaps, one of the 350W desktop minimills all the way up to a 400 lb./1 HP machine. DRO would be nice. Included tooling wood be nice. Anybody seen a used one for sale at a good value?

I moved my Bridgeport into my garage without a forklift. As long as your garage floor is pretty flat, it's actually quite easy to do with a helper or two. The only equipment you'll need are four cast-iron pipe sections, about 2 feet long and about 1 inch in diameter (readily available at Home Despot). Then, you just roll it in on the pipes. You can turn the mill by changing the angles of the pipes. The key is to take your time and don't rush anything.

I have used bench-top mills, and once you use a full-size machine, you'll never want to go back to a dinky unit.

If you're interested in a full-size mill, contact me privately and I may be able to provide some leads.

Also, believe it or not, eBay can be a good source (for both full-size and bench-top mills). I found my mill on eBay, and it turned out to only be about 6 miles from here, so it was very easy to ship -- just got a flatbed tow truck to haul it from its old location to mine.

[jhsmith]

Bill,

I've gone back and forth on the mini mill vs a full size bridgeport. I could be talked into either given the right deal. I worry that I don't know how to do a pre-buy inspection well enough on a large mill so there is less risk to me with a smaller mill. The other issue is moving it into my basement. I can't get a vehicle with a liftgate back there. Last time I got a tool delivered, I transferred it to a trailer then struggled to get the trailer into the right spot. Prior to that I used a bucket on a borrowed tractor but that tractor is limited to 600 lbs. So it doesn't have to be a benchtop mill but a 3000 lb. Bridgeport will be difficult. Once the mill is on the basement floor, I'm sure I can get it in place.

So, twist my rubber arm to buy a Bridgeport, but you (and 6 other guys) need to help me get it in place. Any volunteers?

Jim

Originally Posted by BillC

I moved my Bridgeport into my garage without a forklift. As long as your garage floor is pretty flat, it's actually quite easy to do with a helper or two. The only equipment you'll need are four cast-iron pipe sections, about 2 feet long and about 1 inch in diameter (readily available at Home Despot). Then, you just roll it in on the pipes. You can turn the mill by changing the angles of the pipes. The key is to take your time and don't rush anything.

I have used bench-top mills, and once you use a full-size machine, you'll never want to go back to a dinky unit.

If you're interested in a full-size mill, contact me privately and I may be able to provide some leads.

Also, believe it or not, eBay can be a good source (for both full-size and bench-top mills). I found my mill on eBay, and it turned out to only be about 6 miles from here, so it was very easy to ship -- just got a flatbed tow truck to haul it from its old location to mine.

[jbailey930]

Capt Obvious - get Charle to find your mill!

[BillC]

Originally Posted by jhsmith

Bill,

I've gone back and forth on the mini mill vs a full size bridgeport. I could be talked into either given the right deal. I worry that I don't know how to do a pre-buy inspection well enough on a large mill so there is less risk to me with a smaller mill. The other issue is moving it into my basement. I can't get a vehicle with a liftgate back there. Last time I got a tool delivered, I transferred it to a trailer then struggled to get the trailer into the right spot. Prior to that I used a bucket on a borrowed tractor but that tractor is limited to 600 lbs. So it doesn't have to be a benchtop mill but a 3000 lb. Bridgeport will be difficult. Once the mill is on the basement floor, I'm sure I can get it in place.

So, twist my rubber arm to buy a Bridgeport, but you (and 6 other guys) need to help me get it in place. Any volunteers?

Jim

Well, you just changed the requirements. In your first post, you said "garage", now you're saying "basement".

If it's going in your garage, it's a fairly simple process to roll a Bridgeport or clone into place from the driveway. If it's going into your basement and the basement doesn't have a walk-in entrance with a wide door, that is definitely going to be more work. You might be able to find a rigger to move and install it for you, but it won't be cheap.

One other consideration is power. Most benchtop mills take 120 VAC single phase power. Every Bridgeport I've ever used required 220 VAC 3-phase, so you'd need to add the cost of a 3-phase converter and installation.

[jhsmith]

He (Charlie) is working on it. (And he agrees with Bill, bigger is better.)

Originally Posted by jbailey930

Capt Obvious - get Charle to find your mill!

[jhsmith]

Bill,

You are correct, I should have been more specific. The basement to my garage is also a garage with a 10 ft wide by 9 ft high door. But it is down a slippery slope and requires 4wd to get there. No driveway (long story, lots of arguing with the county, no driveway to the basement just some grass and gravel). My 911 can get down there (and back up) with an LSD, but my Miata with a Torsen Diff struggles and at times requires a tow. So, I could get a liftgate delivery and let the driver worry about getting towed back out of there (but I think I'm more kind than that.)

The garage basement has overhead trolley lifts that can hold 4000 lbs. It has a 9000 lb. Challenger lift and a cherry picker engine hoist. I've moved other equipment around in the 2000 lb range with metal dowels down there. But getting things to the threshold is the issue. I could rent a 4wd forklift, but that is less money to spend on the mill. I did borrow a neighbor's tractor to get some things in, but its bucket only handles 600 lbs. So, it is complicated.

For the accessible part of my garage, the first floor, I can't put large tools in. I made the space too nicely finished and my wife likes it for holiday get togethers and social distancing during COVID. Originally, much of this stuff was planned to go there but was relegated to the basement. I can still store cars upstairs but they have to move out during parties and holidays. Sorry if this sounds like whining, my lovely wife was kind enough to let me build this garage so I can't complain if she wants to use part of it from time to time. Most building projects are compromises...

You are also correct on power. Only 2 phase on our street. Nearest 3 phase was about 1500 feet away so I didn't even ask Dominion for the price to run it. I did get a separate 200amp feed (2 ph) for the garage. I'd need a 2 phase motor or a converter. I see there are capacitor-based converters, but I've never used one. Are they robust? Or would you use the old style motor/flywheel/generator?

Originally Posted by BillC

Well, you just changed the requirements. In your first post, you said "garage", now you're saying "basement".

If it's going in your garage, it's a fairly simple process to roll a Bridgeport or clone into place from the driveway. If it's going into your basement and the basement doesn't have a walk-in entrance with a wide door, that is definitely going to be more work. You might be able to find a rigger to move and install it for you, but it won't be cheap.

One other consideration is power. Most benchtop mills take 120 VAC single phase power. Every Bridgeport I've ever used required 220 VAC 3-phase, so you'd need to add the cost of a 3-phase converter and installation.

[BillC]

Originally Posted by jhsmith

Bill,

You are correct, I should have been more specific. The basement to my garage is also a garage with a 10 ft wide by 9 ft high door. But it is down a slippery slope and requires 4wd to get there. No driveway (long story, lots of arguing with the county, no driveway to the basement just some grass and gravel). My 911 can get down there (and back up) with an LSD, but my Miata with a Torsen Diff struggles and at times requires a tow. So, I could get a liftgate delivery and let the driver worry about getting towed back out of there (but I think I'm more kind than that.)

The garage basement has overhead trolley lifts that can hold 4000 lbs. It has a 9000 lb. Challenger lift and a cherry picker engine hoist. I've moved other equipment around in the 2000 lb range with metal dowels down there. But getting things to the threshold is the issue. I could rent a 4wd forklift, but that is less money to spend on the mill. I did borrow a neighbor's tractor to get some things in, but its bucket only handles 600 lbs. So, it is complicated.

For the accessible part of my garage, the first floor, I can't put large tools in. I made the space too nicely finished and my wife likes it for holiday get togethers and social distancing during COVID. Originally, much of this stuff was planned to go there but was relegated to the basement. I can still store cars upstairs but they have to move out during parties and holidays. Sorry if this sounds like whining, my lovely wife was kind enough to let me build this garage so I can't complain if she wants to use part of it from time to time. Most building projects are compromises...

You are also correct on power. Only 2 phase on our street. Nearest 3 phase was about 1500 feet away so I didn't even ask Dominion for the price to run it. I did get a separate 200amp feed (2 ph) for the garage. I'd need a 2 phase motor or a converter. I see there are capacitor-based converters, but I've never used one. Are they robust? Or would you use the old style motor/flywheel/generator?

The easiest thing is to just convince your wife that a Bridgeport is a wonderful example of modern industrial art and needs to be shared with your guests!

However, given that unlikely prospect . . . .

Do you think it might be possible to get a flatbed tow truck down there? Maybe with chains on the wheels? If so, load the mill on the flatbed and have it drive around to your basement garage. Then, just use the winch to slide it down the bed and into the garage, onto the rollers.

The static converters work okay, but will reduce the output of a 3-phase motor to ~2/3 of its rated value. If you want full-power out of a 3-phase motor, you really need a rotary converter. The size of your mill's biggest motor will drive the size converter you need -- basically, you want a rotary converter rated at least twice that of your biggest load. If you shop around, you can find a 5-HP rotary converter for about $500 and a 10-HP for under $1K.

[smdubovsky]

Originally Posted by BillC

The solid-state converters work okay, but will reduce the output of a 3-phase motor to ~2/3 of its rated value. If you want full-power out of a 3-phase motor, you really need a rotary converter.

BS. A modern VFD will not only match standard 3-ph input it will give you more top end speed, better low end torque & speed control, smooth reversing (think power tapping), and active braking (think safety). The only downside is that motor winding life might be a bit shortened on old motors as they aren't VFD rated (VFDs output high freq square waves which results in some capacitive current through the winding insulation.) For hobby use this is a non-issue if the motor isn't already close to failure.

[BillC]

Originally Posted by smdubovsky

BS. A modern VFD will not only match standard 3-ph input it will give you more top end speed, better low end torque & speed control, smooth reversing (think power tapping), and active braking (think safety). The only downside is that motor winding life might be a bit shortened on old motors as they aren't VFD rated (VFDs output high freq square waves which results in some capacitive current through the winding insulation.) For hobby use this is a non-issue if the motor isn't already close to failure.

No, not BS. He asked about "capacitor-based converters", and what I said above was correct -- a normal, capacitor-based static converter reduces motor output to ~2/3 of rated power. And, a properly-sized rotary converter will support full-power output from a motor.

A VFD can also work, but was outside the scope of the discussion. If you want to give advice on choosing and setting up a VFD, go right ahead.