Menu
What's new

Shop built bowl lathe

Not meaning to hijack this thread but I do have a question concerning something that has been mentioned. I am quite familiar with electronics and circuitry, and with 120/220 home wiring. But when the talk is about 3 phase, I am lost. My question, well 2 actually, is what is the differences and why would I want to switch between a 2hp single phase motor and a 2hp 3ph? And I take it a "VFD" is some type of converter so one could run a 3ph on single? So how does one go about figuring out what size VFD they'll need. My curiosity is up since it was mentioned about 3ph motors being cheaper!! Cheap is one of my favorite 5 letter words!!!
 
Last edited:
Okay, here is the home made lathe from the UK I mentioned earlier. Since my scanner and PC are having a few differences in opinion, I just took a picture of the picture in the article.

Found in the September issue of Woodturning (UK). Marion Randolf is the turner. Specs from the article: The lathe will turn up to 38" diameter bowls. 2hp 220v. 2 speed ranges, low= 53-155rpm and high= 220-645rpm. He used a 3 speed transmission from a lawn mower to have 3 speeds in each range plus reverse. 2 1/4" shaft mounted in pillow blocks. 8" face plate. 700lbs of lead ballast (obtained from indoor shooting galleries) and can handle over 300lb pieces without difficulty. He says in the article that he does have an older 12" Powermatic (cropped out of pic) for turning, uh, smaller bowls!!!

2008-10-18_200803_DSCN9708.jpg
 
Greg Cozad said:
Not meaning to hijack this thread but I do have a question concerning something that has been mentioned. I am quite familiar with electronics and circuitry, and with 120/220 home wiring. But when the talk is about 3 phase, I am lost. My question, well 2 actually, is what is the differences and why would I want to switch between a 2hp single phase motor and a 2hp 3ph? And I take it a "VFD" is some type of converter so one could run a 3ph on single? So how does one go about figuring out what size VFD they'll need. My curiosity is up since it was mentioned about 3ph motors being cheaper!! Cheap is one of my favorite 5 letter words!!!
Click to expand...
I can answer a some of this, but I'll leave other parts for the guys who know more about it than I do...

A VFD is a Variable Frequency Drive. In the case of lathes, the VFD provides two things: A way to plug a 3 phase motor into a single phase 220v outlet, and a variable speed controller for the motor. VFDs are rated based on the number of horsepower they can control, so you'd just need to get one that matches or exceeds your motor's horsepower. Here are a few to read about.

In addition to costing less (especially in the used market), 3 phase motors also have better torque, I believe.

BTW, nice-looking refurb on the Delta, Mike. :thumb:
 
M Toupin said:
Bart, there's more to it than just grabbing some bearings and metal rod. Bearings need tight tolerances to run true. A press fit for bearings are generally between .0003 and .0005. You're not going to find those tolerances at the metal rack of your local borg. You might get away with some pillow blocks and a piece of rod for a small spindle lathe, but a large chunk of out of balance wood is going to raise havoc with a sloppy bearing fit and cause you nothing but grief. That puts you right back to machining issue and cost.

Look at the article on the shop built lathe Greg showed. The builder, who obviously has a bit of fabrication knowledge, used a reclaimed Rockwell headstock. There's a reason for that, it's just not cost effective to try and make your own unless you have the proper machines to do the machining on hand.

Your 3hp, 3ph unisaw motor would have plenty of power, but it has a proprietary mounting system. You'll have to engineer a mounting system for it, which is ok, but consider this. If the motor goes bad in the future then you'll either have to find another uni motor or rework the existing mount. Used 3ph motors are cheap, check junk yards and scrap dealers in your area. I paid $20 for a 2hp 3ph motor new in the box. They go cheap, basically for scrap prices because there's no market for used 3ph motors.

A 2-3hp VFD will run you around $145-$185 for a FM50. You can scrounge a cheaper one, but it's buyer beware... Controls can run you anywhere from a few bucks for cheap radio shack toggle switches to stupid prices for off the shelf commercial solutions.

Steel can be had fairly cheap from scrap dealers and junk yards. You'd be amazed what industry throws away.

I acquired and referbed a Rockwell/Delta 1460 with a 2hp, 3ph motor and VFD for right at $200. I had some of the parts on hand like the tubing for the base and an old base, wire, wood for the box and several of the switches which kept the cost down. I think you could reasonably scrounge all the parts from scratch for a lathe like the one in Greg's post for around $350 to $500 (with a new VFD) with some careful scrounging.

Mike

View attachment 24742
Click to expand...


Mike can you shed some light on your picture for me. I see you have your lathe mounted on a mobile base. How does that work out for keeping it solid when turning something heavy. I am way behind all you guys in this post, I bought one of those lathes mentioned ealier in the post like the one from Grizzly except from Busy Bee which is the local supplier here. I ended up with sheet metal legs that rattle. I have wanted to mount this cast iron base on a bench but have woried about how solid the whole thing needs to be. Can anyone shed some light on this topic for a newbie.
I would love to do away with the sheet metal legs.

Thanks for the interesting post here guys. I am definitely going to put a welder on my shoping list.
 
Rob Keeble said:
Mike can you shed some light on your picture for me. I see you have your lathe mounted on a mobile base. How does that work out for keeping it solid when turning something heavy. I am way behind all you guys in this post, I bought one of those lathes mentioned ealier in the post like the one from Grizzly except from Busy Bee which is the local supplier here. I ended up with sheet metal legs that rattle. I have wanted to mount this cast iron base on a bench but have woried about how solid the whole thing needs to be. Can anyone shed some light on this topic for a newbie..
Click to expand...

The mobile base was a matter of necessity, I have a 1 car garage packed with commercial duty old iron machines. That means there's little working room and anything that can be moved needs wheels. As you can see, 50% of my "shop" is driveway. I'll be the first to say that a mobile base on a lathe is not a the optimum. If I had my way it would be bolted to the floor, but that's just not an option with my current setting. The mobile base does work well if you work within the limitations. Most important is to keep the speed down on out of round blanks until you get it round/balanced. The VFD makes this possible, my speed range is literally zero to 4800rpm. I've turned 12" green bowl blanks over the bed and 24" platters outboard with that lathe. Careful speed selection and care on mounting your blanks goes a long way in reducing vibration from the beginning and keeps from beating up your machine too.

Mike
 
M Toupin said:
The mobile base was a matter of necessity, I have a 1 car garage packed with commercial duty old iron machines. That means there's little working room and anything that can be moved needs wheels. As you can see, 50% of my "shop" is driveway. I'll be the first to say that a mobile base on a lathe is not a the optimum. If I had my way it would be bolted to the floor, but that's just not an option with my current setting. The mobile base does work well if you work within the limitations. Most important is to keep the speed down on out of round blanks until you get it round/balanced. The VFD makes this possible, my speed range is literally zero to 4800rpm. I've turned 12" green bowl blanks over the bed and 24" platters outboard with that lathe. Careful speed selection and care on mounting your blanks goes a long way in reducing vibration from the beginning and keeps from beating up your machine too.

Mike
Click to expand...

Thanks Mike for the feedback.
 
You must log in or register to reply here.
Top