The Heart of a Lathe

[Mark Lindquist]

Here is a video about changing out an old US Motors Vari Drive Gear Motor with a Baldor 3 HP 180 Volt DC Motor and custom controllers. I've used the old motor for over 35 years. The belt in the sheave drive was slipping at low rpm's, then catching and quick-accelerating, something I couldn't abide with 2ft plus diameter x 6ft plus pieces. So I finally changed the motor out. The second part of the video is testing the new motor and drives and using a new tool. I've always been interested in the sounds lathes make and I experimented with slow motion and the rhythms of the machine cutting wood. Some may find part 2 tedious, others may enjoy the music. -Mark

View: https://m.youtube.com/watch?v=nBzZtM2ItAA

PS - Video is best at 720 HD and played with a good monitor and speakers.

 

[olaf Vogel]

That's a beautiful conversion of a great old lathe (is it an Oliver 20?).
Thanks for sharing the details. Beautifully done. And an impressive set tooling in your shop.

I had looked at using a large commercial DC motor, but balked at the cost of these and the difficulty of sourcing these on the used market.

I'm also surprised that you are using a hook tool to do the roughing, but it is an impressively robust hook. Thanks for the video!

 

[Mark Lindquist]

Hi Olaf-
Thanks for your kind words. I never have been able to determine who the maker of the lathe is.

I got an amazing deal on the motor by buying it on eBay. There was a brand new 3 HP permanent magnet DC motor branded Emerson. I knew enough that another company made the the motor and after doing a lot of research, found that everything looked the same as a Baldor. Since the price was very reasonable ($295.00) + shipping, I thought I would take a chance on it. When it got here, sure enough it was made by baldor, repainted blue and re-branded. There was a break in the end fan cover, either from shipping or an original damage. I removed the fan, and hacked a tachometer/generator add-on by drilling and tapping into the end housing where there were luckily corresponding pilot holes that fit the bolt circle of my tach/gen. I bought 4 spacers and 4 stud bolts from McMaster Carr, did some machine work on a connecting shaft, and was able to couple the tach/gen to the motor. The tach gen provides closed loop feedback control to the controller with greater speed regulation, as the controller provides increased current and constant torque, particularly at low rpm's.

This motor lists for $3,000+ new. The seller hads a 100 percent feedback and was just looking to offload excess new old stock from their inventory. So I got lucky, and knew enough to take a risk buying it.

I've retrofitted the lathe with DC motors and controllers. Since I jacked it up to increase capacity very early on, and it's really a workhorse, I haven't been too concerned about cosmetics or aesthetics in making modifications. The main reason for using this lathe and retrofitting it is because of the exceptional vibbration free characteristics of the cast iron bed and legs. Also, the shaft is 2 -1/2" diameter and has #4 Morse taper, as does the tailstock.

The hook tool is a copy of an original that came with a Yates American 8' diameter inboard capacity pattern maker's lathe that I also have. A local machinist reworked the original design and milled the tool and heat treated the tool steel. I have subsequently done much more shaping and sharpening of the cutting edge and it's now cutting really well.

 

[William Rogers]

That is impressive Mark. It must have been a real joy when you completed that conversion. What a lathe, thanks for the video.

 

[Charlie Knighton]

Tks for the viedo.....what final form did you shape the box elder ???????

 

[Mark Lindquist]

Tks for the viedo.....what final form did you shape the box elder ???????

I roughed out 3 bowls that are currently drying. There is a technique in pottery making called "throwing off the hump" Where multiple forms come from the same mound of clay. With the piece still held between centers, I turned and mostly hollowed 3 simple footed bowl forms. Sawing through the small diameter sections holding the bowls together was a simple task, and I just put them back together in the shavings in a plastic bin. When they are good and dry, I'll finish them.

The Flame Box Elder was sent to me as a gift by a friend, Kevin Jaynes, just before he passed away.
I had planned on using the cylinder for part of a sculpture, but decided to turn the bowls in rememberance of Kevin instead.

 

[Gerald Lawrence]

A very interesting video, although aside from the sound there is a part like watching paint dry. You could use that sound to make a pop hit for sure. I have a question that I did not see/or understand. How do you advance the tool and is the holder locked down on the lathe?

 

[Mark Lindquist]

Watching paint dry? Maybe like watching grass grow Gerald, LOL. Fair point.
I've already done a lot with the sound track. Admittedly it's long, but that has helped me in other projects. This was a beginning and has become a good jumping off point.
I'm working on a low profile cross slide - trying to keep it as tight and low as possible.
At this point I just use a mallet and thump the end of the tool. It causes the front of the tool to pivot around and take a deeper bite. Experience has shown me how much to bump it. This method is so simple yet surprisingly fast and effective.
When I need to reset for any reason, I just unlock the tool holder and reposition the cutter, just like you would reposition a banjo and tool rest.

 

[Mark Lindquist]

Answering further Gerald's questions about the tool holder, here is another video that shows the tool holder and tool. This thing works amazingly well on green wood - fresh cut holly in this case.
I had reground the incannel of the hook tool and sharpened it more carefully.

View: https://m.youtube.com/watch?v=IWduEWYwd1o


About half way into the video, the tool cuts an endless stream.
For any of you who don't pick up on it at the beginning of the video, the guy shown is our oldest son Ben, who was visiting from Washington, DC.

 

[Charlie Knighton]

more cowbell

 

[Mark Lindquist]

more cowbell

Ba ha ha ha!!!

 

[olaf Vogel]

I've retrofitted the lathe with DC motors and controllers. Since I jacked it up to increase capacity very early on, and it's really a workhorse, I haven't been too concerned about cosmetics or aesthetics in making modifications. The main reason for using this lathe and retrofitting it is because of the exceptional vibbration free characteristics of the cast iron bed and legs. Also, the shaft is 2 -1/2" diameter and has #4 Morse taper, as does the tailstock.

The hook tool is a copy of an original that came with a Yates American 8' diameter inboard capacity pattern maker's lathe that I also have. A local machinist reworked the original design and milled the tool and heat treated the tool steel. I have subsequently done much more shaping and sharpening of the cutting edge and it's now cutting really well.

Well I'm hearten to see that even the very well known professional turners still build there own solutions.
Looking through the video, you have a VERY impressive and enviable collection of tooling. The big Yates is awesome.

I'm particularly impressed by the amount of different tools, retrofitted in ways not originally intended, so they can create shapes and patterns way outside the norm. Extremely innovative, both creatively and technically.

Since you fit all the electronics onto the DC motor, does that allow you to use it as a positioning motor? i.e. instead of an indexing wheel?

I know DC motors are known for low end torque and you seem to have eliminated all other gearing. Simple.
Torque is the reason I was looking at them, since I do large diameters. I've finally settled on a 5 hp, 8 pole motor, running at 880 rpm (I call it the Hemi), with a 3 spd transmission. But its complicated and loud.

From looking at your second video, your doesn't seem to have a feed mechanism integrated with the main drive, but its clearly self feeding. So I suspect you have a secondary gear motor running the feed? And possibly a reversing trigger on either end?

Thanks again!

 

[Charlie Knighton]

Well said Olaf......I had wondered about that myself.....the feed was to steady to be manuel, but I am not knowledgeable enough to ask what was being done.....this is interesting.....just need a barn find now

 

[Mark Lindquist]

Olaf and Charlie,
The lathe has a simple carriage or saddle like a metal lathe, but with just a simple T-Slot running the width of it. It was powered originally by a hand wheel running a rack and pinion gear set.

Years ago I replaced the hand wheel with a right angle DC gear motor. It is somewhat cumbersome and hangs down off the shaft that goes to the pinion gear. I have a separate DC controller that powers that gear motor.

So finally, there is the main DC motor controller,

then a simple on off push button switch in its own box with a length of cord that controls relays on the main controller.

Finally, there is an additional controller that is for running the carriage (saddle) up and back.
That controller has on, off, forward/reverse and speed. So three boxes with cords to control the whole shebang.

I usually have only the on/off switch tethered to the carriage. They all have magnetic bottoms so they can stick wherever I put them. I'll try to find photos and will show you.

 

[Mark Lindquist]

Well I'm hearten to see that even the very well known professional turners still build there own solutions.
Looking through the video, you have a VERY impressive and enviable collection of tooling. The big Yates is awesome.

I'm particularly impressed by the amount of different tools, retrofitted in ways not originally intended, so they can create shapes and patterns way outside the norm. Extremely innovative, both creatively and technically.

Since you fit all the electronics onto the DC motor, does that allow you to use it as a positioning motor? i.e. instead of an indexing wheel?

I know DC motors are known for low end torque and you seem to have eliminated all other gearing. Simple.
Torque is the reason I was looking at them, since I do large diameters. I've finally settled on a 5 hp, 8 pole motor, running at 880 rpm (I call it the Hemi), with a 3 spd transmission. But its complicated and loud.

From looking at your second video, your doesn't seem to have a feed mechanism integrated with the main drive, but its clearly self feeding. So I suspect you have a secondary gear motor running the feed? And possibly a reversing trigger on either end?

Thanks again!

Thanks Olaf. I added photos to the post above.

I mostly build/retrofit older machines because of the build quality, plus the materials used and to keep costs down.
I have worked with DC motors and controllers for over 20 years and know enough to get by. It turns out that IR Comp and Torque adjustments of certain controllers enable a tremendous amount of constant torque at low RPMS's - you just have to know how to tune them under load.

Fitting a tachometer/generator does significantly enable constant rpm's and extreme torque at low RPM's:

I quit using gearing and sheave pulley systems and have just determined the speed range from low to high that I need and have instead used as small a pulley as possible on the motor and then try to double the diameter on the shaft. That enables a better ratio and significant low end speed/torque advantage with the tach/gen setup.

This is a four quadrant closed loop system with the tach/gen hack, but it doesn't allow for positioning and indexing.

I do have that capability on the Yates pattern makers lathe however.

On this lathe, I have simple 2P2T (double pole double throw) reversing switches.

These controllers do not do plug reversing (instant and immediate reversing), but it's no big deal to simply stop and throw a toggle switch to reverse.

I do try to make things very simple and direct. DC motors and controllers can be profoundly powerful in the right circumstances, but also really frustrating if you don't know what you're doing.

There are two types of people who do electronics:

Those who use fuses, and those who will.

-Mark

Modification edits.

 

[Charlie Knighton]

I take it if there is not a fuse to blow there is a motor to blow......fuses are cheap....great tip for us in the below beginner grin stage

 

[john lucas]

I remember the first turner I saw who was turning large work was using the rear end of a car as his lathe. Had the whole rear end and axle mounted on an I beam. He ran it with a large motor of some sort but used a lawn mower transmission to change the speeds. He was doing 3 foot hollow forms using a tool he made from a lawn mower blade. That was up in Beersheba Springs Tn probably around 1980. Don't remember the guys name.

 

[Mike Brazeau]

Mark, I welcome your particpation here at the AAW forum and hope you find time to stop by often. After buying a used Delta Homecraft lathe when I got my first house in 1969 and using it infrquently, I started my born again phase of turning about 20 years ago and discovering your article about spalted wood in an early FWW book of turning articles was part of that restart. Yesterday I had booted up a YouTube video about something on my iPad and saw a link to your Heart of a Lathe video, which I had seen in your posting earlier. It was a lazy Saturday morning and the rhythmic sound of your modified hook tool was perfect accompaniment to my morning coffee. Kept saying to myself, this could be done quicker with a spindle roughing gouge but suppressed the thought and watched and listened until the end. Keep your videos coming.

 

[Mark Lindquist]

Hi Mike,
Thanks for your comments, much appreciated. Actually I do stop by often, and I have in the past as well, just haven't been moved to participate. Forum participation is the issue, especially as discussed in the recent thread on the same topic.

Glad to hear that my early articles on spalted wood had an influence. They were very early in the inception of FWW Mag, like 1977, and '98. My article on harvesting burls came out a few years later.

So The Heart of a Lathe video (second part) was for kicks - something I have been toying with for a long time, playing with lathe sounds. In reality, I was testing both the new DC motor install, especially wanting a long time use of the motor to check for any overheating issues. The gouge was new and really had not been broken in at all, and the wood was not green, so it didn't cut dramatically. The video is overly long because of the slow motion recording. Later, on another occasion, when my son was visiting, we played with a freshly cut holly log and I properly ground the incannel of the hook tool, and oh boy, huge difference. I now know that that combination is capable of serious performance.
If you check out the next video, which was done just for fun, you'll see what I mean, as the tool produces an endless stream of shaving, and huge cuts in roughing.

Currently, I'm working on a major video series called "Spalted Wood" based on Dr. Sara Robinson's recent visit to our home and studio a few weeks ago. Her book, Spalted Wood is selling world wide and is available on Amazon in case you haven't seen it.

Mark

Here's the link to the second video showing the super performance of the hook tool (probably posted it earlier). I would prefer to just link to youtube, but it seems to put the video in automagically.

View: https://m.youtube.com/watch?v=IWduEWYwd1o

 

[Zach LaPerriere]

Thanks, Mark, for sharing the videos and photos of your inspired lathe and the inner guts. I'm following with the eagerness of a teen watching an old Mustang go back together, though I doubt I'll ever be doing that level of engineering.

It's such a beautiful thing seeing the love of both tradition and innovation in the shaping of wood.

 

[Mark Lindquist]

Thanks, Mark, for sharing the videos and photos of your inspired lathe and the inner guts. I'm following with the eagerness of a teen watching an old Mustang go back together, though I doubt I'll ever be doing that level of engineering.

It's such a beautiful thing seeing the love of both tradition and innovation in the shaping of wood.

You hit the nail right on the head, Zach. Tradition/Innovation - it's what we all do the moment we put hand to tool. Well put.
Mark

 

[Mike Brazeau]

Thanks Mark. A few years ago, we hosted Sara at our guild when she was doing her first Post Doc at the Faculty of Forestry at the Unversity of Toronto. I had the peasure of picking her up in Toronto and thanks to slow traffic we had lots of time to chat. I live in a White Pine grove and have a great natural spalting yard due to all the shade. Have some hard maple in fact I need to get at and see what is happening to it. I have to say that all the various people I have encountered in wood turning through guild leadership and various web forums and AAW participation has made my retired life far more interesting than I ever imagined. Yours is one of those memorable times.