Monster Lathe Update #5,000

[David DeCristoforo]

I got the switch and potentiometer moved up to the front of the tower. The way I have the motor hung, the controls are on the bottom of the box and even if they were on the top, it's still on the back of the lathe and totally out of reach. I talked to the tech support guy at Dynamotor and it turns out to be a pretty simple job requiring only some cat5 cable which is routed through the wire chase Mark built into the tower:


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One look at the inside of the box and you immediately recall Ringo Starr saying "This is not your fathas Oldsmobile!" The motor is controlled by an onboard microprocessor which you can see here:


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This motor is also configurable via a computer interface (see the ethernet ports up there on the right?) so things like braking torque are "user configurable" I haven't got that far yet but the tech guy told me that braking is set to zero by default. You have to reconfigure it if you want electronic braking. Since I do not, I can leave that alone.


The controls are unnervingly small to "someone like me", used to big wires and heavy duty switches. But this is a "high tech" unit and incorporates a completely different set of rules. It's hard to think about that tiny pot and switch controlling a 1.5HP motor but that's technology I guess!


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I had to make up a cover plate for the switch box. My only "gripe" so far with Mark's design… the box is right between the motor mounts bolts and it's a bit congested…

[Rick Markham]

Look at that! That is certainly slick David. Very nice job for sure. The switch looks nice between those shiny bolts. So my question is, how does it sound? Is it "strange" or different in an unnerving way? Technology has come along way with brushless motors, certainly leaps and bounds when it comes to Electronic speed controllers. It will be interesting to see how this all turns out. <---(I'm ashamed of myself for that one)

[James Roberts]

Wow, David, you're really dabbling in the dark arts now. Computer interface, on board microprocessor, Ethernet ports. Like you said,"...not you fathers Oldsmobile...". You must be tantalizingly close to spinning some low tech lumber by now, I'm looking forward to pics of bowls and shavings and things on sticks from this beast.

[Josh Bowman]

David, I can't wait to say this any longer! "It lives"!!! Well almost. Really I can't wait to see the fantastic art you will produce with this thing. When will you plug it in?

[David DeCristoforo]

"When will you plug it in?"

Oh, I've already plugged it in. Runs too! But now i need to rearrange my space to fit it in (right now it's on a cart in the back yard) and get the tool rest made up. should not be long now...

I am working on a full review of the Dynamotor and I will try and include some sound/video. Little time... much to do!

[Dale Miner]

David,

Electronic braking is pretty nice. Without some type of braking, it takes a long time for a medium size bowl blank to coast to a stop.

[Sid Matheny]

Seems to be coming together nicely DD. Hope it keeps rolling forward and everything works out the way you want.

Sid

[Tim Rinehart]

David,

Electronic braking is pretty nice. Without some type of braking, it takes a long time for a medium size bowl blank to coast to a stop.
Pretty much what I was thinking too David. May want to at least get comfortable with what needs to change in the program to enable it, if you don't already know.
I like your progress so far...you sure haven't let any dust settle on it, that's for sure!

[David DeCristoforo]

Braking... now there's another topic for discussion. Pros and cons? I'm a bit leery of it after the chuck launching. The Titan has a "grub screw" to lock it down with but I have trouble seeing that tiny screw doing much to hold back a big blank if the motor stops suddenly. Thoughts?

"...you sure haven't let any dust settle on it..."

That could be taken in a number of ways! I'm going as fast as time will allow but I have not made any dust with it yet!

[Dale Miner]

Braking... now there's another topic for discussion. Pros and cons? I'm a bit leery of it after the chuck launching. The Titan has a "grub screw" to lock it down with but I have trouble seeing that tiny screw doing much to hold back a big blank if the motor stops suddenly. Thoughts?



Not sure of how your motor handles braking. Most VFD drives have the ability to control the rate of deceleration, and a 'sudden stop' is avoided by that parameter. The grub screw handles the braking on every lathe I've used. In fact, withouth the grub screw tightened (not a good idea), the chuck seldom comes loose if the chuck is tightend securely. Roughing the corners from a large blank does a pretty good job of 'securely' tightening the chuck.

Might be a good idea to talk to the motor supplier for information about braking and rate of deceleration.

[Reed Gray]

The only time I have had the chuck try to unwind is when I am hand sanding and put too much pressure on the piece. I don't use a grub screw either, just hand tighten onto the lathe.

robo hippy

[Don Orr]

I think you should seriously consider the electronic braking feature. You can set up how quickly or slowly the lathe will come to a stop. I think it would eliminate the flying chuck problem. Most new VFD lathes come with this feature these days. If I undestand it correctly the controller pushes current back into the motor to act as resistance to bring it to a smooth halt. (You probably know this already). I believe you can also set up how fast the lathe comes up to speed as well.

Your progress is impressive. This is fun to watch.

[Harry Robinette]

David
I have my Vega 2600 braking set at 4 on a scale of 1 thru 10. I always set the grub screw and haven't lost a piece of wood or a chuck with the screw tight. Now I have almost lost a 23" by 14" deep bowl blank when I forgot to tighten the grub screw it came to about 2or 3 threads of coming off. Mine was set to 1 when I bought it and it took for ever to stop a large "balanced" piece.
Hope this might help

[David DeCristoforo]

The tech guy is going to set me up with the computer software so I can "play around" with the settings. Braking will just have to wait till then and I will absolutely see how it works. But with "some caution" after the chuck launching!

[Olaf Vogel]

I'm guessing that your flying chuck was loosely threaded on.

Keep in mind that once you mount up a real piece, the chuck will automatically tighten up a fair bit.
The torque, force of cutting and the tiny bit of vibration will do the tightening.

I just found this out through experience.... just finished the largest piece to date and for the life of me can't remove the chuck. Have tried every trick in the book (well my book...) and the only solution I have now it to drill a hole in the spindle and use a pin spanner to hold the spindle.

I use the VFD to brake (lightly) and have never had a piece fly off, despite not having a grub screw.

The monster looks awesome for a bowl lathe. Have fun!
I'm trying to set up a large myself, but on a very different path.