Christmas in March!!!!!

[LBMiller5]

Had a cool thing happen at work today. It looks like Christmas is coming early in San Diego this year!

A little background info. I work for a company that provides Ocean Floor and Coastal Survey & Mapping services. We have a group of 10 Sound Velocity probes that we use when doing underwater survey work. They measure the speed of sound in water so you can calibrate your equipment to read properly. Well anyway, all the ones we have use this tiny little connector at the end that keep failing during use. The company that makes them has since switched to a bigger, more robust connector that works much better. Now these thing cost about $2500.00 each, and the factory wants to charge us $250.00 each to drill out the case and install the bigger connector. We can get the connectors wholesale for about $50.00 each, so they are charging $200 each to drill out a hole and solder in the new connector.

My boss told his boss that we could do the work here, if we had a lathe. As much as it would cost to have it done, we could do it here and buy our own lathe with the money we saved. Then it would be here forever for future use. So my boss came back to me and asked me what we should get considering we had about $1500 to spend on a machine and accessories. I suggested a larger 3-in-1 machine that could be used for small milling operations as well.

Long story short, I just got the OK to buy one. This is what we are ordering:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44142

We are also getting a quick change tool post set, and a bunch of drills, cutting bits, parting tools, a live center, a boring bar set, and a set of digital calipers.

Pretty cool huh!!! And the best part of all is that I am the only one at work that knows how to use it, so it is basically mine to do with as I please!

It looks like I will probably be spending most of my lunch hours playing with it and be staying late after work a few times a week now to make parts for some new motors.

I am going to have too much fun! It should be here by the end of the week! I will post some photos after it arrives.

Later everyone!

Lucien

[swatson144]

Congrats.

Things I have learned since I got my mini lathe.

Harbor frights QC TP sucks. but it is worthwhile to hold a parting tool. the square holder ain't too bad for most work Mount a couple AR5 & AL5 and change tool posts for specialty tools, parting, single point, etc.

www.onlinemetals.com for material
www.use-enco.com for tools

use a 4rpm gear motor for carrage drive.

Make a chip shield behind the apron. 5x5x1 N50s will fasten it easily.

enjoy,

Steve

[DadHav]

Sounds good Lucien. I'm looking forward to seeing some pictures of your new motors. My Grandfather used to tell me " Make everything RRRound Shhmoooth Und Shqvuare" Is that the way to write a with a German accent?
Good Luck

[paulvi]

Way cool. I guess we will never see you on the threads again.. :)

[LBMiller5]

Oh You will still see me Paul, plus I can get those motor mounts done for you in very short order! It might get here today, but I am not holding my breath.

I will post a detailed report on the machine after I get it set up and make a few parts on it.

Lucien

[DadHav]

Hurray, Hurray, It's motor mounts for everyone!!!
Hi Lucien, I just had to put a new motor in my old South Bend Lathe, After about 50 years of service it finally got so loud that you couldn't hear yourself think. Actually I picked up a motor from Harbor Freight. I was leery about the quality, but it really seems to be OK. The machine is so quiet know that I can hear the part drawings as well as see them.
Back on the other topic. Here is the pole combinations that I tried. The 8 pole option is the one that vibrated so much. I changed to the 6 pole with more magnets and the motor runs smooth after the initial jig-jog before she goes in the right direction. Interesting: the motor starts to sound like a jet turbine when approaching half speed. All in all though. I think I'm chasing an imposible dream. It seems as though I can't get a pitch speed of 50 to 60 mph and still get the 20-24 ounces of thrust I need for the fast little yellow plane. I've looked hard to find someone who has been able to do this but not found anything. I can get 10,-12,000 RPMs with props like 7-4 and pull about 20 ounces thrust, but as soon as I go up in pitch, I go over the 12 amps or so that would be practical and loose my thrust. I might have to go back to a Hacker inrunner or something. That or scrap the project and put a nitro engine back in the plane.
Here's the pole configurations: 8 pole vibrated but was a AaABbBCcC wind. The 6 pole worked without vibration with the same flux ring and bell housing, but was an ABCABCABC wind. hmmmm. Somebody said something about the other running out of symmetry.
Anybody know how to make a 12 amp. 10,000 rpm. 20 oz. thrust motor that swings a 6-5 or 7-5 prop? or any combo to get 50-60 mph ptich speed and 20 oz. thrust?
Gratefully.
John

[latrans]

Hmmmm............ so you say that the vibration stopped when you went to a symetrical winding scheme do you? Crow - anyone?

Sorry couldn't resist.

[DadHav]

Now I remember who said that. Crow dosen't bother me. I've had it prepared and dished out by many. I'll say though, that I experienced nearly the same characteristics with a 20 mm diameter triple motor. Both these motors are really stout, and the vibration actually felt as though it was a product of induction rather than something pulled out of balance.
Man, There's so much to learn about this stuff before the retailers start selling motors for less than it costs to make them.
John

[latrans]

Dadhav,
That comment was absolutely not directed at you :oops: . It was really ment for someone else and was ment to be all in fun. I fully admitt that the asymetry may not be the problem but I would wager that it is one part of it. In fact I can't even claim that your result proves anything as you also changed the numer of magnet poles and the amount of magnet coverage (two important facts as someone else pointed out).
I couldn't agree more about the amount to learn, sometimes it makes my head spin, but I suspect that's part of the fun for those of us with a scientific inclination.

Good luck and I applaud your efforts.

Latrans

[DadHav]

Believe me Latrans. Even if the comment was directed at me it would have still been taken in fun. The problem with writing things is that it can be read to reflect three or four different dispositions the writer might have. You can't see the guy laughing as he writes. :D Maybe that's why they invented smily faces. I'll give it a try. I'm just happy to be part of all the fun here. I think I might take a break and build an airplane or something though. :idea: Or maybe I'll take my float plane out on the snow. Ya, thats what I'll do. The snow. No motors until at least next week :lol:
C YA

[latrans]

What is this a-i-r-p-l-a-n-e thing that you speak of? I thought that we only built motors :P .

Have fun,

Latrans

[LBMiller5]

My thought on the magnet placement and size is that once the magnet (or 2 or 3 magnets making a pole) gets wider than the head of the stator arm, you are wasting magnets. Looking at your 6 pole diagram above, with 3 magnets making up each of the poles, the magnet poles are about 1-1/2 times as wide as the head of the stator. It would appear to me that once the trailing edge of the stator head reaches the back edge of the magnet, you are at the point of maximum attraction. In the diagram above, you could rotate the motor an additional 10 degrees or so before the leading edge of the stator head begins to go past the other end of the magnet. To me this would mean 10 degrees of rotation where no work is being done and no torque is produced.

I could be wrong here, but I would speculate that the 6 pole magnet configuration with 2 magnets per pole, and a larger gap between the magnets, would be just as effective as the one shown with 3 magnets per pole.

From all the charts I have seen, it appears that the best combinations of Stator Arms and Magnets occur when the numbers are close together. For 9 arm stators either 8 or 10 magnets seems best, for 12 arm stators either 10 or 14 magnets is the way to go, and for 6 arm stators either 4 or 8 magnets is best.

Anybody else agree with this?

As always, other views are welcome and encouraged.

Lucien

[swatson144]

Yep I agree...kinda I agree with the premise that magnet placement is part of the equation. Though I'll with hold any speculation on what is too long or too short until I do some more smeariminting :) .

I'm committed to build a 25x5mm which I could use several of and have enough 5x5x1.5 mags that I'll not have much use for so that'll make a nice test bed and at that thickness I can part several cans from one turning to save time. I may even make the cans with a small flange on the end so I can press out the end bell and press it onto a different flux ring with another magnet setup.

I also have a wing cut out and I'll machine while the glue dries. Hee hee I decided to put a cessna 140 profile wing on a slow stick for an aileron trainer for son and buddies. That profile should make it a floating slow dream to fly.

Had winds under 5mph today and got to break a few props learning to drive my 24" 3d with a gbv on it. Plane came out fine tough lil bugger. That plane takes 1 little screwup and augers straight in.

[DadHav]

Hi Lucien, I might try geting some of the magnets off the 6 pole flux ring to try a comparison. Two things to add to what we are talking about: Keeping the magnets thin enough to be about the size of the stator head might give you so much space that you loose power or effieciency also. No? The idea of keeping the pole pieces as close to the number of stator legs, is producing the best results for me also. Here once again though: When you're having what seems to be optimum operating characteristics with these motors, you're pretty much still looking at using it for a 3D plane, Bipe, or some other slow flying plane. At least that's the way it seems to me. I have a 12 leg 10 pole motor and two 12/14 motors. This combo works great for the slower flying models. Lets see what Swatson comes up with. I have a couple of 36 mm stators prepared to enter into a design. It should be interesting to see what they will do. I've seen on a few strings from another forum that builders are happy to get a small motor producing 20 ounce of thrust while using 15-19 amps. They can show the motor running at great efficiency with their tests. But guess what? You can probably build a bigger motor pump 19 amps into it and fly a three pound airplane. So I'm not sure how I want to understand motor efficiency to be. I'm thinking that going to four lithium cells might get the speed on some of these. When I get my popped power supply working again I'll give it a try.
Happy Motoring.
John

[Happy|Harry]

you lucky man!, now how can i wangle getting a lathe when i work in IT, any suggestions lol :D

phil

[saitrix]

you lucky man!, now how can i wangle getting a lathe when i work in IT, any suggestions lol :D

phil

By the way how is your DSP receiver getting on?

[Happy|Harry]

testing of the dsp rx is going great, but i need for the weather to change so as i can get the spitfire out and do some long range testing, as the microheli gets too small too fast lol :)

phil

[LBMiller5]

Well, I finally got the lathe set up and running at work a couple days ago. The machine actually works very well! I was able to make a couple bearing tubes today for some motors. Compared to the little Unimat Lathe I was using earlier, this thing rocks! It would take about 3 hours to make a bearing tube in the Unimat lathe, and in this one I can do it in 20 minutes. What a joy to work with!

Here is a photo on the Lathe/Mill/Drill combo sitting on the custom stand I built.

http://innov8tivedesigns.com/rcgroups/Lathe.jpg

The table is 54" wide and is built from 2 x 6 Lumber with a 1" thick plywood top. The top edges were rounded with a router, and the whole thing got a couple coats of grey Rustoleum paint.

Here is a shot of me standing next to it to get an idea of the true size of the machine.

http://innov8tivedesigns.com/rcgroups/Me_Lathe.jpg

Finally, here is a photo of the first 2 motor parts I made on the lathe. These are bearing tubes that will hold the stator shown in the photo. I turned them down out of 6061 T6 aluminum bar stock. The mounts are 24mm long x 10mm in diameter with a 9mm step for the stator to fit on to. There will be a 3 x 6 x 2.5 bearing pressed into each end.



http://innov8tivedesigns.com/rcgroups/Tubes.jpg


This particular machine has automatic feed in both directions, so it does all the work for you. You just line up the cutting bit, pull up on the engagement lever, and off it goes making perfect cuts. When you get to the end of a cut, you just flip the lever down and it stops.

Well one of these days, I will go into work on a weekend and make a bunch of stuff.

Till Next Time!

Lucien

[Q]

Lucien, if you ever think of parting with your small lathe, let me know. I have half an Unimat Mini Lathe (same as yours) and need some extra parts to be able to use it. Just can't find any parts on the net or in second hand shops.

[Happy|Harry]

lucien that is an amazing setup 8), would you be interested in making a few small parts for $$ for the poor latheless me :D

phil

[LBMiller5]

Q,

The lathe does not actually belong to me. It belongs to my brother-in-law. He uses it to turn down wax rings to make molds for casting jewelry, so I will be returning it to him now that I have the big machine.


Harry,

As you know, the parts made for these motors are labors of love. There is no way to "Save Money" by making parts yourself, unless you figure your labor is worth about 50 cents an hour! :wink:

That being said, I would not mind making a few parts here and there for some of the members, as I enjoy the "Creative Process", but I don't have the time to go into full fledged production of motor parts.

If you have a specific part you would like to have made, pop me an email to lbmiller5@cox.net and I will see what I can do.

Lucien

[ScubaSteve]

Lucien,

Noticing your coffee cup... you work for Thales?

[LBMiller5]

I used to, My division got bought out by another company 1-1/2 years ago. It is now called Fugro. Before that we were Thales Geosolutions, Pacific.

Lucien

[Happy|Harry]

that's great lucien, what i'm desperatly needing is a tail motor mount for my hybrid microheli but it's more of a milled part that lathed so my usual machinist can't do it as he has no mill. i'll draw it up in autocad and email it to you to see what you think, is acad 2004 dxf ok? or would you prefer a different format?

thanks again
phil

[LBMiller5]

DXF is fine for me.

Lucien