Bought myself a mini lathe..

Well I will never learn to leave well enough alone. Yes I could use my lathe by starting it a certain way, but I sent an e-mail to the tech line and they told me to set the VFD parameters up to the motor. I followed the instructions and pushed the run button on the unit with the lathe in the off position and the VFD blew up. I mean loud bang and whole garage went off, it blew the 200A breaker on the power panel.
I am waiting to hear from the manufacturer about what happend. All I can do is think positive, it is too hot to work in the garage any way.
Jimf5
 

NYECOGunsmith

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Holy Crap! There must have been a short in the VFD somewhere, no other reason for it to let the magic smoke out so violently. Its just a simple inverter, takes the 220 single phase, converts it to pure DC, then converts it to AC with 3 true phases.
With the lathe OFF, the only place a short could be would be in the VFD itself.
 

Pcmaker

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I went overseas for awhile. I just got back Friday night. They're remodeling our bowling center at work. My co worker says there's a bunch of metal stuff from the pin setters that should be good for me. A lot of aluminum rods, he says, around 1" in diameter. Gonna check tomorrow and see what's of interest to me.
 

NYECOGunsmith

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^^^^^^ OOOOO, awwwww, drooling in jealousy! Yah, grab all that stuff you can, it's all useful and best of all, FREE! Practice material plus working material all in one.

When I make something for someone, or repair something for someone and they ask what they owe me, I generally tell them "Just keep your eyes open for scrap metal, steel, aluminum, brass, etc. in sheets, rods or bar stock, and hang onto it, that replenishes my stock of stuff and lets me make things or repair things for free by using donated metals.

Been doing that for 40+ years, rarely ever have to go buy any metal for a lathe or milling machine made project as a result.
 

NYECOGunsmith

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Knowing where the zero is on the hand wheel (in terms of how many revolutions of the hand wheel) is easy.
First off, you have to learn how to turn the hand wheel properly. It is done with the handle between the thumb and forefinger, with those two fingers touching tip to tip and forming a circle.
By putting the handle in the circle, and then moving your entire hand in a circle in the direction you want to turn the wheel, you move it continuously, with no "dead spots" (pauses in the motion) at 12 and 6 o'clock, like there would be if you grasp the handle tightly in your hand.

Now you have your other hand with the fist clenched, (or open, your choice) and for each full revolution of the hand wheel past zero, you extend or close a finer (your choice). And if it is more than 5 revolutions, you still have three fingers on the hand turning the wheel to extend or close to keep count.

When you reverse directions, you just open (or close, whichever is the opposite of what you did to begin with) the fingers once each time the zero mark comes past the tally marker, until you have all the fingers you opened or closed back where they started, then you are back at the ZERO you started from.

Sounds more complicated than it is, may have to get Geo over here with his camera and make a video for ya.

With the DRO, all that plus the wink in the table gear train goes out the window, DRO only shows real movement, and you can zero it anywhere (just as you can with the hand wheel) and then wind it back to zero without doing any counting.
 

TexasJackKin

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As NYECOGunsmith knows, before DROs, you had to be a real machinist to keep track of all that stuff! I've known machinists that could keep 6 or 8 things going in their head at once (not me!) DROs are a godsend for guys like me! Most DROs nowadays come with built in software for things like bolt circles, and what not. Great stuff!
 

NYECOGunsmith

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Yup, before DRO's, if you wanted to drill or mill a circle of holes, say for a round cover on a pipe flange, you had to do the math yourself to figure out the X and Y movements from the X and Y zero points, using Right Angle Triangle Math (Trigonometry) to figure out how much to move the table from the zero center point of the circle to get to each hole location on the circle line.

The DRO probably has (most do now days) a Trig calculator built in, and a bolt hole circle calculator as well. You punch in the diameter of the circle, or on some DRO's the radius, the number of holes , the diameter of the holes and hit go and it tells where to move the table for X1, Y1 hole, X2, Y2 hole, etc. for however many holes you have.

But doing it manually isn't difficult and is handy to know so if the calculator is out to lunch or you are out in a cornfield without your DRO but you do have your calculator with you (or your trig tables book!) you can git'er done.

Old Chief SOH CAH TOA will help you with this one as well as many other things in the shop.
 

Pcmaker

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I'm trying to come up with an idea for a collet holder. I'm thinking a block of wood or aluminum and bore out the specific diameter for the collets. Will a DRO help me figure out where to drill on the block once I get the edges of the work piece?
 

NYECOGunsmith

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Yes.
Once you locate the edges of the block in the X and Y axis, you can select one of them on the DRO, and hit the "1/2" button, the DRO display will change by half in that axis, then you just turn that axis crank until the display reads zero and you are at the middle of the work piece for the selected axis. Repeat for the other axis and now your spindle centerline is over the center of the part.

What type of collet are you wanting to make a holder/closer for? 5C, R8, ???? You can buy them pretty cheap, for a beginning machinist getting the taper angle right can be difficult, and unless it's right the collet won't close properly.
 

NYECOGunsmith

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OK, here are the dimensions you need to know. https://www.bing.com/images/search?...608008999002243605&selectedIndex=0&ajaxhist=0

R8 Collet Dimensions from Bridgeport.jpg

So you will need to first bore your block to the shank diameter of the R8, then step bore the nose end at a couple of points to get it close to the taper, then bore it on the taper angle of 16 degrees 51 minutes to match the taper angle of the collet. You can put a set screw down through the shank bore area to engage the keyway to keep the collet from rotating as you draw it in.

You will need a large washer on the back end of the block, one with a hole diameter of about 15/32, and an outside diameter of over 1 inch, to let the 7/16-20 draw bar pass through, or, just don't drill / bore all the way through the block with the R8 shank diameter of .9495 , make it a blind hole and then drill the rest of the way through with a 15/32 drill to let the draw bar in.

I would suggest you add a thousandth or two to the above dimensions when drilling and boring the hole in your block for the collet, as you will need a bit of clearance so the collet slides in smoothly, and then collapses as you tighten the draw bar.

If your goal is to be able to hold stock in a R8 collet and the collet held in a vise so you can mill on it, I would suggest instead that you invest in a set of 5C collets, and get the 5C collet block set as well, it will have a square block and a hexagonal block in it that hold the 5C collets and tighten them down, so then you can hold the block in the mill vise and machine one side, 2, 3, 4, 5 or 6 sides as needed.

If you are thinking of being able to use the R8 collets to hold work in your lathe, again, the 5C is a better choice, you can get a 5C chuck for most lathes reasonably priced, I have one and use it frequently for repetitive work where I don't want to have to dial in a 4 jaw, but I need as little runout as possible.

The 5C collets are cheaper than R8's for this purpose (R8's are normally only used to hold end mills and drill bits, etc. in the mill's spindle) and you can get spin indexers and the collet blocks and other types of 5C collet closers fairly cheaply that will let you do this sort of work.
And 5C collets come in a much wider range of sizes than R8's do, there are only 27 sizes of R8 collets out there in SAE, and about that many in Metric, but there are 72 standard SAE sizes of round opening 5C collets, that many in Metric AND you can get 5C collets that hold hexagonal stock and square stock. The 5C , for holding work pieces, is much more versatile than the R8, which has a limited size range (usually 1/16 to 1" in SAE) and only holds round objects.

Just my .02 worth, Earthquake and TexasJackKin work at this trade, so they probably have more recent info or better ideas on how to handle this, my info comes from the day when a captive dinosaur powered the lathe and mill that I turned rock on or milled rock on.
 
Ah, when I said I wanted to make a collet holder, I meant I wanted a collet organizer kind like this:



Also, today I made a roller indicator tool to straighten up wobbly work pieces before tightening the lathe chuck



and I worked on my flashlight. I added some knurling at the top where I normally grab it out of its holster:

 

TexasJackKin

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[QUOTE="NYECOGunsmith, post: 1255998, member:
Just my .02 worth, Earthquake and TexasJackKin work at this trade, so they probably have more recent info or better ideas on how to handle this, my info comes from the day when a captive dinosaur powered the lathe and mill that I turned rock on or milled rock on.[/QUOTE]

So, did the dinosaur just turn a line shaft? and you change speeds with a broom stick? This even predates me, and that doesn't happen all that often! What did you feed the dinosaur? This is all very interesting! Oh, by the way, I used to work at this trade, I'm retired and living the dream now!
 

NYECOGunsmith

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Nice work PCM!

And TJK, yup, the dino walked inside a hamster wheel, a very LARGE hamsterosuarus wheel to be exact, turning a dolomite granite pulley with a T-Rex hide master jack belt supplying power to the petrified redwood line shaft, with more granite pulleys and millwork transfering the power over to the counter shafts, with a polished triceratops horn on a stick that we used to shift the T-Rex power drop belt from the loose idler pulley to the fixed running pulley, or to shift the machine belt among the speed change pulleys.

I grew up with that system in the shop on the ranch, power there came from a water wheel when the stream was running, or from a windmill if the stream was low, or from a steam donkey engine when there was no water or wind. The first two were the preferred means of powering the shop machinery, as they required no additional labor. The steam donkey had to be fed wood, and the water level in the boiler watched as well.

Later my grandad converted the machines to electric motors once we had a generator on the place for electricity, and he added a large one cylinder diesel motor that could run alongside the Steam Donkey in place of it if need be.

Later still my Dad and I added hydraulic and pneumatic motors that could be swapped in quickly so we had lots of power sources. All of it still works just fine, although I think my brothers and I are the last ones who know how to lace up a leather power transmission belt correctly, lacing a 12 inch or wider belt ain't all that easy at my age!

Dad and Grandpa and I all believe in no single point of failure, and being nearly 50 miles from a very small town, and a couple of hundred from a major city, we had to be able to make repairs on nearly anything, and to do that we had to be sure all the machine tools were always available, and could be spun up somehow.

Most of the time now they run off either the hydraulic or pneumatic motors because they tolerate the desert heat better and if you stall the motor somehow, no harm done, it just sits there until you either increase the line pressure or decrease the load.
 

NYECOGunsmith

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Only if you make it so.
RTFM, twice, look the parts all over, check inventory sheet to make sure you got all the parts, look at your mill and hold the various parts up to it to see how they are gonna fit, lay out the tools you will need to do the install, read the forkin manual again, take a deep breath and have at it.
It'll work out in no time.