Gingery Lathe and Accessories

[DavidF]

Do you ever get the feeling that VTsteam could be dropped off on the moon butt naked one day and then fly himself back to earth on his home built space shuttle in less than a week????

[vtsteam]

Here is the lathe tailstock cast and ready to break out of the mold. The heat of the molten aluminum has burnt up the binders in the baked sand core. It is now just loose grains of blackened sand, ready to pour out of the hole. The core is till intact outside of the casting.

To the right of the tailstock you see the sprue -- the hole down which the aluminum was poured, and the gate which delivered the metal to the casting proper.

I didn't mention the sprue in previous casting photos, and I hope everyone realizes these are cut off, and not part of the casting. A second sprue like column of metal is also sometimes attached. This is called a riser, and it is a reservoir of molten metal that is used to feed the casting as it solidifies. Metal shrinks as it does so, and the riser is necessary to feed more metal to prevent a castig flaw called a shrink cavity.

[vtsteam]

Do you ever get the feeling that VTsteam could be dropped off on the moon butt naked one day and then fly himself back to earth on his home built space shuttle in less than a week????

I wouldn't want to leave all that cheese behind, though.

[vtsteam]

Last picture of the evening. This is the lathe in its simplest form assembled to try out a test bar. You can see all of the parts cast earlier (and if you're interested you can probably pick out the pattens for each in the first photo in this thread).

The tailstock is in place, but not finished. It is only bored out but with no hand wheel or taper slide yet. A dead center of pointed rod is in place held by a couple of machinery collars. The headstock and a faceplate have been made, and the motor and drive are built. I haven't got photos of these things under construction, but do have more to say about them next time. You can see that many of the parts have been filed smooth -- this was before I had a milling attachment made up, or any chuck or work holding device other than the faceplate and a drive dog made out of some keystock and bolts (you can see it at the faceplate) for that matter.

The motor, by the way, was taken out of a clothes dryer. I went to an appliance store asking about motors, and they sent me out in back of their building to take as many as I wanted from mountain of broken or traded in washing machines and appliances destined for the scrapyard.

[vtsteam]

The moment of truth. 

This was a test bar I was turning just after I had made and mounted the tailstock and its slide. The idea was to see how far off the tailstock (and lathe in general) was, and set the tailstock over to compensate for the error.

Errors would be a result of headstock bearing bore, headstock bearings, headstock base attachment position, tail stock bore and attachment position, accuracy of bed ways and accuracy of scraping.

When I was finished turning the full length of the bar, I measured the ends and middle with my dial caliper. The total taper was less than 1/2 a thou over the full 12" length of the bar. I couldn't actually read it, since it was just over the line on the dial by a hair. I was amazed that I didn't have to adjust the tail stock set over at all.

How was this accuracy achieved with primitive tools and practically no measurement of position or angular orientation when building the lathe? The answer actually lies in the clever way that the headstock and tailstock are bored, and this is one of the more fascinating things about building this lathe.

To bore the headstock on a Gingery lathe, you complete the headstock base slides. Even though it will later be fixed in place, the headstock still has hand scraped slides, gibs and gib screws initially. You then mount the headstock and adjust the gibs for a close sliding fit. You fasten the headstock to the apron, so that it can be driven -- as if it were the cross slide. The cross slide is not yet mounted on the lathe.

Next you assemble a second temporary headstock, made out of angle plates and pillow bearings -- basically a bolt together structure that will support a driven boring bar. The boring bar is made up out of rod and a piece of lathe tool and placed in the temporary headstock. drive pulleys are added to the boring bar, and it is spun by the lathe motor.

You will start the boring bar rotating, then engage the leadscrew, which drives the apron and attached headstock onto the boring bar.

Now te question comes up, how do you get the boring bar exactly straight, at the proper height and perfectly parallel with the bed ways, because this will have a critical effect on the accuracy of the lathe.

Well the answer is, you don't. You just do the best you can by making a little gage out of sheet metal that the bar rests on while you tighten up the temp headstock bolts, and that's it for measurements.

Yet the bore comes out absolutely parallel (within less than a half thou over 12") because of the way you are boring it! By sliding the headstock over the ways, the bore MUST be parallel with those ways. Even if your boring bar is slightly angled (and it won't be angled much) the bore will be parallel. The hole it bores may be very slightly elliptical, if the bar is angled but nevertheless parallel to the ways.

Not only that but the height is also not overly important either. Because after you bore the headstock, you are going to remove the temporary headstock, and replace it with the  freshly bored casting and fasten it down permanently. Then fit it with bearings in the bore hole, ad the boring bar and pulley and get it ready to bore the tailstock. You will do this in exactly the same fashion you bored the headstock -- driving the tailstock with the apron onto the boring bar as the casting slides along the ways.

This means that not only will the tailstock be bored exactly parallel with the ways, but also that its center height will exactly match the center height of the headstock, and their bores will be exactly concentric!

This is a wonderful thing. At least it was to me, at the time. Precision without measurement, simply by the nature of a procedure. Pure elegance. There are several of these moments in the building of a Gingery lathe -- the making of square angle plates in a rotational machine, the boring of headstock and tailstock concentric and parallel, and the making of accurate surface plates by the method of threes, and hand scraping to high precision by simply looking at the pattern of oil paint on a surface.

These are amazing things that we can do.

[Meldonmech]

The machining procedures are very well thought out, Gingery must have spent a long time developing them with only a hand drill. What brilliant concept.
                                                      A captivating post, well done    David

[Henning]

I have a hard time believing this! 

Please continue! 

[mattinker]

vtsteam,

Would you mind if I posted the link to here on the Yahoo Gingery Machines?

Regards,Matthew

[vtsteam]

Okay, Henning I might get some more up tonight if I have time -- I have to look through the photos, shrink them and get them up to photobucket, so it takes a little while but I'll definitely keep this thread going as I can. Thanks so much for the feedback! 

matinker, why not?   

[nel2lar]

VS
Have you seen the new book out. Build a back gear for your lathe.

I must say you have the touch, your casting is top shelf.

Enjoyed looking at you post and able to keep up with the build.

Don't stop now, it's a good feeling isn't it. Knowing you can make anything your mind comes up with.

I'll be watching you

Nelson Collar

[vtsteam]

Hello nel2lar!
I've seen the back gear book advertised, but haven't read it. My Gingery lathe improvement program stopped a few years ago when it was packed away while I built a house. I'd love to get it back in commission and try a lot of new ideas I have for it. I hope that will happen this summer. Meanwhile I am able to access my Sears/Atlas lathe in a storage shed (well, access barely), so that's what I'm using now while working on the 4 cycle engine to steam project. Thanks for the molding compliment -- can't wait to start pouring iron when warm weather arrives.

To continue the story:

Here is a photograph of the stock Gingery lathe counter shaft and pulley drive setup for the lathe arbor and lead screw. I usually try to build things the way the original designer intended, rather than modify them from the get-go. Modifications are fine once I have an understanding of the original design and operation to compare them with. I don't like modifying major aspects of a design before I try out the original. I trust the designer made choices for specific reasons that I may be unaware of. On the other hand, once I've built something and tried it out in its stock version, if I think I can improve it for my own needs, I'm more than willing to start up the foundry furnace!

The Gingery style lathe drive uses an over-center lock to tension or slacken the drive belts with the pull of a big accessible handle (barely visible at the top of the photo). The frame is fabricated out of angle iron, and as in all things Gingery, is designed to teach the builder some new construction skill. In this case riveting -- using sliced-off pieces of 1/8" and 1/4" steel rod.

You can also see my homemade cast aluminum and sintered bronze (Oilite) pillow blocks in use. I mounted them on wood shims (not a part of the Gingery instructions)  -- I like these in general because they allow me to adjust the shaft alignment by adjusting the compression of the attachment bolts. Wood will compress a little compared to metal.

The angle iron for the motor mount came from a discarded bed frame. The open frame motor as mentioned earlier was salvaged from an appliance -- a case would make it safer, btw -- Terry Aspin shows one in his casting books being molded. Project for the future.

The belt tensioner Dave Gingery designed allows easy speed changes, instant emergency stopping of the drive, and easy removal of the lathe arbor -- which became important to me later on when I started to use cast-on arbors and a milling arbor with my lathe and the milling attachment I designed.

The leadscrew reduction drive belts are circular sectioned vacuum cleaner belts -- available most anywhere, often on sale for $1. I have a lifetime supply. Actually the original shows no sign of wear.

[Henning]

I must say you have the touch, your casting is top shelf.

Understatement!

Now I'm waiting for more pic's!

[vtsteam]

You guys must have missed the shrink cavities on the back of the faceplate in the photo above!!!
 

Well it's my accessory faceplate -- I have several, one is perfect. The one shown seemed good enough not to re-melt. But I have my good pours and not so good, just like everybody else. I had to re-cast my milling table twice.

But thank you all!

[vtsteam]

Here's a view from the other end of the lathe. At this point I had made Gingery's steady rest, on the ways here, and a bell chuck (holding the shaft to be machined on the faceplate.) The tailstock had been finished.

Gingery accessories also seen in the lower part of the photo on the table, right to left, two homemade boring bars, lathe dog made from bolts and keystock,  pair of cast smaller angle plates bolted together to be used as a faceplate vice -- similar in action to a milling vice -- with a built in parallel attached to keep the work square and near the end of the vice for facing. A larger cast angle plate.

And finally (non Gingery) a plumbing floor flange and short pipe nipple which I drilled tapped and set-screwed to to a stub arbor, and faced (the flange) flat. This became my first face plate, onto which I mounted the larger raw cast faceplate to face it and bore that square. Then I swapped out the pipe flange for the real faceplate and had a lathe!

[vtsteam]

Now that I had a lathe, I wanted to move on from making machine tools to something interesting. I planned to return and build Gingery's horizontal mill and maybe the shaper, too, but now I wanted to do something different.

What had caught my eye was a book by Cairns about Tesla disk turbines, and in it was a small turbine Cairns had built. Well I'd also been reading another old reprint of a magazine from the twenties that showed Delaval turbines of roughly the same size, and these also appealed to me. They had an old fashioned look I liked. Then I started reading Kurt Schreckling's book on the earliest model aircraft turbines he built, and finally decided I wanted to combine some features of all three. Cairns and the DeLaval' turbines had dual bearings -- in the case front and back. While Schreckling's had a central bearing tube. I thought about trying the Tesla turbine as either a steam turbine or a compressor, and this seemed to favor a cantilevered approach with a bearing tube out back. But for a case style I went with the old model DeLaval.

Well this thread is about the lathe, not the turbine, so to return to the subject, it became real clear to me that I needed a milling machine if I wanted to build it, because a Tesla turbine's disks have radial milled ports around the central shaft. I looked at the Gingery horizontal mill book and imagined spending months more building that. But I began to realize that the mill was essentially just a beefed up version of the lathe, with the addition of a mill head that could raise and lower. I'd also seen milling attachments for a lathe that raised a slide up and down. So I decided to combine features from some of this stuff, plus a rotary table so I could mill the Tesla disk slots.

First step I decided was to make a boring table for my lathe, and then mount a vertical slide on that. The vertical slide could take the rotary table. Well really the first step was to turn up a milling arbor that I could substitute for the lathe arbor, to hold end mills. If you look at the photo last post, that rod blank was being set up to become the new milling sindle.

Here I'm starting to make it:

[vtsteam]

Here it is turned to shape:

[vtsteam]

And then, using the "Gingery way" I removed the lathe arbor (easy) and substituted for it the new milling spindle in the headstock, with a bronze thrust bearing, and reattached the lathe pulleys.

I could now drill it and bore it perfectly centered in the lathe headstock, running in the bearings, in exactly the position it would have when acting as a milling spindle.

[vtsteam]

Withe the arbor ready, next step was making a pattern for a boring table and casting that. The design was somewhat like the Gingery lathe slides, though quite a bit heavier and longer. The tang is buried in the sand here already, so not visible.

[vtsteam]

As I mentioned, I had to cast this one twice. But finally got a good pour.

[vtsteam]

Adding the boring table to the lathe was straightforward, file and scrape ways, add gib and gib screws, and it was attached. But still a rough casting. Now I needed to mill it flat. Of course I didn't have a mill yet. Or even a milling attachment, naturally, since that was what I was building!

So I decided to make a fly cutter that I could attach to an arbor between centers to do the surface milling on the lathe. It needed to be fairly wide in diameter to reach the milling table, and I wanted to use a lathe tool in it to do the cutting.

I made up a pattern of the right dimensions, and used a piece of 1/4" square keystock as a ruling guide, and later, a piece of it as a core in the pattern.

[vtsteam]

Patterns for the fly cutter laid up in the mold:

[jcdammeyer]

Nicely done.  One of the things I did on my Gingery was make a wider casting foot for under the head stock.  I cast ears onto it with the intention of pivoting the belt drive countershaft from that instead of the plywood base.   I found the wood between the belt/motor assembly and the headstock flexed leading to vibration.

Never did finish that as other projects got in the way.

[vtsteam]

The castings broken out. You can see the steel core which will be knocked out to leave a space for the lathe tool.

[vtsteam]

Drilling the arbor hole in the base of the fly cutter.

The casting  was then bored to size, the cover plate attached with screws, and the casting cleaned up all around.

[vtsteam]

After cleanup and boring the base side, the flycutter was turned round and the cover plate was drilled and bored.

The boring tool is homemade, per Gingery -- a piece of 1/4" drill rod (silver steel) forged, hardened, and tempered with the charcoal furnace, then ground to shape. It is somewhat flexible, but will open out a very small bore. You just need patience, and the realization that there is some spring involved. The last few cuts are made without moving the carriage, as the spring in the tool is gradually relieved to finish the bore.