lines left from turning steel (striations)

[Dan]

Herold, I extrapolated your suggestion and made a bushing and broached it. I had shopped around for one but is a very odd depth so could not find one. Really bizarre but it almost dawned on me when I realized I could just make one. Really cool moment. And slightly embarrassing.

But after the first try, (is a story and I don't look well) it came out perfect. Just so great to need some thing and be able to make it. I imagine no big deal to you folks but I was "yehaaa" lol.

This just keeps getting fun-er.

[Harold_V]

Congrats on your success.
It helps to keep an open mind and to explore creative thoughts.

Harold

[Dan]

Thanks Herold!

Quick question. Is one ten thousandth good enough for tailstock alignment? About annoyed my self to death but can't seem to get it better.

Used a coaxial to test with shortest curved probe I have.

[Harold_V]

Quick question. Is one ten thousandth good enough for tailstock alignment? About annoyed my self to death but can't seem to get it better.

Used a coaxial to test with shortest curved probe I have.

If you're making reference to the quill of the tailstock being dead concentric with the spindle, yes, that's more than acceptable. In fact, you may not notice even a couple thou misalignment, depending on what you're doing. However, what you really need to know is if the lathe turns without a taper, and that may or may not be the case. You may find that the tailstock will need to be offset a little, due to so many possible variables that you may not recognize. That can include the fact that the quill may or may not be dead parallel with the spindle, so the extension distance will influence concentricity. The tailstock can run up or down hill, or even be off side to side, as could the headstock.

Bottom line; when a project is critical and involves the tailstock, you may have to make an adjustment that suits the operation at hand.

If you've established concentricity via the method you suggested, and find you get a reading of .0001" variation, do keep in mind, that's a TIR (total indicator reading), meaning you actually have the centerlines within .000050". Far closer than anything you can hope to accomplish on a lathe.

Harold

[Dan]

Been looking around and wondering what would you folks suggest to make holes in aluminum plate?

plate is 1/4 thick. 2 holes (about 2" dia) are just access and 2 are for press fit bearings and have to be exact.

Last step and my first major project is complete.

[Torch]

For "about 2" in diameter" then even a hole saw is probably good enough. For press-fit bearings, the boring is the way to go. If it is a through-hole, then you can drill out a big chunk first -- drilling is probably the fastest way to remove metal, but not especially precise. If you've never done any boring before, you might want to practice a bit in a piece of scrap, just to get a feel for it. You will, of course, need a boring head and a boring bar to fit the head if you are doing this on your mill.

Alternatively, if the piece is small enough to fit in a 4-jaw chuck or on a faceplate, you could bore it in the lathe using a boring bar in the toolpost. If you lay it out and centerpunch the location, you can use the tailstock to help centre things.

Finally, you will need some method of measurement. I assume you are still pretty new to this, and if your experience is anything like mine, it takes a while to build an affordable selection of measuring instruments. Calipers are not really precise enough, although if that's all you have and if you are very careful and a little bit lucky, you might get an acceptable fit. If it's too loose, well, there's always shim stock...

Better are telescoping bore gauges, although there are two opportunities to make a mistake with those -- once when you set them and again when you measure them. But they are certainly cheaper than inside micrometers.

For a one-off or until you get something better, you could make your own go-nogo gauge on the lathe. Turn the end of a scrap piece, 1/2" or so, to the bearing diameter - 0.005". Turn the next 1/2" or so to the bearing diameter - the interference fit. Polish with sandpaper on the lathe to remove another 0.0005". Turn the next 1/2" to the bearing diameter.

When the first 1/2" goes in, you are getting real close. The next 1/2" should just barely slide in. If the third 1/2" goes in, you went to far. The advantage of this method is that you only need one measuring tool (ideally a micrometer) to effectively measure the inside and the outside. Any error or deviation from standards inherent in your micrometer doesn't affect the final result. With two tools, you have to ensure that both are reading exactly the same.

[Dan]

Awesome, awesome, awesome. TY Torch. go/no go is the way to go fer me. It is 2be production pc's.
So glad, as always, I asked. The information is around but my wee lil brain gets confused with the options.

The bearings are particularly intimidating for me. It don't get much more exact, right or wrong than that for me yet.


I almost bought a set of telescoping bore gauges the other day. Shoulda.

Seriously, thanks for taking the time to help me. Just a solidified plan of action alone, makes it so much more fun.

Jus' thanx

[Torch]

Well if this is to be production work, by a beginner on home-shop equipment with limited ability to measure precisely, then maybe you want a slightly different approach. You can get away with less precision in the boring operation with the use of a tolerance ring:

http://www.usatolerancerings.com/index. ... nformation

[Dan]

"by a beginner on home-shop equipment with limited ability to measure precisely,.."

LOL, but I am blessed with not knowing I can't do stuff. So I go ahead and do them. I joke about this bushing costing 5 years, 8 months of school and $21,000. 'cause it has. Built a shop just for this equipment and just bought a mill to replace the mill portion of my 3-in-one machine. Just to much time switching back and forth. As advised, buying a boring head and set, Telescoping Gauge Set, as advised. (Thanks again!)

But even though there is a learning curve, after this prototype, it has to be right and have been using tolerances in the tenths when I could be a lot more liberal.

I have the great, good fortune that my main endeavors will pay for any other tools needed and not gonna miss a meal.

When I am pulling my hair out in frustration, mostly due to the learning curve. My mantra is "Gotta be right and tight" Really does get me through. That and having you folks to ask. A great resource.

This wall of text was brought to you by the exxon corporation. The letter 3 and no apparent reason.

[Torch]

I'm not trying to dissuade you, just pointing out an alternative. As a hobby, we can take all the time in the world. Production requires, well, production. If you can get things right reliably and repeatedly at an acceptable rate with what you've got, then have at it! It's what the pros would do.

[Harold_V]

Having so much fun with this I am sitting here in the shop drinking coffee and watching the sunrise every morning I can in the shop and quit about 7 or 8 at night.

Chuckle!
All I can say is, back in '83, when I closed the doors on my (commercial) shop, I hated the very sight of my machines. Were it not for a burning desire to use them for making things I can not buy, I wouldn't care if I never touched them again.

Running machines for twelve hours daily, year after year, does get old.

In my opinion, the worst thing a guy can do is make his hobby his livelihood. Not true for everyone, but it certainly was for me. As much as I enjoyed refining precious metals, I grew weary of that, too.

Come to think of it----I'd probably whine if I was hung with a new rope as well!

Harold

[Torch]

One of the things I like about my job: you never know what's going to happen 5 minutes from now. Just when you think you've seen it all, they come up with something new. No time to get fancy, just deal with it and move on to the next thing. But it can get to you too. Spending time in the shop, be it machining or tinkering or whatever is a nice way to unwind and bring some peace and order into my life.

However, doing it for money on somebody else's schedule? It just wouldn't be the same.