Hey Mikey!!!

Catshooter

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So, once again, acting on your advice I bought a rear-mounted cut off tool from Sherline. Had it for a couple of weeks before I needed it. Had piece of unknown aluminum to part. Whatever alloy, it was gummy as all get out to machine so I was really wondering about the parting.

But it went just like you said it would! I had to lube it a bit (gummy, very gummy) but it worked a treat. Not only did it part off at a pretty fast rpm/feed but the tool feed in the full 1" straight as you said it would. Thank you!

On another note, did you ever post up anything on building the live center you made? Sherline's works, pretty much, most of the time but yours looks like the ticket and I'd love to see a write up with lots of pics.

Thanks again for your sound advice.


Cat
 
Hey Cat, glad the rear mounted parting tool worked for you. I don't understand why Sherline doesn't make that part of their standard tooling and provide it along with the tailstock.

I have the live center written up but it needs polishing. I'll try to get to it when life allows, okay? I also need to write up my stupid simple lathe tool height gauge, make a shear tool and then I might even get to do something for me! I gotta' warn you, though; that live center requires you to be able to bore pretty accurately so start practicing!
 
Mikey,

What bearings did you use and where'd you get 'em? Bearings are a big deal, I'm finding out. Not cheap either, or at least some aren't.


Cat
 
Cheaper on Amazon than ebay. It's a Nachi 5200-2RS-NSL double row angular contact bearing. This is cheap for a bearing of this quality. See that 10mm part and the 30mm part? Those are the dimensions of your arbor and bearing housing bore, respectively. Exactly those numbers - you have to hit them, okay?
 
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Great, thank you.

Mmm. Just went and looked eBay doesn't have them but Amazon does. There is no ABEC rating shown - do you know why? Do I care? Did you use one or two in your center?

Thanks for the help. I'm not a complete newby, I've had my Sherlines for more than twenty years and use them quite a bit. But by no means am I any kind of machinist. So thanks for the help.


Cat
 
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This bearing has no ABEC rating that I know of. I chose it because of it's back-to-back configuration and high load rating. I figured this would allow it to handle any radial or axial load I could throw at it, and if it can take a 900# load then that's good enough for a Sherline lathe!

I also chose it because it is a critical part of the design. Most live centers are made so the central hub, the part that holds the tips, rotates in the bearing(s). The hub projects back through the body of the live center and the end of it rides in a bushing or thrust bearings; this provides a lot of support so the live center can handle major weight. However, it also requires a massive housing. A Sherline long bed lathe is like, 35# soaking wet maybe? The loads we experience will be in the single digit pound-wise, mostly. Using the double row configuration to sustain those loads makes more sense and greatly simplifies the design requirements. My live center is now over 15 years old and is still tight and accurate; it has zero run out with the short tip so I guess I can say that it works. At the very least, it beats the Sherline live center and their adjustable live center hands down.

Happy to help where I can. I'm no machinist either, just a hobby guy like you. This is a good project for you , Cat, because you have enough experience to tackle it. When I say you have to hit a specific ID and OD, you know that I mean both have to be dead on target, with tolerances of +0.0000/-0.0001". It takes a bit of experience to turn and bore like that.

My mother in law is just about to get out of the hospital. We've been almost living there for a month, which makes it hard to get other things done. I ask for your patience as I take care of my family first, then I have to grind some tools for another member, and then I can get to writing up this project for you.
 
Mikey,

That sounds like the right bearing. If it's given you that much service it'll work for me for sure. Looking at that bearing and it's construction I couldn't imagine how our little bitty lathes could tax it. Yea, 900# should do! :)

That's a tight tolerance to hit. But I'm buying a three foot piece of stock, so we'll see. I shouldn't have to buy any more than that. :)

No worry on the write up. I asked because I had seen that it looked like a project you had done some time ago. Couldn't find the write up and figured most likely I had just missed it. The live center isn't next on my list to do. A buddy and I are building three gun stock makers vices just now so I'm occupied for the moment.

Take good care of your family, their important.


Cat
 
Three feet!!? Now that is insurance, that's for sure! :laughing:

I'll be honest with you and tell you that I nearly missed the bore on mine. I somehow screwed up a measurement when I was really close to final size and I thought I had more room than I actually had. I was just about to take my final roughing pass and something told me to recheck the bore. If I had roughed the DOC I initially set I would have gone past the size I needed. I was able to adjust that pass and then take my two final finishing passes to come in on size but I almost blew it and would have had to start all over again. I nailed it on my first try but I had a butt-squeezing moment there!

The arbor is easier but you do have to cut an accurate OD for the bearing and on the same piece, cut a MT0 accurately. I used two 4 jaw independent chucks to do this; one to dial in the arbor accurately and another chuck that held a dowel pin to set the angle of the headstock for the Morse taper. Then I just swapped chucks and turned the taper. This made life a whole lot easier.

Like I said, it's a good thing you aren't a newbie. This looks like a simple project but it requires extreme accuracy, a well-tooled shop and really good lathe tools. At some point, you may be cursing me!
 
You mean when I'm lying on the shop floor, kicking my heels and crying? Good thing Hawaii is a loooooooooooong ways from here. Otherwise you might have to kick an old man's butt! :)

It looks like fun really. I'm up for a challenge and I'd like a better center than what I have.

Besides, it's too hot where you live for me. Our low last night was 2. :)


Cat
 
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