Logan 820 Spindle Took Damage

Sorry to say, but I think you are trying to fix something that wasn't broken. Good luck.
Well yes I had a tooth missing on my back gear so I had to do that anyway.
As the first 1/2" of the inside of my spindle was carved away about 3/16th so changing the spindle out was a reasonable thing to do seeing as I had a spare already .

I just did not expect to go from perfect ir at the nose to a thousandths out with the new spindle!

Before I changed spindles I could easily remove jobs from a 3 jaw and put them back in without loosing concentricity on any noticeable level maybe a quarter of a thousandth worst case

Can't do that now. Considering putting the original spindle back in

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Sorry to say, but I think you are trying to fix something that wasn't broken. Good luck.
True, the back gear needed to be addressed, but was there a functional issue with the old spindle? I understand what you are saying about the first 1/2" of the inside of the spindle having been machined out about 0.19" - but do the HS spindle tools hold properly? You pointed out that the chucks hold repeatably to very little run out.

What is the spindle taper? If it is supposed to be an MT3? - did you try putting a center into the taper, or perhaps a drill chuck? What if you just confirmed that there are no burrs, clean it up a little if need be and see if it will hold spindle tools well. Randy may have a very good point that you are trying to fix a spindle that does not have an operational problem.
 
True, the back gear needed to be addressed, but was there a functional issue with the old spindle? I understand what you are saying about the first 1/2" of the inside of the spindle having been machined out about 0.19" - but do the HS spindle tools hold properly? You pointed out that the chucks hold repeatably to very little run out.

What is the spindle taper? If it is supposed to be an MT3? - did you try putting a center into the taper, or perhaps a drill chuck? What if you just confirmed that there are no burrs, clean it up a little if need be and see if it will hold spindle tools well. Randy may have a very good point that you are trying to fix a spindle that does not have an operational problem.
Well that's the thing I've only been operating this old beast for 2 years and seeing as I do not turn between centers very often was not sure if there WAS a functional issue. I did have some difficulty holding consistent numbers while periodically checking run out with a 12" piece of 3/4 inch drill rod. (Of course this could very well be due to my general lack of experience and crappy tools lol.) I thought that I would pull the old spindle and rerun that test, but have not gotten to that as of this moment.

So perhaps I run that tomorrow and decide.

The m3# tools "seem" to hold just fine. But mentally I have a hard time trusting using them due of course the missing 1/2 " of spindle.

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And I just really want a quick thank everyone for their opinions. It makes me feel like I could go back to the original spindle and not worry about it. I've removed it several times due to Belt issues and it always centers itself in there the same with zero IR so I'm confident if I put it back it'll be just as good

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I really think the problem is your expectations of the lathe. I for sure wouldn't go changing anything with zero run out. One broken tooth I don't think would make a difference in use. You've got a machine that's working well keep looking for problems and you'll find them or cause them.
Why not use it till something don't work. As long as parts come out right don't look for trouble. This isn't a China made redo machine. Just my advise.
 
Are you sure the original spindle was damaged? I have had a lot of 10 and 11" logans. I had one 10" turret machine (don't recall the model) that I bought as a parts doner. The spindle had a relief machined in the end of the bore. I think it was meant to have a front mounted collet closer of some sort. I don't recall if it had a taper behind the relief. I'll have to dig around tomorrow and see if I still have it. I couldn't imagine someone cutting into the spindle with a boring tool and not realizing that they had gone too far.
 
When we turn between centers we place a round in the 3 jaw and make a point.

Always true center that way.

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I couldn't imagine someone cutting into the spindle with a boring tool and not realizing that they had gone too far.[/QUOTE]
After looking at a few spindles this morning it's obvious that some people don't listen to the machine while boring. 3 of 4 had been cut into. Here's a pic of the one I mentioned that has relief cut into it....now I'm wondering if this was factory or just user error. I inserted a MT3 center and it seems to seat well in the taper. The upside is: once you've had the spindle out it's only about a 30 min job to do it again. Anyone who forgot to put the spindle through the belt the first time knows this...LOL20170924_082002.jpg
 
I couldn't imagine someone cutting into the spindle with a boring tool and not realizing that they had gone too far.
After looking at a few spindles this morning it's obvious that some people don't listen to the machine while boring. 3 of 4 had been cut into. Here's a pic of the one I mentioned that has relief cut into it....now I'm wondering if this was factory or just user error. I inserted a MT3 center and it seems to seat well in the taper. The upside is: once you've had the spindle out it's only about a 30 min job to do it again. Anyone who forgot to put the spindle through the belt the first time knows this...LOLView attachment 242453[/QUOTE]Mine is worse than this but a 3mt seats fine.

I have decided to put new grease in this bearing cuz there's a little bit of clicking going on and then reinstall the much much much much better spindle. I have removed these back and forth in there is absolutely a gigantic difference in the run out. I want the old spindle back in no question about it.
I'm currently removing the old grease from the front bearing and I have a question. Anyone that's repack one of these bearing certainly must have dealt with the cage? They say Do not fill more than 1/3 on this particular bearing but how in the hell am I going to tell what a third is trying to squeeze grease down past the cage? Bending up all those little **** to take the top part of the cage off seems undoable as I would mess it up break at least one. How do people get around this simply guess?

This is the process of used up to this point

Hot Simple Green suspending the spindle just slightly off of the bottom of the container occasionally lifting it out and let it drip out in and out in and out in and out for an entire day I then rinsed it out with several cups of thinner there's no Clickety clicking anymore to prevent it from rusting I have it soaking in a narrow container in very thin oil non detergent. I was thinking of trying to estimate the volume of the bearing slightly warm up the bearing grease I'm going to use until it's liquidy pour it in and let it solidify some will leak out but eventually it'll stop itself up.

Please tell me if I'm doing anything wrong.

I know people think that I'm doing unnecessary things to this lathe but this is very important to me the run-out is so drastically different between these two spindles. It is absolutely 100% worth switching things out it does not take that much time is very easy process.

I am not without a lathe while doing this I have a hardinge

This whole business with accuracy is made me realize that I have to migrate to a much much better lathe I'm looking for a monarch at this point. You can find them fairly cheap in the Detroit area lots of old machine shops. Shyt you can buy a hardinge fully tool for $1,000

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I can tell you that nothing that I have found dissolves the old grease better than soaking the bearing in a container of pine -sol. Thats what is suggested by Scott Logan. I use one of those little needles that you insert in the nozzle of the grease gun to shoot the grease in. I think I got them at NAPA.
 
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