Reply with QuoteWow I just threw the coaxial indicator on the tail stock and it is off by .030... gotta work on that
HF 7X10 Runout Adjustments
I have noticed some run-out on the lathe and I puled out the dial test indicator and at 1/2 out from the jaws I have a run-out of .0025 with a new piece of 1/4 HSS round tool stock. The chuck itself it .0015 off. When I first started down the path of machining that didn't seem like much but now it is to much. =]
Is there anyway to adjust this and how do I go about doing it?
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Wow I just threw the coaxial indicator on the tail stock and it is off by .030... gotta work on that
If I am understanding you have .001 runout. I think you are in the zone for a 7 x. Some may have more or less, but I think you are close to as good as it gets. You would have to adjust the bearing in the spindle, or upgrade them to do better. I've not done that and don't know where to look, maybe google "7 x spindle bearing adjust" or something.
You might do another test before going after bearings. Put and indicator on the chuck, then lift it with moderate pressure. If the bearings have worn in and getting sloppy, you should easily deflect the indicator at least as far as your measured runout. Probably further. If you can wiggle it and feel it move, like a click for lack of better word, you better get after the bearings, because they are sloppy loose.
If you need <.001, IMHO, your best bet is a 4 jaw chuck. You can dial those in to about nil. After you do it a few times, it becomes second nature. I never use a 3 jaw anymore, except on the mill.
You can also make collets. Mark your chuck if you haven't already. Chuck up bar of Al, brass or what ever soft metal you have, and mark it to correspond to the mark on the chuck. I used jaw 1 before I went 4 jaw, now I don't bother. Then face it, very carefully center drill it, drill it in steps to the size of what you will chuck, or a thou or two over. Boring bar should be even better, if your collet will be large enough for your smallest BB. BB also takes your tailstock out of the picture. Take it out and cut a slit down the side. If you want to get fancy, you could cut two or four slits partway through, but always just cut one slit all the way through. If you do just one slit, just make sure it will be between jaws. Then you just put the part in the collet and chuck it up with the mark on the collet lined up with that on the chuck. If you are working with several sizes, you might stamp the size on the collet, preferably before you drill it, so it won't deform. I did this for years before I mounted up a 4" 4-jaw. It works well, especially for tiny parts.
Wen I was young, I spent most of my money on fast women, slow horses, and cheap booze. The rest of it I just wasted.
I would start by indicating the runout on the taper (the inside surface of the spindle). If that is dead-on, then the problem is more likely to be headstock alignment, which is fixable, but your have to tear the whole thing apart.
Regarding the tailstock, one thing that made a huge improvement was replacing the screw and plate that clamp the tailstock to the ways. The stock one on mine was made of a thin slice of Chinese cheese and would deform as you tightened it, and you could watch it wag the tailstock all over the place. I made a cam-lock, and as part of that, made a new plate out of 1/4" 1018, and it made a HUGE difference. Looking back, I wish I made the cam-lock mod when I first got the lathe, but if nothing else, you can replace the screw and plate in very little time and $$$ and I think you'll see an improvement in repeatability.
I also recently replaced my bearings with taper roller bearings using a kit bought on eBay from lbakeland and these instructions:
http://www.arceurotrade.co.uk/projec...ges/index.html
I had replaced bearings on my mini-mill spindle before, so the procedure was pretty familiar (both machines use the same headstock assembly), and I also had already made all the tools to pull the bearings. It is a pretty involved project if you haven't done this sort of thing before, but doesn't require any special expertise or wizardry if you follow the directions.
Now, was it worth doing? So far, I feel like the lathe runs a *little* better, but it's not a huge difference. The bearings only cost $20-$30, and I haven't thrown anything really hard at it--before I did the upgrade I once tried turning some ballscrews, and that was an epic fail. I'd like to try that again before writing it off as a waste. But for my usual turning stuff--aluminum, brass, and 12L14 1" or less in size--I'm not convinced it's made much of a difference there.
Last suggestion--make parts to use them, not to measure them. That's not to say you shouldn't try make parts to .0005" tolerances when the application requires it, but you can often get by with a lot less, and get a lot more done.
You might also find this interesting: http://www.arceurotrade.co.uk/projec...on%20Guide.pdf
bob
Thanks guys. I got the run-out of the chuck to the tailstock down to a total of .005 and that will work for what I do. It just seems weird how .005 didn't seem like much when I first started out.
