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Old 03-14-2010, 10:14 PM   #1
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Default Dead center and filing

I need to turn some 7/8" diam by 9" long pieces out of 1" 6061. I didn't get a live center when I bought my lathe (used). I'm assuming that I need to use some kind of oil/grease with the dead center. What should I use? I'm new to a lathe and haven't used a center yet. Any tips?

I also need to put a gradual concave curve about 4" long. The curve radius isn't critical as this is not part of a mechanical assembly. I thought I would use a 1/2 round file. Is using a hand file while its turning ok?


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Old 03-14-2010, 10:44 PM   #2
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Default Re: Dead center and filing

Hello Hob, to answer your first question, yes you should use a lubricant when using a dead center to ease the frictional heat build up. The best type that I know of is a leaded lithium type white grease. Just a small-ish dab is all that is required, enough to not be slung all over the room when operating the machine is all. don't apply excessive pressure from the tailstock, just enough to support the piece, after all you aren't drilling for oil. In a pinch, I have even used motor oil but had to continually apply it and it gets quite messy in a hurry. Any high pressure grease will give you optimal results if you do not purchase a live center before hand. Now to address your second question, *harumph* yes. To properly use a file on a part being turned in a lathe requires extra attention to what is going on. Hold the file by its forward most end firmly and at the rear, do NOT hold it so that the tang is in line with your palm, that is grip the file off the one side or better yet, grind the tang completely off or get a wooden handle for it. Be certain you know where the chuck jaws are by applying some white out correction fluid the jaw edges so they are visible when the machine is powered on. To get satisfactory, even tapers, may I suggest you use a cut off tool to make grooves cut to the depth you want along a given profile and then cut away and file to these grooves. This technique is used extensively by woodworkers when they wish to cut specific outlines. I do hope this helps you some and please do use the utmost care with those files, they can be dangerous.

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Old 03-14-2010, 10:55 PM   #3
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Default Re: Dead center and filing

Jim is right on all counts. Using a file with a handle is necessary for all applications, but on a lathe is is absolutely necessary.

One other thing is that the file will probably clog up on the aluminum, so a file card or some other means to clean the file every few strokes will be necessary. If you don't it will leave gouges from the particles in the file teeth. Some people use chalk or kerosene on the file to reduce the clogging.

Also, check the tailstock pressure regularly. The aluminum will expand from the heat and the pressure will increase so you will probably have to back off the tailstock occasionally. If you leave the job for a while and the aluminum cools off check the pressures as it will probably need increasing.

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Old 03-14-2010, 11:22 PM   #4
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Default Re: Dead center and filing

Gail you stated, (Using a file with out a handle is necessary for all applications, but on a lathe is is absolutely necessary). I don't mean to be judgmental, but I know of NO time when it is safe to use a file with out a handle.

Have a great day!

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Old 03-14-2010, 11:51 PM   #5
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Default Re: Dead center and filing

Thanks Rex.

I knew what I was trying to say, but screwed up the typing. The post has been edited. I should proof read my posts more carefully.

EVERY File in the shop should have a handle at ALL times.

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Old 03-15-2010, 12:45 AM   #6
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Default Re: Dead center and filing

Gail, I had visions of people running to their shops and removing the handles (Ha Ha).
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Old 03-16-2010, 12:51 PM   #7
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Default Re: Dead center and filing

Be sure to take note of the need to adjust the tailstock pressure as the work heats up. This is not a big deal; you can do it while the lathe is running. Just back off the tailstock ever-so-slightly, then advance it again until it "feels right." You'll know. I generally adjust it at the end of each cutting pass. It takes only a few seconds.
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Old 03-16-2010, 02:12 PM   #8
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Default Re: Dead center and filing

Rex & Gail,

I fully support you in the fact that if a file has a tang, it MUST be fitted with a handle. A great many nasty accidents have been caused by not following that rule.

But just to mention another way.

I have been using files on the lathe with the tangs cut off for as long as I can remember, and especially now that I don't have a lot of strength in my arms and hands.

For me personally, a long file with a handle on is downright dangerous, and short files are only just acceptable with handles on. I am so far away from the pressure point of the file when using the handle that I have very little control over it and it is liable to slip off the piece I am filing or into the chuck jaws.

Another thing, I think people try to remove too much material with a file, I rough shape with the lathe tool first, then only use a file for removing the machining marks or slight adjustment to the profile. Like at the bottom of this post, where I made a shaped handle.

http://madmodder.net/index.php?topic...sg7755#msg7755

I also use a lot of files with the tangs cut off when dressing materials on the workbench, I find them much more controllable, holding them by fingertip, it gives a lot more 'feel'. Actually, the only time I really use files with handles on is when I am filing something being held in my bench vice, but more often than not, I use an air driven power file instead.

I am not saying that my way is correct when you look at all the documentation written about such things, but I personally find that the written way doesn't suit my way of doing things, and in fact, I feel decidedly unsafe when using files with handles on the lathe. So if you feel unsafe using files with handles on, maybe you should try them like I do.

So now when you see files in my pics, you will most probably notice that they don't have handles on, because there are no tangs. Unless it is a set up shot to explain a method.

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Old 03-16-2010, 02:45 PM   #9
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Default Re: Dead center and filing

Quote:
Originally Posted by Mainer
Be sure to take note of the need to adjust the tailstock pressure as the work heats up. This is not a big deal; you can do it while the lathe is running. Just back off the tailstock ever-so-slightly, then advance it again until it "feels right." You'll know. I generally adjust it at the end of each cutting pass. It takes only a few seconds.
You should only adjust the tailstock pressure (if the work is held in a chuck) while the lathe is running. If you are working a piece between centers stop the lathe before adjusting the tailstock.

SAM


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