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stevehgraham
11-15-2016, 06:56 PM
I haven't used my 3-jaw lathe chuck in a while. I used it to do some threading in cast iron hand wheels. Now I'm learning about the perils of cast iron dust.

The lathe was doing 20 RPM when I did the threading, so dust wasn't flying all over the ways of the lathe, but there is quite a bit of dust in the chuck. Should I take it apart and clean it before I use it again?

Toolguy
11-15-2016, 07:48 PM
It would be a good idea. Normally all you need to do is take off the jaws, clean them good and clean the scroll, put the jaws back in.

10KPete
11-15-2016, 08:55 PM
Cleaning out the chuck should be a routine part of cleaning the lathe....

It gets dirty, clean it!

Pete

Mcgyver
11-15-2016, 09:00 PM
i would take it apart, it should be clean, but don't go through life too worried about cast iron dust (some seem to). afaik the issue is sand castings can sand on the outer crust which is abrasive and the outer scale of the casting or hunk of durabar is slightly abrasive (same as hot rolled steel)....but once past that and into clean cast iron I don't think its to be worried about more than other chips

DS_park
11-15-2016, 09:05 PM
Now I'm learning about the perils of cast iron dust.

Ok I'll take the dunce cap.
Used to turn rotors and drums at a repair shop. Very messy and we had a dedicated shop vac for the machine.

From a home shop perspective, what are some of the perils of cast iron dust we should be aware of?

stevehgraham
11-15-2016, 09:55 PM
What I have seen and read is that people consider cast iron dust to be an abrasive which is similar to lapping paste.

It would be very nice to hear that this isn't true, since I got quite a bit of it on my chuck and the front of the carriage.

dalee100
11-15-2016, 11:07 PM
Hi,

It kind of, sort of, maybe could cause some accelerated wear. Unless you constantly are turning cast iron, there isn't much to be worried about. Wipe exposed surfaces when done and blow it off it it seems really dirty. I certainly wouldn't strip a chuck down just because I turn a bit of iron.

But, it's your shop and your machine. You must do what you are comfortable with.

Dalee

10KPete
11-15-2016, 11:13 PM
More important with machining cast iron is protecting your lungs. A vacuum extractor at the source really helps you and the machine! I've blown enough black snot out to know....

Pete

Blazemaster83
11-16-2016, 12:08 AM
I machine cast iron often, and use an 8" 6 jaw chuck. It is a pain in the ass to take apart and clean, but it needs to happen. I made up an adapter for my electric drill so I can take the jaws out quickly. I also have an adapter on my shop vac that goes really small, to get into the jaw slots. It's one of the small jobs I hate doing lol.

Joel
11-16-2016, 12:47 AM
Easier than cleaning (at least when grinding or sanding) is to keep stuff from getting in there in the first place. I often stuff a piece of foam in the chuck behind the part to keep crap out, and on occasion, have even put masking tape over the open slots.

Joe Rogers
11-16-2016, 05:54 AM
Ok I'll take the dunce cap.
Used to turn rotors and drums at a repair shop. Very messy and we had a dedicated shop vac for the machine.

From a home shop perspective, what are some of the perils of cast iron dust we should be aware of? The dust from brake rotors/drums is nasty. The last time i used the lathe without a mask I had a sinus/bronchitus infection that was hard to overcome.
Joe

Mcgyver
11-16-2016, 06:47 AM
What I have seen and read is that people consider cast iron dust to be an abrasive which is similar to lapping paste.

It would be very nice to hear that this isn't true, since I got quite a bit of it on my chuck and the front of the carriage.

post #4

Doozer
11-16-2016, 08:16 AM
If you use your lathe any amount,
take out the jaws weekly and clean the slots.
Maybe once a year, split it and clean the scroll annulus.

-Doozer

Fasttrack
11-16-2016, 11:57 AM
Yep - definitely clean your chuck. It should be a routine thing and CI dust mixed with some oil or, worse yet, a little bit of moisture, will quickly become a thick goopy (or downright hard, cement-like) mass that makes your chuck nasty to use.

That said, I'm with Mcgyver. Brake rotors are a special case, as is chilled cast iron and the skin on sand castings, etc. but once you get through the skin on a machinable cast iron, I'm not sure I believe that it is more abrasive than anything else commonly machined. Maybe the issue is just that the dust is much finer and tends to get places where a big chip couldn't get. But the dust from ductile cast iron is really just iron and carbon (aka graphite as in the stuff you use as a dry lubricant).

I've done a fair amount of work with CI fixing up old machines and I try to be reasonable about the cleanup. From my perspective, the biggest danger is the dust mixing with oil or moisture and setting up like concrete!

stevehgraham
11-16-2016, 05:48 PM
I'm taking it apart. Unfortunately, I ran out of brake part cleaner, so I'm stuck waiting until the infernal traffic dies down and permits me to go get more.

Surprisingly, almost no cast iron got on the screws or scroll.

I'm reading up on lube. It looks like I put grease in it last time, and that was a bad idea, because it caught swarf and tried to jam up. I've read that Vactra and moly gear oil are two good choices. I have both. I am leaning toward the moly stuff because it's made for high pressure. Someone holler if there is a good reason to use something else.

Andre3127
11-16-2016, 06:00 PM
From a home shop perspective, what are some of the perils of cast iron dust we should be aware of?

Dry surface grinding. Wear a mask, it's a must.

You get that iron taste in the back of your throat and welders snot. Those disposable (reusable for a long time, really) surgical masks do just fine.

stevehgraham
11-16-2016, 08:11 PM
I guess I was smart to take it apart. Taking a 16" set-tru chuck apart is quite an adventure. The scroll did not want to come out, and I believe this was caused by crud that had made its way between the scroll and the chuck housing.

The chuck has some kind of thick grease behind the scroll and around the pinion. I don't have anything like that, except high-pressure center lube, so it looks like it will be moly gear lube for me.

J Tiers
11-16-2016, 08:59 PM
Regular cast iron isn't so bad. The big issue with it is generally that it makes dust, and not chips. THAT is more of a problem than the actual CI composition, which is, after all, carbon and iron, just like steel.


The dust from brake rotors/drums is nasty. The last time i used the lathe without a mask I had a sinus/bronchitus infection that was hard to overcome.
Joe

Brake drums and discs ARE NASTY.....YES. The problem with them is the rust on them.

Rust is the same material as rouge polishing powder, so it is indeed an abrasive, and would function as a lapping compound, although it is usually used as a final polishing compound.

CI is not alone in rusting, steel does too, so ANYTHING rusty is bad news, drenching the machine in polishing powder. You'll want to clean THAT off. But dust from clean CI? Maybe no big deal aside from being a powder that gets in where chips cannot fit, and may have some abrasive qualities.

Certainly it is more abrasive than plain oil.......

pinstripe
11-16-2016, 11:13 PM
I'm reading up on lube. It looks like I put grease in it last time, and that was a bad idea, because it caught swarf and tried to jam up. I've read that Vactra and moly gear oil are two good choices. I have both. I am leaning toward the moly stuff because it's made for high pressure. Someone holler if there is a good reason to use something else.

Bison uses and recommends grease. Fuchs Gleitmo 805 anywhere, or "Machine grease 2" for the scroll and teeth. http://www.fuchs-lubritech.com/products/pastes-and-grease-pastes/overview/product/show/gleitmo-805-661.html

They also recommend oil every eight hours for "heavy operating conditions". Inspection every six months, and a tear-down at least every year.

big job
11-17-2016, 03:50 AM
My attack plan is a big zip lock over the chuck with a big elastic. And the air gun not allowed in here....

boslab
11-17-2016, 05:13 AM
Related or unrelated you decide, we used to sample iron from 2 blast furnaces, the disks were about 4-5% carbon, hard so they were dry ground with an 80 grit cup wheel, the dust was sucked out with a dust extractor, that was the problem, free carbon in the form of graphite, very fine it used to clog the filters of the dust extractor, short out the motor and coat the room we did it, it was everywhere, black dust.
It got silly, I gave up grinding and bought a mill to do the samples, a fanuc robodrill, much better, even glass hard samples milled easily.
For a while I got the pleasure of making standards, they were turned, the lathe was getting stinking, I ruined a chuck, so I used to put a plastic bag over the new one, poke it up the bore and tywrap it round the spindle, kept the grunge out
Mark

stevehgraham
11-17-2016, 03:13 PM
I got it open and had quite a time getting rid of the old grease. The manufacturer used something like thick Vaseline in there. Getting it out was no fun at all. Brake cleaner barely disturbed it. I had to use paper towels, a toothbrush, and dishwashing liquid. Then I had to oil it up to keep it from rusting.

I put high-pressure lube on the gears. I figured it was closer to the original lube than moly gear lube.

I've learned a lot about chucks. I can see why American and European chucks cost more. This chuck only has one pinion, which works fine but isn't quite as luxurious as three. The machining inside my chuck is adequate but somewhat unfinished. For half the price, I am not complaining.

I saw a Tubalcain video where he took an old Burnerd apart. It was constructed so it was very hard for swarf to get to the gears. Not so with my chuck. There was enough crud below the scroll plate to convince me all the lube had to go.

I plan to put it back on the lathe and adjust it as soon as I find the M8-1.25 cap screw I misplaced.

J Tiers
11-17-2016, 04:01 PM
Many of the best quality chucks have one pinion. They will vary as to the accuracy you get with each, since the scroll moves with the force. Always using one means you always get the same result. If an adjist-tru, you will stay "adjusted true" better using the same pinion always.

stevehgraham
11-17-2016, 06:35 PM
I got it down to around half a thousandth of runout, and I called it quits. Adjusting these things is a pain. You zero it, you tighten it down, and the zero disappears. You loosen it, you zero it, you tighten it down...

Fasttrack
11-17-2016, 07:28 PM
I got it down to around half a thousandth of runout, and I called it quits. Adjusting these things is a pain. You zero it, you tighten it down, and the zero disappears. You loosen it, you zero it, you tighten it down...

Sounds excellent to me. Even though it's a "set-true", it's still a 3-jaw ;) If I need better than a few thousandths, I pull out a 4-jaw or collet.

stevehgraham
11-17-2016, 09:31 PM
It's great, but if you work on it, you can get one of these things so accurate, you can turn a piece, turn it around in the chuck, turn it again, and barely be able to detect the point where the cuts overlap. I was just tired of fooling with it. That gunk the factory put in the chuck made the job last three times as long as it should have.