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pntrbl
07-10-2007, 02:38 AM
Still being at the aspiring grasshopper level I get a kick out of the small mundane aspects of machine life that most of you guys would probably find trivial. That being said ... take a look at this pile of cast iron swarf under my lathe!

http://i115.photobucket.com/albums/n300/pntrbl/CastIron001.jpg

There's a 5" magnet under there somewhere ....

I won't be adding much more to the pile because I've finally managed to find most of the 2.25x8tpi backplate that was inside that 6x2 round I started with. Still got the final OD to fit the chuck and 4 holes to go but I'm thinking I'm over the hump.

http://i115.photobucket.com/albums/n300/pntrbl/CastIron002.jpg

The kick I got out of the pile was nothing compared to the satisfaction of screwing that thing onto my spindle, but hey, I'm enjoying all of it.

SP

Forrest Addy
07-10-2007, 03:59 AM
Thing about cast iron is it's so dirty. Graphite and dust everywhere. Fortunately the chips are mostly small and granular and suck up with a shop vac very well. You do need good suction so use a fresh filter in the vac. An old one used for sawdust etc is most likely clogged to about 25% available flow.

I work a lot of cast iron and I've found a shop vac to be an essential adjunct of a clean, low dust shop is important to you. By the way. Don't wait too long between emptying the vac; 16 gallons of chips can weight several hundred pounds.

slim_jim
07-10-2007, 04:03 AM
Hmm.....I never thought I would hear the words "cast iron" and "fun" in the same sentience.
although it can be amazing how fast CI chips accumulate cut the nasty stuff all day at work (CNC of corse) And along with 13 other guys we manage to fill a 20 yard dumpster in about a week. And if all that iron was not enough we use flood coolant. The CI powder sticks to the coolant oil and makes a nasty past that gets everywhere. since all we make are pulleys, we call the stuff
"pulley poop"
Now I Know what you are thinking, a 20 yard dumpster full of chips has cut to be heavy. If I am not mistaken iron weighs about 499Lb per cubic Ft. and I do know that a pile of chips is approximately 2/3 air. You do the math......
Almost forgot what I was getting at, the back plate looks good, nice surface finish. Keep up the good work.

Evan
07-10-2007, 06:12 AM
Nice job on the back plate. Save the turnings. They are a good nutritional supplement. :D

Iron in your cereal (http://www.physicscentral.com/athome/iron.html)

Your Old Dog
07-10-2007, 07:48 AM
Who does the body and paint jobs on you cars and lathes? :D That lathe looks too nice to use!

No cast iron experience here. I'd be OK if it stayed that way.

pntrbl
07-10-2007, 08:55 AM
My painter is me YOD, but it's nuthin' special. Just a couple brushed coats of oil based enamel. No primer, bondo, etc. I did dis-assemble and thoroughly clean before painting. SOS pads in a sink of hot soapy water on everything but the bed, but only because it wouldn't fit in the sink! I did get a little anal on sanding the old paint down to feathered edges ....

Something had to be done for the poor thing. This is what it looked like when I met it.

http://i115.photobucket.com/albums/n300/pntrbl/before-1.jpg

It's already getting some chips on the carriage but that's OK wit' me. No garage queens here. As a matter of fact I never liked the looks of a dirtbike until I'd rubbed some paint off the frame with my boots.

SP

pcarpenter
07-10-2007, 11:46 AM
You did a nice job on the lathe and the backplate looks good too!

Was the picture taken part way through? The reason I ask is that it needs a "register" cut carefully to just fit into the recesss on the back of the chuck. This helps define center and keeps it from sliding on the backplate under load. If you already knew that, forgive me for insulting your intelligence.

Watch the cast iron dust. You will find gray stuff when you blow your nose...you might ought to wear a dust mask if you are working with lots of it dry. Dry is considered the standard way to machine it by the way. I am sure coolant would help with the dust and may be the only reasonable option in a production environment. I have heard stories of grind shops working on cast iron where the air was just a haze. I'll bet that's a life shortener. I would think you could get black lung that way.

Do be sure to clean the cast iron grit off the lead screw, thoroughly. I like using an old toothbrush as you can press the bristles into the threads and let it work like sort of a wiper while the lead screw turns. Lead screws are a delimma. On many lathes like mine, you don't use them but for threading...but by the time you need it, its lubricant is imbedded with all sorts of chips which make a horrible lapping compound for the half nuts and lead screw. With all the mechanism down at the apron and the half nuts hovering close to the screw itself, a cover for the lead screw is not really practical. I have it on my list to order a spare pair of half nuts for my chinese lathe before they become unavailable.

Paul

Seastar
07-10-2007, 12:01 PM
Good job, and it looks like you used the correct color for that old but good Logan.
At least it looks like the color on mine.
Bill

Mcgyver
07-10-2007, 12:17 PM
never understood the aversion to machining CI, I love the stuff, well at least if it's the good stuff like nice Stuart castings or continuous cast bar. It machines so nicely and no stringy chips

Paul just read your post, never really noticed the dust, and isn't only chips from the crust of sand cast that you have to worry about, so far as the grit getting into things? if there was a lot of dust (ie i wear a mask when surface grinding dry) it would bother me.

lazlo
07-10-2007, 12:24 PM
never understood the aversion to machining CI, I love the stuff, well at least if it's the good stuff like nice Stuart castings or continuous cast bar. It machines so nicely and no stringy chips

Same here -- I like machining fine-grained cast iron. It crumbles off. Like Forrest suggested, I vacuum off the table every couple of passes, but man does it make a mess inside the shop vac if you have anything wet in there :)

I also wear a paper mask if I'm milling (because my face is closer to the work), and when I come inside the house my Wife and Daughter tell me that I look like a coal miner with a clean spot in the center of my face ;)

I've only machined DuraBar/VersaBar and a couple of finely-made gray castings, but I have read about issues with machining foundry castings that haven't cooled uniformly, so there are chill (hard) spots the endmill hits.

pcarpenter
07-10-2007, 12:32 PM
My only aversion to it is that it makes grit that goes under way wipers and clings to lead screws where a long stringy chip will not. Even good way wipers only protect the very portion they wipe. They don't do anything for lead screws, under compound and cross slide ways (where there are no wipers), etc. I have heard the recommendation that you wipe the lube from all the way surfaces. Thats fine if you don't then use it dry very long. Not to mention that I worked hard to replace all the ball oilers and put in felts to hold oil so that they release oil even between squirts from the can. If this works right, there is no such thing as a dry way surface.

The magnet idea is sort of a joke with anything but a tiny job. I used a really powerful rare earth magnet out of a large hard disk drive and it still only holds the grit that falls close by. The rest of the shower of cast iron goes everywhere. The magnet and bag are one more thing to clean up. You still have to get out the shop vac to clean up the rest of the lathe as Forrest said.

I guess I am a little soured as my last experience with it was truing the 12" face plate that came with my lathe. That may be worse than ordinary as it was large in diameter and had slots in it that guaranteed that it really flung the nasty grit. It was like a giant paddle wheel in a way.

Paul

Frank Ford
07-10-2007, 12:45 PM
When I first did some cast iron, I got the stuff everywhere, so next time I cut some 1/6" neoprene sheeting to cover the ways as if I were planning to grind. It worked so well, I keep the sheets in place virtually all the time. They are hardly in the way, and they keep the machine really clean. My wipers have nothing to wipe.

http://www.frets.com/FRETSPages/Machining/Magnets/RubberSheet/rubbersheet01.jpg

Got 'em on the mill, too:

http://www.frets.com/FRETSPages/Machining/Magnets/RubberSheet/rubbersheet.html

Mcgyver
07-10-2007, 12:48 PM
but I have read about issues with machining foundry castings that haven't cooled uniformly, so there are chill (hard) spots the endmill hits.

yup, trying to do the brother-in-law a favour with a set weights (reboring the hole), what a disaster. other guys have used weights as a source of CI without trouble, but CI is one material where the variance between good and crap will leave you loving it or hating it.....stay away from barbells and window weights and stick to Stuart castings and Durabar if you want to like machining CI :D

mklotz
07-10-2007, 01:17 PM
"There's a 5" magnet under there somewhere ...."

I hope you remembered to put that magnet in a Ziploc baggie before you put it there.

Joel
07-10-2007, 02:43 PM
I keep one of those .99 cent shower rod covers over my leadscrew. It does a great job of keeping it clean between threading jobs.

http://img.photobucket.com/albums/v186/JoelinTX/CStop3.jpg

Timleech
07-10-2007, 03:13 PM
This made quite a pile of CI chips:-

http://web.onetel.com/~duttondock/Pictures/Clutchcone.jpg

It's a clutch operating cone, made from 7" dia bar, with a 4.25" hole up the middle.
I tried to get cored bar, but there was nothing available.

Tim

pcarpenter
07-10-2007, 03:45 PM
Joel-- great tip on the rod cover. I didn't even think of something that was thin enough that it would slip *inside* the half-nuts for lead screw protection. It probably has the added advantage that it prevents accidental half-nut engagement while the feeds are engaged...something that is present on better US made lathes and not on some of the cheaper lathes.

Paul

lazlo
07-10-2007, 04:39 PM
I keep one of those .99 cent shower rod covers over my leadscrew. It does a great job of keeping it clean between threading jobs.


That's very clever! I was thinking of something complicated like a telescoping ballscrew cover :)