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Getting near the limits?

DPittman said:
SMOKE SHOW!
I used a thick sulfur based thread cutting fluid:rolleyes:?

I started off at .025" doc and then went to .050" doc. The .050" cut started about at 10 seconds in the video. I didn't notice alot of difference in machine noise or shake.
I upped the table feed to about 10"/min and things seemed about the same but more smoke, sparks and noise but nothing much worse???

I am surprised at the great finish it is doing.

Should the sparks be alarming or a sign I need to SLOW down?

Would it be a mistake to use no lubricant?

I'm afraid to try .100" doc.

The cutterr was never making full surface contact because of the rounded surface of the rail. Next passes will be different.


View attachment 31165
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If its sparking, drop the speed to 550-600rpm.

Try no cutting fluid. If not flooded, it can cause more problems. Use compressor air to clear the cuttings.

Also you are climb milling which is great for solid set-ups, try conventional milling and see if theres a difference.
 
I Googled rail steel composition:

Most modern railway tracks are made of hot rolled steel with a grade of 1084 or higher. This is a medium carbon steel, made by rolling rail steel with natural iron ore. This commonly creates a mix of steel with .7% to .8% carbon and 07.% to 1% manganese, which can handle more abuse than rolled steel alone.

So change the material parameter on your app to: Plain high carbon steel.
 
thestelster said:
I Googled rail steel composition:

Most modern railway tracks are made of hot rolled steel with a grade of 1084 or higher. This is a medium carbon steel, made by rolling rail steel with natural iron ore. This commonly creates a mix of steel with .7% to .8% carbon and 07.% to 1% manganese, which can handle more abuse than rolled steel alone.

So change the material parameter on your app to: Plain high carbon steel.
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Yes I found that same info but I selected the one I did cuz it was the only one I saw that said "medium carbon" I will go back and change that parameter and see how changes things.

I did slow things down and rhe sparks reduced and it felt better but didn't seem to make much difference on finish. Finish is pretty good imo, I can feel a bit of a ridge where the two passes meet however.
20230223_190133.jpg
20230223_190231.jpg

I squared up the edge with a carbide end mill and although I was taking just light passes and finished with climb milling, the swarf came off like needles. The thick sulfur lubricant I used made the swarf stick on the vertical side behind the cutter.
 
That ridge is prolly a slight issue with your mill tramming.

Ya, sometimes I get swarf sticking like that too. Some compressed air aimed at the right spot fixes that issue.

Glad you got it going nicely.
 
Speed kills, feed goes. At one point recommended SFM for HSS started at 30, and you would get chewed out for wearing out endmills by going faster. I’m not sure about the 100plus SFM without coolant-blast. Safe to start at 60 in mild steels, dry, forget squirting Wd40, (maybe mixed with Varsol for aluminum ) the vegetable compound sprays or pastes are pretty good but inhaling the smoke is vile.
Slotting is worse case scenario for heat build up so even lower SFM is desirable, light side milling @ .030 depths or less are far less sensitive to speed so crank them up
Climb milling also increases tool life over conventional,
HSS needs coolant over lubrication, water is an excellent coolant, emulsified coolants have the added bonus of lubrication, bandsaw blades require more lubrication than endmills.
Keep everything short as possible, long series endmills need to go slower to avoid chatter, can’t be avoided.
Your 5/8 endmill should be less than 500 RPM, it looks like a long series, so less speed and play upwards with the feed, once the chatter changes to a low frequency you are flirting with overloading in heavier cuts.
In steel, the chips should not change colour with HSS, except maybe stainless which will be straw coloured, if in steel if it’s straw or getting to blue back off the speed, keep the feed.
The reason I use carbide endmills is simply the speed and longevity and my aversion to using coolants or even lubricants, unless drilling or tapping of course.
There is excellent product coming out of Korea, Japan , Germany, UK, but are expensive and geared to controlled parameters which we cannot enjoy on a open hand controlled machines.
In short, you aren’t going to hurt anything by being conservative on speed, feed “feel” becomes increasingly difficult as you go down in size ie keyways smaller than 3/16”.
Keep the setup as short and close to the spindle as practical.
Machining railroad rails is difficult, very tough and often hardened surfaces,, HSS doesn’t like it that much. Face milling with an indexable cutter requires a cautious approach until it shows it’s colours, conservative speed 200SFM maybe and work up ,same with DOC and feed, once under the skin things should go better.
Unknown steels , same thing, difficult to know if it’s high Vanadium spring steel or Moms 80s Chevette courtesy of the scrap yard melt.
Rule of thumb with indexable milling, carbide should be either dry or wet, tossing a shot of coolant on hot carbide is not advisable, keep it dry or keep it wet.
Cheers Tim
 
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DPittman said:
Ya just for fun and experience.
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This is a fantastic way to learn. A big honkin' hunk of steel that you can fool around on! You learned:
1-that you can take large DOC, and high feeds, and still come up with a good finish.
2-you can trust that speed/feed app, (as long as you put in the correct parameters)
3-that you can depend on what you see (nice big blue chips, sparks). What you hear, (chatter, screeching). What you feel (vibrations). And adjust accordingly.

Well done.

Where can you find railway tracks?
 
thestelster said:
Where can you find railway tracks?
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How much do you want? I have some here that will never get used.

Used to be you could swipe used chunks off the side of any railroad track. They were happy to see it disappear. Then folks started turning it into a business and suddenly its off limits to anyone but the scrap dealer.

I'd just go for walks along the local tracks and look for it overgrown with weeds in the side hedgerows, then go see the farmer who owns the hedgerows (and whatever is in them). Better have a buddy my size to help you load it. The farmer prolly won't let you cut it where you found it.

Or.... Place a Kijiji wanted add.
 
Have any of you boys seen an old section hand break a rail to fit a repair. In my town there used to be a section crew stationed here full time, the section boss was an old Polish freedom fighter from WWII....( I knew too of them and believe me, the toughest dudes I ever knew, nobody, and I mean nobody ever screwed with them on their "bar nights" together).
The one guy on the RR crew could break a rail with a sledge hammer and big cold chisel in two whacks. Ive seen him do it when I was a kid. He hit the rail top on one side and then rolled the rail over and hit it again exactly opposite the first hit and that damn chunk of iron came apart like a noodle. The chisel was welded to a 3 ft handle so the holder was safe and that ol' dude took a full round house swing with that big hammer as if he was trying to ring the bell at the fair.
 
If you think rail is tough, try turning / re-trueing the wheels that were in constant contact with the rail. A specialized area making large turning inserts specifically for that application.
 
thestelster said:
If its sparking, drop the speed to 550-600rpm.

Try no cutting fluid. If not flooded, it can cause more problems. Use compressor air to clear the cuttings.

Also you are climb milling which is great for solid set-ups, try conventional milling and see if theres a difference.
Click to expand...
Carbon sparking, that’s not unusual in high carbon steel, as mentioned stay dry, or stay wet with emulsified coolants. The selection of the insert is crucial to performance, grade selection and edge prep of the insert matters, but in the end getting the job done is what matters. A good all around general purpose insert can be made to work by adjusting the parameters, I don’t have an insert for every different job, I’m also not doing it for a living anymore.
 
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