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WaterH

WaterH

Well-known member
Joined
May 20, 2020
Member Number
602
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North Florida
I am making a part out of scrap yard steel. Not sure what this chunk of steel came from, but it appears to be good stuff by how hard it was to marching on the lathe. Now I need to cut a slot on the mill as you can see here.

IMG_0498.JPG


I want to cut the end from top to bottom to that shoulder on the right. I've got the vise tight as hell, but you see it's grabbing a round surface. I figured it would be hard, so I just tried a 1/4". It took five minutes and the piece got hot. I'm turning the roughing endmill slow and I have no coolent on this mill. Should I be spraying it with WD40 or cutting fluid? How deep would you cut in one pass? Is the endmill going to explode sending flaming metal through my safety glasses into my eyes?

For reference, the part I'm trying to cut is over 3" in diameter.

Any advice would be welcome.
 
I’m not a machinist.... and I mostly do CNC.

bjt 1/4” is a big DOC for steel, especially if that’s a HSS end mill. I would do .005 and go from there.

I use a fog buster as far as coolant
 
Coolant always helps. Used motor oil will be a significant improvement over dry.

You need V-blocks if you want a prayer of holding that steady.

If you want to insist on a deep cut get a smaller end mill and make the slot in multiple passes.
 
Soluble oil is what I mostly use in a recirculating bath.
 
Wd40 is close enough, use a smaller mill to rough it out first. If its really that hard you run the risk of pulling the mill out of the collet. R8's aren't that strong.
 
Also, move it down so you're grabbing on the diameter you're mill on. Hang the bigger end out of the vice.
 
Also, if you don't have a good power feed on the table you can plunge rough it with the big endmill using the quil power feed.
 
dude, spin the part 90 degrees and cut in Y, then you will be grabbing on the flat faces and it will hold much better.

how many RPM's are you spinning? 1/4" sounds like a bunch, but if your machine is still spinning it, have at it. Personally, i'd probably have tried closer to 1/8" at first and then bump it up by ~0.025 or 0.050 DOC per pass just because you say you arne't sure what is going on with it.

how hot are the chips coming off of it? how hot is the cutter getting? the part is going to get hot regardless. I can't really make out any colors or anything on the picture/this computer
 
bdkw1 said:
Also, move it down so you're grabbing on the diameter you're mill on. Hang the bigger end out of the vice.
Click to expand...
This.

Also, fuck Wd for that application, you would just be turning money into smoke.


A squeeze bottle with soluble oil as mentioned above would be best.

Somewhere between .030 and .050 would be a decent cut.
 
rockmup said:
Why would you ever clamp it like that ?

Water as coolant would be better than nothing. .050 would be a fair DOC for that tool
Click to expand...
I almost always cut dry, never use straight water.

i've got a saw that get's straight water added to it and sometimes ends up with a pretty weak mix, but it's just a saw so nobody really gives a shit about the rust, which we clean and scrub from time to time. There is no way in hell i'd introduce that kind of life to a mill.

straight water is no good, steel can be cut just fine dry though you do need to slow it down comapred to with coolant. depth of cut is determined by the nuts of the machine and the cutter so that you don't feed it too hard and snap the cutter. if the chips are coming off black, you've got a problem. if they are coming off and turning purple as/after they peal off, you are fine
 
bdkw1 said:
Also, move it down so you're grabbing on the diameter you're mill on. Hang the bigger end out of the vice.
Click to expand...

I thought about this, but wouldn't it get loose when I cut the end open?

Provience said:
dude, spin the part 90 degrees and cut in Y, then you will be grabbing on the flat faces and it will hold much better.

how many RPM's are you spinning? 1/4" sounds like a bunch, but if your machine is still spinning it, have at it. Personally, i'd probably have tried closer to 1/8" at first and then bump it up by ~0.025 or 0.050 DOC per pass just because you say you arne't sure what is going on with it.

how hot are the chips coming off of it? how hot is the cutter getting? the part is going to get hot regardless. I can't really make out any colors or anything on the picture/this computer
Click to expand...

I don't think my vise will go that wide. Also how would I cut out the end?

Not sure of the rpms, but that's the speed I use on that rougher in previous jobs.

The chips are not real hot. (Still silver) They were much hotter coming off the lathe. (Burn immediately)

Provience said:
what diameter is that rougher? are you using power feed or cranking it by hand?
Click to expand...

It's 7/8". Feeding by hand. I wish I had a powerfeed.

It would appear everybody thinks I should do shallow cuts. I thought I was being a pussy. At .050" a cut, it will take forever. I don't know if it can be seen, but there is a 3/4" through hole right at the end by the shoulder. Maybe I could set up the band saw or a chop saw and cut two slices to that hole. It would be a bitch to set up and my band saw doesn't like this stuff either. (It would get allot of material out of there.)

I'm not in a rush for this, so I guess I could just make a few passes and let it cool while I work on something else.
 
WaterH said:
I thought about this, but wouldn't it get loose when I cut the end open?



I don't think my vise will go that wide. Also how would I cut out the end?

Not sure of the rpms, but that's the speed I use on that rougher in previous jobs.

The chips are not real hot. (Still silver) They were much hotter coming off the lathe. (Burn immediately)



It's 7/8". Feeding by hand. I wish I had a powerfeed.

It would appear everybody thinks I should do shallow cuts. I thought I was being a pussy. At .050" a cut, it will take forever. I don't know if it can be seen, but there is a 3/4" through hole right at the end by the shoulder. Maybe I could set up the band saw or a chop saw and cut two slices to that hole. It would be a bitch to set up and my band saw doesn't like this stuff either. (It would get allot of material out of there.)

I'm not in a rush for this, so I guess I could just make a few passes and let it cool while I work on something else.
Click to expand...
I thought you were just cutting a slot.

As to the bold, LOL, story of my life. I do this shit every day and slow is the least of your/my worries. Wrecking tooling and or your job/one off unobtanium part will make going slow look like fun.

Using the bandsaw (Which is why I recommend everyone have a good one) is how this would be done in a shop.

Bandsaw blade stock (We make our own blades from stock) is cheap, endmills and shop time are expensive by comparison.


At your level (No offense) powerfeed would not be your friend in this application.
 
WaterH said:
I thought about this, but wouldn't it get loose when I cut the end open?



I don't think my vise will go that wide. Also how would I cut out the end?

Not sure of the rpms, but that's the speed I use on that rougher in previous jobs.

The chips are not real hot. (Still silver) They were much hotter coming off the lathe. (Burn immediately)



It's 7/8". Feeding by hand. I wish I had a powerfeed.

It would appear everybody thinks I should do shallow cuts. I thought I was being a pussy. At .050" a cut, it will take forever. I don't know if it can be seen, but there is a 3/4" through hole right at the end by the shoulder. Maybe I could set up the band saw or a chop saw and cut two slices to that hole. It would be a bitch to set up and my band saw doesn't like this stuff either. (It would get allot of material out of there.)

I'm not in a rush for this, so I guess I could just make a few passes and let it cool while I work on something else.
Click to expand...
if your ships are coming off silver, then i'm not sure what your question is.

you can turn it up a little bit in RPM until you are getting gold, but over time it might just heat up. nice thing about cranking by hand is you are unlikely to break the cutter, so keep the pressure up on it while it goes.

I do not think you should take a 0.050 cut with that thing, i just don't typically start at 1/4" if you haven't cut it before :laughing: sounds like it is fine. the great thing about the rougher is that it doesnt' care about depth of cut nearly as much, as long as your machine will keep it spinning.

why would you let it cool if your chips are still coming off good? is your cutter getting heat marks that won't go away?

if your vice won't go that big, that makes sense. V blocks will give you a better hold, but if it is working out, then keep at it and just make a few passes. ripping the part out of the vise sounds like a bad day
 
WaterH said:
A slot the whole way through. Lol. Yea, I want it split into two halves to the shoulder.
Click to expand...
do the top half, flip it over, then do the bottom half.

it might be easier if you put a shim underneath the snout when you flip it over, that way the vice is still holding the larger diameter shoulder and the slot you just cut can settle and hold it flat against the shim on the bottom, less measuring and eyeballing that way
 
Provience said:
do the top half, flip it over, then do the bottom half.
Click to expand...

I like this idea. What if I grab the part I'm milling and cut the top half. Then flip it over and cut all but a 1/4". Then go back to grabbing the big diameter to do the final cut?
 
2020AT4 said:
Why the hell would you do that?

IIRC its only rated for 3/8" drilling, youll break expensive shit doing that.
Click to expand...
You would only be taking like .200 step over, a Bridgeport will do that all year long. Not sure what they are actually rated for, but I have pushed plenty of silver and deming drills through steel with the power feed. Max feed is only .006 per rev so it's not going to ever be loaded that much.
 
WaterH said:
I like this idea. What if I grab the part I'm milling and cut the top half. Then flip it over and cut all but a 1/4". Then go back to grabbing the big diameter to do the final cut?
Click to expand...
that'd work, i'd probably leave less than a 1/4" maybe 1/8" beacause #fuckit but that amount really doesn't matter.

it would at least give you a bit more rigid hold than just grabbing the large OD and would set the small diameter deeper into the jaws
 
Provience said:
I almost always cut dry, never use straight water.

i've got a saw that get's straight water added to it and sometimes ends up with a pretty weak mix, but it's just a saw so nobody really gives a shit about the rust, which we clean and scrub from time to time. There is no way in hell i'd introduce that kind of life to a mill.

straight water is no good, steel can be cut just fine dry though you do need to slow it down comapred to with coolant. depth of cut is determined by the nuts of the machine and the cutter so that you don't feed it too hard and snap the cutter. if the chips are coming off black, you've got a problem. if they are coming off and turning purple as/after they peal off, you are fine
Click to expand...
I said it'd be better than nothing, I didn't say it was the way to do it. You can always ad a little dish soap to it if it bothers you, still better than nothing.
 
rockmup said:
I said it'd be better than nothing, I didn't say it was the way to do it. You can always ad a little dish soap to it if it bothers you, still better than nothing.
Click to expand...
agree to disagree, nothing (dry) is better than water for steel cutting.

water doesn't lubricate, it keeps the chips from drawing away the heat, it makes a damned mess and it corrodes the part and the machine:flipoff2:

edit: his chips are coming off silver, so he isn't running hot anyways
 
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Provience said:
that'd work, i'd probably leave less than a 1/4" maybe 1/8" beacause #fuckit but that amount really doesn't matter.

it would at least give you a bit more rigid hold than just grabbing the large OD and would set the small diameter deeper into the jaws
Click to expand...

I just set it up and took another .200" and it went great. It probably didn't go any differnt, but it sure feels more secure cyologicly. I used a little cutting fluid.

IMG_0499.JPG
 
bdkw1 said:
You would only be taking like .200 step over, a Bridgeport will do that all year long. Not sure what they are actually rated for, but I have pushed plenty of silver and deming drills through steel with the power feed. Max feed is only .006 per rev so it's not going to ever be loaded that much.
Click to expand...
Why not just use the quill handle like a normal person?

The power quill feed is for boring where you need a good finish.
 
WaterH said:
I just set it up and took another .200" and it went great. It probably didn't go any differnt, but it sure feels more secure cyologicly. I used a little cutting fluid.

IMG_0499.JPG
Click to expand...

how are you going to prevent the vise from crushing it as you slot the other half completely through?
 
bgaidan said:
how are you going to prevent the vise from crushing it as you slot the other half completely through?
Click to expand...
cut most of the way through, leave 1/4" or so of ledge to hold it all together, grab it by the large diameter than isn't being cut, move the cutter down so the middle-ish is cutting out the floor and send it on in, hoping that it doesn't vibrate too much. I guess keep the feed a bit lower due to the worse hold.
 
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