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FP2 logn reach head nod, can it be?? (very long post)

thanvg

Hot Rolled
Joined
Mar 3, 2015
Location
Greece
Dear all of the Deckel-party hi,

I would like to share my latest adventures today, trying to perform a highly advanced machining operation, and ask for your thoughts on, at least one, of the problems I...faced! The advanced machining operation was to ... face the top of a 400 x 250 mm cast iron plate flat...

My machine is of the early, 500 mm X variety, so the 400 mm of the plate should pose no issues. Regarding the 250 mm dimension, I did not feel like moving the piece or the long-reach head, so I just opted for a largish (100 mm) indexable face mill. Sure, it is not ideal not to exit the piece at both sides for each pass, but nevermind, the requirements for accuracy and finish are not tremendous.

So, I mounted the part on an old mag chuck and started experimenting with speeds/feeds. (the latter did not end up well at all, see end note for this...). Took the first pass along the X, then moved the Y (in the direction away from the machine) and took another pass along X. To my surprise, there was a considerable step between the first and the second pass!!! Did not measure it, but it seemed and felt like 0.1 mm at least, which is huge! And the funny thing, the second pass, the one further from the machine, was HIGHER!

attachment.php


Unable to explain it at the moment I reversed my way of working, switching to facing along Y, stepping over at X and taking the next pass along Y. (of course, since I was not able to exit the part after each pass, the finish was 'compromized', as if it was any good at all to begin with...). Now there was no step between one pass and the next one, so I went on like this till the end. (my old mill has a bit of knee rock, but not so much that it would end up showing as step between each pass after stepping over at X).

Trying to explain my initial issue, I tried to analyze the (crappy) finish, have a look:

attachment.php


(you can all see the excellent quality of the casting, I think I would have done it better if I tried myself...)

Ignoring the awfull rubbing during stepping over, one can see that my face mill is not cutting all the way round. It seems to be cutting only with the part furthest from the machine as would be the case if the head was not perfectly trammed in the nod direction and, of course, if it was a Bridgeport and could nod! (ok, there are Deckel heads that can nod also, but not mine). If the head is set this way, that is the axis of the spindle not parallel to the Z ways, but at an angle towards the Z screw (you know, nod), then I would both see the head cutting only at the front when working along Y and see a step when working along X and stepping over along Y, which exactly what I have. Nod it is then...

Unless I am completely stupid, these stand:
- the setting of the tilting table, or the condition of the mag chuck, don't play any role at all. Whatever you place under the spindle and hold it firmly enough, should end up flat.

- since Y on our machines is not on the table, there are no weight transfers and table droops for the different Y settings. (flexing could be increased milling further from the table base, but would not end up in such huge problems)

- since my mill is far from new, there could be wear in the Y ways that would end up in ram droop as it exits the machine. However, this droop would be gradual and would not end up in steps or uneven facing, it would just mean that my machine's Y axis is not any more square to Z. I would have trouble in squaring items but they should still be flat!

Based on the above, I can only imagine that there is some kind of nod in the long-reach head. I can't imagine why the round front surface that allows for tilting would have worn unevenly but I have to check.

At this point I have to admit that I have mistreated my long-reach head since I got the machine, one year ago. I mean that should have repaired the rear clamp (manual's "clamping strap") which is worn to the point that the slot has closed (I think this is a regular failure) and, well, replace the front missing clamping strap, which was absent when I got the machine....I know, many points removed from me for that....A good friend suggested I should ask Singer for the part, I said I'll make it a project, and this is what it still is, one year later...

In any case, since I am not at the workshop and I am not sure about the geometry, could the missing clamp, if installed, help raise the front part of the head? I recall that the head has an angled surface there and the clamps press against it, it could be that, if the clamp was there, it would push the head upwards and restore the nod?

If I have got it all wrong here, can anyone think of a, realistic, explanation of the nod, or my problem with the steps altogether?

Looking forward to the forum's input!
Many thanks in advance!

BR,
Thanos

ps. So, my speeds/feeds (1250 rpm, around 100 mm/min) were not good. Or, at least, not for the depth of cut (very shallow, 0.2 mm tops) I needed. So, I think I ended up rubbing instead of cutting, piece got hot, facemill got hot, spindle got hot, quill got hot, and, exactly at the last mm of machining, something seized! Spindle stopped, quill did not move, IR thermometer measured 100 deg C at the face mill and around 80 at the spindle and the head casting....I did not do anything stupid with water or spray cans, just dunked the face mill in motoroil and dripped motor oil onto the casting as well. After a while it cooled down, and it seems to be working ok now. Still, I think I should take it apart and replace the grease on the spindle bearings, since it took some heating and that can't be very good...
Not only do I lack the experience to properly set my machine/cutting tools, I also lack the common sense to probe for temperature increase. Just put your damn hand on the head stupid, it would suffice....
I should probably have gone to the beach instead of the workshop today...
 
Also, I have some trouble finding a way to measure this nod and prove it's there.

On our machines, you can't trust anything mounted on the vertical X slide, actually the head is used as a reference to set tilting table square (or, tram a fixed table).
The X slide itself will induce possible droop errors, which can easily be 'fixed' in real life with the tilting table.

All I need to check, I think, is how off from square is the spindle from the Y travel...Now how would I do this???
 
Hi Thanos,

I'm not familiar with the long reach head so can't offer any specific suggestions. That being said, why not quantify how much nod there is by either sweeping the table or indicating a shaft placed in the spindle.

I'm not sure I would use the surface finish of your part to make an assessment of your head geometry. At 1200 rpm, you were running anywhere from 2 to 12 times too fast depending on your inserts and whether there was coolant involved. You likely destroyed the inserts early on and cutting forces and heat could have more to do with what you are seeing than head nod.

Teryk



Sent from my XT1710-02 using Tapatalk
 
Sorry posted before seeing your second post.

You can check for nod by placing a ground shaft or alignment bar in the vertical spindle and sweeping it with an indicator along the Z travel. On my FP1 with the tilt swivel table I do this before adjusting the table to make sure I am setting it flat when swept with an indicator in the spindle.

Teryk

Sent from my XT1710-02 using Tapatalk
 
Hi Teryk, thanks for the replies,


Hi Thanos,

I'm not sure I would use the surface finish of your part to make an assessment of your head geometry. At 1200 rpm, you were running anywhere from 2 to 12 times too fast depending on your inserts and whether there was coolant involved. You likely destroyed the inserts early on and cutting forces and heat could have more to do with what you are seeing than head nod.

Sent from my XT1710-02 using Tapatalk

You are right for sure regarding the destruction of the inserts, they're completely shot. However, I selected such high speed after checking some generic quidelines online regarding cast iron machining. Also, only going higher than 1000 rpm did the finish start trying to shine a bit. It was dull lines for lower RPM. Did use some oil to stop sparking, though I, till now, have always followed the 'machine CI dry' suggestion.

Anyhow, back on subject: I think I noticed the step even during my initial tests, that is even for much lower speed/feed!

Sorry posted before seeing your second post.

You can check for nod by placing a ground shaft or alignment bar in the vertical spindle and sweeping it with an indicator along the Z travel. On my FP1 with the tilt swivel table I do this before adjusting the table to make sure I am setting it flat when swept with an indicator in the spindle.

Teryk

Sent from my XT1710-02 using Tapatalk

Well, as I mentioned earlier, this is the obvious approach, and I'll give it a shot, using the machine's setting arbors. But, in principle, some table droop where Z ways are mostly worn could mess with the results. But, indeed, if one tries a couple of setups with different DTI base extension lengths, that would lead to working on different regions on Z, and gets the same results, no need to look further.

However, it would be nice if I could do a direct test, that is check perpendicularity of the spindle axis to the Y ways.

BR,
Thanos
 
most likely that face mill has too many inserts for that particular mill to handle (rigidity wise), meaning - each insert curing the cut is producing a pressure on the spindle (z axis), the more of them you have engaged in the work at any given time - the more pressure you put on the spindle (why it got so hot), condition of the inserts, geometry, material etc all influence with what you can get away with

the first diagram shows this very well (I added side view in the attached picture to explain) - think about from where the cutting edge is coming into the work - if it comes from the edge of the part - there is no pressure from below and it can take the cut to the set depth, but when it is over the work and lots of inserts are in contact with the just cut plane - there is pressure generated and the face mill as a whole is pushed up

solution (if you want to keep using the 100mm face mill) is to reduce the number of inserts, just take out most of them, or leave just one and use it as a fly cutter, it will be a lot slower, but there will be a lot less pressure generated as well, might solve the problem and get the job done

flat_facing.JPG

p.s. if you look at the part just like it is shown in the picture, most likely if you measure the height of just machine surface, you will see that the right and the left side are actually on the same height, and then gradually it becomes higher going from left-right till you reach the step line
 
To my surprise, there was a considerable step between the first and the second pass!!! Did not measure it, but it seemed and felt like 0.1 mm at least, which is huge! And the funny thing, the second pass, the one further from the machine, was HIGHER!

I should probably have gone to the beach instead of the workshop today...

Beach detour or no, you sure as Hell need to do some serious reading.

Not a Deckel specific "problem".

There's just a great deal more to being a mill hand than knowing which handles move what and in which direction. The only "surprise" is that you didn't have even WORSE outcomes. Yer poor Deckel was trying to save yerazz, but even a Deckel cannot do miracles ALL the time! Not HEAVY mill class "miracles", anyway.

Study-up!

You need to grow yerself more "understanding" before others can find the hooks to hang even the most basic of advice onto.

HINT #1: You do NOT have to replicate every sub-optimal move ever made on a mill.

It is not "cheating" to ascertain BEST practices and go directly to them. There be books on this s**t. Also PM's archives.

Common sense about basic lever arms? Thot that was once a "local product", your part of the world?

:)

PS: HINT #2: Waddya suppose happens if you set that part up at 90 degrees ... use the Deckel's HORIZONTAL capability to work the face of it, instead of the top? WITH appropriate tooling, speeds, and feeds, even?

All machine-tools and their tooling have strong points. They also have not-so-strong points.
Try to work into their strengths, always. Their weaknesses, never.
 
most likely that face mill has too many inserts for that particular mill to handle (rigidity wise), meaning - each insert curing the cut is producing a pressure on the spindle (z axis), the more of them you have engaged in the work at any given time - the more pressure you put on the spindle (why it got so hot), condition of the inserts, geometry, material etc all influence with what you can get away with

the first diagram shows this very well (I added side view in the attached picture to explain) - think about from where the cutting edge is coming into the work - if it comes from the edge of the part - there is no pressure from below and it can take the cut to the set depth, but when it is over the work and lots of inserts are in contact with the just cut plane - there is pressure generated and the face mill as a whole is pushed up

solution (if you want to keep using the 100mm face mill) is to reduce the number of inserts, just take out most of them, or leave just one and use it as a fly cutter, it will be a lot slower, but there will be a lot less pressure generated as well, might solve the problem and get the job done

View attachment 234867

p.s. if you look at the part just like it is shown in the picture, most likely if you measure the height of just machine surface, you will see that the right and the left side are actually on the same height, and then gradually it becomes higher going from left-right till you reach the step line

Hi jz79, thank for the reply,

I value your input, but, there are signs proving that this is not what I am dealing with here: As I mentioned, I switched to zig-zaging the other way, that is cutting along Y and stepping over along X. Due to Y travel limitations I was not able to exit the part before stepping over, so the cutter was engaged at all times. However, there was not steps parallel to the Y axis as should be according to your explanations. There are tooling marks on the part, can't feel step with the nail.

BR,
Thanos
 
Beach detour or no, you sure as Hell need to do some serious reading.

Not a Deckel specific "problem".

There's just a great deal more to being a mill hand than knowing which handles move what and in which direction. The only "surprise" is that you didn't have even WORSE outcomes. Yer poor Deckel was trying to save yerazz, but even a Deckel cannot do miracles ALL the time! Not HEAVY mill class "miracles", anyway.

Study-up!

You need to grow yerself more "understanding" before others can find the hooks to hang even the most basic of advice onto.

HINT #1: You do NOT have to replicate every sub-optimal move ever made on a mill.

It is not "cheating" to ascertain BEST practices and go directly to them. There be books on this s**t. Also PM's archives.

Common sense about basic lever arms? Thot that was once a "local product", your part of the world?

:)

PS: HINT #2: Waddya suppose happens if you set that part up at 90 degrees ... use the Deckel's HORIZONTAL capability to work the face of it, instead of the top? WITH appropriate tooling, speeds, and feeds, even?

All machine-tools and their tooling have strong points. They also have not-so-strong points.
Try to work into their strengths, always. Their weaknesses, never.

Hi thermite, thanks for taking the time to answer although it seems that I forgot a disclaimer in my original post and got a bit of a hostile reply...So, please take into account that I am not a machinist, I've taken no courses on machining and I have zero professional experience in machining. However I love machining and I am trying to learn as much about my hobby and my machines, some times with the help of this forum explaining what exactly goes wrong. So bear with me, some things that are obvious to many here may not be to me.

Trying to decode your hints, I think that you mean something similar as jz79, that the long-reach head is flexible, so after the increased load of the facemill making full contact with the part it raised a bit (hence the 'lever arm' and ancient Greeks reference). If this was the case then I would have the same problem when I changed direction of zig-zaging, as I mentioned in my reply to jz79.

Regarding your second hint, why did I not work horizontally, well, I guess there is not much to be said here: flat mag chuck allowing machining of the whole face at once VS angle plates, clamps etc.

Which of course, I would do, if I got advice from the forum that this kind of job is too much for the FP2 vertically. Is this what you are saying? I see facemills up to 160 mm in Deckel's manual, and no mentioning that they are intended only for the horizontal spindle or for maching plastics or aluminum. My feeling is, as yourself said, that this is no FP2 limitation, it can handle this job as I set it up. But, either there is a nod issue that I have to solve, either I was WAY wrong with cutter setup, which I certainly was.

So, any recommendation on cutter type and speeds/feeds that the FP2 can handle horizontally for machining CI? Or any ideas regarding the, possible to me, geometrical bug in my machine?

BR,
Thanos
 
Hi jz79, thank for the reply,

I value your input, but, there are signs proving that this is not what I am dealing with here: As I mentioned, I switched to zig-zaging the other way, that is cutting along Y and stepping over along X. Due to Y travel limitations I was not able to exit the part before stepping over, so the cutter was engaged at all times. However, there was not steps parallel to the Y axis as should be according to your explanations. There are tooling marks on the part, can't feel step with the nail.

BR,
Thanos

the same effect I described is most certainly affecting the outcome when you switched to the step over axis, but probably to a lesser extent, the rubbing you're seeing when you're stepping over is indication of that, it shouldn't be there if things are going well, least of all on cast iron

I had this very same problem with a tool steel block I was squaring on a Russian FP1 like mill, switched over to more rigid horizontal spindle, reduced step over from 80-90% to 30% with my 50mm 4 insert face mill and it the issue was fixed, reducing the step over in my case meant that instead of 3 cutters engaged in the cut in the 80% step over case I had only 2 in the 30% step over, and that was enough in my case, FP2 most certainly is a much more rigid mill the the USSR 679, but 100mm face mill at those speeds and conditions IMHO is a push over...

also - with the speed you were cutting, and cast iron sparking, I'm pretty sure you were hardening the surface, which ruined the cutting edges and exaggerated the issue

I also think that one shouldn't expect much in the way of "shiny" finish when milling cast iron
 
Hi thermite, thanks for taking the time to answer although it seems that I forgot a disclaimer in my original post and got a bit of a hostile reply...So, please take into account that I am not a machinist, I've taken no courses on machining and I have zero professional experience in machining. However I love machining and I am trying to learn as much about my hobby and my machines, some times with the help of this forum explaining what exactly goes wrong. So bear with me, some things that are obvious to many here may not be to me.
That's not "hostile" unless your actual PLAN is to NOT learn but rather play the perpetual ingenue. Even then, I'd be indifferent rather than hostile.

You have no "mentor" at your very elbow to convey the lore directly. Most folk my age did have. Several mentors, actually.

Not your choice. Not your fault. Not even your location. Time and circumstance, mostly. They've gone scarce, anywhere, and scarcer-yet outside of an active major shop of long-standing.

Ergo you need to read. No help for it. And not just PM, but that, too.

Regards,

Bill
 
the same effect I described is most certainly affecting the outcome when you switched to the step over axis, but probably to a lesser extent, the rubbing you're seeing when you're stepping over is indication of that, it shouldn't be there if things are going well, least of all on cast iron

I had this very same problem with a tool steel block I was squaring on a Russian FP1 like mill, switched over to more rigid horizontal spindle, reduced step over from 80-90% to 30% with my 50mm 4 insert face mill and it the issue was fixed, reducing the step over in my case meant that instead of 3 cutters engaged in the cut in the 80% step over case I had only 2 in the 30% step over, and that was enough in my case, FP2 most certainly is a much more rigid mill the the USSR 679, but 100mm face mill at those speeds and conditions IMHO is a push over...

also - with the speed you were cutting, and cast iron sparking, I'm pretty sure you were hardening the surface, which ruined the cutting edges and exaggerated the issue

I also think that one shouldn't expect much in the way of "shiny" finish when milling cast iron

Yet, last time I tried, with my favorite face mill with SEKN 1203 AFTN inserts (very friendly for lightweight machines) I did get an, almost, mirror-like finish. Problem is that is is only 70 mm so it would be tight to try and mill the whole surface in one setup.
 
Ergo you need to read. No help for it. And not just PM, but that, too.

Regards,

Bill


Hi Bill, thanks for the reply.

So, as friendly as can be, I must say that the 'you need to study' advice is a bit indefferent...You have all the rights in the world to be indifferent to the next amateur that is messing with your profession and wasting your time, but if you want to help, this is not helping much.

I certainly need to learn a lot about insert milling. Not only regarding speeds/feeds/power but also regarding type for each specific work. Any pointers apart from the carbide manufacturers' datasheets that are a bit biased and, mostly, aiming at more powerfull and new machines?

Also, studying aside, do you think that the FP2 cannot handle a 100 mm cutter for light facing with the vertical head? (stemming from your hints to switch to vertically) If this is a fact, this is wisdom that I can derive only here...somebody musth have tried this for sure. (I cannot provide data on the face mill at this point, but it has positive rake and squarish inserts with only the point in contact with the work. I mean, it was not a monster with a flat or rounded bottom that would need dozens of kW to work properly)

Hope you can help

BR,
Thanos
 
Thanos,

I think that Teryk is right on the money. Your speed/feed was way off.

A good cutting speed for carbide in hard cast iron is perhaps 80 meters/minute. The circumference of your facing head is about 315mm, so each 3 revolutions is about a meter. Thus a good speed would have been around 250 rpm. You want each insert to cut away perhaps 0.05mm, so if there are 6 inserts that means 0.3mm per revolution which at 250 rpm at around 80mm/min feed. I tend to be conservative with feeds, and a faster feed might be better.

A further point. Sometimes cast iron parts have a "skin" which is harder than the inside if the part, because they cooled faster on the outside. So when you cut, it's smart to go deep enough that you are UNDER this layer. In your case, if you were only removing a fraction of a mm from a "raw" casting, you might be inside this harder layer, which is more difficult to cut.

Last point to keep in mind, if your facing head is "rattling" a lot as the inserts enter/leave, then snug up the bronze brake ring at the top of the vertical head; that's what it's for.

Hopefully you did no lasting damage to the mill.

Cheers,
Bruce

PS: Ignore the critics above. All of us (including those critics!) have made plenty of mistakes. The key thing is to learn from your mistakes so that you don't make them again. This is especially true for mistakes where you are injured or could have been injured.
 
Hi Bill, thanks for the reply.

So, as friendly as can be, I must say that the 'you need to study' advice is a bit indefferent...You have all the rights in the world to be indifferent to the next amateur that is messing with your profession and wasting your time, but if you want to help, this is not helping much.

I certainly need to learn a lot about insert milling. Not only regarding speeds/feeds/power but also regarding type for each specific work. Any pointers apart from the carbide manufacturers' datasheets that are a bit biased and, mostly, aiming at more powerfull and new machines?

Also, studying aside, do you think that the FP2 cannot handle a 100 mm cutter for light facing with the vertical head? (stemming from your hints to switch to vertically) If this is a fact, this is wisdom that I can derive only here...somebody musth have tried this for sure. (I cannot provide data on the face mill at this point, but it has positive rake and squarish inserts with only the point in contact with the work. I mean, it was not a monster with a flat or rounded bottom that would need dozens of kW to work properly)

Hope you can help

BR,
Thanos

Thanos, life is waaay too SHORT to learn anything much at all "the hard way", effectiveness of poison, venomous snakes, bullets to the brain, or parachute / no parachute personal testing choices only the really OBVIOUS ones.

The way humans progress is to learn as much as we possibly can from OTHER PEOPLE's mistakes, just as much as from their successes.

It's faster, even if the "mentors" are not pleasant.

You can choose to put in the effort to master the machines.

- Deckel capability and limitations were well-known a very long time ago. Querying them NOW is not the goal. You plan to re-design the beast?

UNDERSTANDING and respecting what IS should be your near-term goal.

Or you can f**k around with NOT BOTHERING to make that investment .... so you can carry-on a socially pleasant "discussion" of each new f**k-up for long weeks, each go.

Your choice.

- Talented amateur, ever learning and growing.

- Or perpetual dilettante who skips RIGHT OVER several basics, so as to debate minutiae as if the REAL issues mattered not a wit.
 
Thanos,

I think that Teryk is right on the money. Your speed/feed was way off.

A good cutting speed for carbide in hard cast iron is perhaps 80 meters/minute. The circumference of your facing head is about 315mm, so each 3 revolutions is about a meter. Thus a good speed would have been around 250 rpm. You want each insert to cut away perhaps 0.05mm, so if there are 6 inserts that means 0.3mm per revolution which at 250 rpm at around 80mm/min feed. I tend to be conservative with feeds, and a faster feed might be better.

A further point. Sometimes cast iron parts have a "skin" which is harder than the inside if the part, because they cooled faster on the outside. So when you cut, it's smart to go deep enough that you are UNDER this layer. In your case, if you were only removing a fraction of a mm from a "raw" casting, you might be inside this harder layer, which is more difficult to cut.

Last point to keep in mind, if your facing head is "rattling" a lot as the inserts enter/leave, then snug up the bronze brake ring at the top of the vertical head; that's what it's for.

Hopefully you did no lasting damage to the mill.

Cheers,
Bruce

PS: Ignore the critics above. All of us (including those critics!) have made plenty of mistakes. The key thing is to learn from your mistakes so that you don't make them again. This is especially true for mistakes where you are injured or could have been injured.

Hi Bruce, thanks for the rrply,

I've checked more thoroughly now and it, indeed, seems that the SFM value I trusted was intended for way larger/faster/more robust machines. Still, my initial attempts at much lower surface speeds resulted in that semi-rough CI finish. Isn't there a way to do better on the FP2? E.g., Bruce, when working on your lathe's cross slide replacement, what kind of finish did you settle with?

Regarding CI surface scsle, I am aware, and feared it especially on this crappy casting. That's why, I, initially, took the part yo a friend with a huge shaper and had it roughed out. Worst thing, you'd have to regrind a Hss bit, no biggie! (See, I do care about my mill!)

So, it seems I'll redo the part, at reasonable speeds/feeds and see whether that step insists, since that's what you all suggest...

BR,
Thanos
 
Thanos, life is waaay too SHORT to learn anything much at all "the hard way", effectiveness of poison, venomous snakes, bullets to the brain, or parachute / no parachute personal testing choices only the really OBVIOUS ones.

The way humans progress is to learn as much as we possibly can from OTHER PEOPLE's mistakes, just as much as from their successes.

It's faster, even if the "mentors" are not pleasant.

You can choose to put in the effort to master the machines.

- Deckel capability and limitations were well-known a very long time ago. Querying them NOW is not the goal. You plan to re-design the beast?

UNDERSTANDING and respecting what IS should be your near-term goal.

Or you can f**k around with NOT BOTHERING to make that investment .... so you can carry-on a socially pleasant "discussion" of each new f**k-up for long weeks, each go.

Your choice.

- Talented amateur, ever learning and growing.

- Or perpetual dilettante who skips RIGHT OVER several basics, so as to debate minutiae as if the REAL issues mattered not a wit.

Hi Bill,

What more can I say.... I've been asking for some help since the first post, you keep saying that I need to learn, get mentored, learn from others' mistake, but spent so many words wihout sharing knowledge, mentoring me, sharing your (or others') mistakes....

I mean, come on, how can I not skip the basics if you keep them to your self?

The CI surface scale, the fp2's increased robustness in horizontal and the fact that I was going too fast are some basics I know (or learned today). If you can share the rest of the basics, you'll certainly help. And you can bet, I won't bother you again with the same basics, I am a good learner...(can't promise about other basics though, as we've said, too much way in front of me).

bR,
Thanos
 
It seems like people haven't mentioned anything about cast iron work hardening, if you try to cut it like aluminum you might as well not try at all.
The best advise I can give to a machinist who insist on finding fault in the machine he runs is to take a look at the chips he's making; they have all kinds of information if one is smart enough to look. If sparks are coming off cast iron forget about machining, might as well try facing it with a cutting torch.
Dan
 
It seems like people haven't mentioned anything about cast iron work hardening, if you try to cut it like aluminum you might as well not try at all.
The best advise I can give to a machinist who insist on finding fault in the machine he runs is to take a look at the chips he's making; they have all kinds of information if one is smart enough to look. If sparks are coming off cast iron forget about machining, might as well try facing it with a cutting torch.
Dan

cast iron is a highly variable material by nature, and while my first reaction to a 100MM face mill going 1200 rpm on an old manual mill was "good god" (or something like that), SOME occasional sparking in cast iron is not necessarily a de facto indication of the operator doing something wrong, as CI can and will have iron carbide inclusions and other hard spots such as occasional sand or investment inclusions, even in good quality castings.

as to work hardening, properly seasoned graphitic iron is about the least likely to undergo work hardening of anything I can think of, and white cast iron is hard as glass to start with, so CI can be inconsistent, but WH? I don't think so, not like stainless (particularly the higher carbon stuff).

Thanos, hang in there buddy! some of us will try to tell it to you straight, without trash talking and piling on, but don't expect to get all your instruction, or even just the basics, here. you can also get some really bad advise here too!

one thing I will say, the heat buildup you were seeing should have told you SOMTHING was deeply wrong here, didn't you notice it smelled hot? now there is a tip, one reason to use a lube, wax like Boelube or oil even on cast iron is just to monitor the temp of your operation.

a good machinist uses all his senses.
 








 
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