Cut-Off on Swiss

[Ox]

I have Iscar Tang Grip cut-offs on one of my Swiss lathes.
The holder is upside down, and is used as a stop (hold - not bump) for feed-out.

I hadn't had any issues before, but the last cpl days or so it has been spitting inserts out about once a day.
But the inserts go in tight, so ...

Fortunately I am running 1/4" currently, and so - even tho the insert is MIA, the holder is fine.
But that will change when I go back to 3/4" next.

Has anyone else seen this issue?

What cut-offs are you using that don't have this issue?

Maybe just put the cut-offs (main and sub) on the other side so that they are right side up?


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Think Snow Eh!
Ox

 

[Micmac1]

We have had issues with the Iscar (and haas) cutoff tools, pretty sure iscar is making the ones for haas. where inserts are pulling out of pocket on retract from the partoff groove after a few boxes of inserts, i believe the pockets get stretched out a bit from the tool used to insert & remove them.

 

[Booze Daily]

This has happened to me before with those inserts. I had to go more past center, where the back edge of the insert wouldn't catch the barstock when it reclamped. Also made a Z move away from the stock before going home.

 

[Ox]

We have had issues with the Iscar (and haas) cutoff tools, pretty sure iscar is making the ones for haas. where inserts are pulling out of pocket on retract from the partoff groove after a few boxes of inserts, i believe the pockets get stretched out a bit from the tool used to insert & remove them.

I have heard of your issue, but that should NOT be the Tang Grips?
Doo to their design, they are s'posed to resist what you are dooing.

I am not even running a sub on this job tho.


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Think Snow Eh!
Ox

 

[Ox]

This has happened to me before with those inserts. I had to go more past center, where the back edge of the insert wouldn't catch the barstock when it reclamped. Also made a Z move away from the stock before going home.

With this type?




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Think Snow Eh!
Ox

 

[zSwiss]

Adjust the force the bar feeder is putting on the bar? Or go further past X0 in attempt to get more of the stock pushing on the holder vs the insert?

 

[Ox]

OK, I edited my program to go to X-.25*, and then W-.02 before retract.

Thinking about what y'all are saying, maybe when running 3/4" v/s 1/4", maybe the OD of the 3/4" bar is pressing on the holder more?

I have these tools on a cpl other machines (fixed head) that run way more volume, and I've never had this issue.



Does anyone switch to a turning tool for feed-out?
(my next option)



* Should I go more? If so I will need to adjust my holder out.



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Think Snow Eh!
Ox

 

[Micmac1]

I have heard of your issue, but that should NOT be the Tang Grips?
Doo to their design, they are s'posed to resist what you are dooing.

I am not even running a sub on this job tho.


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Think Snow Eh!
Ox

Correct we are using the self-grip style, however i believe both tools (i could be wrong here) use similar tools for removal of the inserts. If the operator is putting to much force on the tool then this can stretch the holding pocket out over time. I think most would agree that partoff tools are universally the most frustrating holder on a lathe, always an issue and we have used almost every style. Just no such thing as a "great" universal partoff tool in my opinion.

 

[Ox]

Well, you can't over-insert the Tang Grip as they bottom out to a shelf.

I haven't used the "self grip" type hardly ever. I had it on a Brownie, and I sold that 20 yrs ago, and haven't used them since. I never liked them.


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Think Snow Eh!
Ox

 

[chad883]

I am running a job in my swiss now that is 3/8" material. When I unclamp to grab more material I could see my cut off flex a bit, then a big face cut. Pusher is pushing to hard on that small material. Is this on your Iemca? from the keypad in manual mode, push F1 Clutch, then F1 to reduce and F2 to increase. Then the arrow to push the bar to exit the clutch menu. Probably around 30 or so should be good. Set it back up for bigger heavier bars.

 

[Ox]

I have looked through the manual a lot looking for that info and never found it!

Thanks, I will try that, although I am on my last bar of 1/4 now.


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Think Snow Eh!
Ox

 

[chad883]

I say 30 or so because that is what trail and error got me to on 3/8. My collet sprung, so I am loading bars manually and with the clutch set at 20 it will not push through the main, let alone the guide, 40 was the setting that visibly flexed the cut off, so as much of a guess as anything when I say 30ish

 

[Ox]

I was at 48.

That was too low for the 3/4 as it was gitt'n stuck on the way in sometimes, but was flexing the 1/4" bars enough to throw the "movement" alarm. That may help my issue on the 3/8 as well.

I still have it popping out of the pusher now and aggin, but I think this will help a lot.
This info must be in a different manual than I was looking in...


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Think Snow Eh!
Ox

 

[cnctoolcat]

One thing I've done after years of cut-off frustration is to go with a wider tool than you normally would.

Certainly with expensive stainless and others, it stings to lose more material with each parting, but wider tools can help with problem jobs.

I've never run anything smaller than 3/4" dia. in my fixed-headstock machines, so not sure how wider-than-typical cut-off tools would work on the small stock in a Swiss...

ToolCat

 

[guythatbrews]

As you say above the bar to small for the method. It will work but sometimes bad stuff happens.

I always use a hard stop if the bar gets small enough that it solely pushes on the insert. For a 1/4 bar I would use a hard stop. Takes a bit longer but the parting insert stays put.

 

[Ox]

As you say above the bar to small for the method. It will work but sometimes bad stuff happens.

I always use a hard stop if the bar gets small enough that it solely pushes on the insert. For a 1/4 bar I would use a hard stop. Takes a bit longer but the parting insert stays put.

That's what I was leaning towards.
When I found out how the machine was set to run like this, I got wide eyed to say the least....

I take it that you are just dooing a slight face pass (+/- .005 or whatnot?) and feed into the turning tool?
You're not really feeding to a "stop" are you?

My old swiss is a sliding bushing, which is not a very common design I don't think, and thus - it feeds just like a fixed headstock. (real "stop") So I have a slight learning curve on these new(er) ones.


It sounds like my issue is common, so I guess I feel better now.


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Oh despair and agony on me!
Ox

 

[zSwiss]

Kinda funny you post this, and I am in the middle of brushing up on my swiss programming now that I have my machine up and running. Found a pick-off example that went to X-.3 after parting off (X-.03), before returning to start. Not sure I would have made the connection if not for this thread.

I am a total noob (or is it boob), but I have never seen a part off tool like that run in a swiss. For whatever that is worth.

 

[guythatbrews]

That's what I was leaning towards.
When I found out how the machine was set to run like this, I got wide eyed to say the least....

I take it that you are just dooing a slight face pass (+/- .005 or whatnot?) and feed into the turning tool?
You're not really feeding to a "stop" are you?

My old swiss is a sliding bushing, which is not a very common design I don't think, and thus - it feeds just like a fixed headstock. (real "stop") So I have a slight learning curve on these new(er) ones.


It sounds like my issue is common, so I guess I feel better now.


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Oh despair and agony on me!
Ox

No there is actually a flat stop in an axial drilling location. I use the back end of a broken 3/8 carbide endmill. I have considered using a turning tool insert but doesn't sound good to me, and very little time savings over a stop anyway. You can just use a piece of stock in a stick tool location too. I like the drilling style stop it seems more "right". Put a divot in the center to clear any parting tit if you need it, although i never have needed to.

At the start of the program the stop is positioned a bit in front of the stock, .050 or so.

1. Collet opens
2. stock stocks out
3. collet closes
4. Stock retracts from stop
5. Machining commences

I don't know what a sliding bushing machine is. Can you explain more?

 

[guythatbrews]

Kinda funny you post this, and I am in the middle of brushing up on my swiss programming now that I have my machine up and running. Found a pick-off example that went to X-.3 after parting off (X-.03), before returning to start. Not sure I would have made the connection if not for this thread.

I am a total noob (or is it boob), but I have never seen a part off tool like that run in a swiss. For whatever that is worth.

I don't think mine will go to x-.3 with the tool sticking out the standard amount. The stock would still hit just the insert at x-.3 but sure wouldn't have as much leverage so it would help.

When first starting out with the swiss the training tech said some shops never stock out against the parting tool but always use a stop. In my experience the parting tool has worked fine as long as the stock is big enough to bear on the blade and not solely on the insert. But I switch to a stop quick with small stock.

I've seen programs where at the start the parting tool just retracts in x and drags the insert across the stock. I always make a small z move, then retract x. I don't like to drag that insert like that. It can't be good.

 

[Ox]

No there is actually a flat stop in an axial drilling location. I use the back end of a broken 3/8 carbide endmill. I have considered using a turning tool insert but doesn't sound good to me, and very little time savings over a stop anyway. You can just use a piece of stock in a stick tool location too. I like the drilling style stop it seems more "right". Put a divot in the center to clear any parting tit if you need it, although i never have needed to.

At the start of the program the stop is positioned a bit in front of the stock, .050 or so.

1. Collet opens
2. stock stocks out
3. collet closes
4. Stock retracts from stop
5. Machining commences

I don't know what a sliding bushing machine is. Can you explain more?

Does your barfeeder not fault out if it sees movement?


Sliding bushing:

There is a fixed feedstock, and the bar is fed out from it like a regular lathe. But right ahead of that is a whole moving wall that has the guide bushing, as well as turret1. And it all slides together.


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Think Snow Eh!
Ox