# Clapped out & Climb vs Convential Milling



## Hukshawn (Mar 7, 2017)

I was reading something someone posted about a clapped out Bridgeport.
What does that mean exactly? 
Just worn out? Sloppy bearings? dovetails that won't tighten? Slop in mating/sliding serfaces? Etc.
Why would they have said that climb milling is NOT a good idea? 
Just curious.


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## brino (Mar 7, 2017)

Shawn,

You are right, simply saying a machine is "clapped out" isn't specific enough.
It does mean worn and sloppy, but as you ask where is the slop?



Hukshawn said:


> Why would they have said that climb milling is NOT a good idea?


Climb milling has the tool rotating in such a way that it tries to pull the work into the tool. If you have worn lead-screws/nuts and or dovetails the tool rotation can pull the work in. In the best case that can mean chatter and rough finish, in the worst case a broken tool from trying to take to deep of bite.

-brino

EDIT: As has been pointed out below the true "worst case" is worse than I stated above. It can result in the work piece being ripped out and thrown at you, and/or the machine damaged beyond economical repair.


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## Uglydog (Mar 7, 2017)

Great question!
And I may have been the one to use the word.
Clapped out to one person means completely usable and/or rebuildable to another.
Really depends on the tolerances you require to do your work, and your ability, interest and time available to rebuild.
I'm not sure that anything is completely unsalvageable.
A few years ago I had a 1984 1ton Chev pickup. Huge in-line 6, and a three speed with the low-low gear (for heavy pulling under 5mph). 
Lots of miles.
The floor in the cab was completely gone the box flapped in the wind, couldn't add oil fast enough. 
I gave her to a guy who wanted a project and a . 
She had some years left in her. I just didn't want to mess with her.

Daryl
MN


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## Hukshawn (Mar 7, 2017)

It wasn't on here. And it wasn't so much reading. Not sure why I wrote that. 
I was watching a video of AvE. He said his mill was clapped out and did NOT recommend climb milling.


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## Billh50 (Mar 7, 2017)

I have seen things happen on worn out leadscrew machines. Such as not only breaking end mills, but parts being pulled out of vises or completely out of clamps and flying off the machine. Heads needing to be trammed again because they moved. Bits of broken end mill hitting people in the face.
That's why it can be dangerous to climb mill with a worn leadscrew if taking too much of a bite. So always be careful when climb milling.


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## Uglydog (Mar 7, 2017)

Billh50,
Is it true that climb milling is harder on cutters (horizontal and vertical) regardless of machine condition?

Daryl
MN


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## Billh50 (Mar 7, 2017)

That is something that depends on many factors. Machine rigidity, sharpness of the cutter, amount of cut, etc.
I myself only use climb milling as a finish cut. And then no more than .005 of a cut on a good machine with very little backlash.


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## T Bredehoft (Mar 7, 2017)

The explanation I got was that when regular milling, the individual teeth momentarily skidded along the surface before there was enough pressure to 'bite.'  Climb milling they had solid material to bite into, therefore climb milling was easier on the individual cutting surfaces than  regular milling.  Logic says this may be right, I have no experience with that level of study.
I'm with Bill on finish cuts. It leaves a much cleaner surface.


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## RJSakowski (Mar 7, 2017)

Here is a good explanation of the differences, advantages and disadvantages of conventional and climb milling.
http://www.harveytool.com/secure/Content/Documents/Tech_ConventionalMillingVsClimbMilling.pdf


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## Hukshawn (Mar 7, 2017)

This was more informative than I anticipated. Even beyond the clapped out explanations.


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## Uglydog (Mar 7, 2017)

I ran down the the local tech today and asked questions.
The CNC guru stated he advocates climb milling on the super accurate CNC machines with ball screws.
Never on the manual machines unless during final passes after conventional milling.

Daryl
MN


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## Tozguy (Mar 7, 2017)

A clapped out mill would mean a worn out mill good only for scrap. Its the contrary to clapped out jeans which are worth much more than when they were new.


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## Ken from ontario (Mar 9, 2017)

If AvE was the one who said it, it must mean Fd up. he was just being unusually polite that day.


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## darkzero (Mar 10, 2017)

AvE isn't the only one that says clapped out, it's not a term from his own vocabulary (those who know what that means). Aside from machines, cars are often called clapped out. But really anything can be clapped out, even people. 

For machinery, I often only hear Bridgeports clapped out. A lathe could very well be clapped out but I never hear anyone say it. They just say the lathe is worn.


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## darkzero (Mar 10, 2017)

But yeah, as Tozguy stated, clapped out to me means badly worn, as in scrap or not worth fixing.

The first time I found out why it's recommended not to climb mill on a manual mill, it scared the dingle bells out of me. I took a machining course at the local college with my little brother. They had 4 Bridgeports, every single one of them quickly reminded you not to climb mill not matter how tight you locked everything

On a new tight mill you can get away a lot more climb milling.


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## Downunder Bob (Mar 11, 2017)

brino said:


> Shawn,
> 
> You are right, simply saying a machine is "clapped out" isn't specific enough.
> It does mean worn and sloppy, but as you ask where is the slop?
> ...


Also a broken or bent machine. I have seen horizontal spindle mills with the spindle bent from climb milling.


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## Downunder Bob (Mar 11, 2017)

Hukshawn said:


> I was reading something someone posted about a clapped out Bridgeport.
> What does that mean exactly?
> Just worn out? Sloppy bearings? dovetails that won't tighten? Slop in mating/sliding serfaces? Etc.
> Why would they have said that climb milling is NOT a good idea?
> Just curious.


In my book clapped out means well beyond worn and sloppy usually implies badly abused.

Climb milling is not a good idea except for fine finishing cuts, it's the single biggest reason for machines being Clapped out. I have seen machines broken from climb milling.


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## Downunder Bob (Mar 11, 2017)

darkzero said:


> But yeah, as Tozguy stated, clapped out to me means badly worn, as in scrap or not worth fixing.
> 
> The first time I found out why it's recommended not to climb mill on a manual mill, it scared the dingle bells out of me. I took a machining course at the local college with my little brother. They had 4 Bridgeports, every single one of them quickly reminded you not to climb mill not matter how tight you locked everything
> 
> On a new tight mill you can get away a lot more climb milling.


Perhaps, but it won't stay new and tight for long. If you have any respect for your machine you will not climb mill except only as a very light finishing cut.


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## darkzero (Mar 12, 2017)

Most guys here have hobby size mills which probably can't climb cut anyway except for light finishing. I've never even tried to take a moderate climb cut on my mill before, I wonder.


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## Rustrp (Mar 13, 2017)

Hukshawn said:


> This was more informative than I anticipated. Even beyond the clapped out explanations.



Thanks for asking the question. What I got out of this are details for two machining methods with one not recommended on a machine with worn lead screw or nut, although the recommended method may not be the best when backlash is eliminated or compensation has been made. 

 Perception changes with education, then the cycle begins again.


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## Rustrp (Mar 13, 2017)

RJSakowski said:


> Here is a good explanation of the differences, advantages and disadvantages of conventional and climb milling.
> http://www.harveytool.com/secure/Content/Documents/Tech_ConventionalMillingVsClimbMilling.pdf



Short and informative, thanks.


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## pstemari (Mar 19, 2017)

The one thing it doesn't mention is why backlash is a huge problem for climb milling. When moving towards the workpiece you're are one limit of the backlash. If you're conventional milling, when the workpiece touches the cutter, the cutter pushes the machine back into the drivescrew and all that happens is that the resistance to advancing the cutter increases. If you're conventional milling, when the workpiece touches the cutter, the cutter pulls the machine forward against the drivescrew and it suddenly jumps forward by the amount of the backlash.

Climb milling isn't a problem if the mill is tight and only has a thou or two of backlash, or (in the CNC case) if you're using gentle entry techniques when approaching the workpiece (e.g. rolling into the piece from the side.). As long as you don't have that initial cutter-snapping jerk, there's no real difference in how the machine behaves.


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## Rustrp (Mar 19, 2017)

pstemari said:


> The one thing it doesn't mention is why backlash is a huge problem for climb milling. When moving towards the workpiece you're are one limit of the backlash. If you're conventional milling, when the workpiece touches the cutter, the cutter pushes the machine back into the drivescrew and all that happens is that the resistance to advancing the cutter increases. If you're conventional milling, when the workpiece touches the cutter, the cutter pulls the machine forward against the drivescrew and it suddenly jumps forward by the amount of the backlash.
> 
> Climb milling isn't a problem if the mill is tight and only has a thou or two of backlash, or (in the CNC case) if you're using gentle entry techniques when approaching the workpiece (e.g. rolling into the piece from the side.). As long as you don't have that initial cutter-snapping jerk, there's no real difference in how the machine behaves.


One important tip I picked up was which side of the chip cutting begins, along with the heat generated or not generated in different materials and the benefits.


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## Downunder Bob (Mar 19, 2017)

pstemari said:


> The one thing it doesn't mention is why backlash is a huge problem for climb milling. When moving towards the workpiece you're are one limit of the backlash. If you're conventional milling, when the workpiece touches the cutter, the cutter pushes the machine back into the drivescrew and all that happens is that the resistance to advancing the cutter increases. If you're conventional milling, when the workpiece touches the cutter, the cutter pulls the machine forward against the drivescrew and it suddenly jumps forward by the amount of the backlash.
> 
> Climb milling isn't a problem if the mill is tight and only has a thou or two of backlash, or (in the CNC case) if you're using gentle entry techniques when approaching the workpiece (e.g. rolling into the piece from the side.). As long as you don't have that initial cutter-snapping jerk, there's no real difference in how the machine behaves.



I still say don't do it except for very light finishing cut. I've seen new machines badly damaged from climb milling. If you take a heavy cut, even one or two thou' as you suggest can make all the difference and do a lot of damage. People who insist on climb milling are just showing their lack of understanding and a degree of laziness, some in fact many don't really know what it is until it's too late.


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## KBeitz (Nov 11, 2018)




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## pstemari (Nov 11, 2018)

Downunder Bob said:


> ... People who insist on climb milling are just showing their lack of understanding and a degree of laziness, some in fact many don't really know what it is until it's too late.



I'm sorry, that that's a totally ridiculous statement. Climb milling has a known set of issues, but it certainly has its place in machining and the notion that it's going to make a machine somehow explode is nuts.

Yes, if you have a clapped out mill with 5-10 thous of backlash, climb milling is not going to work, but that's because the mill is fubar.

However, because climb milling takes the maximum chip thickness at the start of the cut and not the end, you can can take light cuts without skipping and rubbing, and it generally gives a much better finish.

Sent from my Pixel XL using Tapatalk


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## Downunder Bob (Nov 11, 2018)

Don't be sorry , be correct. you said it yourself "you can can take light cuts without skipping and rubbing, and it generally gives a much better finish." Light cuts is the operative phrase. 5 to 10 thous does not constitute a clapped out mill it's very common.

I have seen it too often, when people who think they know better, start taking increasingly heavy cuts while climb milling and all of a sudden the cutter grabs. And if a ruined workpiece and a bent spindle is all the damage, then they are lucky.

Just because you haven't been caught out doesn't make it right.

Remember this forum is here to educate there is no future in promoting misleading information.


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