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fretting marks on toolholders, problem? how to fix?

ianwatts

Plastic
Joined
Oct 14, 2021
Location
Los Angeles, CA
I'm getting fretting marks on my toolholders. Below are some examples, it is like that on most of the tools. Those lines can be rubbed off with my fingers, mostly those bigger dots. I also attached pictures of what the inside of the spindle taper. Only one side of the taper has marks.

I have not had a significant crash, though if it is from crashes my guess would be on some face mills where a part is dislodged from the workholding. I do not need super accurate machining, I am making a consumer product for my own company so no medical, aerospace, etc. requirements.

Is this a significant issue? Right now I am just using a Scotch-Brite pad whenever I take a toolholder out, which mostly removes the marks (clearly not a long-term solution). If so, what are my options? Do I need to get maintenance? Is there something I can do myself? When do I need to get new toolholders?

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What torque on pull studs?
did you use loctite?
are you driving all these tools hard, ie roughing?
why is there no grease on your pull studs, and why are they rusty?
Is drawbar force correct?
Are pull studs correct?
what coolant are you using? what percent?
do you ever oil or clean the tool holders or spindle taper?

 
Those spots look like contamination and the lines, if fretting, are something I have never seen. Fretting usually covers larger areas generally on the large end of the taper. Does your machine have an air blast to clean the taper when the tool changes? How do your tools blue up in the spindle taper?
 
Those spots look like contamination and the lines, if fretting, are something I have never seen. Fretting usually covers larger areas generally on the large end of the taper. Does your machine have an air blast to clean the taper when the tool changes? How do your tools blue up in the spindle taper?
I agree looks less like fretting, more like rust. I would check coolant quality, oil level, ph... but also a better possibility is spindle air blast with water in the air lines. Or a machine with a auto air oiler that has a issue or bad or low, or non pumping oil getting to the spindle.
 
Is this a significant issue? Right now I am just using a Scotch-Brite pad whenever I take a toolholder out, which mostly removes the marks (clearly not a long-term solution).
Agreed with others that it doesn't look like fretting. You could probably bump up your coolant concentration a bit. If 7% is your target, shoot for 9-10% knowing that it'll dip on occasion. The penalty for running slightly rich is higher coolant costs. The penalty for running lean is rust, and possibly an entire sump going bad.

As for Scotch-Brite, it's just a necessary thing. It won't ruin your holders or your spindle unless you're affecting the tapers dimensionally, which is pretty hard to do for anyone with common sense.
 
Agreed with others that it doesn't look like fretting. You could probably bump up your coolant concentration a bit. If 7% is your target, shoot for 9-10% knowing that it'll dip on occasion. The penalty for running slightly rich is higher coolant costs. The penalty for running lean is rust, and possibly an entire sump going bad.

As for Scotch-Brite, it's just a necessary thing. It won't ruin your holders or your spindle unless you're affecting the tapers dimensionally, which is pretty hard to do for anyone with common sense.
Depends on the Scotch-brite pad type, we use the maroon ones with Aluminum oxide in them, they will ruin a tool holder or spindle or vise body in a few swipes.
I use Blue magic metal polish cream and a rag.
This will remove things like this but doesn't scratch the surface or remove metal aggressively like a abrasive Scotch-brite.
 
Check your drawbar retention force.
Taper doesnt look great..
And dont repeatedly use scotch brite on anything you care to retain dimensional accuracy, you are removing material and therefore exacerbating the problem.
 
anyone with common sense.
And there is the problem, it's just not common. Beware of monkey see monkey do, I have seen spindle tapers destroyed with red scotchbrite pads so I have a very healthy respect for them, and don't use them on surfaces such as tool holders or spindle tapers unless they are already pretty much toast.
 
If it's coolant it may be the ph being off and it's now somewhat acidic. It would be worth buying some ph test strips and doing a comparison between a freshly made coolant mix of the correct concentration and what you have in the sump.

If the machine is an older Haas I'd still suggest a drawbar force test. The bellevilles don't last forever.
 
I'm with the others on not touching a tool shank or spindle taper or machine way surface with a Maroon Scotch Pad. I might lightly use the one finer then that which is some kind of green gray? WD40 and a white one is good on rust too.

Never seen such localized spots appearing either. Very strange.

I never touched a Haas in my life, and never greased a pull stud in my life either. Can't see how it would make a difference with fingers pulling on a 90 degree shoulder like a Mori uses.
 
This has gripper balls, which is why the grease is suggested.
I didnt realize this was a Haas.. definitely check retention force, I see these drawbars fail daily.
 
yeah I've only been using the green/gray pads, tho will lay off and get some
Our Haas machines will start to make a pop noise when the pull studs arent greased.
what grease do you use? looks like Haas recommends Red-I tho it's hard to come by, will Mobile XHP-222 do the trick? Haas has it listed with Red-I on their website, from my research they seem pretty close.
Check your drawbar retention force.
Taper doesnt look great..
And dont repeatedly use scotch brite on anything you care to retain dimensional accuracy, you are removing material and therefore exacerbating the problem.
what specifically doesn't look great about the taper? just the rusting?
 








 
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