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My deckel seems to be eating it's leadscrew nut

DennisCA

Hot Rolled
Joined
Oct 20, 2017
I've noticed it for some time but haven't had the chance to do anything about it.

I was seeing a yellowish sheen on the threads after a while and oil that ran out around the sides of the saddle where the lead screw was, would be blackish (on closer examination it glittered like bronze), I guess with bronze particulates. Obviously this isn't good. The backlash doesn't seem to have noticeably increased though. This has led me to use the machine sparingly to boot.

I was wondering if I had the gibs set too tight but I've tried with them entirely loose and the resistance is about the same, so there seems to be a base resistance to the system. It's not as easily sliding as the head is along the Y-axis, but it's also a lot lighter, but that's real easy and smooth in comparison. It slides easier with the gib set than the X-axis does with the gibs removed.

I took out the gibs and yes as I already knew the gibs are worn, I believe they need to be rescraped for bearing to get a better oil film.

So I think I also need to scrape the ways on the vertical table and saddle to reduce friction. I don't think this is that difficult once disassembled, since I am not altering any geometry. I'm not taking about flaking deep grooves here, that'd only be done on the gibs that are not exposed, Stefan Gotteswinter explained it well in his video where he scraped his shaper.

I removed the nut last night and found it was full of debris. I think some of it was stuff I was not able to get out when I first worked on the machine as I restored it because there was this sleeve on the nut.

I wasn't able to get off back then and I just reassembled it, figuring I had cleaned it well enough.... Well I got the cover this time with a slide hammer and was able to remove some more debris that was behind it.

I am gonna give it an even better clean now and in the ultrasonic cleaner as well. I can feel burrs on the inside so I will probably need to use something to get rid off the burrs, few licks with scotchbrite wrapped around a dowel perhaps. I am thinking this stuff is what was being eaten, the nut itself seems to look the same as last.


I will flush out the inside of the vertical where the nut sat with copious amounts of mineral spirits. Hopefully this will help a little, for now.

Though I feel I really need to take this machine apart again some day and re-scrape the bearing surfaces and backing plates. I have this hunch that the worn sliding surfaces are introducing too much friction and causing this extra wear on the screw.

I am also considering moving to Vactra #2 (68 weight) instead of #4 (220 weight), because while #4 was what I was being recommended, I live quite far north and my shop is quite cold a lot of the year (around 8-10c), I think the way oil might be too viscous under those conditions so I am thinking of moving to the 68 weight oil. I have this gut feeling that oil that is too viscous when cold would add to the making the sliding parts more difficult to slide against each other.


That's my plan for now, any feedback or ideas of your own. Anyone else encountered this?
 
I've noticed it for some time but haven't had the chance to do anything about it.

That's my plan for now, any feedback or ideas of your own. Anyone else encountered this?

Well.. mills do this s**t. Not limited to just the one axis, either. Lathes do it too. So it isn't unique to a Deckel.

Before making a plan to invade the heathens, just fit the cleaned-up nut back with the swarf TF out of it and check again?

Regardless, screw/nut & end bearings et al, can be a separate project from ways/gibs.

"downtime" is the overlap. Plan according to YOUR needs and schedule. JFDI.
 
Hey Dennis,

I don't think wear on the ways can increase drag to dangerous (for the nut) levels (actually, a worn machine is 'lighter' on the handwheels).

Your X leadscrew has a slot, check it for burrs or deformation from mishandling.

BR,
Thanos
 
Oh I don't remember this, but does the lead screw come out the door side? I really don't wanna take off the other side cover.

Nevermind went outside and figured it out...
 
I would definitely go for a thinner oil if the shop is so cold most of the year. That will make a difference. Re. the nut I suspect some misalignment crept in somehow - that's a pain to track. Try use a dental mirror to see if the screw binds in the crest of the nut or vice versa. If that's a manual machine, FP1/2/ or an LB etc I wouldn't worry much as one can make new nuts easily and from better materials. Clean it, oil it and use it.
Yes, if the ways are very worn you WILL get increased friction and stickiness and you could touch them with a scraper to get some oil going. But with a VERY light hand and keeping away from edges !!! as not to make trouble for yourself later if you scrape for alignment. Also, this is an application where some MoS2/graphite will help.
 
Hey Dennis,

I don't think wear on the ways can increase drag to dangerous (for the nut) levels (actually, a worn machine is 'lighter' on the handwheels).



BR,
Thanos

Yes, it can and quickly so when combined with adjusting gibs badly.
 
I've noticed it for some time but haven't had the chance to do anything about it.

I was seeing a yellowish sheen on the threads after a while and oil that ran out around the sides of the saddle where the lead screw was, would be blackish (on closer examination it glittered like bronze), I guess with bronze particulates. Obviously this isn't good. The backlash doesn't seem to have noticeably increased though. This has led me to use the machine sparingly to boot.

I was wondering if I had the gibs set too tight but I've tried with them entirely loose and the resistance is about the same, so there seems to be a base resistance to the system. It's not as easily sliding as the head is along the Y-axis, but it's also a lot lighter, but that's real easy and smooth in comparison. It slides easier with the gib set than the X-axis does with the gibs removed.

I took out the gibs and yes as I already knew the gibs are worn, I believe they need to be rescraped for bearing to get a better oil film.

So I think I also need to scrape the ways on the vertical table and saddle to reduce friction. I don't think this is that difficult once disassembled, since I am not altering any geometry. I'm not taking about flaking deep grooves here, that'd only be done on the gibs that are not exposed, Stefan Gotteswinter explained it well in his video where he scraped his shaper.

I removed the nut last night and found it was full of debris. I think some of it was stuff I was not able to get out when I first worked on the machine as I restored it because there was this sleeve on the nut.

I wasn't able to get off back then and I just reassembled it, figuring I had cleaned it well enough.... Well I got the cover this time with a slide hammer and was able to remove some more debris that was behind it.

I am gonna give it an even better clean now and in the ultrasonic cleaner as well. I can feel burrs on the inside so I will probably need to use something to get rid off the burrs, few licks with scotchbrite wrapped around a dowel perhaps. I am thinking this stuff is what was being eaten, the nut itself seems to look the same as last.


I will flush out the inside of the vertical where the nut sat with copious amounts of mineral spirits. Hopefully this will help a little, for now.

Though I feel I really need to take this machine apart again some day and re-scrape the bearing surfaces and backing plates. I have this hunch that the worn sliding surfaces are introducing too much friction and causing this extra wear on the screw.

I am also considering moving to Vactra #2 (68 weight) instead of #4 (220 weight), because while #4 was what I was being recommended, I live quite far north and my shop is quite cold a lot of the year (around 8-10c), I think the way oil might be too viscous under those conditions so I am thinking of moving to the 68 weight oil. I have this gut feeling that oil that is too viscous when cold would add to the making the sliding parts more difficult to slide against each other.


That's my plan for now, any feedback or ideas of your own. Anyone else encountered this?

I agree with your assumption on viscosity.
The #2 is probably all you need, and that might even in the cold be too thick.
What is the avg temp is your shop during the cold, and during the warm times?
 
Oh I don't remember this, but does the lead screw come out the door side? I really don't wanna take off the other side cover.

Nevermind went outside and figured it out...

"Meanwhile' get yourself a can of Wurth HHS-K or HHS-2000 "Hinge Lube".

- clean the ways with solvent spray until the black "stuff" ceases to appear.

Those are metal particulates, product of what an ex BAE Engineer who had done his Doctoral theses on it called "fretting corrosion". We chikn's without a PhD just call that wear and friction!

- spray the Wurth in. The light vehicle that carries the magic evaporates and leaves a molecular film so slippery you'd think Moly was sand by comparison.

And it is durable. From hinges to motorcar suspension joints that have to operate in nasty road-splash.

HHS-K hinge lubricant aerosol can 500 mL | Specialty Lubricants | Lubricants | Chemical Product | Wurth USA

NOW your choice of conventional way-lube has a sort of fall-back, under it and reinforcing it.

Downside is that it works SO very well I just haven't had to BOTHER restoring the way lube systems built-in to my 10EE's.

Wurth is all they get!

OTOH? No tacifiers. Swarf doesn't stick to it! The ways look "bare". But are not.

:D
 
I agree with your assumption on viscosity.
The #2 is probably all you need, and that might even in the cold be too thick.
What is the avg temp is your shop during the cold, and during the warm times?

Right now it's around 8C to 15C in the shop depending, since I am currently testing my homemade solar collector and using it to heat it. When it gets warm it'll be between 18-25C most times without any heating whatsoever. Usually turn on the heating around october and run it till late april.

I will look into that wurth stuff
 
I would definitely go for a thinner oil if the shop is so cold most of the year. That will make a difference. Re. the nut I suspect some misalignment crept in somehow - that's a pain to track. Try use a dental mirror to see if the screw binds in the crest of the nut or vice versa. If that's a manual machine, FP1/2/ or an LB etc I wouldn't worry much as one can make new nuts easily and from better materials. Clean it, oil it and use it.
Yes, if the ways are very worn you WILL get increased friction and stickiness and you could touch them with a scraper to get some oil going. But with a VERY light hand and keeping away from edges !!! as not to make trouble for yourself later if you scrape for alignment. Also, this is an application where some MoS2/graphite will help.

It's a manual FP2. What's the better material, over say bronze that these are used from? I was reading last night about half nut repair and reading of people using moglice to cast nuts and repair worn ones.
 
I will look into that wurth stuff

Jaguar forum guys were touting it for suspension parts. The NICE thing is that special "grease" it leaves behind CAN be removed easily if/as/when need be. It doesn't interfere with good paints as "Silicon" lubes are notorious for doing.

So it was "temporary". Until it proved to work and last so well it has become semi-permanent on ways. And not-only. The motorcars, too, and even.. ta da.. would you believe it?

Door hinges!

Go figure.

:D
 
Seems it's an american product, or they have another name for it in europe. I can find Wurth HHS 2000 instead, which seems like a similar product.
 
Seems it's an american product, or they have another name for it in europe. I can find Wurth HHS 2000 instead, which seems like a similar product.

Same stuff. Different volatile carrier AFAIK. Air-Nazi thing?

I use whichever one I can most-easily get, haven't noticed any difference.

A 10EE has a wider carriage than its total 20" traverse. So I slacked the hold-down rollers. Jacked it up a hair, kept washing and blasting with solvents and the air-gun solvent blaster until all the old particulate debris-in-Vactra-snot was out from between ways and carriage.

THEN applied the Wurth.

It still glides like silk even when there doesn't seem to be any LEFT on the ways.

Really easy to keep clean without the # 2 Vactra acting like b****y flypaper, too!
 
Hi Dennis,

I think what Thanos wrote earlier is most likely. With the relatively light use that you are giving the machine, the only process that will eat the nut is a sharp edge or burr on the lead screw which can scrape away the bronze. So take out the lead screw and with a file and stone and sandpaper make sure that the key slot which runs along it produces no sharp edges in the thread profile. You should ensure that everywhere the thread is cut by that slot, the edges are lightly chamfered or rounded.

Cheers,
Bruce
 
Yes, it can and quickly so when combined with adjusting gibs badly.

I am sure Dennis won't have the machine binding at the end of it's travels. So, it should be light enough in the most-used part of the travel where there'll be some wear.
 
I've adjusted it so the handwheel it's still turnable at the edges. I used to use an indicator and try and lift the table and see how much it deflected to get an idea, when I had less than a hundreth near the end of travel I thought that was good enough.

But I have to say, a lot of the force in turning the wheel comes from the setup itself. I removed the nut and turned the handwheel and screw and expected it to turn without resistance, but it felt not a lot lighter than when when in actual use.
 
But I have to say, a lot of the force in turning the wheel comes from the setup itself. I removed the nut and turned the handwheel and screw and expected it to turn without resistance, but it felt not a lot lighter than when when in actual use.

IF.. what you did at the initial go.. did not get the rocks, birdshit, and cat fur .. out of the nut.. there could be bearings packed with orphaned condom shreds and petrified Rhinoceros turd?

Or at least some fermented swarf seems like it!

It's a Deckel. They have this thing called "Fasching".

You've NO idea....

:D
 
...

But I have to say, a lot of the force in turning the wheel comes from the setup itself. I removed the nut and turned the handwheel and screw and expected it to turn without resistance, but it felt not a lot lighter than when when in actual use.

I guess you won't escape removing the operator's side X axis cover... You might have squeezed something there (or just, overdone it with the lock nuts). Of course, this is a different thing to your initial nut wear issue...

BR,
Thanos
 
I am sure Dennis won't have the machine binding at the end of it's travels. So, it should be light enough in the most-used part of the travel where there'll be some wear.

I'm sorry - I don't understand. What is the connection between the adjustment at ends and the "most-used part of the travel" ?
Am I missing a post ? Sorry for that, then.
 








 
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