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deckel fp1 hit bottom in autofeed, z axis has friction now

gustimusti

Plastic
Joined
Mar 25, 2021
Hi all,

A Deckel FP1 MK2 (1960) issue.
As the threads title indicates, i managed to hit the bottom of the z axis because i forgot to reinstall the autostops after cleaning. Happened after moving the machine with the table in its lowest position, wanted to raise the table the lazy way, but hit the shifter to wrong direction. In a fraction of a second I realized what happened. But too late, too stupid.

Good thing, the shear pin snapped, so no damage there.
Bad thing, the table was stuck at the bottom. I released the bolts and tapered pins on the block that holds the elevating screw and bevel gear, and some gentle taps, to release a bit of pressure. And turned with some force (no tooling, but turned the handwheel with two hands to get the table loose.
It worked, but the z-axis handwheel turns not smooth anymore. It feels like a constant friction in the elevating mechanism... The powerfeed turns ok by hand.

1) Could It be possible the z axis nut has been deformed because reaching the end of the threads on the rod?
2) Or worse, did I bend the handwheel axis because to much force?
3) Or... could it be possible something happened on the z axis elevating screw rod? Misaligned bushing?


I read some threads on 'hitting the bottom', but none says anything on a z axis handwheel with friction afterwards...
 

AlfaGTA

Diamond
Joined
Dec 13, 2002
Location
Benicia California USA
My guess is that you have distorted the threads in the nut...
But some additional info will paint a clearer picture of your troubles.

First off doubt that you bent the lead screw as in the lowered position it is right up to the nut and there would be little free length of the screw to bend...
Second the elevating handwheel is out of the picture...it does not drive the slide when using power feed...Its just along for the ride and would not see any force when the slide bottomed out....

If the tightness is the same for the full length of the vertical movement (top to bottom) Then most likely its not an alignment issue, although it won't hurt to
"float" the nut with the slide lowered as much as you can and still get to the bolts that hole the nut....Just lower the slide, loosen the nut retaining bolts, then re-tighten....

My guess is that you have damaged the nut. Time to pull the vertical slide up to get the screw clear of the nut...Remove the nut and inspect...test it on the screw , it should be free ,no binding.
For info about lifting the slide search this forum, some good info posted that others have provided .

Cheers Ross
 

Alan

Cast Iron
Joined
Nov 28, 2002
Location
Perth, Australia
Some good guidance provided by Ross, I will expand slightly based on my machine which is the same era as yours. Where the Z axis screw goes into the lower housing, remove the 2 screws and lift the cover with the oil access point, this will reveal the power input feed bevel gear and the drive shaft for all axis.
The Z axis bronze feed nut is in front of that shaft and held in with 2 cap screws, if you lock the saddle and support it with 2 pieces of timber its possible to undo these screws and wind the handwheel and withdraw the bronze nut up the screw and then it will provide some indication of where the restriction is.
Where the Z axis goes into the saddle casting there is a thrust bearing under the external housing and its possible this may have been pushed up slightly and is binding, there should be some clearance between it and the housing. Alan.
 

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gustimusti

Plastic
Joined
Mar 25, 2021
My guess is that you have distorted the threads in the nut...
But some additional info will paint a clearer picture of your troubles.

First off doubt that you bent the lead screw as in the lowered position it is right up to the nut and there would be little free length of the screw to bend...
Second the elevating handwheel is out of the picture...it does not drive the slide when using power feed...Its just along for the ride and would not see any force when the slide bottomed out....

If the tightness is the same for the full length of the vertical movement (top to bottom) Then most likely its not an alignment issue, although it won't hurt to
"float" the nut with the slide lowered as much as you can and still get to the bolts that hole the nut....Just lower the slide, loosen the nut retaining bolts, then re-tighten....

My guess is that you have damaged the nut. Time to pull the vertical slide up to get the screw clear of the nut...Remove the nut and inspect...test it on the screw , it should be free ,no binding.
For info about lifting the slide search this forum, some good info posted that others have provided .

Cheers Ross

Thanks for the guidance! I've removed the saddle just before this accident to clean the whole machine. But did not clean the clutch system inside the saddle (was in pristine condition). At that time I had the horizontal spindle removed before the saddle. Is it possible to not remove the horizontal spindle and lift the saddle high enough to clear the z axis nut and bevel gear feed rod drive?
 

gustimusti

Plastic
Joined
Mar 25, 2021
Thanks!
I will check both options, first the nut, and if that is not the case hopefully it's just the thrust bearing. Could it be possible the nut in the fourth picture holding the gear sprocket is also providing preload/play on the thrust bearing? Or is it just holding the gear on the axle?
 

Alan

Cast Iron
Joined
Nov 28, 2002
Location
Perth, Australia
From memory its holding the gear on the axle and of course that holds the whole assembly in place, my photos didn't capture a lot of detail in that area unfortunately. Alan.
 

gustimusti

Plastic
Joined
Mar 25, 2021
Thanks!
I will check both options, first the nut, and if that is not the case hopefully it's just the thrust bearing. Could it be possible the nut in the fourth picture holding the gear sprocket is also providing preload/play on the thrust bearing? Or is it just holding the gear on the axle?

Well... it is not the bronze nut. I lifted the table until de spindle thread was out of the nut, but still friction when turning the handwheel. Proceeding to next option: removing saddle (again) from mill, and checking the assembly inside. Hopefully I can fix it without the need to remove the gearing assembly inside.
 

gustimusti

Plastic
Joined
Mar 25, 2021
Well... it is not the bronze nut. I lifted the table until de spindle thread was out of the nut, but still friction when turning the handwheel. Proceeding to next option: removing saddle (again) from mill, and checking the assembly inside. Hopefully I can fix it without the need to remove the gearing assembly inside.


Well, found the time to remove the saddle (again). And it is the nut. It was impossible to turn the nut on the axle by hand. Normal position got stuck at 2 turns. Reversed, it managed to go almost to the end, and stuck about two turn from the end. So problem was in the beginning of the nut. The wings at the nut have been bend by the uplifting force and, my guess, deformed the upper (thin) part of the nut. Maybe also a bit of twisting, deforming, who nows?

Given the idea the lower part (pressed in casting part) was ok, I slit open the upper part to give it some relieve. When remounting I added a spanner to just hold it tight when lifting the table all the way up. Its better now, but still at the least worn part of the axle is a bit harder to turn the table up or down.

If anyone would have the same stupid issue as I created myself, please check and recheck the bottom nut carefully ;)
 








 
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