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rambaudi v2 spindle

BobbyM

Plastic
Joined
Feb 22, 2018
Hello

I'm Bob and this is my first ever threat.
I bought a rambaudi v2 mill witch i am fixing/reconditioning.
As i was checking the spindle and bearings,because i had some chatter,i saw that the bearings dont have a press fit but can slide over the shaft/spindle.
The spindle assembly is the same as that of a bridgeport.
I measured the shaft,and its 34.99mm on "virgin" part of the shaft.
ofcourse the id of the bearings is 35.00mm.
the bottom bearing has made some weare on the shaft and made it 34.98mm.
my question is,is this normal/exeptable for this type of machine?
Are the bearings going to stay in place just by the preload?
I put new bearings in and everything sounds and looks good as far as i can Judge.
But i cant let go of the thought that the bearings dont have a press fit,and was hoping somebody could tel me if this is normal with older machines.
its an early model v2.
I will try to put in some pictures.

thanks in advance to you all
 
If you want to improve it you can have it cromed
With only a 0.01mm layer no need to grind it probbably
Or nickle plating That you can do yourself with tampon plating You could do that in the lathe
The bottem one ,depending on design ,could also be fixed in location with locktite
On some designs you can glue both bearings in place
I know Rambaudi had several spindledesigns. I saw 3 already

Peter
 
Thank you Peter , that sounds to be a good solution.yet strange its factory ground 0.01 undersised.
 
For metric dummies like me that 0.01 =0.0003937008." or .0004"

You Said

I measured the shaft, and its 34.99mm (1.3775591")on "virgin" part of the shaft.
of course the id of the bearings is 35.00mm (1.37795").
the bottom bearing has made some wear on the shaft and made it 34.98mm (1.3775591").
.0004" is .0002" per side. Are you a hobbyist doing work in 0.0254mm (.001") or a production machinist doing 0.00254mm (.0001") ?

I say...lol

If it was a precision grinder I would have it chromed and ground, but it's a milling machine doing hobby work, I might just leave it alone and loc-tite it with the green or blue color.
 
I agree that Loctite assembly compound should be a good enough solution.
Moreover, I am pretty sure that the cause of the chatter is somewhere else and not in the spindle.
Check the "lost motion" on table, saddle, and knee, and adjust the gibs to leave no more than 0.05 mm of play (unless the ways are unevenly worn and the saddle and table bind somewhere else).
You might have excessive play between the quill and the housing as well.

Paolo

PS The "lost motion" is the movement perpendicular to the sliding direction. To test the lost motion between the table and the saddle, you would mount an indicator on the saddle and measure horizontally on the edge of the table, while pushing and pulling in the Y axis direction.
 
Also on some worn machines I leave the quill, knee, saddle and table lock snug or a slight bind when moving them. If the machine is worn and you tighten the gibs up in the middle where they are worn, they will get stuck when you move to the ends. I do lock solid when I am not moving the other slides. also if you cut against or conventional and not climb milling. Climb milling will pull the work into the cutter and if the screw and ways are worn, you can screw things up big time. Be sure the cutter is sharp and tight in the collet.

here is an explanation:

In Conventional Milling, the cutter rotates against the direction of the feed. During Climb Milling, the cutter rotates with the feed. Conventional Milling is the traditional approach when cutting because the backlash, or the play between the lead screw and the nut in the machine table, is eliminated

milling machine conventional cutting and - Google Search
 
Thanks for the reactions.
very cool to get a reaction from you mr King sir.
I am very interested in the art of scraping and love reading about it here on the forum.
I am indeed a hobbyist, and that is the reason i dont know if 0.01mm is a problem in this case.
Just in case i am going to put some locktite between the bearings and the shaft.That sound like a good solution.
The mill is worn but useable and i wil check for the lost motion.my surfacemill gave a very nice finish in one direction with "circle scratches",in the other direction it gave a half circle pattern.
maybe this explanes something about the lost motion.
Thabnks again for the help.
 
Thanks for the reactions.
very cool to get a reaction from you mr King sir.
I am very interested in the art of scraping and love reading about it here on the forum.
I am indeed a hobbyist, and that is the reason i dont know if 0.01mm is a problem in this case.
Just in case i am going to put some locktite between the bearings and the shaft.That sound like a good solution.
The mill is worn but useable and i wil check for the lost motion.my surfacemill gave a very nice finish in one direction with "circle scratches",in the other direction it gave a half circle pattern.
maybe this explanes something about the lost motion.
Thabnks again for the help.

When you're using " Loctite " bearing fit be very careful not to get any of the liquid inside the bearings. It happened to me once and it's a beggar to remove.


Regards Tyrone.
 
That finisch is probably because your head is not at 90 ° of the X motion
I would also check the spindle and half nut on the X axe
This is of a particular design with a long half nut mounted under the table and a short 2pc spindle in the saddle. OD is about 60 mm
That spindle can be adjusted for backlach If that half nut is worn you have a problem

Peter
 
Ive got the head trammed in as good as possible,With the wear and All, and the half nut and the spindels look like new.
But today i found out that it was hard to turn the Spindle bij hand,and i think the preload was too much. So i backed down a bit.
Witch gives a a bit more vibration .
That makes me think the slop in the bearings wit the shaft has something to do With it...
 
If the head is exactly right you get a cross hatch patern Not that easy to get

No preload on that half nut please That gives a lot of wear
Adjust it for as little as possible clearance at the end of stroke where wear is the least

Peter
 
Ive got the head trammed in as good as possible,With the wear and All, and the half nut and the spindels look like new.
But today i found out that it was hard to turn the Spindle bij hand,and i think the preload was too much. So i backed down a bit.
Witch gives a a bit more vibration .
That makes me think the slop in the bearings wit the shaft has something to do With it...

As Peter said, there should be no preload on the nut and, any drag should be set by adjusting the gibs, compatible with the irregular wear.
Like Richard said, on worn machines, you could "gently" use the lock to compensate for too much wear in that position on that axes. This should reduce/remove the vibrations.
Make also sure that the cutter you are using is a sharp one. Blunt cutters cut only by brute force (i.e. very rigid machines with a lot of HP), producing tons of heat and vibrations, on the top of bad finish. (If it is not clear from this sarcastic sentence, blunt cutters should not be used anywhere.)

Paolo
 
I,m sorry guys,at the end i was talking about the head spindle.
A bit of a confusing story, sorry about that
 
I knew you were talking about the head-stock spindle. We are trying to help troubleshoot your problem. But we are trying to help you understand not all vibration issues are caused by bad bearings. It could be loose gibs, backlash in the feed nuts, dull end mills, climb milling.
 








 
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