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Spindle Bearing Replacement For The Rf-31 Mill/drill
- Thread starter mikey
- Start date
- Joined
- Nov 10, 2018
- Messages
- 8
yess..
- Joined
- Nov 10, 2018
- Messages
- 8
Hi Guys
I thought I make an addition to the information found here. I have spent most of the evening figuring out all the dimensions on the quill and the spindle, and made a rough drawing of it as to help myself to get an understanding of the positions of the upper and lower bearings in relation with the quill. I have made some notes on the sheet but the picture didn't come out so good so I think it might be an good idea to write it here to.
When the lower bearing have a race of 17mm. and the original has 18mm. the result is then that the spindle goes 1mm. deeper into the quill.
This gives us 229mm. from the lower bearing to the shoulder where the upper bearing are "supposed" to be on the spindle.
When you look at the quill you will see that from the upper surface of the lower ball bearing to the upper shoulder of the quill is a length of 238mm. This is a difference of 9mm. longer and it will make the upper ball bearing lay on the quills shoulder and not on the spindels shoulder, the lower side of the upper bearing will be about 9mm. above the shoulder of the spindle. And the ball bearing will have 13mm. of its surface to rest on the spindle surface not on it's full 16mm.race. The adding mikey did with the 2mm. thick spacer is on it's place..... It seem to me that the upper bearing should have had a larger surface of the race to rest on, to short/bad engineering?
I thought I make an addition to the information found here. I have spent most of the evening figuring out all the dimensions on the quill and the spindle, and made a rough drawing of it as to help myself to get an understanding of the positions of the upper and lower bearings in relation with the quill. I have made some notes on the sheet but the picture didn't come out so good so I think it might be an good idea to write it here to.
When the lower bearing have a race of 17mm. and the original has 18mm. the result is then that the spindle goes 1mm. deeper into the quill.
This gives us 229mm. from the lower bearing to the shoulder where the upper bearing are "supposed" to be on the spindle.
When you look at the quill you will see that from the upper surface of the lower ball bearing to the upper shoulder of the quill is a length of 238mm. This is a difference of 9mm. longer and it will make the upper ball bearing lay on the quills shoulder and not on the spindels shoulder, the lower side of the upper bearing will be about 9mm. above the shoulder of the spindle. And the ball bearing will have 13mm. of its surface to rest on the spindle surface not on it's full 16mm.race. The adding mikey did with the 2mm. thick spacer is on it's place..... It seem to me that the upper bearing should have had a larger surface of the race to rest on, to short/bad engineering?
- Joined
- Nov 10, 2018
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If anybody want a copy of the drawing, mail me and I send you one. I have checked the number several times and i get to the same result every time, so I guess they are fairly good. I had to make the drawing due to the numbers did not seem to add up, but with the drawing i scale 1:2 I got the picture and could see how the relation was between the quill bearing and the spindle. I got my FAG bearings at a price of 4325bath it's 135$ US from FAG supplyer her in thailand, but one thing I like to ask, shuldent you need the same quality/precision on the drive sleeve bearings also but you only radial?
BRG's
Knut
BRG's
Knut
- Joined
- Dec 20, 2012
- Messages
- 9,408
Knut, I admit that I'm not clear on what you're trying to say with your numbers. Could you clarify?
As for the radial bearings on the drive sleeve, they do not sustain any axial load. They only need to constrain the radial loads at the spindle at the top. Therefore, radial bearings are sufficient and a normal accuracy class is fine. Deep groove bearings can sustain heavy axial and radial loads anyway so they are a very good choice for the drive sleeve.
As for the radial bearings on the drive sleeve, they do not sustain any axial load. They only need to constrain the radial loads at the spindle at the top. Therefore, radial bearings are sufficient and a normal accuracy class is fine. Deep groove bearings can sustain heavy axial and radial loads anyway so they are a very good choice for the drive sleeve.
- Joined
- Nov 10, 2018
- Messages
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Hi mikey
the numbers I'm talking about are the dimensions of the quill and the spindle. I was working late last night so I see the the drawing contain an error but the dimensions are all right. The error is the drawing around the upper bearing, on the drawing the upper bearing is resting on the shoulder of the spindle but in real life it's lying 9mm. above it and resting on the shoulder of the quill. I am going to make a new drawing.
as I said, the reason I made the drawing is to get an understanding of where the ball bearings position on the shaft and the quill, before I start to assemble it, so nothing gets *****d up.
Thank you for the information on the sleeve bearings .
BRG's knut
the numbers I'm talking about are the dimensions of the quill and the spindle. I was working late last night so I see the the drawing contain an error but the dimensions are all right. The error is the drawing around the upper bearing, on the drawing the upper bearing is resting on the shoulder of the spindle but in real life it's lying 9mm. above it and resting on the shoulder of the quill. I am going to make a new drawing.
as I said, the reason I made the drawing is to get an understanding of where the ball bearings position on the shaft and the quill, before I start to assemble it, so nothing gets *****d up.
Thank you for the information on the sleeve bearings .
BRG's knut
- Joined
- Dec 20, 2012
- Messages
- 9,408
The placement of the bearings is defined by the shoulder on the lower end of the spindle itself (that one fits into the lower end of the quill and stops at a shoulder inside the quill) and the shoulder at the upper end of the quill. The replacement FAG bearings are each 1mm thinner than the stock bearings so a 2mm or thicker shim is required to allow the bearing preload to be set properly. The distance between the bearings is what it is on your machine but their limits, the shoulders, are what determines their positions.
- Joined
- Nov 10, 2018
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Hi Mikey
Thats exactly what I wanted to see. that was the intention with making the drawing, to give me a visualization of the relation between the quill and the spindle.
I thought it (the upper bearing) should rest on the upper shoulder on the spindle. but I was surprised to see that only 13mm. of the 16mm. race of the upper ball bearing was touching the area of 30mm. diameter surface. About 3mm of the ball bearing is above it. when the outer diameter is resting on the shoulder of the quill.
The 30mm. diameter for the upper ball bearing is 22mm. long so the ball bearing is 9mm. above the shoulder of the spindle and then the ball bearings race is 16mm wide, so it seem to me that this area on the spindle on my mill is 3mm. short. 9mm. +16mm.=25mm and I only have 22mm. I dont know if this is the same on all RF31's or if it realy make any difference, these figures are checked and rechecked several times but I get to the same measurements every time. One thing is sure and that is that it should not be any problem to press the bearings on the spindle or the quill. But one thing I think now is that I need to measure the gap between the nut and the upper ball bearing before I complete lock the spindle bearings.
I bought my mill new a year ago, and did not start use it for more than about a week ago, after a couple of cut it came intolerable noise from the quill area, I thought that the bearing was dried and that's the reason for the noise. But no the grease was fine so there is something else that caused the bearing(s) to break down I can't tell. I just have to wait till I get the new bearings and see how it all aligned and measure it to see if everything is all-right and then I am thinking about the 2mm. spacer the preset pressure, god knows what that is supposed to be? "only to be tight enough to hold it in place?
I am a beginner with mechanics, so I might go the idiot way to figure it out. so with this, no offense meant Mikey the information you gave in the description of disassembly and assembly is good, but I just need to go this way to assure myself and I like making these drawings
, and I'm not of english origin (Norwegian berserk) so it's take some time to formulate and use the right terminology, both English and mechanical.
knut
Thats exactly what I wanted to see. that was the intention with making the drawing, to give me a visualization of the relation between the quill and the spindle.
I thought it (the upper bearing) should rest on the upper shoulder on the spindle. but I was surprised to see that only 13mm. of the 16mm. race of the upper ball bearing was touching the area of 30mm. diameter surface. About 3mm of the ball bearing is above it. when the outer diameter is resting on the shoulder of the quill.
The 30mm. diameter for the upper ball bearing is 22mm. long so the ball bearing is 9mm. above the shoulder of the spindle and then the ball bearings race is 16mm wide, so it seem to me that this area on the spindle on my mill is 3mm. short. 9mm. +16mm.=25mm and I only have 22mm. I dont know if this is the same on all RF31's or if it realy make any difference, these figures are checked and rechecked several times but I get to the same measurements every time. One thing is sure and that is that it should not be any problem to press the bearings on the spindle or the quill. But one thing I think now is that I need to measure the gap between the nut and the upper ball bearing before I complete lock the spindle bearings.
I bought my mill new a year ago, and did not start use it for more than about a week ago, after a couple of cut it came intolerable noise from the quill area, I thought that the bearing was dried and that's the reason for the noise. But no the grease was fine so there is something else that caused the bearing(s) to break down I can't tell. I just have to wait till I get the new bearings and see how it all aligned and measure it to see if everything is all-right and then I am thinking about the 2mm. spacer the preset pressure, god knows what that is supposed to be? "only to be tight enough to hold it in place?
I am a beginner with mechanics, so I might go the idiot way to figure it out. so with this, no offense meant Mikey the information you gave in the description of disassembly and assembly is good, but I just need to go this way to assure myself and I like making these drawings
, and I'm not of english origin (Norwegian berserk) so it's take some time to formulate and use the right terminology, both English and mechanical. knut
