Spindle Bearing Replacement For The Rf-31 Mill/drill

[mikey]

On my RF-31 clone I made a thin wall sleeve that I pressed into the quill to block off the slots. I also made a seal carrier that replaces the lower bearing cap and a plate to block off the opening in the head casting. All three mods work great at keeping swarf and coolant out of the lower bearing. If you want to see pictures let me know and I'll post some.

Tom S.

Thanks, Tom. Yes, I would very much like to see what you've done. As simple as these machines are, there isn't a whole lot of info on this site about them. I'm thinking that the more we share and innovate the better off we, and all those that follow, will be.

I meant to credit Canuck75. He has shared what he's done and I hope to follow that example.

 

[mikey]

Mikey.

Sounds like you have a good handle on the issues at hand. I'm now going to look at the drive pulley bearings to make sure they are okay.

With regard to the angular bearing orientation, this crosssection drawing shows what I am referring to. I don't understand why FAG suggested otherwise. In our particular installation, and the way you have installed them, the preload is driving the bearing races apart. The way I have installed mine, the preload drives the bearing races together - big big difference!

View attachment 132930

Really appreciate trading ideas and information. These are great little mills. Here is a pic of mine hard at work making 1 1/4" wheel spacers for my Ford Ranger.


Cheers
Canuck75

Yeah, I had a rather long discussion with my local bearing company last year about this very subject (bearing orientation). The gist of it was that the configuration of the races are near mirror images of each other but there are small differences. That is why they suggest you install them either way but both must face the same way. I argued that this meant that if the bearing inscription pointed down on one bearing then it should point in the same direction on the other bearing - down. I was told no, if one faces down then the other should face up. I was doubtful but I listened to the guy. When it came to this project I asked FAG about it and they said it doesn't make a lot of difference either way but did confirm what the bearing guy said. I wish I kept that email but I tend to keep my inbox clean and I dumped it. Didn't seem important at the time.

I think this is something we'll just have to wait and see. If my bearings fall apart and things go totally awry then I'll readdress it at that time. For now, I'm comfortable with what I understand and have done.

It seems like the RF-31 is a great little mill and a lot of people seem to like them. I don't know much yet but I will soon. Much of what I do is done for other people and I've been able to hold some of them off because my Sherline mill was too small. Now I don't have that excuse. Thing is, my Sherline is very accurate, is fully tooled up and has handled 90+% of the things I do. It has about 0.0001" of runout but has maintained it for over 20 years. I seriously doubt the RF-31 will be as precise as my Sherline but then again, I can do bigger stuff now. We'll see.

 

[xman_charl]

castellated tabbed washer

notice there is a lot of variation in those tabbed washers.

shinny is from Grizzly, other is enco





Charl

 

[Canuck75]

Mikey
I'll just say one more thing on the angular bearings and then leave it alone. Look at that crossection and visualize how the load on one side, vice the other, affects the amount of inner/outer race contact with the balls. When the races are pushed together on a specific bearing the balls run on a large surface on both races. This is by design. When the races are pushed apart on a specific bearing (as in your installation), the angular contact angle flips, and the running surface contact with the balls is greatly reduced.

Just for interest I have made the following mods to my mill:

a. quick release belt tensioner
b. angular quill bearings
c. longer X and Y adjustable nuts
d. rack accurately pinned to the column with tight guide blocks on the head to maintain X setting after head height adjustment
e. locking screws on the back end of the gibs to reduce dovetail clearance
f. windlas system inside the head to exert return pull on the quill instead of the pinion to get rid of Z backlash
g. torrington thrust bearing on the drawbar to improve the tightening force on the collets
h. 3 axis Yadro DRO system
i. motor reverse witch
j. cover plate for the bottom hole in the head casting
k. grade 8 head clamp bolts vice the grade 5 (or less) originals

Cheers
Canuck75

 

[mikey]

Maybe do some pictorial "how to's"? I think there is a silent group of RF-31 guys out there who would be interested, including me.

 

[Canuck75]

Mikey

I too am interested in anything H-M members do to theses machines. Regards to some of the mods that I have done, surf this forum for any threads posted under Canuck75. I tried to enclude as much detail as possible and photos. Always happy to answer questions.

Canuck75

 

[TomS]

Thanks, Tom. Yes, I would very much like to see what you've done. As simple as these machines are, there isn't a whole lot of info on this site about them. I'm thinking that the more we share and innovate the better off we, and all those that follow, will be.

I meant to credit Canuck75. He has shared what he's done and I hope to follow that example.

I'll take some pictures tomorrow. Worked all day in the shop in 107 degree heat. Not anxious to go outside at the moment.

Tom S.

 

[TomS]

Thanks, Tom. Yes, I would very much like to see what you've done. As simple as these machines are, there isn't a whole lot of info on this site about them. I'm thinking that the more we share and innovate the better off we, and all those that follow, will be.

I meant to credit Canuck75. He has shared what he's done and I hope to follow that example.

Here are the pictures. I did these mods about five years ago.

Tom S.

The lower seal housing is made out of aluminum. I sourced a double lip seal that fit the spindle snout then made the seal housing to fit the seal. I added a couple of holes for a spanner/pin wrench.



The cover plate was made from a scrap piece of 18 or 20 gauge steel.


Sorry for the fuzzy picture. You can see the sleeve through the slot. As I recall I had to bore the quill then make the sleeve.

 

[mikey]

Thank you, Tom. I had intended to make the plate under the head. Now that you and Canuck have both recommended sealing the quill ports I guess I'll have to take a good look at how to implement that, too.

That's a serious seal you made to cover the lower bearing. I don't think a chip could get past that!

 

[Ludvigsen]

Thank you guys, it is very helpful information. By the way, do any of you replaced the ball bearings on the spindle taper sleeve and can give any information on the ball bearings? I have just removed the quill and spindle and removed the ball bearings and trying to find a supplier for it. So now I can't take off the spindle taper sleeve as I have nothing to hold back on to remove the nut. I would like to buy bearings for the spindle taper sleeve also so then all should be i top shape.

By the way the drawing for the the spindle shaft is wrong, on mine Rong Fu RF31 mill, the tabbed washers was in between the two nuts, not like on the drawings, below the two. but it only locked to the top nut but I guess you could just as well lock both nuts with the tabbed washer.

thanks for the help.

Brg Knut Erik