IH - RF45 bearings


Page 1 of 2 12 LastLast
Results 1 to 12 of 21

Thread: IH - RF45 bearings

  1. #1
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default IH - RF45 bearings

    Hi guys,
    While working with my machine today the lower spindle bearing started to heat up pretty good. I was on borrowed time with the belt conversion running 6500 rpm and stock tapered roller bearings.

    My question is about angular contact bearings for the spindle. It is my understanding that in a perfect world one would have a double set of AC bearings at the bottom of the spindle with a single regular bearing at the top. This eliminate the thermal expansion messing with the pre load I guess.

    So on our less then perfect machines (RF-45 types) do you simply replace the tapered roller bearings with AC bearing (one on top and one on bottom) and get the pre load as close as you can? Or have you guys been machining out the lower spindle for a double set of bearings at the bottom?

    I am looking at:

    7207BMU Nachi Angular Contact Bearing 35x72x17 Brass Cage C3 Japan Ball Bearings... $40.00 each.

    Or

    7207 Nachi Angular Contact Bearing Steel Cage C3 Japan 35x72x17 Ball Bearings... $23.00 each.

    Thank you for your help.

    Similar Threads:
    Kelly
    www.finescale360.com


  2. #2
    Member arizonavideo's Avatar
    Join Date
    May 2008
    Location
    USA
    Posts
    1151
    Downloads
    0
    Uploads
    0

    Default

    I think the preload is stabilized a bit by the fact that the spindle shaft is so long that it stretches a bit under high preload!

    Both of the new bearings are slightly shorter than stock TRB's but the spindle nut will thread on further and almost needs a shim to set preload but should work with no mods.

    I did mine and it was no problem and I found a brass cage USA bearing for $22 that gave .0002" runout.

    I often end up milling deep profiles with larger cutters in steel like a 5/8" x 4" carbide cutter and I don't see the single bearing being a problem, machine flex and tool pullout yes, but not the bearing so far.

    My preload ended up a bit high so I still have a fair amount of heat but no problems so far. Its making about half the heat of the TRB.

    There is two small drilled holes in the lower spindle housing to help you drive out the lower race, they are not real easy to see if you don't look for them. The fit is tighter than really needs to be so clean the seat well or the new race wont seat. The upper race can be driven out by a long screw driver with a bent tip or just a shaft with a bend at the end.

    If you don't go over 6500 RPM much the top bearing could be left in. It is smaller and will do better at high speed than much larger TRB at the big end.

    I bought a spare 7207 Nachi to have sitting around just in case I need to do a quick replacement.

    I think with some luck you could change out the lower bearing in around two hours.

    I don't think there is enough metal in the housing for two bearings and considering how long a single should last and the replacement cost of a spare bearing, keeping a spare around might be just as well.

    I did spend some time looking for a good low cost spindle grease as I have 4 that need re packing. I went with Mobil SHC100 NLGI 2 lithium synthetic.

    It has a similar melt point and thickness as the Kubar NBU 15 and cost about $13 a 13oz tube. McMasters has it.

    "The official grease of NASCAR."

    So far so good on the IH A/C spindle bearings.



  3. #3
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default

    Great info AV !

    Did you have different size bearings in the spindle? I see 7207 on both the top and bottom of mine. The spindle is out but not the bearings.

    EDIT...
    Never mind, the top and bottom bearings are different size. I will order the AC bearings today.

    Last edited by skray775; 09-09-2012 at 01:58 PM.
    Kelly
    www.finescale360.com


  4. #4
    Member ninefinger's Avatar
    Join Date
    Sep 2006
    Location
    Canada
    Posts
    473
    Downloads
    0
    Uploads
    0

    Default

    Hi Kelly,

    Mind sharing what the top bearing size is? I might just buy some bearings in prep for a belt drive mod...

    Mike



  5. #5
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by ninefinger View Post
    Hi Kelly,

    Mind sharing what the top bearing size is? I might just buy some bearings in prep for a belt drive mod...

    Mike
    Sure Mike,

    Ordered them today from VXB Bearings.

    Code Product Quantity Price/Ea Total
    Kit10017 7207 Nachi Angular Contact Bearing Steel Cage C3 Japan 35x72x17 Ball Bearings 1 $22.88 $22.88
    Kit10016 7206 Nachi Angular Contact Bearing 30x62x16 Steel Cage C3 Japan Ball Bearings 1 $17.88 $17.88

    Kelly
    www.finescale360.com


  6. #6
    Member arizonavideo's Avatar
    Join Date
    May 2008
    Location
    USA
    Posts
    1151
    Downloads
    0
    Uploads
    0

    Default

    If you have not driven in a lot of bearing races the big problem is having the race tilt sideways and skim a thin sliver of metal in front of the race which will stop the race from seating flatly. They fit really tight and others has said the same. If your race does caulk sideways it is good idea do drive it out and look for a burr.

    I made a plug from aluminum to drive it in but I also made a 6" shaft that fit the plug so I could hold it straight while driving the race in.

    The force is high so the bench was not stiff enough so I used the floor with a piece of soft aluminum as a buffer and a good size hammer.

    I have done hundreds of bearing replacements as I use to be a mechanic so the job was no big thrill but a race driver that fit well really helped.

    Have fun
    Dave



  7. #7
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default

    Thank you AV,
    I have done a few bearings but never hurts to listen to other people experience.

    So I have the bearings in hand an tell me if I am wrong on this....

    In the picture the lower spindle bearing surface was sized to have the tapered roller bearing pressed onto the shaft and the bearing race pressed into the quill.

    With AC bearings shouldn't the bearing be a very tight fit but still be able to slide onto the shaft with light pressure? If you have to press the bearing on the spindle and then press the bearing into the quill housing it would make it pretty difficult to set the pre-load unless the upper bearing can slide on the shaft as well.

    I was thinking of lightly sanding the bearing surface until the AC bearing will start to go on with light tapping/pressure.

    What are your thoughts on this?

    Attached Thumbnails Attached Thumbnails IH - RF45 bearings-mtw-md001-spindle-003-jpg  
    Kelly
    www.finescale360.com


  8. #8
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default

    All done and back together.

    Its late so I will do the testing in the morning.

    Kelly
    www.finescale360.com


  9. #9
    Member arizonavideo's Avatar
    Join Date
    May 2008
    Location
    USA
    Posts
    1151
    Downloads
    0
    Uploads
    0

    Default

    A light slip fit would not be OK for the inside race, you need a fair amount of preload on all surfaces to maintain a ridged system under load.

    Mine was not too bad. A press would be easier but if you set up the drivers well it is fairly easy with a hammer and a piece of pipe with a squared end.



  10. #10
    Member
    Join Date
    May 2005
    Location
    USA
    Posts
    3786
    Downloads
    0
    Uploads
    0

    Default Do get back to us.

    Quote Originally Posted by kregan View Post
    All done and back together.

    Its late so I will do the testing in the morning.
    I'm a little late but have a few pointers for the next time.

    Freeze the spindle and heat the bearing about to be pressed on. If you don't have a bearing heater a toaster oven can do the job. The bearing inner race at the spindle nose has to be a press fit at normal temperatures ( on most spindle designs), however nothing says you have to assemble at normal temperatures. Do consult with the bearing supplier for maximum temperatures for the bearing. With the right temperature differentials the bearing should slip on or at least be much easier to put on.

    On spindle designs where you have adjustability for the preload the rear bearings inner race shouldn't be as tight of a press fit. That would lead to adjustability issues. However sloppy is not acceptable. The adjustment nut should be able to push the inner race forward with a spanner wrendh applying torque to the nut. if it can't with reasonable effort your chances of properly adjusting the preload is thin at best.



  11. #11
    Registered
    Join Date
    Mar 2011
    Location
    USA
    Posts
    525
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by wizard View Post
    I'm a little late but have a few pointers for the next time.

    Freeze the spindle and heat the bearing about to be pressed on. If you don't have a bearing heater a toaster oven can do the job. The bearing inner race at the spindle nose has to be a press fit at normal temperatures ( on most spindle designs), however nothing says you have to assemble at normal temperatures. Do consult with the bearing supplier for maximum temperatures for the bearing. With the right temperature differentials the bearing should slip on or at least be much easier to put on.

    On spindle designs where you have adjustability for the preload the rear bearings inner race shouldn't be as tight of a press fit. That would lead to adjustability issues. However sloppy is not acceptable. The adjustment nut should be able to push the inner race forward with a spanner wrench applying torque to the nut. if it can't with reasonable effort your chances of properly adjusting the preload is thin at best.
    I was able to get the spindle nose bearing pressed on without issue using the pipe method AV talked about below.

    For the upper bearing I did sand or polish slightly the bearing surface so the inner race could move and adjust the pre load.

    Same principal as the ball screw ends supported by AC bearings... something has to move so the nut can control the pre-load.

    Now I did fight the pre load setting most of the day but I think I got it. I sure am tempted to cut a hole in the front of the spindle housing to get at that adjusting nut from the front panel without having to remove the spindle. Since I have a belt drive the gear box is empty anyway!

    I am getting .0005 run-out on the finished edge of a Tormach TTS holder. I wonder if I should skim the spindle nose with a lathe tool again since it has new bearings.

    Kelly
    www.finescale360.com


  12. #12
    Member arizonavideo's Avatar
    Join Date
    May 2008
    Location
    USA
    Posts
    1151
    Downloads
    0
    Uploads
    0

    Default

    What runout did you have before?



Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

IH - RF45 bearings

IH - RF45 bearings