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Countershaft very HOT.

Discussion in 'ATLAS, CRAFTSMAN & AA' started by ThunderDog, May 23, 2017.

  1. Rustrp

    Rustrp United States Active Member Active Member

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    As has already been stated, McMaster Carr is a good source or try any industrial bearing supply house in your area.

    As you stated, there's a lot of good information here, and opinion based on our experiences. Oilite bearing come in many different shapes sizes and configurations.

    https://www.oilite.com/PDFs/castBronze_designData.pdf
     
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  2. markba633csi

    markba633csi United States Active Member Active Member

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    To clarify; an Oilite bearing has a distinctive look, once you've seen it you'll recognize it- they're made of tiny bronze particles which are sintered (pressed with heat) into a solid shape. There's also a similar looking product used as a filter for various liquids and gasses.
    Mark S.
     
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  3. wa5cab

    wa5cab Downloads Moderator Staff Member H-M Supporter-Premium

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    We know that with new original bearings and proper size V-belts, the Atlas mills ran OK. AFAIK, you don't know for certain what the bushings in the countershaft hanger are. So my suggestion would be to replace the bushings and the belts with OEM parts, and start from a point that we know worked.

    On the Depth Of Cut (DOC) issue, I should have said at the beginning that DOC isn't perhaps as well defined for milling cutters as it is for normal lathe tooling. On a lathe (most of the time), you have a nominally single point tool with not much width in the longitudinal direction. So DOC is pretty well defined and how large the cutter or insert is doesn't much matter. So there are only three variables, DOC, Feed, and SFM (related to work RPM and diameter). With an end mill, face mill, or slabbing mill you have a fourth factor added, which is the width or circumference of the cutter actually engaged with the work. If you are using an end mill (which you are) or a face mill, then I think that most people would call the direction where you show movement of .010 to .015 the DOC. Which if I understand your sketch would be set by moving the table and work toward the spindle. And the 1/8" dimension would be table or knee lift. On a lathe with milling attachment, the .010" to .015" would be carriage traverse and the 1/8" would be milling attachment lift or drop. If the arrow indicates the direction that the work is moving into the cutter, it is backwards. With a normal end mill turning in the normal direction, moving the work in the direction shown would be climb milling. The only movement of the end mill is rotation. At any rate, with a similar setup on my lathe, I would be using 3/8" or 7/16" instead of 1/8" if the end mill diameter is 1/2".

    Anyway, my guesses as to the cause of the hot bearing is either excessive belt tension in order to prevent belt slippage or no oil getting to the shaft because the bushing isn't porous (solid brass or pores plugged or some of both.
     
  4. Silverbullet

    Silverbullet Active Member Active Member

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    Have you inspected the pulleys , the sides should be flat on the angle on each side . If the pulleys are grooved has I suspect they should be changed also . The sides are where the traction is the v drives the machine. It's a pain to install but the original belt should last for years. I'm pretty sure all these things are causing the trouble. You might be able to do some work on it and install needle bearings with seals and then oiling them the machine will run forever. If mines bad when I get to it I'm going that route , needle bearings and felt or o ring seals on the ends. My atlas is waiting along with several other machines.
     
  5. ThunderDog

    ThunderDog United States Active Member Active Member

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    Thought I would give an update.

    Installed the belt as recommended by forum member wa5cab in this thread. That made a DRAMATIC improvement. Now, I'm beginning to think my other machines in the garage need their link belts swapped.:D Replaced the bushings with new Oilites from Macmaster. Also replaced the 5/8 shaft with a piece I had left over from Speedymetals. It's listed on their site as "stress proof".

    For future readers: I had to drill a small hole in both bushings from Mcmaster for oil to make it to the shaft. I initially ran it without the holes drilled while I setup the alignment. They obviously heated up, so a simple fix of drilling the holes and now both bearings run very cool. 83° vs my original 150° is a major improvement. Plus, it's so much quieter than before. I never had a reference as to how quiet the machine should have been.

    Thanks to all.
     
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  6. woochucker

    woochucker United States Active Member Active Member

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    If they were oillite all you need to do was soak them in oil. No hole. The hole works against you. W/o the hole the oil will fill the bearing and be a source of oil. With a hole it will just travel to the shaft and possibly exit quickly.
     
  7. Rustrp

    Rustrp United States Active Member Active Member

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    I think as greedy as oilite is, not much oil will escape, especially if TD put new felt in the oil gits to slow the flow. :D
     
  8. Tozguy

    Tozguy Active User H-M Supporter-Premium

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    TD glad you have solved the hot bearing problem. I had to repair a similar bearing that had run dry and hot. It burnt the felt and residual oil to black. It cleaned up well and I keep a sharper eye on it now. Only question left for me is what is the best oil to use.
     
  9. ThunderDog

    ThunderDog United States Active Member Active Member

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    woochucker, I totally hear what you're saying. Thank you for the clarification.

    Here's what I did: (Learn from my rookie mistakes!!:D:D)
    Simply wiping oil on the exterior and interior of the oilite bearings is NOT the correct procedure. If you're wondering what oil I'm using it's Mobil Velocite #10. I use it because it's what I have and I've used it for my lathe spindle.

    Here's a link from Mobil for the future readers.
     

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