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1/2" ID ball bearing interference fit

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  • Fasturn
    replied
    Originally posted by Doozer View Post

    Killer dude!
    You are doing it right.
    Bravo ! ! !
    A cut above.

    Deltronic pins.

    -Doozer

    -D
    On your game mr Doozer. If you own a good mic, you can turn a piece of brass to make a gage. Go and maybe no go. You can turn steps too @ .0002 increments. Many laugh, but I do this lot. If you are a Doozer type- lathe man, you can make gages.

    You just paper in the last .0002 - 0004 tenths.
    Last edited by Fasturn; 01-14-2022, 06:38 PM.

    Leave a comment:


  • DaveD44
    replied
    Originally posted by Doozer View Post
    Deltronic pins.
    -Doozer
    Doozer, maybe for you but not for me. I'd need 10 or so in increments of 0.0001, at $20 each! For one time use. I did make a go/no go peg at 3/4" diameter years ago on my cylindrical grinder using the sine plate and, if I remember right, a .001" lift under one end. That worked well until it stuck in a bore and got ruined when I pulled it out.

    Originally posted by Doozer View Post
    Hey, are you Dave Scalavi ? (sp)
    or TrainMan 282 (I think) on youtube?
    That dude is straight up, real deal.

    -D
    Not me! Dave is one of the real resources in live steam. I enjoy his posts and his videos as well, although we have had a disagreement or two over the years.

    Originally posted by Doozer View Post
    Use a boring head in the mill maybe.
    -D
    I can't do that very easily either. Here's a photo of the truck side frames and journal boxes. The nearest is inside up and shows the bearing bore; the next back is outside up and shows the journal box cover opening, and it is not in any way in line with the rear boss. Nor are the sides, since whoever did the machining didn't bother to make everything square. I've had to do a lot of adjusting to get the bearing bores to even face each other across the way! (Man, if only whoever he was had left all that alone. Take a look for example at the two bearing bores at the bottom, left and right. Even in this photo you can see that the bores aren't consistently in the same spot. The one on the right is visibly off center to the right.) In the rear is part of the assembly, sans wheels and a section at the bottom to keep the width correct (as does the cast iron bolster at top). BTW, I can, as someone suggested, add the wheels loosely to these dummy axles and do most of my fitting with that setup.

    Click image for larger version

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    Originally posted by Rich Carlstedt View Post

    Loctite 641 , Bearing Retainer - Absolutely trust it as a retainer,,, as long as there is no oil on either component AND you let it cure !
    Why do you need to measure the bore of the bearing . If you bought them (R8),, then look at the makers spec ( R8 = Bore 8/16= .500 +.000/-,003 )
    A low grade R8 can be 3 tenths under , so if you make the shaft .4995 and use Loctite, no problem
    If you do not intend to disassemble , use a shrink fit., Grind the axles to ..5002" and then heat the bearing by placing them on a incandescent lamp ( ie 69 watt)
    When they reach 375 F , you will have about a thousandth growth on the .500 bore for a shrink fit ( work fast !)
    If you want to really check the bore and have a TP Grinder, it is simple.
    Chuck a piece of stock in the lathe and grind steps about 3/8" wide and make the diameter .5000 , then .4999 , and .4998 or what ever as a stepped stick
    now you can check

    Rich

    PS 641 will really hold well, it is used commercially to hold precision bearings in tool grinders
    I'm beginning to get the distinct impression that Loctite bearing retainer is the way to go and will give me a strong, lasting, bond. In any case, I have options that I hadn't worked out earlier before coming here. Thanks again!

    Leave a comment:


  • Rich Carlstedt
    replied
    Originally posted by DaveD44 View Post
    T................................................. ......... But that brings up a question: How do I accurately measure the bearing D?..............
    ..............................Or can I assume that these "Made in USA" Nice bearings will all be close to an even 0.500 ID? The specs do state ID Tolerance -0.0005" to 0".

    Rich Carlstedt (and others): Should I really trust a slip fit with Loctite retainer to hold up to heavy usage?
    Loctite 641 , Bearing Retainer - Absolutely trust it as a retainer,,, as long as there is no oil on either component AND you let it cure !
    Why do you need to measure the bore of the bearing . If you bought them (R8),, then look at the makers spec ( R8 = Bore 8/16= .500 +.000/-,003 )
    A low grade R8 can be 3 tenths under , so if you make the shaft .4995 and use Loctite, no problem
    If you do not intend to disassemble , use a shrink fit., Grind the axles to ..5002" and then heat the bearing by placing them on a incandescent lamp ( ie 69 watt)
    When they reach 375 F , you will have about a thousandth growth on the .500 bore for a shrink fit ( work fast !)
    If you want to really check the bore and have a TP Grinder, it is simple.
    Chuck a piece of stock in the lathe and grind steps about 3/8" wide and make the diameter .5000 , then .4999 , and .4998 or what ever as a stepped stick
    now you can check

    Rich

    PS 641 will really hold well, it is used commercially to hold precision bearings in tool grinders

    Leave a comment:


  • Doozer
    replied
    Originally posted by DaveD44 View Post
    ... the journal box castings were also machined for a fairly tight fit on the bearing OD and since they are somewhat rectangular It would be difficult to chuck up eight of them individually to open up the bore. Perhaps someone has suggestions about how I could make that happen, perhaps by hand with emery cloth spinning with a wobble that would not matter?
    Use a boring head in the mill maybe.

    -D

    Leave a comment:


  • oxford
    replied
    Originally posted by DaveD44 View Post

    Rich Carlstedt (and others): Should I really trust a slip fit with Loctite retainer to hold up to heavy usage? And yes, the shafts are and will be 1018.
    IMO, yes.

    Leave a comment:


  • Doozer
    replied
    Hey, are you Dave Scalavi ? (sp)
    or TrainMan 282 (I think) on youtube?
    That dude is straight up, real deal.

    -D

    Leave a comment:


  • Doozer
    replied
    Originally posted by DaveD44 View Post
    ...I didn't mention this but yes, I plan to grind the axle shafts, both the wheel fit and the bearing fit, with my tool-post grinder. Like you, I love doing this as it best satisfies my appreciation of precision machine work.
    Killer dude!
    You are doing it right.
    Bravo ! ! !
    A cut above.

    -D

    Leave a comment:


  • Doozer
    replied
    Originally posted by DaveD44 View Post
    ... How do I accurately measure the bearing ID?...
    Deltronic pins.

    -Doozer

    Leave a comment:


  • DaveD44
    replied
    Thanks for a bunch of useful responses. Before I comment, some background. I've been building this locomotive (and now, tender) for many years, after finding a good set of castings that were for the most part untouched. But the one group of castings that had been messed with were the tender side frames and journal boxes, and the work had been done poorly. First, since wheels and their carriages (main driver boxes, trucks) on locomotives and tenders have to deal with quite a bit of unevenness and misalignment because of the tracks they have to traverse, I used Cagerol bearings--with barrel-shaped rollers that allow a fair amount of lateral runout. But whoever had messed with the tender trucks used these standard electric motor type bearings, so unless I had new journal box castings made (or went through a lot of trouble sleeving the ones I have) I had to go with what was already done. And since these ball bearings are in general use on live steam railroad cars, they should work.

    The bearings were present and never used, but since they were at least 30 years old and some had visible rust and didn't turn well, I replaced them all. That's a thought for going forward, like MikeL46 suggested. I could use those until final assembly if it would not be too much trouble to grind the IDs.

    But the journal box castings were also machined for a fairly tight fit on the bearing OD and since they are somewhat rectangular It would be difficult to chuck up eight of them individually to open up the bore. Perhaps someone has suggestions about how I could make that happen, perhaps by hand with emery cloth spinning with a wobble that would not matter? Then I could leave the bearings on the axles and pop them in and out of the journal boxes, finally giving them a dose of Loctite retainer when ready to roll. (Yes, I know that the outer bearing races should be a slip fit, but remember, these bearings have to help with truck dimensional stability.)

    Originally posted by Doozer View Post
    . . . for a .500" shaft, I would go with a .0002" to .0004" press fit. The standard of .0005" to .001" press fit per inch of diameter is a good rule. So .0004" would be on the tight side and .0002" would be on the loose side. These numbers are not too easy to hit. Keep in mind, that surface finish is related to size. With press fits, even more extremely so. If you have a coarse finish and do your measuring and you think you have everything right, just remember that you are measuring the peaks of the surface. Once you press on the bearing and press it off again, you will have knocked the peaks down into the valleys, and it will measure smaller. Most electric motor manufactures cylindrical grind their bearing seats on their rotor shafts. And for good reason. I figure most home shop guys will turn it oversize on the lathe and then polish the shaft to side with emery cloth. It hurts me pride to do this. So I have purchased some good lathes and even a few cylindrical grinders. That makes it easy with a cylindrical grinder. It actually makes it fun. A lot of fun running a cylindrical grinder and being able to take a tenth of a thou. I even bought an ID grinder because it titillates me so. . . .
    --Doozer
    I didn't mention this but yes, I plan to grind the axle shafts, both the wheel fit and the bearing fit, with my tool-post grinder. Like you, I love doing this as it best satisfies my appreciation of precision machine work. (Even better with my surface grinder and my DoAll cylindrical grinder that glues itself to the surface grinder chuck and even has a built-in sine plate--but these shafts are too long for the DoAll.) so with the tool-post grinder I can swing the compound rest over to a large angle and get mighty close to a tenth at a time additional metal removal. So it will be around .0003 over the ID. Does a nicely ground shaft bearing seat change the recommendation above to not assemble/disassemble and then reassemble the parts? Plus, the advice of eKretz and others to not press on the outer race to disassemble...

    But that brings up a question: How do I accurately measure the bearing ID? I haven't had much success with that, even with some fairly expensive bore measurement tools, all too large. My smallest telescoping gage doesn't get me there with any repeatable measurements. Or can I assume that these "Made in USA" Nice bearings will all be close to an even 0.500 ID? The specs do state ID Tolerance -0.0005" to 0".

    Rich Carlstedt (and others): Should I really trust a slip fit with Loctite retainer to hold up to heavy usage? And yes, the shafts are and will be 1018.

    Leave a comment:


  • Mcgyver
    replied
    IF you do use loctite, use the right stuff.....the low strength one that gives it up with a bit of heat. I forget the number, but fail to heed that and there's a chance the parts won;t survive disassembly. Personally I favour the bearing co's recommended interference fits, but I get its not always easy to machine to those tolerances

    Leave a comment:


  • oxford
    replied
    Originally posted by Doozer View Post
    And Loctite in my mind is a good engineering solution. Just don't let it wick
    into the bearing. Ask me how I know. It will even enter a rubber sealed
    bearing. Baaahhh ! ! !

    -Doozer
    I’ve done that before.

    Leave a comment:


  • Sparky_NY
    replied
    Originally posted by Doozer View Post
    If you harden the shaft to Rc 35-40 then it can take many pressings on
    and pressings off. Or you can buy half-hard 4140. Even 1144 is Rc30
    to Rc34. If it is bugger soft 1018, you are not going to enjoy the experience.
    And Loctite in my mind is a good engineering solution. Just don't let it wick
    into the bearing. Ask me how I know. It will even enter a rubber sealed
    bearing. Baaahhh ! ! !

    -Doozer
    All great advise you are giving ! You can tell its not your first Rodeo.

    Leave a comment:


  • Doozer
    replied
    If you harden the shaft to Rc 35-40 then it can take many pressings on
    and pressings off. Or you can buy half-hard 4140. Even 1144 is Rc30
    to Rc34. If it is bugger soft 1018, you are not going to enjoy the experience.
    And Loctite in my mind is a good engineering solution. Just don't let it wick
    into the bearing. Ask me how I know. It will even enter a rubber sealed
    bearing. Baaahhh ! ! !

    -Doozer

    Leave a comment:


  • Tim Clarke
    replied
    I'd consider making a set of dummy bearings for easy disassembly, and use the ball bearings at final assembly

    Leave a comment:


  • Rich Carlstedt
    replied
    Keep it simple--if you want to assemble/disassemble multiple times, just make it to size -.0002" (ie) and then use
    Loctite bearing retainer when doing final assembly of your R8 bearing.

    Rich

    Leave a comment:

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