Darren,
Heating metals to install bearings, whether it be steel or aluminum, does NOT require high enough temperatures to change the color. Again, if you are doing that or think you need
to do that, you are way past where you need to be as far as temp. That applies to ball bearings and plain bearings.
As a matter of fact, if you have a bearing bore in steel which is a thou or three oversize, you can shrink that ID by heating it evenly to dark red to cherry red, and walking
away and letting it cool naturally. Larger bores, you can get more than .003¡±.
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A better word for what is done for bearing installation, and may or may not need to be done, is
warming.
And again¡.lot of over thinking going on here¡..Hopefully you have ¡®em installed, and have figured that out.
;)
Bill
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From: 4x6bandsaw@... [mailto:4x6bandsaw@...]
Sent: Tuesday, December 18, 2018 1:57 PM
To: 4x6bandsaw@...
Subject: Re: [4x6bandsaw] Re: Bainbridge blade guides
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Bill,
I'm notorious for doing just that, ant hills into mountains. I have the case in the house, about 76¡ã f. The bearings are frozen by now. I think with a bit of lube and a some light taping they may just fall into place. If not, and I'm careful,
I can back them out and try a bit of heat. Steel, I'm good with. ( I like colors.) Aluminum IS THE DEVIL. No color change at melting point?!?! C'mon.... :) It's as if aluminum has a mercury complex or something. I think aluminum is just angry that us Yanks
miss spell it's name. :)
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Here¡¯s a question¡..how much effort did it take to remove the old bearings? New ones should install with similar force, and arguably less, since you cleaned up the housing., the bearings are new & clean, and there¡¯s no paint on anything.
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You don¡¯t need so much heat, as to worry about melting something. That is extreme.
If you use some lube to the bore of the housing, even if you heat it, it will not all go away, unless, again, you get extreme. If you must use a torch, keep the flame away from direct contact with any lube. Burnt lube, whether it¡¯s
oil or grease, takes up space. Put some lube on the outer race of the bearing too. It doesn¡¯t trake a lot. Keep the bearing aligned with the bore when installing. The outer races are radiused, so it¡¯s really not a big deal, and not so easy to start damaging
the housing when installing the bearing.
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I think some people are making a very simple job into a scary disaster film¡¡
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Bill
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Great idea. However, I don't have a lathe, yet. That's coming in Q1 of 2019. Also, as soon as I sent the last question, I realized the error in my thoughts. If the aluminum is hot enough to sizzle spit, it'll probably burn off the grease. Or at least break
it down past the point of usefulness. Looks like it'll be one or the other. Bearings and seals are in the freezer. :) Now I just need to play with some scrap aluminum and my little MAPP torch to be sure I don't melt the casing...
Weather is too cold to paint anyway. :)
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JV,
That makes sense to me. Any issues with following both procedures? Temp and lube?
? I saw where JV said the casting is aluminum . Mine is cast iron - which is still worth heating it up a bit though it won't expand as much as the aluminum . I have had very good luck installing bearings with a piece of threaded rod or a long enough bolt and
some properly sized washers . Sometimes I'll machine a slug that is a slip fit in the bore (with a hole in the center for the rod) to keep the bearing square with the bore . But I don't know what tooling you have available ...
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There's the whole science of reliability engineering behind it.. Contrary to popular belief, properly installed and lubed rolling element bearing don't wear out, they fail randomly.
The biggest cause of failure in bearings in general is improper installation, with being dinged from hitting them into place and skewed alignment the main culprits. That's why you never replace bearings as 'preventative maintenance'.
So anything you can do to ease installation is worth doing. The main ones are heating the outside/cooling the inside so less force required to get it in place, along with jigs to push or pull them in squarely and applying the pressure to the correct side of
the bearing (i.e. never push on the inner to get the outer to seat) - jv
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