Which is the correct orientation for this lathe headstock oil seal?
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    Default Which is the correct orientation for this lathe headstock oil seal?

    My Colchester Chipmaster lathe is leaking significant amounts of oil from the headstock onto the components of the clutch shaft. There are two oil seals in this assembly. Upon disassembling the whole mess, I find that the smaller, most outboard seal is indeed chewed up, but surprisingly the larger, most inboard seal looks to be in excellent condition. However, I would swear that the seal is in backwards. The attached photo shows the side of the oil seal that faces into the headstock oil reservoir. Note that the conical lip of the seal points away from the oil to be contained. A search of the internet revealed a lot of very confusing opinions about this. This is my first experience with oil seals, but it seems to me that the conical lip of the seal should be pointing towards the fluid to be contained, so that any pressure from the fluid will cause the lip to close down more tightly onto the shaft it is supposed to seal (although the garter spring around the periphery of the seal also provides some clamping force, I guess).

    I just want to be sure about this before I remove the original seal and install a new one facing the opposite direction. Thanks and happy new year.

    Mike

    chippie-original-backwards-oil-seal.jpg

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    [QUOTE=Mikel Levy;3098580]My Colchester Chipmaster lathe is leaking significant amounts of oil from the headstock onto the components of the clutch shaft. There are two oil seals in this assembly. Upon disassembling the whole mess, I find that the smaller, most outboard seal is indeed chewed up, but surprisingly the larger, most inboard seal looks to be in excellent condition. However, I would swear that the seal is in backwards. The attached photo shows the side of the oil seal that faces into the headstock oil reservoir. Note that the conical lip of the seal points away from the oil to be contained. A search of the internet revealed a lot of very confusing opinions about this. This is my first experience with oil seals, but it seems to me that the conical lip of the seal should be pointing towards the fluid to be contained, so that any pressure from the fluid will cause the lip to close down more tightly onto the shaft it is supposed to seal (although the garter spring around the periphery of the seal also provides some clamping force, I guess).

    I just want to be sure about this before I remove the original seal and install a new one facing the opposite direction. Thanks and happy new year.

    Mike

    chippie-original-backwards-oil-seal.jpg[/I]

    It looks like the seal is correct. The < lip on the outside edge is keeping oil from escaping and if the outer bad one was in > the opposite direction that keeps the dirt out. Many of the newer seals are flimsy as heck and I hate installing them. Ive been told by the bearing seal company I buy mine from that the "modern" seal is made to seal both ways. When I can I try to buy wider 2 metal sided seals like Garlock used to make them. SKF bought out many of the smaller seal Mfg's so they maybe SKF seals now. Also check the shaft where the seal rides.

    They can get gouged out or worn and where the lip rides will help or they Chicago Rawhide (which I believe SKF bought) made a metal ring you could press over a shaft where the worn ring was to cove the worn ring. It's called a Speedie Sleeve. It had a raised or flared bigger OD and they gave you a cup to used to press it on, then your suppose to use a needle nose pliers to remove the flared ring much like the old sardine can worked. Many times i just left the flared ring on if it didn't get in the way.
    Example of right configuration. dirt side or outside __>I__I<____ oil side or inside. crude but I hope that helps answer the question. Replace both seals even if it looks OK, cheap insurance.

    PS. Use some .005 brass or plastic shim stock say 1" wide and the wrapped around the shaft when installing the shaft so you don't ruin the lip if you have to push the shaft in through the seal. Then after it's in grap the shim with pliers and remove it.

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    On every seal I've ever used, the lip tension spring goes to the oil / grease side.

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    Some applications use a seal facing both directions. Such as Blanchard grinder gear boxes. They have 2 seals with the lip facing to the inside of the box and one facing out. I suppose the one facing out is supposed to keep the grinding grit out and the other two will hopefully keep the oil in.

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    Fitting the seal with the spring on the inside also means the writing is on the outside where you can see it. That's handy if you need to order new seals whilst the machine is still working. Same with ordinary ball and roller bearings.

    Regards Tyrone.

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    Quote Originally Posted by Tyrone Shoelaces View Post
    Fitting the seal with the spring on the inside also means the writing is on the outside where you can see it. That's handy if you need to order new seals whilst the machine is still working. Same with ordinary ball and roller bearings.

    Regards Tyrone.

    Also means it can be removed without gouging the shit out of the bore that it sits in.

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    I don't think pressure build up is a problem on a Chipmaster, the filler cap has a vent hole drilled through it?
    As far as orientating the seal I've seen applications where the spring is out side presumable so if something causes damage to the seal the spring will not get into the inner workings?
    I wouldn't worry too much about it and just follow your instincts, I'm betting at some time the machine was run low enough on oil to damage the seals and new ones will fix it right up.
    Dan

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    On the bigger seals you can sometimes shorten the garter springs if you have a problem with leaks.

    Regards Tyrone.

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    Quote Originally Posted by tdmidget View Post
    Also means it can be removed without gouging the shit out of the bore that it sits in.
    I had a fitting with a self tapping screw in the end that I used with my slide hammer if the seal was awkward to remove.

    Regards Tyrone.

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    Your instincts are correct,the spring side of the seal always goes to the side that you want to stop from leaking,the lubricant side.The "double lip" seal was developed to stop external debris from contaminating the main seal and is available in most common sizes.

    Some off road equipment shops deliberately install seals backward to stop mud & dirt from getting into gear boxes and the lube is total loss which flushes some debris from the seal.If there is room two seals can be installed,one each way.

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    I used to do work for " BUSS AG " the Swiss plastic machinery maker, they fitted two twin lipped oil seals of absolutely top quality in each end cap of their gearboxes ! They were fitted both facing the same way with the garter Spring to the inside. The Swiss don't talk chances, they also fitted two lubrication pumps inside the gearboxes.

    Regards Tyrone.

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    Quote Originally Posted by Tyrone Shoelaces View Post
    I had a fitting with a self tapping screw in the end that I used with my slide hammer if the seal was awkward to remove.

    Regards Tyrone.

    Not much help if installed as the OP has shown.

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    Quote Originally Posted by tdmidget View Post
    Not much help if installed as the OP has shown.
    No but 90% of the time the seals are fitted the " right" way around so my extractor worked pretty well. Sometimes you had to pull in two places at 180 degrees to each other. Other methods are available of course. The " top quality " seals I mentioned earlier had a metal inside as well as a metal outside so you could get at them both ways if necessary.

    Regards Tyrone.

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    Default Difficult to find consensus on this issue

    I came across this statement on www.globalspec.com : "For proper installation, the seal lip should point towards the medium being contained." I interpret this to mean that the seal on my lathe is indeed installed backwards. Also, I do not understand how the orientation of the garter spring has any relevance, as it exerts the same amount of force either way.
    --Mike

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    Quote Originally Posted by Mikel Levy View Post
    I came across this statement on www.globalspec.com : "For proper installation, the seal lip should point towards the medium being contained." I interpret this to mean that the seal on my lathe is indeed installed backwards. Also, I do not understand how the orientation of the garter spring has any relevance, as it exerts the same amount of force either way.
    --Mike
    But the seals are designed with the spring to the oil as a standard. The "cup" created by the seal housing with spring also takes advantage of any internal pressure to force the seal tighter to the shaft. See picture from SKF

    Seal analysis pays | Evolution Online

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    Quote Originally Posted by Tonytn36 View Post
    But the seals are designed with the spring to the oil as a standard. The "cup" created by the seal housing with spring also takes advantage of any internal pressure to force the seal tighter to the shaft. See picture from SKF

    Seal analysis pays | Evolution Online
    The link included in your response clears things up. I was mistakenly thinking that my seals had a lip that could best be described as a pre-cupped circular flap, whereas closer inspection reveals that they actually have a vee-shaped cross section similar to the one shown in the illustration on the page you linked to, and I agree that for the construction shown in that illustration, the orientation as pictured is the more effective one.
    --Mike

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    Quote Originally Posted by Richard King View Post

    It looks like the seal is correct...
    Thank you, Richard (and all who replied). After some initial confusion and misunderstanding on my part, I do agree that the seal is indeed facing the right way.
    -Mike


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