FP1 vertical head bevel gear bearings
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  1. #1
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    Default FP1 vertical head bevel gear bearings

    Investigating a bit of noise in the vertical head on my Circa 1965 Ser#37843. I have the operators manual with a drawing of the spindle assembly and this corresponds pretty much to what I have. At some stage in the mills life the spindle has been dismantled as evidenced by there being one 1/4" ball missing from the top thrust race, as there are 16 balls in the race probably no harm done leaving one out!

    The lubrication instructions for the head specify OIL, once a week through a nipple on the spindle shroud . the drawing of the assembly shows 2 ball races locating the vertical bevel gear, On dismantling the assembly the top bearing is a Fag 6008zz P6 bearing and the lower one is a Fag 6008 P6, no shields. Does anyone know if these bearings, top one with two shields, bottom one no shields are correct? The drawing in the manual does not specify the two bearings and doesn't seem to show shields.

    The set up as it is allows oil to pass through the top bearing, in a sort of controlled manner and duly lubricates the bottom bearing, gravitates to the back of the bevel gear and then on to the teeth of both bevels, wends its way down to lubricate the body of the spindle housing.

    The spindle bearing lubrication system seems to be by way of the key way slot, the driving key has a groove machined in it to allow oil to pass the key and go down to the top thrust bearing, continue to the bottom thrust and finally to the needle race at the bottom.

    With all of this in mind it would seem to rule out the use of grease on the thrust balls and the needle bearings as it would be simply washed off by the oil over time. Likewise the shielded top bearing in the bevel gear assembly would also have its grease eventually replaced by oil. Likewise any grease used on the bevel gears would eventually be washed off by oil. On dismantling the head there was no evidence of grease on the gears, the gears are in pretty well new condition so perhaps grease has either washed off or was never used.

    However, there was an accumulation of very fine debris in the body of the housing and the only place it could have come from is the top shielded bevel bearing, the bottom one seems to be good but as the shielded one can't be inspected visually without ruining one shield I suspect it may be the cause of the noise. The nut, L/H was very very tight, I had to make a pin spanner with long handles and strong arms to move it and as the this nut can give preload to the bearings the tracks or balls have probably started to spall.

    So, What I would like to know is what would the correct bevel gear bearings be and are P6 bearings really necessary here?. If sealed bearings were originally supplied grease would be necessary for the bevel gears, if so, what type of grease?

    Cheers, Peter.

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    Hi Peter,

    Others here can answer your questions better than me. But there is one thing I am quite confident about. You describe how oil can make its way into the spindle via the key way slot and then go down to the needle bearings. If I have understood you correctly, that path should be blocked by a felt piece, so that no oil gets inside the spindle. The spindle is greased inside during assembly, and then sealed. It should NOT have oil coming inside it at a later time.

    Cheers,
    Bruce

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    Quote Originally Posted by Peter F View Post

    So, What I would like to know is what would the correct bevel gear bearings be and are P6 bearings really necessary here?. If sealed bearings were originally supplied grease would be necessary for the bevel gears, if so, what type of grease?

    Cheers, Peter.

    P6 bearings (DIN 620) are garden variety..same as ABEC class 3. (electric motor) Nothing special. General bearing house stuff!

    Bearing Tolerances and Precision Levels | AST Bearings

    Cheers Ross

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    Hey there,

    sK40 spindle? Just checking...

    BR,
    Thanos

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    Hullo Thanos, the spindle is MT4, only one needle roller bearing K 55x60x17, probably Nadella, with a ball thrust bearing just above it, sixteen 1/4 inch balls in a cage running between integral tracks ground both on the spindle and spindle body then another similar bearing, slightly smaller but still with sixteen 1/4 inch balls at the top of the spindle with one track ground on the spindle and a sleeve with an internal track on top of which the adjusting nut and lock nut abut to adjust the axial clearance. I have a drawing of the assembly in the 1964 Deckel operators manual.

    Ross, thank you for the information on the suffix P6. I guess what I really need to know is whether the two bearings at present in the vertical bevel gear assembly are the right ones, ie, top one with 2 shields and the bottom one with no shields. I have a drawing of the later spindle assembly with the SK40 spindle and this has the two bearings defined as being both zz's but I also see that unlike my spindle there is no provision to introduce oil to the top of the bearings so shielded bearings would certainly be the go, though I am at a loss to see how oil is introduced to lubricate the body of the spindle housing or lubricate the drive shaft through the keyed bevel gear when extending or retracting the spindle. Plus I assume that the bevel gears would be lubricated with grease.

    Ballen, Thank you for your reply, as you can see by the above the spindle in question is apparently the second iteration following the bronze bushed version and not the third iteration with the two needle roller bearings and the two thrust bearing in tandem at the top of the spindle. your point about the use of grease on these bearings is certainly right from all I can glean from the numerous earlier posts on this subject and the felt buffer with the small tongue blocking the keyway slot would certainly prevent any oil getting down to contaminate the grease but as there appears to be no way of introducing oil to the slot, perhaps its purpose is to act as a buffer? Maybe i am over-complicating things!

    Cheers, Peter
    Last edited by Peter F; 11-23-2019 at 01:06 AM.

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    Right, just checking it is not bronze bushing.

    BR,
    Thanos

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    Talk about not seeing the wood for the trees,of course there is nothing to stop one simply squirting oil from a can down the open top of the protective shroud to the keyway slot to get oil to the spindle housing body on the later type of head, advanced years is my only "excuse" for this missing of the obvious!

    Peter


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