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  1. #16
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    With regard to the second issue, both shafts will rotate - it is 'normal'. There is a lock out arrangement that means you can't engage the thread cutting and the feed at the same time.

    Rather than teflon, I would suggest phos bronze or similar to reline the bore rather than teflon. With normal oil flow (I can only assume the lathe was run with low or no oil in the headstock), it will be lubricated. Nothing says you can't cut some grooves in the bore to ensure oil gets in. Teflon (or another bearing plastic) will work, but I would be concerned about rigidity/ movement over time.

    Looking at the parts diagram for the head stock, I don't think that scoring will matter too much (although it should be cleaned up). That surface is for the gear to run against when engaging the dog clutch. If you are going to bush the bore of that part, perhaps machine some off the front and make the bush flanged rather than plain.

    Michael

  2. #17
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    Ahh Michael, once again preventing me doing something daft and unnecessary. Thank You!!

  3. #18
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    Quote Originally Posted by caskwarrior View Post
    Ahh Michael, once again preventing me doing something daft and unnecessary. Thank You!!
    Not hard to tell who the engineer is around here, or maybe he's done it before?
    Kryn
    To grow old is mandatory, growing up is optional.

  4. #19
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    Plenty of updates in the last month, I have now got everything together and working. I ended up rebushing the front half of the problem gear, I used two pieces of scrap bronze to do it as i didnt have a chunk deep enough in the scrap bin so there is a flanged ring and backup ring both press fit in there. Very happy with the fit.
    20180524_215205.jpg20180524_215212.jpg20180524_215218.jpg

    I then cleaned out the sump which of course was absolutely disgusting, just filled it full of sawdust and shovelled the resulting batter into binbags.

    20180529_185655.jpg

    I am now dealing with my last issue, there is a faint chatter like pattern in the work present at all speeds and regardless of power feed rate or hand feed, there is no detectable surface irregularity with even a 0.001 indicator, I suspect the rearmost spindle bearing has had some crap sucked through it. I will replace it and see where we get to. But any other ideas welcome.

    I had also suspected the scarfed joint on the flat drive belt but its a very long belt and i think the frequency of the chatter is too high.

    20180629_221104.jpg

  5. #20
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    Oct 2011
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    I carefully sanded the heat fused part of my belt so that it was not proud of the surface and so did not make an annoying noise every revolution.

    As for your chatter pattern, I'm not quite sure. Before replacing the bearing I'd check that things were snug/ tight. You may get something like that if the bearing preload is not up to scratch, but it could be something flopping around as well, so check anything that can be tightened or may have loosened off. That sort of pattern makes me suspect vibration first, so check that gibs don't have play in them, that chucks are secure, tools are tight in posts and so on. Even something like a centre that is not quite engaged can cause surface patterning.

    Because of their construction, CVA lathes with the isolated motor/gearbox and long flat belt drive should not be transmitting motor vibrations so at least it is not one of those things that there is no cure for.

    Michael

  6. #21
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    I think you were bang on with a lack of preload, the rear bearing cover which resists thrust on the outer race was not fully secured. Also the bearing cage had chipped in a few places so I suspect that also wasn't helping.

    I'll have a new bearing in tomorrow so will know for sure then.

  7. #22
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    Aug 2008
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    What sort of bearing is in the rear? The 10EE has a double row angular contact in the early one and the later ones went to back to back angular contact bearings.
    Light red, the colour of choice for the discerning man.

  8. #23
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    This was a double row, I don't know if it was angular contact though. 90mm od 50id by 23mm thick the only markings were RIV-8 7AA made in Italy.

  9. #24
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    okay rear bearing is all replaced but unfortunately the chatter remains. Im not in the mood to pull the spindle for a 6th time so its going to wait until friday, my last hope is to increase the preload on the main spindle bearings as im now sure the back bearing is under some preload. I could only source a plain double row bearing in that 23mm thickness though not angular contact. (the bearing in there was also a plain double row, though i suspect not original)

  10. #25
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    Apr 2012
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    Ralph maybe check your tool post is sitting flat on the compound and the compound is sitting flat on the saddle, a bit of blue should give you an idea, even put and indicator onto the tool post and give it a bit of a push and pull just to see that is not flexing.
    I think that when you have a bit of a sneaky problem it is best to go back to basic's, have a good look a the simple things and exclude them first.
    cheers, shed

  11. #26
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    Quote Originally Posted by caskwarrior View Post
    okay rear bearing is all replaced but unfortunately the chatter remains. Im not in the mood to pull the spindle for a 6th time so its going to wait until friday, my last hope is to increase the preload on the main spindle bearings as im now sure the back bearing is under some preload. I could only source a plain double row bearing in that 23mm thickness though not angular contact. (the bearing in there was also a plain double row, though i suspect not original)
    Double row angular contacts are very thick, but the style that Monarch originally put in there were preloaded double row bearings and not available today, that is why they would have gone with the back to back angular contact bearings. All they did was change the rear retainer to fit them as they are thicker again.

    I am surprised CVA put a plain radial ball bearing in there. It must have been good enough.
    Light red, the colour of choice for the discerning man.

  12. #27
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    I checked to see what kind of axial load they could take and FAG quote 50% of radial, the bearing I put in is 60kn radial so it can take a fair whack of thrust. They did not mention anything about acceptable preload though.

  13. #28
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    What I have seen in spindle design one set is always free floating. In many lathes this is the rear bearing. Of course designs that use roller bearings up the front have the rear bearing to take thrust loads.
    Light red, the colour of choice for the discerning man.

  14. #29
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    The CVA spindle is a strange beast. The front angular contacts are preloaded by a collar that screws on from the back, pretty normal. But then in the rear gear cluster there is a free floating inner sleeve which pushes out on the inner race of the rear bearing and must preload it as there is absolutely no room for the outer race to move.

  15. #30
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    After fiddling about on the weekend, I have found two more things which could be it. I removed the actual cams from the camlock spindle nose and they look pretty tuckered out, I think they were shop made replacements and not hardened fully (one of the square sockets is also broached well off center) Also i think the nut that applies preload has backed off a bit but i have to make a strange spanner to adjust them.

    Does anyone have a wrecked d1-3 spindle i could get cams out of, or know of anywhere to order them. An old PM thread they said are available from MSC but I cant order from them according to their website. and the UK MSC website does not list the part number.

    Also are d1-3 cams the same as d1-4 , 6 etc?

    Okay looks like i found mac-it who are the supplier to MSC but i think the groove dimensions at the back of the cam are wrong. Might have to make them from scratch if i can find a print.

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