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  1. #181
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default Captain's log: we been in space for one year now ..

    This weekend one year ago I dragged my visiting mother on her birthday (bless her) to pick up the "basket case". I've been working towards a milestone of getting the lower half back together and operational by one year. So here it is:

    IMAG1826.jpg

    Still some things to do there, like the "knurled knob" and some odd fasteners here and there. But, I have table and crossfeed and other gubbins working. I don't yet know how the 'friction clutch' stuff (with the leather pads etc) is supposed to work - but we'll get there.

    The 35T gear was a success. Happily. Thanks again Michael. Thanks also caskwarrior for the 3/4" reamer.

    IMAG1801.jpg

    And final fitment of the 15T gear to the shaft it travels along worked out well:

    IMAG1807.jpg

    Though I did have some very tight spots between the two gears so I got out the fine valve-grinding paste and worked them until they ran freely.

    IMAG1810.jpg

    Some other random pics:

    IMAG1827.jpgIMAG1823.jpgIMAG1822.jpgIMAG1821.jpg

    Still a lot more to go, but getting there - slowly!

    Greg.

  2. #182
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default

    Hey all,

    Trucking along.

    Got the top plate back on:

    IMAG1835.jpgIMAG1836.jpg

    The handle shaft was worn and needed machining back to get under the wear:

    IMAG1251.jpg

    (the key was left in because it was stuck)

    and some new bushings to match (no pics). The bevels up here are in *amazing* condition - maybe 0.001" backlash. Amazing.

    IMAG1834.jpg

    I finally put into action the serpentine belt kindly donated by forum member Ray-s. Thanks Ray! Apols for getting your forum name wrong in some previous posts.

    I wanted the serpentine to create the belt for the table mechanisms. The table belt is an odd one in that it has to cross over otherwise it hits stuff - this is actually how it is supposed to be.

    I was hoping the serpentine was long enough to also create a small test belt just to get the motor moving the main pulley. It was! Thanks again Ray.

    IMAG1853.jpgIMAG1852.jpgIMAG1846.jpg

    The belt looks a little small on the main pulleys, but the table belt is thinner - so it is pretty good match.

    The serpentine is cut and then rejoined using lockwire. I use the same system on my lathe but with metal eyelets. Not enough width here for the eyelets so we'll see how it goes.

    IMAG1848.jpg

    I wired up the motor using some new 4 core I got and used the VFD on about 10hz to see things working in very slow motion. Auto cross-feed doesn't work. I have to admit I have no idea how the cross feed 'friction' thingy is supposed to work - coz it doesn't! Table direction reversing mechanism needs some attention too - not quite engaging properly.

    Still, nice to see the table moving and nothing crashing into anything else because I fixed it wrong.

    Greg.

  3. #183
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Thanks for the update Greg, nice to see that things are still progressing.
    Kryn
    To grow old is mandatory, growing up is optional.

  4. #184
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default

    Thanks Kryn. For sure, the support is appreciated. Helps gets through bouts of "Grinder Fatigue".

  5. #185
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default Season 2 Episode 1 - the spindle beginnings

    Apols in advance. A while since I posted, so words and pics follow in a post or three.

    So .. yes, erm, the spindle ... <fingers drumming on table> .. hmmm, yes .. spindle ... <staring out window in the middle distance> ...

    This is a toughie. I think I've decided on a path to get it back into shape given the equipment I have. I've not actually done too much except for some preparation and endlessly ruminate over how it can be done in my workshop.

    An old-timer friend said "What would Burt Munro do?" (https://en.wikipedia.org/wiki/Burt_Munro) and I reckon that is good advice - think it through and make it happen with what you have. This is quite a challenge.

    My plan goes like this:

    1. line-bore the bronze bearings in place to re-establish clean and aligned bores.

    This isn't so easy - the precision required is beyond what I could achieve on the lathe. I have considered many ways to mount it and how I might achieve alignment but the lathe is not yet precise enough to line bore to this degree of precision. Plus the grinder spindle head block surfaces are too worn to use for lining it up (I have just one surface I can count on as original). Between the two old girls there are too many variables for precision alignment (such as the worn lathe bedways causing a few thou carriage drop in the area of boring, etc). Though, I think I've got a "cunning plan" to line bore without the lathe and I'll detail more later.

    2. Lap the bored bronze bearings.

    This is to get near-as-dammit-perfect round bore and smooth out stuff after the likely-less-than-perfect-finish line bore. I've got some 600 grit garnett (non embeddding) lapping paste in the mail from brownells.com.au.

    I am considering making a lap like this:

    Internal Laps, Arbors and Expanders

    3. Create a new spindle to fit the bearings.

    This will be a completely new spindle and I'll lap it to fit. I've no idea what a 0.00011" spindle-to-bearing clearance feels like and I certainly do not have any equipment to reliably measure it, so I'll start with "if it *juuuuust* fits in we'll call it a tenth". It'll then come down to running it in and feeling if stuff gets hot. I've yet to determine exactly what oil to use, and also if the clearance is really 0.00011" as per later BS#2 spindles (they changed). Dunno. But with 0.0001" the oil will be like kerosine or diesel I imagine.

    The spindle nose will need grinding to a 3" taper per foot, large-end 1" fit. I've bought some grinding wheel hubs from ebay US for some use, and also to use as a reference to get the taper.

    I am considering making a simple a tool post grinder to help.

    4. Create a test spindle

    This will be to create a test bar that fits the spindle block and can be used for testing alignment and any subsequent scraping.

    For now, I guess, let's begin the journey with some pics of the challenge ahead and some general observations. Coming in the next post.

    Continued ....

    Greg.

  6. #186
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default

    The spindle is mounted in the head with two keyed tapered bronze bearings. The outer ends of the bearings are threaded and held in place by threaded caps that use a differential screw mechanism to simultaneously screw onto the bearings and the head block itself. The bearings are not collet-like in that they close with pressure - they are meant to be stable regardless. They have a 'replacable' phenolic spacer running longitudinally that is meant to be replaced with something thinner to close up to cater for wear.

    Each bearing has a felt oil wick at the base.

    Anyways, the spindle as found. Cripes:

    IMAG0147.jpg

    The front bearing - note the oil channel that will fit under the oil hole and feed a hole in the side of the bearing:

    IMAG1899.jpg

    The rear - note no oiling - I think it must rely on the oil getting to felt wick underneath:

    IMAG1901.jpg

    As an example of the 'differential' thread thing, here is the rear spindle cap:

    IMAG1857.jpg

    The replaceable phenolic spacer in each bearing has already been replaced - which means the bearings likely no longer have a round OD, ..... and the rear bearing has its spacer missing (I suspect to allow it to be force-closed), so it'll be re-made:

    IMAG1903.jpg

    The above pic shows where the felt goes.

    A quick blueing to see what contact is made between front bearing and housing shows hardly any contact:

    IMAG1872.jpg

    There are a number of reasons why - like they are not round anymore as a result of the phenolic spacer replacement and subsequent pinching - and also this: note the lip around the housing edge, and note the gouge at the top. Some chimp has put the bearing in but not got it keyed and tightened it like hell .. and it has walked. So the bearing spent some of it life not actually seated:

    IMAG1859.jpg

    Actually, that is the story of this spindle. People have thought that tightening the caps acts like a collet and reduces play. Which it doesn't, but ...

    IMAG1889.jpgIMAG1886.jpgIMAG1885.jpg

    And these very-used parts probably hardly ever need adjusting. Man they have been abused.

    and you look at a marks like these and wonder what someone was doing:

    IMAG1925.jpgIMAG1902.jpg

    Things are very worn out. I mean really worn out. If I insert the spindle in the mounted bearings I get maybe 20 thou of play. Gents, I that is 200,000 times more than it is supposed go be. No wonder people were cranking on those bearing caps. Sheer optimism:

    Spindle:

    IMAG1930.jpgIMAG1928.jpg

    bearings (note wear strips at base flanks of ID):

    IMAG1918.jpgIMAG1917.jpg

    The bearing surfaces are in pretty bad nick too. Especially the lower portion of the front column ways and the corresponding part of the head. Ouch:

    IMAG1922.jpgIMAG1934.jpg

    (scuse the torch ... it was dark)

    So, all in all, not a great starting point - pretty nasty actually. I'll need to learn a bunch of things to get it across the line, but alas I am demented enough to give it go.

    I have started on phase 1 "line boring" and will details more in the next post.

    Greg.

  7. #187
    Join Date
    Mar 2016
    Location
    Sutherland Shire, Sydney
    Posts
    24

    Default

    Wow I didnt even know what a surface grinder was when you started this off, been amazing to read your commentary and to look at the pix

  8. #188
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default

    Hey Leigh,

    I hardly knew what one was either when I started this. I'd never used one and actually I had never even actually seen one in the flesh! Doh.

    Thanks for the comments.

    Greg.

    Edit: Thinking about it, I had seen some the flesh - I went to an auction to buy an old one and I had also seen one at machtool's workshop. Tut tut. Fibbing.

  9. #189
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default

    More ...

    I mentioned that I thought there were too many variables to accurately line bore the bronze bearings in the lathe. My "cunning plan" is to line bore them in place by making 'caps' that fit each end of the spindle head and using those to align a line boring bar.

    My reasoning is this: the only tangible thing I have for alignment is how the head hold the bearings, so my best prospect of accuracy is to use those. Besides, it seems best to bore the bearings with them held in-place like they would be in actual use.

    I have made caps to fit both ends. Both have reamed bores for a line bore shaft. Both caps were each made with a single setup each so (hopefully) all threads and the bore holes are concentric.

    The front bearing can be held using the stock collar and then a cap mounted external to it:

    IMAG1951.jpgIMAG1952.jpg

    The front collar has the differential thread and a 'through hole' so all good there. The stock rear cap has no through hole so no chance of using it so the new cap I made has to have the differential thread to press the bearing into the head:

    IMAG1975.jpgIMAG1976.jpg

    (the threaded ring in the background is a test piece I made to get the thread fit)

    Both caps have about 1" of reamed bore in them to hold the boring shaft stable. Also, each has some space in them to permit some swarf to go somewhere. I'll likely also drill some 'breather' holes in them so that, during boring, I can set up a vacuum to suck away swarf.

    IMAG1972.jpg

    Added together the two caps attach to the ends as such:

    IMAG1977.jpg

    The idea is that, with the above, to fashion a boring bar to bore the bearings in-place as they would be when in use. Given that each is no longer round (phenolic spacers replaced) it seems the best thing to do.

    Connolly's book says 0.0003" permissible alignment error in the bore. Honestly, I'll be happy to get 3 times that. I would have tested it tonight but I did something stupid and screwed up the 20mm silver steel boring bar I have so can't actual measure the diff right now between caps with the bar inserted. Bugger - but such is life.

    Btw, I am not actually certain how I am going to power the boring bar as yet ... but I suspect it'll be nice and simple and involve a hand drill. Remember, this exercise is not to get a perfect finish, but just to get the bearings re-bored and aligned. I'll lap them to a final finish.

    All comments welcome.

    Greg.

  10. #190
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
    Posts
    843

    Default Confused about alignment - advice sought ....

    Something is not right ...

    I fixed my issue with the boring bar candidate and did a test fit:


    IMAG1978.jpg

    The bar goes through both bores like a dream and turns beautifully. Both bores are 1"+ long and rod to bore clearance is next to zero so misalignment would not give this fine result. That is why I machined the caps so long - to accommodate the long bore for rod stability and to help prove alignment. So my take is the cap bores are *very* aligned. Nice.

    In the above pic, note the surface facing the camera - you can see flaking marks on it. That is my "one reference surface". My assumption is this surface should be parallel in the vertical place to the axis of the spindle.

    So, on my surface place which, using Michael G's repeat-o-meter (thanks Michael), has about 0.0003" variation in the orientation I am measuring (it is from 1971) I mount the block on two good parallels on that 'reference' surface so I can check if the rod is in the same plane:

    IMAG1979.jpg

    Only to find that the rear is about 0.016" or so higher than the front:

    IMAG1980.jpg

    The plate was clean and the parallels are good. So, given how good the rod feels in the bore of the caps I am left wondering why on earth I have such a large misalignment!??

    Both caps have a very good fit on their respective threads with very little play so it ain't that.

    I am left suspecting my reference surface is not actually on the same plane as the spindle. So I measured the machined 'collar' at base of each thread (you can see them both in the first pic - a shiny bit at the base of each thread at both ends). They are 0.001" diff in diameter but, when on surface plate, about 0.010" diff in height.

    Can I test anything more, or is the 'reference' surface not in the same vertical plane as the spindle?

    All help appreciated.

    Greg.

  11. #191
    Join Date
    Aug 2015
    Location
    Melbourne, Australia
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    Default

    I know you're all out there agonising on this but some more just to confuse (or solidify) things.

    I flipped the head and rested it on the two (LHS) bearing surfaces opposite the flaked 'reference' surface (the RHS).

    And now the front is higher than the back - opposite from before - so we're dealing with something that is not square. I can't see any way that the caps I made and their bores are not true to the axis of the spindle so, in effect, this means the bore is not true to the vertical bearing surfaces of the head. Looking at it front the front the spindle must have been pointing slightly to the right.

    But it still makes no sense to me why that is so on such a precision machine.

    Another test verifies the misalignment:

    With it still resting on the LHS bearing surfaces, the 'reference' RHS surface is in the same plane as the those LHS bearing surfaces to within a few tenths, as is the base of gib surfaces. (pics below are relative to each other - not from zero)

    IMAG1988.jpgIMAG1987.jpg

    But ... on the same setup the machined collars at the base of each spindle cap thread are out by 0.005"+ (front high) - though they differ in OD by just 0.001". So, while the bearing surfaces are in alignment, the factory-machined spindle collars are not. The pic below shows the diff (from zero) of the collars.

    IMAG1989.jpg

    Go figure. I am not sure if I am looking at someone else's rubbishy efforts to rebuild an old machine, but somehow, given the state of everything else, I doubt anybody has attempted to rebuild this machine - but you never know ...

    PS. And to those horrified to see a surface plate next to a grinder - the plate is always fully covered. It gets uncovered and cleaned a lot before use.

    All help and comments welcome.

    Greg.

  12. #192
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
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    Hi Greg, is it possible to swap the caps end for end and see if the readings are the same?
    Just a thought, as sometimes a few thou here and there add up.
    Kryn
    To grow old is mandatory, growing up is optional.

  13. #193
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    Aug 2015
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    Thanks Kryn,

    Unfortunately no. The caps are different for each end. My front cap screws onto exposed threads from the bronze bearing - so I am using the stock cap to hold the bearing and my cap mounts external it it. The front bearing has quite some thread length and holds my cap very well. The rear bearing has only about 0.300" of thread and the stock cap has no 'through hole' so I have made my cap to hold the bearing and also screw onto the head using the same 'differential' mechanism the stock cap uses.

    I am almost convinced that my only real path is to bore the bearings as planned and make that axis my datum and ignore everything else. When it comes time for fitment use that 'bore datum' and scrape the head into alignment around that.

    Resting and thinking on it at the moment and seeing if a brainstorm arrives )

    Thanks again,

    Greg.

    Edit: the bar has zero runout when rotating. I measure play in my cap(s) bore -> bar at 0.0002" at both ends. If I put an indicator on the bar just outside each cap and unscrew them then I see a thou or two as it unscrews, so the cap threads are a pretty good fit on the head threads.

  14. #194
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    Aug 2011
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    Melbourne
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    Just a thought, forget about how well the spindle aligns on the surface plate. Test fit the whole assembly back on the actual machine and measure spindle alignment to the table. You may find it's actually all fine.

    Just a thought...

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  15. #195
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

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    Hi Greg,

    I'm no expert by any means, but does the wheel having a few thou of cant to one side actually affect the accuracy of grinding ? The grinding wheel would be trued up before use anyway so its surface would be square to the bed. Also wouldn’t the gib strips on the head alter the angle of the wheel depending upon how thick they were.

    Very interesting and intriguing thread. I do hope that you make sense of your findings.
    Enquiring minds want to know
    Best Regards:
    Baron J.

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