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  1. #21
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    First a correction. In my post #14, I said "UNLIKE crazy glue" it should have "LIKE crazy glue". Cyanoacrylates cure with moisture. It is the moisture on your fingers that glues your fingers together (and other parts of your body).

    Second item is that if there are silicones in the coolant and the part is to be painted, expect "fisheyes" in the paint. Paint will not stick to silicone.

    Tom

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    Back when I was an apprentice 45/ 50 years ago we would spread a mixture of red lead powder and oil and spread it under there. As years went by we only used way oil, wiped off the access with lacquer thinner and then squirted industrial silicone around the outside base and filled up the tee slots. To be honest I never saw them under there again. Never had any calls saying it failed either. No news is good news in the rebuilding business. Rich

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    Quote Originally Posted by Richard King View Post
    I still think it would be worth testing with a bubble. Your assuming to much here, I have discovered in machine tool rebuilding you can't assume anything, you have to prove it.
    Richard, you were right. I put my two levels on the machine and walked around it. My shifting weight had no effect. Nor did I see any effect when I put the level on the floor and moved the table. So I did your test, first shimming the levels to be centered.

    The bubble jumps like mad when the table is shifted, but comes back to rest in exactly the same place. The only time that this does NOT happen is for the last half inch of travel in both directions. I think the table might be coming up against a stop which shifts its orientation slightly.

    One of my levels is an 18-inch Starrett 98. It's not very sensitive, the divisions are 0.005"/foot. My more sensitive level is a South Bend lathe level from circa 1965. I'm not sure what the sensitivity is, I think it's a few times more sensitive than the Starrett.

    These are good enough to tell that there is nothing seriously amiss, but I'm not sure they are sensitive enough to see if the table is still "factory fresh".

    Cheers,
    Bruce

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    Quote Originally Posted by Tyrone Shoelaces View Post
    My idea with the magnetic chuck was to grease underneath the chuck and then run a bead of silicon all around the edge of the chuck.
    I'm only planning to use grease under the chuck, but no glue or sealant. However I might use silicone grease, because of its good mechanical and chemical properties.

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    Quote Originally Posted by adama View Post
    I would go carefull with the silicone grease, silicones used in a lot of anti foam chemicals, it may well play ok chemically with your coolant, but mechanicaly it may not get on so well with the emulsion!
    I'm not worried about the chemical or mechanical interaction with the coolant

    That said, silicones as resistant as hell to wash off
    Hmmm, I had forgotten about this. You're right, stopcock grease is almost impossible to remove. Normal solvents don't phase it, parts need to be boiled in caustic solutions. So I'll scratch the stopcock grease, and look for a silicone-based anticorrosion grease.

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    Quote Originally Posted by ewlsey View Post
    I wonder what some Hylomar would do? Don't use RTV.
    I do have some Hylomar that I have used for sealing gaskets on machine gearboxes and the like. But I'm not going to use either that or RTV or anything else that seals or dries or cures. Just grease, probably silicone-based grease.

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    Quote Originally Posted by TDegenhart View Post
    Second item is that if there are silicones in the coolant and the part is to be painted, expect "fisheyes" in the paint.
    Tom, the only silicone would be in the grease under the chuck, not in the coolant. And all that comes AFTER the paint! In any case I will sand/sandblast the affected areas before priming and painting, and I wipe down with "Silicon Remover" before both of these steps.

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    Hi Richard,

    Quote Originally Posted by Richard King View Post
    Be sure to use a course wheel dressed fast and open/rough so it grinds cooler.
    I have the following two wheels. Are either of these a decent choice for the cast iron table with coolant? I'm some ways from doing that, but if another wheel is needed I want to order it in advance.

    My two grinding wheels come from the "Dorfner Schleifmittelwerk". I've checked in their catalog to translate the codes:

    200 x 20mm, 2A46 K10 VAX white aluminum oxide, vitrified bond, 46 grit, at the harder end of the "soft" range, next letter is "middle hard", middle open structure (not "very open")

    200 x 10mm, 2A80 M12 B9A, white aluminum oxide, bakelite bond, 80 grit, medium hard, more open structure than the previous wheel

    Cheers,
    Bruce

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    Evaporust did a nice job.

    Likely done but might as well put in my 2 cents.
    Thinking about grinding the set pad? At grinding it has to stay cool or it may grind in error. Wet grind and pause off at both ends if the least amount of heat is generated with a course open wheel. That is like grinding the biggest part you can, so watch for heat.
    *But first see that the bed ways are good enough to improve the condition of the set pad with setting on a straight edge shimmed to zero at each end and run a tenths indicator across to find zero at long travel and cross. Not finding zero flat then better to scrape the pad flat or scrape the machine bed ways first.

    I would figure-8 hone it with the smooth side of a "new" 6 or 8" hone and check it for flat and likely not grind it if it checked good. Same with bottom of magnetic chuck. 6 Inches Long x 2 Inches Wide x 1 Inch Thick 42434 - MSC

    Check chuck bottom it and see it is flat as the goal is to have the set-pad and the chuck bottom near dead flat.
    If grinding the chuck bottom set it upright first and lightly bolt it down to the set pad check and mark it for + and - at four corners. Then when you set it bottom-up you will be sure you are grinding correctly and not opposite what you want. Grinding chuck bottom or top another biggest job so cool grind even if it takes twice as long, with end pause and frequent dress to tale load as needed. *Remember most first timers burn the first chuck they grind..dont be that guy.

    I like a 46k AO name brand wheel. Radiak and Norton are good wheels as are a number of other manufactures ..would not use a China wheel. A little wash-board surface is fine. You can figure 8 hone chuck top a tad but the slight wash board doesn't hurt accuracy.
    Never thought much about the under side so just used way oil or lube oil and figured I would pull it once and a while at a regrind.

    I like to set the end of the chuck square, and then grind the back bump rail in place with a dish edge wheel coming .0002 to just clean up the face with having the back rail .030 or so off the chuck. Yes a decent chuck should be square but you never know unless you check it.

    I like to check that hold downs contact inside away from the very edge of the chuck. Tighten with one hand about 5-6" up on a standard wrench and then just a solid wrist tight. Guess that would be about 10 inch lbs. Yes a little tighter if intended for mostly big heavy work or a anybody's use grinder.
    Last edited by michiganbuck; 09-08-2016 at 10:25 AM.

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    Quote Originally Posted by ballen View Post
    h

    First step in assessing the condition of the parts: I've put a 0.01mm = 0.0004" indicator on the wheelhead and run the table back and forth and in/out. The high points are right on the money over the entire surface. The low points are running into the pits and valleys. These look worse than they are, about 0.01 - 0.02mm low. So I think the table and ways are in factory condition, apart from the rust pitting.
    That is not going to tell you how true the table is running. You need either a precision level as Richard has said or you need a straight edge off the table with a dial indicator attached to the table running along the straight edge.


    John

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    ^^^^^
    What John said.

    This is how dealers sell junk grinders.
    Dust the chuck, put an indicator on the wheel head, run it around.
    The chuck could be potato chip shaped if the ways are bad, but the indicator will map it just as the wheel touched it: "0 - 0" everywhere.

    Usually they do it with the "5 block test" which is even harder to fail.

    In your case you are presumably indicating a never-touched-since-factory-new surface on the chuck mounting pad, so it may be better. But maybe not, if it was ground on the machine. I prefer to level a 21 x 18 surface plate, and indicate that. Or you can indicate a good, scraped, parallel straight edge cross-ways, longways, and diagonally.

    smt

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    I got some time in the workshop today, and am now convinced that the transverse and cross ways of the machine are in factory-new condition.

    First thing I did was to print the bottom of the chuck on my surface plate. I did this two times, with similar prints both times.





    The chuck is only making contact at the two ends, not in the middle. However I tried to measure the depth of the hollow, and I was not able to. It is less than 10 microns.

    Second thing I did was to print the top of the table on the surface plate. Here is the plate, upside down on the top of the table



    and here is the print



    I find this very interesting. The places where the plate is making contact are exactly the places where the top of the table has not been rusted away. So it looks as if the geometry of this table has not shifted or twisted since it left the factory 30 years ago.

    The last thing I did was to put the surface plate on the top of the table with the true side up, and use this as a standard to check the geometry. Because the plate is wider than the table, and I did not want it cantilevered off one side, I could only map 120 x 450mm rather than 150 x 450mm. The vertical measurement is being done with a Heidenhan MT-30 gauge and display reading in 1 micron incrememnts.



    The plate was initially about 20 microns out of level along the long direction. I tried to level it, but I did not have any shims that were thin enough and did not want to mess around with jacks. So I mapped the surface at 5 cm increments in the transverse direction and 3 cm increments in the cross direction, including the tilt, and removed the tilt in analysing the results. Here are the raw data before that analysis (vertical displacement in microns). I trust these measurements because after making them I went back to the starting location and some of the intermediate locations, and obtained exactly the same values: they were 100% repeatable.

    Vertical displacement Z in microns from surface plate over 12 x 45 cm region. (The leading zeros below are the only way I could get the table format correct on the PM site.)


    -->X 00 05 10 15 20 25 30 35 40 45
    >Y -------------------------------
    00 | 25 21 20 16 11 09 06 05 01 00
    03 | 30 26 24 20 15 13 10 10 06 05
    06 | 34 30 25 21 19 15 15 13 10 06
    09 | 35 32 30 26 21 19 18 16 15 11
    12 | 39 35 31 29 25 24 23 20 20 16

    I then used an Excel spreadsheet (function LINEST) to do a best-fit subtraction of the linear tilt in the two axes. The resulting offsets from a true planar surface are shown here:

    Vertical displacement Z' in microns after removing best 2-dimensional linear
    fit: Z' = Z + 0.541 X - 1.2 Y - 23.9
    (leading zeros and signs are to make the table format properly on PM)


    ==>X 0000 0005 0010 0015 0020 0025 0030 0035 0040 0045
    >Y ----------------------------------------------------
    00 | +1.1 -0.2 +1.5 +0.2 -2.1 -1.4 -1.7 +0.0 -1.3 +0.4
    03 | +2.5 +1.2 +1.9 +0.6 -1.7 -1.0 -1.3 +1.4 +0.1 +1.8
    06 | +2.9 +1.6 -0.7 -2.0 -1.3 -2.6 +0.1 +0.8 +0.5 -0.8
    09 | +0.3 +0.0 +0.7 -0.6 -2.9 -2.2 -0.5 +0.2 +1.9 +0.6
    12 | +0.7 -0.6 -1.9 -1.2 -2.5 -0.8 +0.9 +0.6 +3.3 +2.0

    They are within the range +-3 microns from perfectly planar. In fact my surface plate came with a calibration map, and it's only good to about +-2 microns, so that might be the source of the largest error.

    So the conclusions are:

    (1) The table transverse and cross-way geometry is as good as one can get with this sort of machine, and is better than I had hoped for.

    (2) The bottom of the chuck seems to be slighly hollowed

    (3) The top of the table is flat, in those places where it is not pitted by rust.

    In the excitement, I did not print the top of the chuck, but I think that's irrelevant at the moment.

    So the question now is, how to proceed? I don't want to remove much from the table top, but I also don't like the pitting that is there. Could I use something like steel-filled epoxy to fill in the pitting, wet-sand this flush with the table top, and then dust it with the 46-grit wheel?

    Cheers,
    Bruce
    Last edited by ballen; 09-10-2016 at 02:32 PM. Reason: trying to make table readable

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  17. #33
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    Grinding the table top is a common practice. Go ahead and dust it for 90% clean up if you feel some of the pitting is too much.

    Then you will want to "float" grind the bottom of your chuck, do not clamp the ends, just block them in and dust the bottom. Keep your wheel dressed very open so it cuts free and does not want to build up any heat.

    Use a table mounted diamond, not your over the wheel diamond when grinding the table and chuck.

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    Hi Cash,

    Thanks for following this.

    Quote Originally Posted by cash View Post
    Grinding the table top is a common practice. Go ahead and dust it for 90% clean up if you feel some of the pitting is too much.
    I feel like the pitting is too much, because the amount of chuck actually in contact with the table won't be very much unless I do something.

    On the other hand, getting to "90% clean up" involves more than dusting. I think I'd have to take off at last 0.1mm = 0.004", and perhaps twice that. Hence I had asked about filling the pitting with JB-Weld or similar. I have done this to fill some scars in cast iron in the past and it's worked well.

    Then you will want to "float" grind the bottom of your chuck, do not clamp the ends, just block them in and dust the bottom.
    OK. This means that the chuck should NOT be magnetised, right?

    Keep your wheel dressed very open so it cuts free and does not want to build up any heat.
    That's clear.

    Use a table mounted diamond, not your over the wheel diamond when grinding the table and chuck.
    Could you explain why? Is the concern that the over-the-wheel dresser might not running parallel to the table top?

    I decided that it would be smart to lift off the table to clean underneath, andto make it easier to touch up the peeling paint.

    Removing the table on a Jones and Shipman 540 is easy: remove the four bolts holding the ends of the hydraulic ram, and lift:



    Here is the bottom of the table:



    And here's the top of the saddle, as first exposed



    and after five minutes of wiping off some goop from the oil grooves and elsewhere.



    It does look in good shape!

    Cheers,
    Bruce
    Last edited by ballen; 09-11-2016 at 03:21 PM.

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    Correct-Do NOT magnetize the chuck.

    You are correct as well for the reason not to use the overhead dresser. It may not be aligned perfect with the table, it could be just a couple tenths off and this will cause you issue.

    Normally in production grinding the over the wheel dresser may be used for roughing the wheel and when you are getting close to size/finish. But it is pretty common to run your finish dress off the table.

    This is not to say that you cant get your over the wheel dresser set pretty close and use it to finish.

    Good call to pull you table and make some checks there and clean.

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    Hi Cash,

    Quote Originally Posted by cash View Post
    Correct-Do NOT magnetize the chuck.
    Ok.

    You are correct as well for the reason not to use the overhead dresser. It may not be aligned perfect with the table, it could be just a couple tenths off and this will cause you issue.
    The machine came with TWO over the wheel dressers plus a block-mounted diamond that can be fixed to the table or chuck. I'll be sure to use that for the final passes.

    This is not to say that you cant get your over the wheel dresser set pretty close and use it to finish.
    Once I am done dressing the tabletop and chuck bottom, reinstalling the chuck and dusting the top of the chuck, I will install my Heidenhain micron probe in place of the over-the-wheel diamond, and measure to see how close or far it is from parallel to the top of the chuck. The mechanism of the over-the-wheel dresser involves several kilos of steel and cast iron parts, including a precision scraped dovetail running in a ground slide with a ground and scraped gib. So it's possible that it's capable of maintaining the necessary precision. Since the maximum width being dressed is about 20mm I guess under a micron of error in parallel over 20mm would be a good target.

    Good call to pull you table and make some checks there and clean.
    My real goal is just to get the machine back in working shape with no nasty hidden surprises lurking there. But to sand/prime/paint the rusty areas in the painted part of the table is just a few hours of work, and now is definitely the most efficient time to do it. So although it was not planned, I am resigned to doing it next.

    Cheers,
    Bruce

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    I think the machine is in great condition. Ran much the same machine with a somewhat a CNC control that I did not like that much.(the control / think they called it the Easy Control), *but It was a very good (great) grinder, smooth and accurate..
    Think the chuck bottom is fine the way it is if it checks flat. Would wash it with some washing soda and warn water and towel dry...then oil it well and let dry, then use Cash’s no-size and oil.. or just oil,.. or just grease.
    I like to use both hold downs because if one should bum the back rail with a heavy part it could get knocked off spot. Then the two bolts should be wrist tight.
    Yes I would check that it is flat at bottom and the set pad is flat.
    Yes It was a dumb move to buy such a grinder because I was doing mostly one-ups and by hand was often better than having any auto feeds. But the shop got a new product and so a big budget to spend

    You have plenty of set pad to mount a swing arm dresser of the set pad..once you get used to it will save a fortune of time as is it allows not making big moves to dress and can be set to be the gauge to dress and then size parts. You raise it to just skim the wheel after first part is made to size.. then you know finish part size is perhaps .002 below every dress.

    [Is the concern that the over-the-wheel dresser might not running parallel to the table top?] agree that over-heads are great but not for chuck grinding. good to set-pad mount the diamond about .005 higher than the wheel so you know exactly where it is going to hit the chuck..
    Remember most first timers often burn the first chuck grind.... so don't be that guy.

    Yes the ways look so good grinding the set pad and bottom of chuck would be fine but unneeded IMHO... and a greater chance to make a burn.

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    Hi MB,

    Quote Originally Posted by michiganbuck View Post
    I think it is in great condition. Ran much the same machine with a somewhat a CNC control that I did not like that much.(the control / think they called it the easy control). but It was a very good (great) grinder, smooth and accurate..
    When I bought it, I had not understand that it was a non-standard J&S 540. (Meaning that it had an electronically-controlled motor driving the crossfeed, and greased rollers rather than oil-lubricated slideways for the same.) So at first I was worried that the crossfeed might be worn out, that the motor might be on its last legs, and so on. But at this point it seems that the condition is good and none of those things is wrong. So with the light use it will get from me, it should stay in good shape forever if I treat it right.

    Think the chuck bottom is fine the way it is if it checks flat.
    But it's not flat! Look at the print from the surface plate. It's only touching at the ends.

    Yes It was a dumb move to buy such a grinder because I was doing one-ups and by hand was often better than having any auto feeds. But the shop got a new product and so a big budget to spend.
    I have already used the auto-cycle feature once. I needed to thin down a pair of washers by about 0.010"=0.25mm. I set it up then went off to have a meal with the family. When I came back,it was finished. I like that better than standing there and flipping a lever at the end of every cycle.

    You have plenty of set pad to mount a swing arm dresser of the set pad..once you get used to it will save a fortune of time as is it allows not making big moves to dress and can be set to be the gauge to dress and then size parts. You raise it to just skim the wheel after first part is made to size.. then you know finish part size is perhaps .002 below every dress.
    That would be the *fourth* dresser, as I already have two over-wheel ones and one that can be clamped to the table or chuck. Isn't that enough?

    Cheers,
    Bruce

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    IMHO your idea of micron dti testing the above wheel dresser to the tables a really bad one, its makeing the assumption the spindle is dead on plumb to the table, not a good assumption to make, when playing with grinders, best to start on the premise eerything is bad to some degree to proven otherwise or corrected. Far easier to simply grind a block, dress the wheel with the dresser then just lower it tenth or 2 verticaly into and out of the ground face, any out of square on the dresser will cause a noticeable taper to that mark, mine needed a single layer of kit kat foil wrapper at the back to hit perfection or as near to it as i can ever imagine! Due to the lovely quirks of geometry, that few tenths depth of mark and the near perfectly round wheel will show you more resolution than you micron indicator will :-)

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    Adama,

    OK, your way of checking is easier and probably more accurate, so I like it better than mine. Were you able to tune your J&S over-the-wheel dresser to the point where it's as good if you were dressing from a diamond mounted on the chuck?

    Cheers,
    Bruce


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