Standard Modern 11" Series 2000 Lathe Spindle Issue

[RobinHood]

I do not know how they make these spindles - from solid or in pieces. The 3 spindles I have had out from my 3 different lathes did not seem to be made from components, rather from solid. Hence my questioning of how can a flange bend without the tube it is part of not distorting? Those are pretty serious junks of steel requiring serious forces to bend. I saw that you have a lantern post - presumably original - it would move out of the way long before any appreciable damage would be done to the spindle. OTOH, that stud on that chuck does really look beat up...

I have a number of known good D1-4 items we could try on your spindle. My problem is this raging pandemic. I am around high risk people and should not take any chances. I would be out in a flash to help you out.

I know you want to make things right and get your lathe in decent shape, but if it were me, replacing the spindle would be my last resort. I would want to make absolutely sure that there is not any other way.

Even if as PeterT just posted, and you have measured, there is a high spot on the spindle nose, your parts should still turn out cylindrical if the spindle runs true in its bearings.

I would mount the 4J and turn a decent size of metal, say 2” diameter by 5” long with about 3” stickout. Turn off about 25 - 50 thou and measure the cylinder. I would not be surprised if that works out. It would indicate that your 3J needs work. I am suspecting it is bell mouthed and the work piece actually moves in the jaws.

 

[PeterT]

Getting back to possibly what Rudy & I were wondering if this was the scenario. If the spindle section outboard of the bearing got bent in an unfortunate encounter, then the the DTI test should show a max runout spot which you have. But the confirmation would be to mark that spot, reset the DTI 180-deg to different position, say underside, rotate & the same spot should repeat. But if I understood correct you detected a bump on the outer cone but not on inner surface? This is aspect I wasn't clear on

 

[Crosche]

I do not know how they make these spindles - from solid or in pieces. The 3 spindles I have had out from my 3 different lathes did not seem to be made from components, rather from solid. Hence my questioning of how can a flange bend without the tube it is part of not distorting? Those are pretty serious junks of steel requiring serious forces to bend. I saw that you have a lantern post - presumably original - it would move out of the way long before any appreciable damage would be done to the spindle. OTOH, that stud on that chuck does really look beat up...

I have a number of known good D1-4 items we could try on your spindle. My problem is this raging pandemic. I am around high risk people and should not take any chances. I would be out in a flash to help you out.

I know you want to make things right and get your lathe in decent shape, but if it were me, replacing the spindle would be my last resort. I would want to make absolutely sure that there is not any other way.

Even if as PeterT just posted, and you have measured, there is a high spot on the spindle nose, your parts should still turn out cylindrical if the spindle runs true in its bearings.

I would mount the 4J and turn a decent size of metal, say 2” diameter by 5” long with about 3” stickout. Turn off about 25 - 50 thou and measure the cylinder. I would not be surprised if that works out. It would indicate that your 3J needs work. I am suspecting it is bell mouthed and the work piece actually moves in the jaws.

I am going to chuck up a piece of material in the 4J and see what the results are; there is no doubt that the 3J was badly abused and probably destined to become a rotary welding fixture.

For chuckles I sent a quote request to Standard Modern for a new spindle, but I am all but certain that the price will make the C-3 bearings look like a bargain.

Where are you working with the high risk patients? I am an instrument technician with AHS down at South Health Campus.

 

[RobinHood]

Where are you working with the high risk patients? I am an instrument technician with AHS down at South Health Campus

Actually it is family member with an immune deficiency. Other than getting food twice and dropping off a tool I made for my brother so he can work on a homogenizer, I have not left my property for 3 weeks.

 

[Crosche]

Getting back to possibly what Rudy & I were wondering if this was the scenario. If the spindle section outboard of the bearing got bent in an unfortunate encounter, then the the DTI test should show a max runout spot which you have. But the confirmation would be to mark that spot, reset the DTI 180-deg to different position, say underside, rotate & the same spot should repeat. But if I understood correct you detected a bump on the outer cone but not on inner surface? This is aspect I wasn't clear on

You are correct. There appears to be a small bump on the cone but not in the bore. I will check to see if the bump on the cone corresponds to the bump on the flat mounting surface on the nose. What I can't seem to wrap my head around is HOW anyone could possibly cause the spindle nose to deflect so much as to distort it? You would have to stress the metal beyond it's plastic limit and there just doesn't seem like there is enough clearance between the back of the spindle nose and the body of the headstock to permit that kind of deformation, but hey I didn't think that the corona virus would shut down the planet either, so what do I know?
OTOH, I don't understand how a bearing would cause a repeatable deflection at the exact same spot on the spindle nose and face? Dabbler spun the shaft several times and the bearing appeared to be fine. However, maybe it's worth pulling the spindle out and checking the bearings? At this point I am not sure what I have to loose.

 

[Tom Kitta]

Yeah, you may want to disassemble the whole spindle and then put it back together also inspecting the bearings and how are they placed in.

About two years ago on my rather beaten lathe I had it run in my garage not well leveled - it was supposed to move to my new garage so I did not "take care" of the beaten up beast. I was making a small part at its top speed of around 1500 rpm (plus 20% or so for 10Hz extra) so around 1800 rpm machining a longer thin shaft (maybe 10 inches so not outrageous). I heard the spindle make whine noises... I stopped the lathe - the spindle was making a noise and grunt and single spot during turning. I think I fried the bearings. Turns out getting large Gamet (UK made) bearings is next to impossible.

My dad helped me dissemble the spindle. I removed and cleaned the bearings. Little cylinders were not scarred and there was just a little smudge on the cup. Re-assembled and this time leveled the lathe. Works fine - at least the bearings. The nose still has some stoned damage on it and bed looks like it went through both world wars.

 

[RobinHood]

Looking into headstock and (possibly) removing the spindle, etc, and giving it a thorough cleaning can not hurt. As Brent mentioned above, check that SKF 6009-2RS rear bearing. Excellent point on inspecting the main bearing Tom. It takes next to nothing to cause things to go out of tolerance. Gives you the chance to set the endplay as well on re-assembly. You have nothing to loose.

 

[Crosche]

Yeah, you may want to disassemble the whole spindle and then put it back together also inspecting the bearings and how are they placed in.

About two years ago on my rather beaten lathe I had it run in my garage not well leveled - it was supposed to move to my new garage so I did not "take care" of the beaten up beast. I was making a small part at its top speed of around 1500 rpm (plus 20% or so for 10Hz extra) so around 1800 rpm machining a longer thin shaft (maybe 10 inches so not outrageous). I heard the spindle make whine noises... I stopped the lathe - the spindle was making a noise and grunt and single spot during turning. I think I fried the bearings. Turns out getting large Gamet (UK made) bearings is next to impossible.

My dad helped me dissemble the spindle. I removed and cleaned the bearings. Little cylinders were not scarred and there was just a little smudge on the cup. Re-assembled and this time leveled the lathe. Works fine - at least the bearings. The nose still has some stoned damage on it and bed looks like it went through both world wars.

Believing that this lathe was going to be my perfect one true love, I broke down and purchased a precision level and made sure that the ways are level.

 

[Crosche]

Looking into headstock and (possibly) removing the spindle, etc, and giving it a thorough cleaning can not hurt. As Brent mentioned above, check that SKF 6009-2RS rear bearing. Excellent point on inspecting the main bearing Tom. It takes next to nothing to cause things to go out of tolerance. Gives you the chance to set the endplay as well on re-assembly. You have nothing to loose.

I just purchased some Prussian blue to map out how the 4J chuck is fitting. Also, I called a friend who believes that he has a 3J D1-4 chuck that I could borrow for some test pieces. After that, tearing the lathe apart seems like the next course of action.

 

[Brent H]

@Crosche - stay with it. - - there is not enough “shaft” to bend on the end. -

Could be a matter of some clean up and a few new D1-4 components.

if you need links to manuals and drawings @RobinHood or myself and some others can supply. It is not difficult to pop out the shaft and even turn it between centres on a larger lathe the see what is the issue. Check that bugger back bearing - see if your adjustment collar is tight - I can set you up with the Timkin conical bearing adjustment if you need.

 

[Dabbler]

wow - I'm sorry I've been offline most of the day... I took a lot of measurements and for me there is no mystery. A chuck was crashed causing a .003 thou deflection int the D1-4 mating outer ring. That bend caused a .0015 deflection on the opposite side, causing a .005 difference in the whole rotation. (don't worry about the ,0005 difference - long story.

On the centre cone: It is not an ovoid or radially displaced. it is deflected almost .002. since the face of the seat is very rough, no reasonable measurements could be taken to verify, but I'm 90% sure.

The tiny deflection on the MT4 bore of the spindle is simple geometry. Assume you make a bend in the tube of the spindle, measuring .003 axial at the flange over 3" from the centre line. by using sin law, the angle of deflection is a little under .0525 of a degree. guessing that the bend, at worst case, is 2"inboard from the measuring point, you get 2 tenths deflection, which is what it was reading, more or less.

Even though I was using a tenths indicator, I wasn't calibrating, and conditions weren't optimal. So all these things should be taken +/- a little - I'm comfortable that the measurements back up the 'bent spindle' theory.

--------------------------------------

Now for the mitigation. The lathe can be used as-is, and will do 'okay' work, if things are done in a single setup. For re-registration and to get the best out of the lathe, some toolpost grinding is in order. I would leave the MT4 as is, as 2 tenths is just fine.

The back flange has to be trued to a maximum axial runout of .0005 wich will require just over .003 grinding No you do NOT need to try to make it totally flat. if you have 2/3 of the backplate perpendicular to the centre line, it will work just fine.

Now to the centre cone. Since a properly fitting chuck won't 'reach' the back plate any more, and since it still has a 'bend' artifact, it will have to be ground as well. you'd be surprised to find that by the calcs, it will need less than a thou of grinding, possibly in the order of .00075 again, 2/3 seating rule.

This won't make a 'perfect' lathe, but chucks will seat properly, and work will be good and repeatable. taking any more will introduce the possiblility of ruining the D1-4, I should stress that none of this should be done in one go. and final fitting will still require honing and/or polishing with diamond grit - but the spindle is salvageable with work.

Now if SM offers a spindle at, say 500 bucks, it's a no-brainer. The lathe will be like new again. I seriously suspect it will be about $1700 instead, hence my mitigation plan.

 

[Brent H]

Hey Dabbler, is it worth pulling the shaft assembly out and checking it all on a true lathe between centres?

 

[Crosche]

@Crosche - stay with it. - - there is not enough “shaft” to bend on the end. -

Could be a matter of some clean up and a few new D1-4 components.

if you need links to manuals and drawings @RobinHood or myself and some others can supply. It is not difficult to pop out the shaft and even turn it between centres on a larger lathe the see what is the issue. Check that bugger back bearing - see if your adjustment collar is tight - I can set you up with the Timkin conical bearing adjustment if you need.

Thanks

wow - I'm sorry I've been offline most of the day... I took a lot of measurements and for me there is no mystery. A chuck was crashed causing a .003 thou deflection int the D1-4 mating outer ring. That bend caused a .0015 deflection on the opposite side, causing a .005 difference in the whole rotation. (don't worry about the ,0005 difference - long story.

On the centre cone: It is not an ovoid or radially displaced. it is deflected almost .002. since the face of the seat is very rough, no reasonable measurements could be taken to verify, but I'm 90% sure.

The tiny deflection on the MT4 bore of the spindle is simple geometry. Assume you make a bend in the tube of the spindle, measuring .003 axial at the flange over 3" from the centre line. by using sin law, the angle of deflection is a little under .0525 of a degree. guessing that the bend, at worst case, is 2"inboard from the measuring point, you get 2 tenths deflection, which is what it was reading, more or less.

Even though I was using a tenths indicator, I wasn't calibrating, and conditions weren't optimal. So all these things should be taken +/- a little - I'm comfortable that the measurements back up the 'bent spindle' theory.

--------------------------------------

Now for the mitigation. The lathe can be used as-is, and will do 'okay' work, if things are done in a single setup. For re-registration and to get the best out of the lathe, some toolpost grinding is in order. I would leave the MT4 as is, as 2 tenths is just fine.

The back flange has to be trued to a maximum axial runout of .0005 wich will require just over .003 grinding No you do NOT need to try to make it totally flat. if you have 2/3 of the backplate perpendicular to the centre line, it will work just fine.

Now to the centre cone. Since a properly fitting chuck won't 'reach' the back plate any more, and since it still has a 'bend' artifact, it will have to be ground as well. you'd be surprised to find that by the calcs, it will need less than a thou of grinding, possibly in the order of .00075 again, 2/3 seating rule.

This won't make a 'perfect' lathe, but chucks will seat properly, and work will be good and repeatable. taking any more will introduce the possiblility of ruining the D1-4, I should stress that none of this should be done in one go. and final fitting will still require honing and/or polishing with diamond grit - but the spindle is salvageable with work.

Now if SM offers a spindle at, say 500 bucks, it's a no-brainer. The lathe will be like new again. I seriously suspect it will be about $1700 instead, hence my mitigation plan.

wow - I'm sorry I've been offline most of the day... I took a lot of measurements and for me there is no mystery. A chuck was crashed causing a .003 thou deflection int the D1-4 mating outer ring. That bend caused a .0015 deflection on the opposite side, causing a .005 difference in the whole rotation. (don't worry about the ,0005 difference - long story.

On the centre cone: It is not an ovoid or radially displaced. it is deflected almost .002. since the face of the seat is very rough, no reasonable measurements could be taken to verify, but I'm 90% sure.

The tiny deflection on the MT4 bore of the spindle is simple geometry. Assume you make a bend in the tube of the spindle, measuring .003 axial at the flange over 3" from the centre line. by using sin law, the angle of deflection is a little under .0525 of a degree. guessing that the bend, at worst case, is 2"inboard from the measuring point, you get 2 tenths deflection, which is what it was reading, more or less.

Even though I was using a tenths indicator, I wasn't calibrating, and conditions weren't optimal. So all these things should be taken +/- a little - I'm comfortable that the measurements back up the 'bent spindle' theory.

--------------------------------------

Now for the mitigation. The lathe can be used as-is, and will do 'okay' work, if things are done in a single setup. For re-registration and to get the best out of the lathe, some toolpost grinding is in order. I would leave the MT4 as is, as 2 tenths is just fine.

The back flange has to be trued to a maximum axial runout of .0005 wich will require just over .003 grinding No you do NOT need to try to make it totally flat. if you have 2/3 of the backplate perpendicular to the centre line, it will work just fine.

Now to the centre cone. Since a properly fitting chuck won't 'reach' the back plate any more, and since it still has a 'bend' artifact, it will have to be ground as well. you'd be surprised to find that by the calcs, it will need less than a thou of grinding, possibly in the order of .00075 again, 2/3 seating rule.

This won't make a 'perfect' lathe, but chucks will seat properly, and work will be good and repeatable. taking any more will introduce the possiblility of ruining the D1-4, I should stress that none of this should be done in one go. and final fitting will still require honing and/or polishing with diamond grit - but the spindle is salvageable with work.

Now if SM offers a spindle at, say 500 bucks, it's a no-brainer. The lathe will be like new again. I seriously suspect it will be about $1700 instead, hence my mitigation plan.

Wow John! I couldn't articulate any of our findings nearly as accurately; not in a million years.

Working backwards from your post. I contacted Standard Modern and they do not have the part number in their system and could not locate a drawing; although that's not a complete surprise since they are working from home. Regardless, getting a new spindle seems like a long shot.

As for your advice last night on tool post grinding the spindle nose, I purchased some plans for a tool post grinder and have been studying DIY grinders on YouTube & Pintrest in preparation of what seems inevitable because it was not my intention to buy a so-so lathe, but rather a good machine able to perform well.

With respect to disassembling the headstock, it's not a task that I relish, but I can't help wonder that if some idiot crashed the lathe so hard as to affect the spindle that the bearings escaped completely unharmed. I am no expert in this matter by any means and if you don't think that energy put into disassembling the headstock is wasted energy then I will focus my efforts on more useful tasks.

I think that I will be able to borrow a 3J chuck from a friend, so I should be able to conduct some further tests. Additionally, I procured some Prussian blue to try and map the contact area of the chuck.

 

[Brent H]

http://vintagemachinery.org/pubs/detail.aspx?id=6935

 

[Dabbler]

Thanks Brent! the drawings were very helpful!

We'll try a few things when you get your loaned 3J in, @Crosche... It will help pinpoint the error better. (I suppoe we should have taken you 4J jaws out and do a few more things!

 

[Tom Kitta]

Unless spindle is very weak in the machine a crash - even hard one seems to do little to it - https://www.practicalmachinist.com/vb/general/curious-what-heck-can-bend-lathe-spindle-162942/

Here is a long read about another D1-4 having issues:
https://www.practicalmachinist.com/...rested-any-approaches-git-er-straight-279738/

On page two they have videos and the spindle clearly is out in both X and Y direction.

Verdict is that problem is not bent spindle but loose bearings that either need replacement or adjustment.

Apparently if spindle is well designed the only way to kill it is place a shaft in the spindle chuck, make sure your lathe is attached to the floor with some bolts and then lift by the bar using a fork lift. I don't know how well you machine is designed through - apparently some home grade machines are so weak you can bend the spindle by looking at it.

 

[PeterT]

Crosche> ...the taper and face of the spindle feel smooth to the touch, no significant scratches, dents or dings.
Dabbler> ...it is deflected almost .002. since the face of the seat is very rough, no reasonable measurements could be taken to verify, but I'm 90% sure

LOL. are we all talking about the same thing here? - the conical spindle surface?

 

[PeterT]

Additionally, I procured some Prussian blue to try and map the contact area of the chuck.

Give it a go but I've actually had better luck with a Sharpie felt pen mark in this particular application. Prussian is kind of a oil based creamy substance, it kind of needs some displacement of the 2 surfaces to show shiny. You might have enough discrepancy gap that either will stand out. As long as they give the same message use either/or but don't do anything drastic just based on Prussian, To remove Sharpie (or Dykem btw) methyl hydrate works great.

 

[PeterT]

This discussion motivated me to measured my Taiwan 14x40 lathe spindle tonight. With a 10-ths DTI I measured 0.0003-0.0004 'oblong-ish' runout on the OD regardless of where I place the DTI ball along the chord. I marked the max deviation line and I have exactly the same thing on the inner MT5 taper. I'm pretty sue this is what I measured on the lathe when new-ish, or more probably when I finally acquired a tenths reading DTI.

Interesting thing, with DTI ball on the surface & lathe under the lowest rpm I get the same min/max needle reading of say 0.0004" but the whole deviation center drifts back & forth maybe 1-2 tenths. I'm not sure if this is vibration, or bearings warming up, or bearing influence...?

Another interesting thing is the rotating spindle back face surface is dead nuts, like not even an honest tenth deviation out. OK, So I guess if the spindle cone was a bit off, but basically tight enough that its making contact, that would allow for some minor amount of off-axis displacement. But if the vertical faces are true & coincident the axis will be parallel to one another & there is a lot more contact area on that surface.

I know this isn't helping the Standard Modern mystery but just providing a data point. Mine isn't perfect either but I'm going to guess this is maybe about right for reasonably used lathe? Did you guys measure the back face as well?

 

[Crosche]

@Crosche - stay with it. - - there is not enough “shaft” to bend on the end. -

Could be a matter of some clean up and a few new D1-4 components.

if you need links to manuals and drawings @RobinHood or myself and some others can supply. It is not difficult to pop out the shaft and even turn it between centres on a larger lathe the see what is the issue. Check that bugger back bearing - see if your adjustment collar is tight - I can set you up with the Timkin conical bearing adjustment if you need.

Thanks very much for the info Brent, I will check the back bearing as you suggest and may even replace it considering it is not very expensive to do so. With respect to the conical bearing adjustment ,are you referring to a tool, a work procedure or preload specifications?
That being said, @RobinHood , you were as precise as the bearings that are used in the machine. According the the drawings provided by @Brent H , they are C-3 bearings which makes sense - precision bearings = precision lathe. I do not know why Standard Modern quoted me the C-2 bearings, but I will certainly be following up with them to ask why. Thank you again for imparting that knowledge upon me.