# Er 32 collet issue



## stirboy01 (Jul 5, 2021)

bought an inexpensive collet set which came with runout issues.. it is a mt3 spindle insert into the head stock and has no runout measured right by the headstock spindle.. the taper in the collet holder is basically dead on measured at several depths ( which is great ) ..  problem being the od of the holder body and threads for the lock nut (bearing type) are out about 0.004 which throws the od of locknut out 0.004 when installed.. im sure this imparts issues on the inner workings of the collet nut when trying to tighten collet into holder.. im thinking about taking a couple thou off the threaded portion of the holder od to help align nut to holder body .. any thoughts b4 i whittle it down ?   thanks  stirboy


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## WobblyHand (Jul 5, 2021)

Have you tried putting in a ground rod, or some other known good rod in a collet and measured the TIR?  Have you tightened down the collet nut tightly?  These collets require you tighten them pretty snug.  Some folks here advised the required torque was near 100 ft-lbs.  I don't do mine that tight, but I torque them a lot closer to 100 than to 10.  This should help snug the collet to the taper which you have measured to be true.

Speaking of which, how did you measure the runout?  A picture is worth a 1000 words.


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## Logan Novice (Jul 5, 2021)

The exterior surface runout can be dead on but, if the center is not running true, that won't matter much.  I'd suggest you clean all mating surfaces, load a known dead nuts accurate gauge material (drill rod comes to mind) into the collet, tighten that down REEEEEL tight, and see how that runs.


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## markba633csi (Jul 5, 2021)

I think the outside dimensions are not guaranteed to be as close as the inner taper and shank portions
It may or may not be a real problem-  check with a known good piece of rod like Logan suggested
-Mark


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## brino (Jul 5, 2021)

Did you install the collet into the nut _before_ putting it into the MT-3 to ER-32 adaptor?

The ER-32 nuts have a small off-centre lip that needs to engage in the collet groove.
It is used to extract the collet from the taper and let go of the part.

If you don't do it in this order then that off-centre lip tries to push the collet off centre as you tighten the nut.

-brino


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## markba633csi (Jul 5, 2021)

I think all the ER series are the same; the collet goes into the nut first
-M


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## T Bredehoft (Jul 5, 2021)

Just a suggestion, use a dowel pin, not a piece of O1 drill rod.  The O1 is ground in a centerless grinder, may have as much as .0003 or .0004 3-lobe effect.


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## Logan Novice (Jul 5, 2021)

T Bredehoft said:


> Just a suggestion, use a dowel pin, not a piece of O1 drill rod.  The O1 is ground in a centerless grinder, may have as much as .0003 or .0004 3-lobe effect.


Here's a little help for that good idea:  https://www.mcmaster.com/dowel-pins/diameter~5-16/oversized-dowel-pins/


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## stirboy01 (Jul 6, 2021)

thanks for the reply's !!  after some more thought into the issue i think i need to rethread the od of the chuck rather than just taking a couple thou off the od.. the root of the thread will still be the same amount off in relation to the 8 degree taper of the chuck and will not let the nut center up with the internal taper for the collet .. problem is i dont have metric gears to run the 1.5 metric pitch on the od of the holder..  thanks  stirboy


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## T Bredehoft (Jul 6, 2021)

I thought maybe an Imperial thread would be close, but.....1.5 mm equal about .0059 thousands lead, or 16.993 (17)  imperial pitch. Memory tells me there ain't no such animal. Sorry had to share my disappointment.

I had to check, too. Machinery's Handbook ignores the number 17 in it's chapter on threads. Not even a fatherless (bastard) pipe thread.

_Edit: _correct typo.


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## mickri (Jul 6, 2021)

Welcome to the forum.  What kind of lathe do you have?  Most imperial lathes can cut metric threads with the right gears.

I find your original post confusing.  It sounds like you are only measuring run out in the adapter and then surmising that there will be run out in the work.  You need to measure something of a know OD to check for run out.  Even if the work has run out to start with once you turn the work there won't be any run out in the turned part.  For example 3 jaw chucks always have run out.  They never hold the work concentric to the spindle of the lathe.  Yet the work is always concentric to the lathe spindle after being turned.

Run out in the threads will not cause run out in the work held in the collet.  The collet registers on the taper of the adapter.  Not the threads for the collet nut.  Look how loose the collet fits in the collet nut.

Tell us more about what you are making and how you intend to make it.


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## Pioneregil (Jul 6, 2021)

brino said:


> Did you install the collet into the nut _before_ putting it into the MT-3 to ER-32 adaptor?
> 
> The ER-32 nuts have a small off-centre lip that needs to engage in the collet groove.
> It is used to extract the collet from the taper and let go of the part.
> ...


Hi I had this problem with my er32 collet, but after I got a tip like yours everything worked fine perfectly,
Egil


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## brino (Jul 6, 2021)

@Pioneregil 

You joined over a year ago, but this is your first post.

So, Welcome to the group!

-brino


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## Pioneregil (Jul 6, 2021)

brino said:


> @Pioneregil
> 
> You joined over a year ago, but this is your first post.
> 
> ...


Egil


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## stirboy01 (Jul 7, 2021)

thanks again for replys..  i have a craftsman 12" and thinking of facing some valves at a later date.  the 8degree  taper of the chuck runs dead on with an indicator at various depths in the 32 taper.  collets snap into the bearing type nut nicely but with about .004 runout on the threads of the chuck im thinking that will put some side thrust on the collet when the nut is tightened. when i blued the internal taper and installed the collet and turned by hand i had great contact between collet and holder.  ordered a couple gears yesterday 44 & 52 T to let me help true up the 1.5 pitch od threads..  thanks for replys  stirboy


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## mickri (Jul 7, 2021)

I have the 52/44 gears on my craftsman 12x36.  They work great to cut the common metric threads.  There is a thread chart in the downloads section of the forum.  I have the chart taped to the cover on my lathe.   This is a great forum.  You should think about supporting the forum by becoming a member.  The cost is nominal for the benefits received.

Before you start messing with the threads on your adapter you really need to check the run out on a piece of round stock held in a collet.  That is the best test for run out.

Putting anti seize on the threads helps with getting the collet nuts tight.  Anti seize is a high pressure lubricant.

 I made an ER32 collet chuck for the spindle on my lathe. https://www.hobby-machinist.com/threads/no-excuse-not-to-make-an-er32-chuck-for-the-lathe.73804/  Or you can buy one from Beall Tool  http://www.bealltool.com/products/turning/colletchuck.php  The benefit of a collet chuck is that you can pass long stock through the spindle on your lathe.

 You might want to consider making a spider for the outboard end of the spindle.  Another one of my projects.  https://www.hobby-machinist.com/threads/making-a-spider-for-the-lathe.88933/

Another project was to make what I call a chuck keeper.  It will keep the chuck from unscrewing if you have to run the lathe in reverse for a project.  See my post #25 in this thread  https://www.hobby-machinist.com/thr...ith-a-screw-on-chuck.88487/page-3#post-795768

If you don't have a QCTP for your lathe you can make one.  Another one of my projects was to make a Norman style QCTP.  Lots of forum members have made them.  Not hard to make.  https://www.hobby-machinist.com/threads/norman-style-qctp.79705/

These projects should keep you busy for awhile.  I would make the QCTP first if you need a QCTP. 

Do you have a copy of the manual for the QCGB.  If not I think that it is also in the downloads section of the forum.  The manual lists all of the possible threads that you can cut through the QCGB by using different change gears.


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## WobblyHand (Jul 7, 2021)

stirboy01 said:


> thanks again for replys..  i have a craftsman 12" and thinking of facing some valves at a later date.  the 8degree  taper of the chuck runs dead on with an indicator at various depths in the 32 taper.  collets snap into the bearing type nut nicely but with about .004 runout on the threads of the chuck im thinking that will put some side thrust on the collet when the nut is tightened. when i blued the internal taper and installed the collet and turned by hand i had great contact between collet and holder.  ordered a couple gears yesterday 44 & 52 T to let me help true up the 1.5 pitch od threads..  thanks for replys  stirboy


The collet nut only is used to press the collet into the taper.  The runout of the nut threads are not relevant.  The taper of the chuck and the taper of the collet (and the trueness of the hole in the collet) is what matters.  My collets have a slight amount of play when in the nut alone.  This play doesn't matter. I can wiggle the nut when screwing on to the chuck.  It doesn't matter.  All that matters is the rod runs true.  So use a known good dowel pin, as suggested, crank down the collet nut tight, and report back your runout.  

I guess what we are all trying to say is, don't fix what's not broken.  The measurement of the dowel pin will tell you if anything is "broken".  If something is "broken" or out of spec, then we can work from there.  Use a dial test indicator (DTI) on the rod, and measure the runout (TIR).  My "wobbly nut" ER32 collet measures under 0.0005" using a DTI on a 1/2" rod.  Maybe yours does too.  Measure it and find out.


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## stirboy01 (Jul 14, 2021)

well i received my two gears to allow me to cut the metric threads.  on first pass they cut a 1.5 nicely but if i shut lathe off and reverse out there is enough wear in the train to allow the spindle to turn some b4 the lead screw begins to drive the half nuts and as a result the tool doesnt track out exactly in the first pass in. i can pull tool out at end of first pass and go back and pick up start of thread for second and remaining passes but lot of dinking around.. i have been looking locally for some dowel pins but they are not to be had and i really have no desire to order a bag of 25 or 50 so will just have to keep my eyes open .


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## WobblyHand (Jul 14, 2021)

For metric threads (on an imperial lathe) one needs to keep the lead screw half nuts engaged (at all times) while threading.  Can't quite tell from your wording if you have done that.  If you have, my apologies for stating the obvious.  Picking up the thread is doable, but tedious at best.

What size dowel pin are you looking for?  There's a bunch on eBay for relatively small money, some with free shipping.  McMaster-Carr has them, but they are more expensive.  Saw packs of 10 or less on both sites.  I take it you have gone to a hardware store?  How about an auto parts store? Might be a possible source, or a farm store to repair tractors or power equipment.  Precision pins are often used to locate engine/tranny parts.


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## stirboy01 (Jul 15, 2021)

yes i was keeping the half nuts engaged but problem was i needed to back the cross slide out and then reverse back past my starting point to pick up where i started the thread. works fine this way.  i should have sourced some pins during my working career as we had them all sizes and lengths but never dawned on me i would have use for them.  almost brings a tear to my eye when i think of all the buckets of bolts we threw away and now have to buy a few at a time !! i will have to look again at ebay but they seemed expensive to me for one at a time..


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## RJSakowski (Jul 15, 2021)

stirboy01 said:


> yes i was keeping the half nuts engaged but problem was i needed to back the cross slide out and then reverse back past my starting point to pick up where i started the thread. works fine this way.  i should have sourced some pins during my working career as we had them all sizes and lengths but never dawned on me i would have use for them.  almost brings a tear to my eye when i think of all the buckets of bolts we threw away and now have to buy a few at a time !! i will have to look again at ebay but they seemed expensive to me for one at a time..


At Farm and Fleet and presumably Fleet Farm, you used to be able to buy nuts and bolts by the pound.  You can mix and match so I would buy handfuls if the various sizes to build up an inventory.  The price was better than DIY prepackaged selections too.


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## stirboy01 (Jul 22, 2021)

my latest measurement of my runout issue was to install the bearing nut onto holder empty and run up by till the movable ring firmed up.  put an indicator on the id of the collet ring and it came out the same amount as od of holder and concentric with it .. both out about 3 1/2 thou.  reached through to 8 degree holder section and ro bout a half.  this is telling me the bearing nut is off around 3 1/2 compared to bore of collet holder..  i have taken two light thread chasing cuts on the threads but as yet have reduced the ro on the od. any ideas appreciated...


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## mickri (Jul 22, 2021)

I must be missing something here.  From what I can tell from reading through all of your posts you have yet to mount anything in the collet and then measure the run out on the piece held in the collet.  And even if there is run out once you turn it there won't be any run out in the turned part.

What are you trying to make with your lathe that has you fixated on the run out on parts of the adapter that should not have any affect on something held in the collet.  Are you looking for repeatability as you preform different operations on a part?

It might help us if you could tell us what you are trying to make with your lathe.


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## WobblyHand (Jul 22, 2021)

Have you procured a dowel pin and measured the TIR?  If so, I missed it.  I don't know, but the bearing nut might not be a problem.  But the only way to know is to measure a known good dowel pin in the collet, properly torqued.  If you have not measured a known good pin, then you are just guessing.  I wouldn't alter tooling unless it was really necessary.


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## stirboy01 (Jul 23, 2021)

mickri said:


> I must be missing something here.  From what I can tell from reading through all of your posts you have yet to mount anything in the collet and then measure the run out on the piece held in the collet.  And even if there is run out once you turn it there won't be any run out in the turned part.
> 
> What are you trying to make with your lathe that has you fixated on the run out on parts of the adapter that should not have any affect on something held in the collet.  Are you looking for repeatability as you preform different operations on a part?
> 
> It might help us if you could tell us what you are trying to make with your lathe.


yes..  i have mounted tools in the collet and checked the runout.  although i do not have any dowel pins i have used items as center drills and milling cutters which i imagine would be as close to being straight as any dowel.  with these im getting ro about same as od of chuck  .0035 .. if i just put the collet into the holder with tool in collet and no clamp nut ro goes down to around 001.. this is telling me the clamp nut is affecting the ro.  what im aiming for is doing some refacing work on some valves.  for this i will need the finished surface of the seat area to be concentric with the stem so i will need very little ro..  thanks  bill


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## WobblyHand (Jul 23, 2021)

Can you post a picture of how you are measuring the runout?  What measuring device are you using?  Where and how is it mounted?  This can matter.  What holds the collet in without a nut?  My collet would fall out.  Is the collet chuck clean and dry?  The collet?  The nut?  No crud, no oil, no burrs, no chips.

I just tried a random 1/2" end mill in my 1/2" collet.  Just to see what it would look like.  With the collet nut tight I get +0.0007" to -0.0004".  _If the collet nut is not tight - you are not testing the way a collet is used._  So no matter how good that is (and it's probably a fluke) it doesn't count!  A loose collet would slip and possibly ruin your work.

Here is my setup.  Probably could measure it better, but this is how I did it.  Didn't super clean anything, just pulled the end mill out of it's paper tube, put it in the collet, and tightened the nut using the nut wrench and a tommy bar.  Made sure that the end mill was adequately pushed into the collet.  You need over an inch inserted in the collet to get best performance.  

It's not the lowest runout measurement that I have made with this chuck.  _Some of my other collets in my set are better._  You could have a bad collet.  Still, 0.0011" TIR isn't bad.  You need to measure TIR near the chuck, it is worse further away.  Honestly, I don't even know if this is a good end mill or not.  Or if the cut out for the Weldon shank matters.



Like you, I don't have any dowel pins to test either.  Found a link for 4 units, 3" long by 0.5" OD dowel pins for ~ $11 on Amazon, so that is an option. They are spec'd between 0.0001-0.0005".  McMaster-Carr has some better ones (naturally) but they are more expensive.  They have 3/8 and 1/2 diameter 3" long dowel pins in 18-8 stainless spec'd at 0.0000-0.0002" for $4.09 and $6.24 each.  If you buy one, get one the same size as your valve stem, so you are testing the exact collet you would be using.  Collets can vary.

The nut still could be the problem, but without describing your measurement technique (in detail) or some good pictures, it's hard to rule everything else out.  Hope this is helpful.


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## stirboy01 (Jul 24, 2021)

WobblyHand said:


> Can you post a picture of how you are measuring the runout?  What measuring device are you using?  Where and how is it mounted?  This can matter.  What holds the collet in without a nut?  My collet would fall out.  Is the collet chuck clean and dry?  The collet?  The nut?  No crud, no oil, no burrs, no chips.
> 
> I just tried a random 1/2" end mill in my 1/2" collet.  Just to see what it would look like.  With the collet nut tight I get +0.0007" to -0.0004".  _If the collet nut is not tight - you are not testing the way a collet is used._  So no matter how good that is (and it's probably a fluke) it doesn't count!  A loose collet would slip and possibly ruin your work.
> 
> ...


i will try to get a pic or two later on but my measuring setup is similar to yours only im setting my mag base on the closet way and using a federal C5M indicator graduated in .0005s for my readings.  i have tried various bits or tools in the chuck and all have resulted with the same ro readings.  i can insert the collet holding a test piece and it will stay in the holder..  i lapped the mt3 shank of the holder into my spindle and have good contact there.. put blueing on the id of the holder and pressed collet in.. good contact resulted ,, i need to check at home depot for dowels as i see they show them online.. thanks  bill


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## WobblyHand (Jul 24, 2021)

When I used a Federal dial indicator I couldn't get very good results.  Perhaps the contact force was too high, or my gauge was a little sticky.  I had the C21 0.0001" indicator.  My dial indicator works fine, but not for this application.

Some of the folks here on HM suggested using a dial test indicator instead and attaching the mag base to the head for a more accurate test result.  All I had was a 0.0005" DTI at the time, but it worked great.  I was able to measure spindle runout and collet runout accurately.  You can buy these very inexpensively on eBay or Amazon for around $20.  That's what this DTI cost.  A DTI is a better choice for this kind of measurement in my experience.


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## stirboy01 (Jul 24, 2021)

I guess you will have to bring me up to speed on these indicators.. i also have a D21 which has the .0001 grads and is similar to a C21.. what the difference is i have no idea other than dial size or stem travel.  ??   my D21 only has around .030 travel so its easy to bottom out setting up. i guess i cant grasp why the style indicator you have pictured would do a better job than a back or side mounted plunger.  i have never used one of the lever type instruments.  i have taken a couple pics of my setup but am waiting for help to get them from my phone to the puter.  thanks  bill


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## WobblyHand (Jul 24, 2021)

Full disclosure, I consider myself a beginner.  So perhaps I can get others to correct me if I'm wrong.  I think the lever style DTI's have (in general) lower force to move the arm than the plungers.  The dial indicators have relatively high mass arms to move.  

I was having unreliable measurements of the spindle and collet chuck runout using a dial indicator.  In the case of the chuck runout, I could not position the plunger to be normal (perpendicular) to the collet chuck surface.  So it was contacting on the side of the plunger not at the tip.  This can create errors.  If I took the measurement multiple times they were inconsistent - sometimes too good to be true and other times quite bad.  I found the tip would exhibit some sticking (stiction?).  

The tips of the DTI's are typically carbide and quite small in diameter.  This reduces the contact surface some.  DTI's can stick, and jump, especially when changing direction when tramming a mill vise, but I think they are a little better than the plunger types with their softer tips.  

With all instrumentation you have to test it that it's working as expected.  Sometimes that means preloading the tip a little more and confirming one gets the same reading again.  If you don't, the measurement is suspect!

Using a DTI allowed me to get very consistent TIR readings.  That's why I use them for this sort of measurement.  I too started out using a dial indicator and have a thread on HM where I asked about TIR measurements.  Learned that a DTI is the correct tool for the measurement.  Hoping to pass that information forward.  Seven months ago: my runout thread  Hope it helps.  I made most of the mistakes that were possible!


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## WobblyHand (Jul 24, 2021)

@mikey can you explain why it is preferable to use a DTI for TIR measurements on collets and spindles?  I'm not sure I have explained it properly.  Thanks!


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## stirboy01 (Jul 26, 2021)

here is a shot of my indicator on the part in chuck.. mag base is affixed to way directly below.. im sure readings are good as the are consistent


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## WobblyHand (Jul 26, 2021)

Thanks for the picture.  It helps to understand how you are measuring.  

I'd recommend you make the stem of the tool perpendicular (square) to the spindle axis.  [Plunger rod is at the max diameter of rod and square to the workpiece.]  I realize you you are trying to measure in close, but having an angle can introduce errors.  Can't tell from the picture if the indicator tip is touching the collet or not.  The tip should only touch the workpiece.  

A tip that I have to share is to try pushing in the indicator further, say by another 0.010 to 0.030".  (Position dial indicator so the initial measurement is at 0.010", as an example.)  The measured relative variation from minus to plus should be the same.  Sometimes the indicator can stick or do something funky at certain positions.  The runout (positive measurement - negative measurement) for the second measurement should be identical to what you measured previously.  If not, something isn't right.  If the collet is tight, the runout should be independent of the initial plunger (dial indicator) setting.


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## stirboy01 (Jul 26, 2021)

i have ordered and returned two other 1/4 collets which have resulted with approximately the same readings as the collet i got with the kit.. this hints to me that im experiencing a common problem coming from the collet itself.. ordered a dowel today and will check when it arrives.. thanks  bill


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## stirboy01 (Jul 31, 2021)

received new ss 1/4 " dowel other day .. checked it in the collet this am and the best reading i could get was a negative .002 give or take a couple tenths.  after clocking the collet around to 3/6/9 and back to 12 the worst ro i had was close to - 0.005..  i got similar results when i was using a quarter inch center drill so i believe the drill bit to be as straight as the new dowel.. im still thinking a little work on the threads of the holder is not going to hurt anything..


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## stirboy01 (Aug 2, 2021)

well i finally took a few passes on the threads of the holder and it didnt hurt anything or help much either.. not much help as about the best reading i can get out of the 1/4 collet is around .002 .. only way i can think of to check the trueness of the od of the collet is to turn a piece of stock to a snug fit on the collet and slide it on and indicate the od to see if it is out of round with the bore..


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## WobblyHand (Aug 2, 2021)

The threads of the holder should have nothing to do with the trueness of the ID of the collet.  It's the runout of the ID of the collet that one is concerned with.  (We are assuming the collet chuck is true, and the collet is correctly made.)  Is the collet clean?  If there is swarf (little chips or metal slivers) in the collet, it could affect runout.  You could clean it out with some thin cardboard, like from a cracker box, or a sheet of paper.  If you have compressed air, you could blow it out (being careful not to get junk in your eyes).  

What does the bottom of your indicator plunger look like?  Is it smooth, or does it have some faceting?  My old Federal C21 had some slight faceting due to wear and being over 60 years old, sometimes it would oddly indicate.  New indicator tips are inexpensive to source, or you could make your own.  The thread should be 4-48.  When you measured the runout was there any oil on the workpiece?  Some people say not to use oil, others do.  I find a very thin coat of light machine oil reduces tip stiction.

However, can we revisit what you are trying to accomplish again?  If I recall correctly it has to do with valves.  If you are facing the part of the valves that face the engine, not the ground edges that seal to the head, then you shouldn't care if there is 0.002 runout or 0.004.  It won't matter.  If you are trying to correct the ground part of the valve, then I wouldn't use the lathe at all.  That one typically "grinds to fit" the head using valve grinding compound.  What is the "end task" that you are trying to do?


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## Winegrower (Aug 2, 2021)

I made an eBay purchase of an R8 to ER32 collet set for my mill.   For $50 for the adapter and 11 collets, I thought how bad could it be?   It’s from India, but when it arrived, I was initially impressed with the appearance and apparent quality.   But checking the runout, it was severe, in the 0.009 to 0.010 range, measured with a 3/8” dowel pin.    I compared with a 3/8” R8 collet and the same pin and found the runout was less than 0.001.    Poking around, the issue was with the adapter, and the manufacturer readily agreed to replace it.   I will report upon its arrival.

Two attached videos show the ”native” runout with the R8 collet, and the runout on the ER32 adapter.


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## WobblyHand (Aug 2, 2021)

Cool videos.  Could be the collet is bad, as Winegrower says.  Or the spindle & collet chuck if for some reason there's an issue with the measurement technique.  Not saying there's an issue, but the overall TIR could be due to multiple causes.  Are there any burrs or dings on the collet chuck, or register?

@stirboy01, I think your last post states that the TIR is 0.002?  That's -0.001 to +0.001, or -0.002 to 0.000, etc.  Or do you mean -0.002 to +0.002, which is a total of 0.004"?  But what is the application again?  What are you trying to do exactly?  There might be an alternate way to do what you need to do, but it's hard for us to suggest an alternate approach if the task is unknown to us.


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## Winegrower (Aug 2, 2021)

WobblyHand said:


> Cool videos. Could be the collet is bad, as Winegrower says.


It was not the collet.   The bad runout was exactly the same with several collets of different diameter, and exactly the same on the outside of the R8 to ER32 adapter.   Pretty easy to see where the problem was.   A new adapter has been shipped.


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## WobblyHand (Aug 2, 2021)

stirboy01 had reported the chuck being ok.  Sorry to have combined both @Winegrower and stirboy01 in the same sentence.  My bad.  Could be @stirboy01 has a bunch of no good collets, or the original measurement was in error?  It is possible to get a bunch of lousy collets, especially if from the same vendor and lot.  

I'm just trying to help and am struggling to come up with the root problem.


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## stirboy01 (Aug 3, 2021)

i am trying to get to the point where i can regrind the seating face of some small engine valves.. i have about .002 ro of a dowel when it is tightened into the collet..  it can be + .002 or -.002 depending on which side of the dowel i zero the indicator on.. its still a total of 2..  other day i put dowel in the vise and slid the collet onto it and indicated the od of the collet.. slowly rotating the collet on the dowel showed the od of the collet to be around .0015 out of round from the id.. i have a starrett 25R point set thats in pretty good shape and various points all yield the same readings.. everything is clean and no oil film and reading are smooth and not jumping around.. like i said before when i measure the bore of the 8 degree holder that is about right on even though the indicator is on a angle to the bore.. if worse comes to worse i can always use my 4 jaw..


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