[xaruum]

Any one have any experience on what the spindle temps should normally run for the taig mill?

Even at the lowest pulley setting ~1100rpm my spindle is getting over 160f ( darn $10 thermometer read any high higher ) in just 5-6 minutes! The bridgeports I used to work on would get warm to the touch, but not burning hot!

I am thinking of putting heat-sinks on the blank faces of the headstock on the right and left sides. But I am concerned about the cooling effect distorting the headstock.

Thoughts?

[cartertool]

Sounds like the spindle preload is too tight, slack the nut that's between the pulley and the headstock about 1/16th of a turn (in other words, just a smidgen) and run it for a bit and see if it improves.

Any one have any experience on what the spindle temps should normally run for the taig mill?

Even at the lowest pulley setting ~1100rpm my spindle is getting over 160f ( darn $10 thermometer read any high higher ) in just 5-6 minutes! The bridgeports I used to work on would get warm to the touch, but not burning hot!

Thoughts?

[Dean W]

Yeah, that's way hot in such a short time. I run mine (both lathe and mill) for hours at a stretch and it never gets more than pleasantly warm.
Nick has your best first option. Let us know if it helps.

Dean

[xaruum]

Well, the pulley is to close to the top of the headstock to fit a wrench in there. I loosened the set screw, and tried heat ( a hair dryer ) and cannot get the pulley off of the shaft in order to loosen the preload on the bearings.

Trying to come up with a shims or something that I can clamp around the nut under the pulley.

[Jeff-Birt]

Do not dray to pry the pulley off. A heat gun or a propane torch (held sufficiently back from the pulley) is what you need. With a hair dryer you'll have to heat it for an awfully long time, all around the pulley to get it hot enough.

[xaruum]

I got a chance yesterday to move the pulley and adjust the spindle nut.

I checked tir on the inside taper first and got .0005". I then loosened the nut about 1/16th of a turn, and ran it for 5 minutes to see how hot the headstock would get. I did this 2 more times to get the headstock to where it was warm but not burning hot, the spindle itself still gets burning hot to where you can't touch the spindle. The tir is now .0008".

I find that I have a real issue now though. There was a slight "click" when I went to put the collet closer nut on the spindle to run a test piece. I got the indicator back out and checked the tir which still read .0008. Using 1 finger I pushed back in the y direction against the spindle and felt the "click" again and the indicator moved .002", I used 1 finger again to move it toward me and the indicator moved .003". I then checked in the x direction and found .0015 of movement.

I decided to run the test piece anyway in order to get a better picture of how this would affect my work. I cut a .25" hole in 1/8 aluminum. This resulted in a parallelogram with one set of corners .251" apart and the other set of corner .224" apart. The mill was just re-trammed and backlash adjusted before replacing the spindle.

(I forgot to put in my original post that this is a new spindle, my original spindle threw a bearing.)

After the test piece I tightened the spindle nut 3/16th of a turn, and the tir returned to .0005 but the play was still there as evidence by another test piece.

The spindle turns smooth with no noise, so the bearings seem good ( they should be considering it is new ). So I am thinking that the bearings are shifting in the headstock. I am not sure I want to try and shim the bearings in the headstock because that would introduce new problems.

So should I try to exchange the spindle again with taig?

[Jeff-Birt]

The bearings/cartridge is heat-shrunk into the spindle housing. There should be no play at all. How did a bearing go bad on your other spindle?

[xaruum]

I don't know "how" the original spindle went bad. It has always made a lot of noise, it just kept getting louder and vibrating more until I decided to check the tir and turn the spindle by hand. I could hear a rattle in the bearing and it felt rough when turning by hand.

I talked to Cliff at taig and he took a look and determined that a bearing went bad.

I have my cam and post processor set to limit feeds and doc to meet the spindle speeds and materials. I usually see a max feed of about 16-18 ipm and doc around .01" to .005" and a spindle of 9800rpm for aluminum on 1/8" to 3/16" endmill. I compared this to my machinery handbook ( 1992 print iirc ) and it seems fine.

But I have only run the 2 test pieces on this new spindle. I spent the rest of the day working on true-ing the spindle to the axis and getting the pulley removed and re-installed.

[Jeff-Birt]

If it is a new spindle (or new bearings/cartridge) then you'll need to run it a while to get it broken in. I would guess that after 10 hours or so of use you should have a good idea of what temp it should will.

My friend purposely destroyed many Taig spindle bearings by running then with no lubrication and milling 6061 Al with a 3/8" bit. It takes about 15 hours in this condition to destroy the bearings. I'm not sure what temp he was seeing though. I'll find out.

[xaruum]

I am a little confused by the "run-in" idea. When I got this spindle I asked cliff how long the run-in should be and at what speed. He said not to worry about run-in and to just go ahead and use it. After your last post I checked for lube, and the bearings are lubed, so I put the belt on the lowest ratio, turned on the motor and walked away. It ran about 4 hours and there was no change in the TIR or play.

I have tried investigating a little farther, I took the headstock off the column and mounted it to the bed, and then mounted my indicator directly in the vise. I get a reading of about .0005 range of movement for a full turn of the spindle.

I have run out of time for today. So I will have to look for the play in the column tomorrow.

[fretsman]

I am a little confused by the "run-in" idea. When I got this spindle I asked cliff how long the run-in should be and at what speed. He said not to worry about run-in and to just go ahead and use it.

I've never heard of this either, and I don't have any Taig documentation that mentions this.

Possibly Nick Carter could chime in as he's been a fantastic Taig Dealer for a very long time, and may know more on this subject.

Dave

[cartertool]

Basically they set the preload nut tight and the grease is fresh. As it wears in the bearings it loosens up and the grease migrates, etc. If it continues to be hot after many hours then it's a problem but for a new headstock then it's pretty normal. When they used to ship the 1/8 HP motor on the mills it often wouldn't run at the highest speed unless you warmed it up at a loew speed for a few minutes.

I've never heard of this either, and I don't have any Taig documentation that mentions this.

Possibly Nick Carter could chime in as he's been a fantastic Taig Dealer for a very long time, and may know more on this subject.

Dave

[Jeff-Birt]

I've never heard of this either, and I don't have any Taig documentation that mentions this.

Possibly Nick Carter could chime in as he's been a fantastic Taig Dealer for a very long time, and may know more on this subject.

A friend of mine purposely trashed a boat load of Taig spindle bearings doing some tests for part of his thesis. We rebuilt two different spindles about a dozen times each so I do know what I'm talking about here.

This is not a phenomenon unique to Taig spindles though. Anytime you assemble a new rotating assembly with bearings it will initially be a bit stiff and will likely run a tad warmer. After a bit of time running, things will loosen up.

When they build the mills at the Taig factory they run the spindle for several hours straight to break them in. I don't think they do this when you buy just the bare spindle but after a few hours of use it should be at its 'normal' broken in state.

I don't know if this was contributing to the OPs situation or not but the point is you need to run a new spindle for a bit before trying to determine if it is running a bit warm.

[xaruum]

Just to clarify, what I found to begin with was a spindle running hot, I have since run it in, and still get 160+degrees. I also found what I thought to be play in the spindle, but it turns out is coming from somewhere else. So I am just adding my investigations to this thread so that more experienced people can point out where I may be incorrect or could improve my practices.

I wasn't sure how to determine play/deflection in a manner that would simulate normal usage so I ran a quick experiment. I have a spring that has 10lb/in of stretch ( I picked it up for a different project ) and connected one end to the top of the column and used my steel straight edge to measure the amount of stretch. I then mounted my vise to the table and clamped the indicator snug in the jaws and tested in both x and y directions against the z way ( the big block that the dovetail mounts to ). The indicator is level and is sitting 1.75" off the table.

It only takes a about 5lbs of force to start causing movement in the y direction. The amount of deflection increased to about .001" at about 15lbs and did not increase above that even at 50lbs.

The x direction saw only .0002 of movement even at 50lbs.

Being that the force was applied to the "lever" at 15-3/8" from the fulcrum that would be equivalent to x amount of force at 3-3/4" from the fulcrum. I don't remember how to solve for x. But if I recall correctly, a general rule is that the amount of force applied increases by a factor of 2 for every inch? I will have to look that up when I get home. Either way, with 269oz/in steppers and feedrates limited to 18ipm max I don't think the column itself is the source of play, so I will ry to measure the play between the z table and column next.

I also went ahead and removed the spindle from the headstock to see what condition it was in. It had to be getting -extremely- hot on the inside bearing race/spindle shaft surface because the oil residue has all been scorched dark brown/black and is flaking off. It only has about 5 hours of run in on it, 99% of which was at the lowest speed.

The assembly is a 6203R-oo at the bottom with a spacer that goes up to 2 face-to-face bellville washers that press against the outside race of a 6203z. I assume the washers allow the tension to be maintained regardless of heat lengthening the spindle. I found that when I removed the spindle nut completely, the bearings remained in place, so the spindle fit is really tight. I also found that the spindle nut is not mating flat to the bearing race, one side meets the bearing about .015 before the other side does.

I think 6203 are just deep grooves. That is fine for the top, and I am pretty sure it is ok for the bottom at the low loads this little mill will see.

More tomorrow.

[Jeff-Birt]

Hopefully you did not press the spindle cartridge out. You just need to evenly heat the spindle housing with a heat gun and it will drop right out. If yours is 160 deg F after 5 hours of use then there is a problem.

[xaruum]

I haven't used a press, I have been using my daughters hair dryer, it has several settings, so just 4-5 minutes and the spindle scooted out with just finger pressure.

Still trying to figure out how to measure the play between the z table and the column.

[xaruum]

I am trying to come up with a way for the spindle nut to meet the race completely flat. I believe the fact that the nut is applying more force on one side of the race than the other could be a major factor in the Heat issue. This is because as I attempted to take the bearings off I found that the majority of the scorching is at the top of the spindle right under the threads for the spindle nut.

One idea is to take a load bearing washer and grind down one side of the face that will meet the face of the spindle nut. The problem would be making sure that the washer and nut stay lined up correctly.

Another idea is to grind down the side of the spindle nut that faces the bearing race. But I think the spindle nut may be hardened which would make that more difficult and the grinding process would weaken the nut.

I don't really want to attempt to run the spindle any more without clearing this up. At this point I am also considering just saving the money to buy an ER16 spindle, but my concern is whether or not the spindle design is the same. If that is the case then I would rather just use the money towards building my own spindle ER spindle maybe a 20 or 25 using real p5 ac's.

Does anyone know if the taig ER spindle design is identical to the Original 3/4-16 spindle?

[Dean W]

Does anyone know if the taig ER spindle design is identical to the Original 3/4-16 spindle?

Sorry, they are not the same. The ER spindle has a 22x1.5mm nose thread to fit the ER-16 closer nut.

Dean

[xaruum]

Hi Dean,

I admire your work and enjoy your website. Just to be fair, Jeff aren't you the author of soigeneris? and of course everybody knows mr. carter, I have browsed over all of your sites for years and they have been the biggest influence on my purchases, as well as very inspirational. I thank each of you for taking the time to respond.

As to the spindle design, I wasn't being clear - I meant the actual build, as in the use of 6203 bearings, spacer, bellvilles, and nut.

I like the simple design and high quality of the taig equipment. I don't want to needlessly pester taig if the spindle is actually functioning as designed. I just have a hard time believing that the amount of heat being generated was intentional.

[Jeff-Birt]

The spindle should not get to 160 deg F. If you run for hours at 10K RPM it will get warm, maybe 110 deg F but that is about all.

Oh yes, I do run Soigeneris but I'm not allowed to mention that here...