# Atlas MFC - loose and jammed arbor?



## brandon428 (Feb 7, 2021)

I hadn't taken off my arbor in a while, and went I went to do it yesterday (my normal method is to take out the drawbar, use a 5/16" brass road sunk against the inside of the female end of the morse taper (past the 3/8" threads), and bumping it out).  Yesterday I bumped it 57 times with a brass bar and it still wouldn't come out.  Two more rounds of PB blaster and the same, but no luck.

So I put this on hold to finish a project, put things back together, and now I noticed the arbor moves back and forth after the drawbar is back before I put the arbor support back on.  Now I've never felt any of this play when changing cutting tools, so it's possible this is normal, but I'm not sure.  I also attached a picture of the bearing on the inside, which looks like it could be further back than it should?  So is this normal?

Now assuming this _is_ normal, and I don't have bigger problems, any tips on how to get the darn arbor off?


----------



## JPMacG (Feb 7, 2021)

I sometimes have trouble removing a Morse taper from the spindle of my Atlas mill.   When that happens I put a 1/2" diameter 12" long steel rod through the spindle and beat on it with a brass mallet.   I do worry that I will damage something, but so far I have not.   I don't understand why these are so hard to remove.  Maybe we are tightening the draw bar too aggressively?

My spindle has no longitudinal play.  I adjusted the bearing nut to remove all play when I changed the belt and it has held.   If you have developed longitudinal play then the bearing nut may be loose.   I'd remove the gear cover and inspect the bearing nut.  Maybe you just need to adjust the nut.  If that is ok then you might need to investigate the spindle.  Maybe the bearings or races (right word?) have shifted.


----------



## brandon428 (Feb 7, 2021)

Not sure I understand.  Are you hitting the shoulder or the female thread or the back of the Morse on the arbor where the drawbar threads into?

Are you hitting the steel rod with the brass hammer?  Wouldn’t that potentially mar what you’re hitting while protecting the steel rod?  Rather than protecting what you’re hitting?

If the spindle isn’t supposed to have play, I’m pretty sure my banging on the arbor is what caused it to loosen up.  Is the bearing/race I attached the one you’re referring to?  It’s possible that arbor was in so tight that I loosened that up instead.


----------



## JPMacG (Feb 7, 2021)

Yes, I'm hitting the outer shoulder of the Morse taper.  The 1/2" diameter rod is about the largest that will fit through the spindle hole.  And yes, the steel rod has marred the Morse taper.   I could just as well use a steel hammer, but I happen to have a brass one.   I watched Rudy Kouhoupt's video and he gives the Morse taper a polite little tap on the loosened draw bar and the Morse pops loose.  I must be doing something wrong.


----------



## 34_40 (Feb 7, 2021)

I think you've overtightened the drawbar.  There was an older thread in here where someone had a stuck arbor but he thought it was from sitting in place for years.  I think he had to pull the shaft and take it to someone with a big press to get them apart.


----------



## brandon428 (Feb 7, 2021)

JPMacG said:


> Yes, I'm hitting the outer shoulder of the Morse taper.  The 1/2" diameter rod is about the largest that will fit through the spindle hole.  And yes, the steel rod has marred the Morse taper.   I could just as well use a steel hammer, but I happen to have a brass one.   I watched Rudy Kouhoupt's video and he gives the Morse taper a polite little tap on the loosened draw bar and the Morse pops loose.  I must be doing something wrong.


Yeah, the manual says to tap it with a brass rod.  Not hammer but tap.

I’ll try a 7/16” or 1/2” brass rod and see if that’ll work.


----------



## brandon428 (Feb 7, 2021)

34_40 said:


> I think you've overtightened the drawbar.  There was an older thread in here where someone had a stuck arbor but he thought it was from sitting in place for years.  I think he had to pull the shaft and take it to someone with a big press to get them apart.


How would I even pull the shaft?  Figured I’d have to get the arbor out before I’d be able to do that.


----------



## brandon428 (Feb 7, 2021)

Oh, and I had this thing off within the past year or two. It’s not like it’s been sitting for decades never having been off.

I did mill some 303 stainless not too long ago which is pretty heavy. Milled it slow and it was fine but certainly heavier than normal.


----------



## DAT510 (Feb 8, 2021)

I had a similar issue when I got my MFC. Not sure what the previous owner did, but the arbor was in there tight. I ended up using a pair of pickle forks as if they were large Jacobs wedges. I placed them between the drive flange and the spindle collar. I gently taped them together and the wedging action popped the arbor right out.


----------



## brandon428 (Feb 8, 2021)

DAT510 said:


> I had a similar issue when I got my MFC. Not sure what the previous owner did, but the arbor was in there tight. I ended up using a pair of pickle forks as if they were large Jacobs wedges. I placed them between the drive flange and the spindle collar. I gently taped them together and the wedging action popped the arbor right out.


Interesting idea. Guess Jacob Wedges could work too, though pickle forks would have more leverage.

Do you happen to remember what size pickle forks you got?


----------



## DAT510 (Feb 8, 2021)

They were two smaller ones from a set I have.  They were just wide enough to clear the MT2 taper but still push on the drive flange of the arbor and drive collar.   Btw, I didn’t pry with them, merely put them tip to tip (overlapping) and as I pushed them together the tapers created a wedging action. Once they were tight by hand I took two hammers and simultaneously hit them together.  After two light blows the Arbor popped out.


----------



## wa5cab (Feb 8, 2021)

brandon428 said:


> How would I even pull the shaft?  Figured I’d have to get the arbor out before I’d be able to do that.


Brandon,

You can actually pull the spindle out with the arbor and arbor driver still in place. 

Remove enough of the countershaft to get the spindle belt free of the countershaft cone pulley.
Remove the front arbor support.
Remove the draw bar.
Remove the nut that sets the bearing preload from the rear of the spindle.
Remove the gear and spacer from the rear of the spindle.
Loosen the set screw in the bull gear.
Rotate the spindle to line up the Woodruff key in the bull gear with the slot in the inner front spindle bearing dust cover.
Remove whatever else I have forgotten.
Figure out how to grab it and pull away. 

However, I don't know that it will be any easier to separate spindle and arbor with both out of the head.


----------



## brandon428 (Feb 8, 2021)

DAT510 said:


> They were two smaller ones from a set I have.  They were just wide enough to clear the MT2 taper but still push on the drive flange of the arbor and drive collar.   Btw, I didn’t pry with them, merely put them tip to tip (overlapping) and as I pushed them together the tapers created a wedging action. Once they were tight by hand I took two hammers and simultaneously hit them together.  After two light blows the Arbor popped out.


I assume you put the forks here in between the pins?


----------



## 34_40 (Feb 8, 2021)

The pickle forks idea sounds like a good one.  Maybe the tools used to remove automotive tie rod ends would work.  I think some of the big chain auto part stores rent/loan them too.  I don't know if they'd fit going between the shaft & pins but maybe inline with the pins?


----------



## DAT510 (Feb 8, 2021)

brandon428 said:


> I assume you put the forks here in between the pins?


 Yes, with one pickle fork coming in from each side.


----------



## brandon428 (Feb 8, 2021)

I measured the morse at the point I could get at with my calipers which is 0.700".  The smallest size pickle forks I can find are 11/16", so might need to shave.  On the other hand, the fork widths are 1/4" each, and the distance between the pins is 1.110, so I'm really surprised you didn't need to shave the outside to get these to fit...


----------



## DAT510 (Feb 8, 2021)

I'll take a look when I get home tonight.

Btw, the pins centered down the gap between the forks.  

I used the pickle forks as large if they were large Jacob wedges.  




Here's a video I found that might better explain it better than I can with writing.



			https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjr0rvq-truAhWZJDQIHTSzBjIQFjABegQIAhAC&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dt-cIjxCMlrU&usg=AOvVaw3ly0-QokwSIeTYDcb9Jcw-
		


The meat of the video starts around the 4min mark.


----------



## brandon428 (Feb 8, 2021)

Ah, got it, oriented that way you don't have to worry about the pins.

Incidentally, it looks like #6 Jacob's Wedges have a .717 inner diameter, so I suppose I could try those as well.  Maybe using a vise like in that video or a C-clamp instead of a hammer.


----------



## brandon428 (Feb 12, 2021)

Ok, tried the #6 Jacob's wedges and they get stuck on the pins before they clamp.  Pickle forks must have more depth.  I may shave off the outside to see if I can get them to fit within the pins.

I also found out what was causing my play -- the middle gear appears to be slightly unaligned from the pulley, which is causing some slop in the rear bearing.  [picture attached].  I'm guessing my hammering must have popped that loose, but I can't get other parts of the spindle to move independently, so I think I need to take apart the spindle to adjust it.

Does anyone have a picture of the nut that sets the bearing preload at the rear of the spindle that's been mentioned a few times.  I can't seem to find that part on my spindle.


----------



## wa5cab (Feb 12, 2021)

Technically, the threaded thingy on the left end of the spindle is called a threaded collar.  When new, it looked pretty much the same as the unthreaded collar in your photo above.


----------



## brandon428 (Feb 12, 2021)

Hmmm, you mean the one on the end that has the set screw?  That’s the nut?


----------



## wa5cab (Feb 12, 2021)

Yes,  The only safe way to tighten it is with a modified pin spanner, with the pin replaced by a screw with the same threads as the set screws.  Remove one of the set screws to do that.


----------



## brandon428 (Feb 12, 2021)

Hmmm. Never seen a pin spanner. Have a link to one online I could use?  Assume tightening by hand wouldn’t cut it.


----------



## wa5cab (Feb 13, 2021)

Go to 









						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com
				




Note that the noun "spanner" means either a box end or open end wrench in the UK but in the US it doesn't.  

The specific type of pin spanner with a loose threaded pin is not carried by McMaster but must be what the factory used to adjust the preload on the spindle bearings.  A standard fixed pin spanner would damage the threads for the set screws in the collar.  And a small pipe wrench would damage the OD of the collar.  A correct size standard pin spanner could be modified by pressing the pin out and replacing it with a short socket head cap screw that fit the set screw threads.  The two set screws would of course have to be temporily removed.


----------



## JPMacG (Feb 13, 2021)

I loosened mine with a small pipe wrench - and I did mangle the surface somewhat.  The lead slug under the set screw grips the threads well, so it takes a bit of torque to break it loose.  

I was able to get the preload on mine by threading in a screw and using the screw as a handle (apply force close to the nut so you don't bend the screw.)  It doesn't take a lot of torque to get the preload, so that worked OK.   

In hindsight I should have made a tool - something like WA5CAB described, or maybe a large thin nut-shaped piece with an ID that slips over the Atlas nut and a radial hole for a screw to engage the Atlas nut.


----------



## wa5cab (Feb 13, 2021)

Another way that one could make a simple tool would be to get a large hex nut (either UNF or UNC) for approximately the nominal diameter of the collar, bore the threads out until the nut is a slip fit over the collar, and then drill one hole through one of the flats on the hex that will match up with one of the tapped holes in the collar.  Use a socket or hex or countersink the hole and use a flat head screw not quite long enough to reach the lead or brass plug to lock the nut to the collar.  Then use whatever you have that fits the nut to turn the collar.


----------



## brandon428 (Feb 19, 2021)

I ended up using electrical tape on some channel locks and managed to loosen it without marring the surface.  It did not take much torque to get it off, so it's possible someone has taken it off in the past.

Incidentally, what is the "pre-load" torque?  How do you know when it's tight enough?


----------



## JPMacG (Feb 20, 2021)

Atlas gave a procedure for adjusting the bearing (or maybe it was for their lathes), but I seem to have lost them.  If I recall correctly, it involved snugging the bearing then running the spindle for awhile to allow the parts to heat up and expand, then snugging it again?

In the absence of directions, I would just tighten it until there is no play in the axial direciton.  Maybe then run it for awhile to be sure that play does not develop and, if necessary, tighten it again while warm to remove that play.  Any axial ply is bad, but having the bearings too tight is bad too.

Maybe Robert or someone else can help.


----------



## brandon428 (Feb 20, 2021)

I assume by axial, you mean longitudinal along the spindle?

Who is Robert?


----------



## 34_40 (Feb 21, 2021)

brandon428 said:


> I assume by axial, you mean longitudinal along the spindle?
> 
> Who is Robert?


Robert aka wa5cab,  keeper of the Atlas scrolls (forum) and general all around nice guy!


----------



## JPMacG (Feb 21, 2021)

Yes, longitudinal, sorry.


----------



## Flyinfool (Feb 21, 2021)

If you can get the spindle out with the stuck arbor, I would do that. Beating on the spindle bearings can destroy them. A TAP is fine, But beating hard enough to mar things can also damage the bearings. Ball and/or roller bearings really do NOT like impact loads at all.

Once you get the spindle out, there are a lot of ways to attack getting the arbor out of the spindle without doing further damage.

Look at how nice and tight a MT holds a drill in the drill press or the chuck in a tail stock by just popping it in with hand pressure. Think how tight it must be if you are agressivly cranking down on a draw bar. My guess is that you are going way to tight on the draw bar.


----------



## brandon428 (Feb 21, 2021)

Thought I had mentioned earlier. I ended up following the pickle fork idea but just used #6 Jacobs wedges at the front with a thin brass shim on the arbor drive side.  Pushed them together hand tight, used a C-clamp to tighten a bit more until, hit the wedge on one side with a hammer and it came right out - one hit.


----------



## wa5cab (Feb 22, 2021)

Instructions for adjusting the spindle bearings in the lathes are in the appropriate Atlas Tech Bulletins, copies in Downloads under Tech Bulletins et al.  There is one also in Downloads for the mill.  But whomever at Atlas wrote it omitted one thing.  First you tighten the threaded collar until there is zero end float in the spindle and bearings.  Then you tighten the collar another 1/16th of a turn.  Which happens to be two teeth on the 32T spindle output gear.  That "two teeth" was omitted from the mill instructions.  Given that the 618 and mill spindles are nearly the same, use the drawings in the mill tech bulletin and follow the slightly better instructions in the 618 one.

One thing that is in the MOLO's but is not mentioned in any of the Technical Bulleting  is to first run the Timkin bearing equipped lathes for 30 minutes to an hour to warm the spindle, and bearings.  And then tighten 1/16 of a turn.  That results in 0.004" preload at room temperature.  So follow the instructions in the tech bulletins.  I will try to remember to ask Tom at Clausing about that next time that I call them.


----------



## griminspector (Jun 4, 2021)

just got my self an MFC with the same issue. i managed to break the arbor loose by running a mill cutter on the arbor and raising a piece of stock in to the cutter till the stuck MT2 torqued it self loose...... definitely to tight on the draw bar, better to have the spindle driving the arbor so you dont have to over torque the drawbar....


----------

