Fadal - Slightly loose toolholder along Y-Axis

Diezul · Jan 30, 2020

Hi, I have a Fadal 2016L with non-locking drawbar. I noticed that I can slightly rock a toolholder by hand in the Y-axis direction by maybe a few thou, but the X-Axis seems solid. First thing to check through forum advice is the belleville washers. I did a replacement of this along with the floater ring with new ones even though all the old washers appeared to be fine. 47 Springs in total making sure they were oriented correctly with he bottom washer cupping downwards. Even with replacement, I still notice the issue.

One thing I wasn't too sure about and hope someone can maybe help clarify, the drawbar seems to have two grooves in it (see attached picture). Does the locking half moons go into the first or second groove from the top? I have it in the first groove as that is how it was on the old setup before replacement. I read a thread where someone mentions that it should go on the second groove from top with an o-ring on first groove?:

"While all that's off look at the draw bar locking half rings, undo the 4 allen bolts and remove the cap, there is an o ring grove above the groove for the locking half rings, if they didn't compress the springs enough they may have used the o ring groove

If the locking half rings are in the right position, and the draw bar is not being pushed from above then it is the spring count/layering that is the issue (first last springs not facing outward)".

Any other advice or recommendations? Appreciate the help.

Ianagos · Jan 30, 2020

Measure your spindle taper. First off put and indicator on it and secondly blue up a good or new holders and see the contact pattern. If you can move it at all by hand even if the drawbar force is low it seems like the tapers are not matching.

Diezul · Jan 30, 2020

Also to add, I've tried multiple tool holders both CAT40 and BT40 with the correct pull studs. Issue seems consistent.

Ianagos · Jan 30, 2020

Sorry I assume that you already did this but clean out the spindle thoroughly.

Then take a new or unworn tool holder of reputable brand and without a pull stud shove it up in to the spindle with hand pressure. While still forcing it up see if it wiggles. If it does seems your taper is dickered good and proper.
That’s just something you can try real quick before you bust out blueing and indicators.

From my very unknowing gues I’m going to say the atc was out of alignment for a long time so the taper from the tool holders had to slide to center wearing out your taper.

Delw · Jan 30, 2020

How much of a gap do you have between the acutator plunger and the top of the drawbar?

I honestly cant remember which one but I am going to say the bottom one ie groove closest to table.
Do you have a force gage thats an easy check with one of those.
Grooves in the drawbaw will causes the beviles to get stuck sometimes. the drawbar does need to be smooth

Diezul · Jan 31, 2020

Ianagos said:
Sorry I assume that you already did this but clean out the spindle thoroughly.

Then take a new or unworn tool holder of reputable brand and without a pull stud shove it up in to the spindle with hand pressure. While still forcing it up see if it wiggles. If it does seems your taper is dickered good and proper.
That’s just something you can try real quick before you bust out blueing and indicators.

From my very unknowing gues I’m going to say the atc was out of alignment for a long time so the taper from the tool holders had to slide to center wearing out your taper.

Thanks for this experiment/exercise. I put a BT40 toolhold in there without much pressure and it wiggles about the same as the issue I'm facing. When applying some pressure, nothing too extreme, it does not wiggle by my hand strength. So seems to prove that it's not getting sucked up enough. Again, I'm thinking it might be the groove where the half moon is supposed to go if someone could confirm this. Thanks.

Diezul · Jan 31, 2020

Delw said:
How much of a gap do you have between the acutator plunger and the top of the drawbar?

I honestly cant remember which one but I am going to say the bottom one ie groove closest to table.
Do you have a force gage thats an easy check with one of those.
Grooves in the drawbaw will causes the beviles to get stuck sometimes. the drawbar does need to be smooth

I would say about 0.2 inches from the actuator plunger and top of drawbar. Is this something adjustable and what should the gap be approximately?

Unfortunately, I don't have a force gauge, but the test Ianagos suggested seems to show that it's not getting sucked up enough.

My draw bar is definitely not smooth where the belleville washers sit judging from my fingernails, not sure if you can see from my picture.

If someone can help confirm which groove the half moons should be placed, I might be able to quickly rule that out. I've searched quite a bit to try and get details on this, but didn't come across anyone mentioning this specifically. Thanks.

gregormarwick · Jan 31, 2020

I'm pointing out the obvious here, but nobody else mentioned it - if the movement is always in line with the Y axis, then unless you're testing with the spindle oriented every time, it's not the taper, as the movement would shift with the rotation of the spindle.

Your spindle bearings may have lost their preload and the races be more worn in the Y direction. I know it sounds unlikely, but it is possible, had the exact same thing years ago on an old Hurco, albeit less than the couple of thou that you are seeing. Rebuilt the spindle with new bearings and no more problem.

Ianagos · Jan 31, 2020

gregormarwick said:
I'm pointing out the obvious here, but nobody else mentioned it - if the movement is always in line with the Y axis, then unless you're testing with the spindle oriented every time, it's not the taper, as the movement would shift with the rotation of the spindle.

Your spindle bearings may have lost their preload and the races be more worn in the Y direction. I know it sounds unlikely, but it is possible, had the exact same thing years ago on an old Hurco, albeit less than the couple of thou that you are seeing. Rebuilt the spindle with new bearings and no more problem.

Very good point I just assumed the spindle was oriented. But one can make no assumptions. I could also be that he is able to put more force back and forth vs side to side.

Anyways to the op did you try what I told you with no pull stud? Does the taper match with blueing?

VTM · Jan 31, 2020

Diezul said:
I would say about 0.2 inches from the actuator plunger and top of drawbar. Is this something adjustable and what should the gap be approximately?

Unfortunately, I don't have a force gauge, but the test Ianagos suggested seems to show that it's not getting sucked up enough.

My draw bar is definitely not smooth where the belleville washers sit judging from my fingernails, not sure if you can see from my picture.

If someone can help confirm which groove the half moons should be placed, I might be able to quickly rule that out. I've searched quite a bit to try and get details on this, but didn't come across anyone mentioning this specifically. Thanks.

Here's a link to the assembly drawing. The locks go in the second groove an o-ring in the first.

https://itscnc.com/images/Parts List - Drawbar Kits.pdf

Tedger · Jan 31, 2020

Diezul
Clips should go into the secong groove down.( The shallow one)It's a bear sometimes to get them in but make sure they are seated before you put it all back together.

gmc1724 · Jan 31, 2020

Diezul said:
Hi, I have a Fadal 2016L with non-locking drawbar. I noticed that I can slightly rock a toolholder by hand in the Y-axis direction by maybe a few thou, but the X-Axis seems solid. First thing to check through forum advice is the belleville washers. I did a replacement of this along with the floater ring with new ones even though all the old washers appeared to be fine. 47 Springs in total making sure they were oriented correctly with he bottom washer cupping downwards. Even with replacement, I still notice the issue.

One thing I wasn't too sure about and hope someone can maybe help clarify, the drawbar seems to have two grooves in it (see attached picture). Does the locking half moons go into the first or second groove from the top? I have it in the first groove as that is how it was on the old setup before replacement. I read a thread where someone mentions that it should go on the second groove from top with an o-ring on first groove?:

"While all that's off look at the draw bar locking half rings, undo the 4 allen bolts and remove the cap, there is an o ring grove above the groove for the locking half rings, if they didn't compress the springs enough they may have used the o ring groove

If the locking half rings are in the right position, and the draw bar is not being pushed from above then it is the spring count/layering that is the issue (first last springs not facing outward)".

Any other advice or recommendations? Appreciate the help.

View attachment 277083

Have you checked the z-axis ways for lift (assuming your clocking the tool movement off the table).

triumph406 · Jan 31, 2020

For whatever reason I don't think your pulling the tool holder into the taper. If you could borrow a tension gage that would tell you right away if you have any drawbar tension.

How does it sound when install a toolholder? there should be a 'thump' when the drawbar pulls the toolholder in to the taper. If it's pulled in with no noise or a distinct thump then it's not being pulled in enough

The crude (as used by some Fadal techs) method of checking drawbar tension is to use a crowbar between the spindle nose and toolholder. If it it can be moved then there's a problem with the Belleviles. Maybe the stack or quantity is wrong.

Where did you get the Bellviles from? If it's from a known Fadal source they'll be correct. If you measured what you had and ordered some from another source, maybe you have the wrong belleviles.

triumph406 · Jan 31, 2020

I suspect the reason the toolholder is loose in the y-axis and not the x-axis is that it's much easier to apply a force in the y-axis direction, at least while standing in front of the machine.

I bet if you removed the side door and push/pulled in the x-axis direction from the side, rather than the front you would see greater movement in x than before

Diezul · Jan 31, 2020

Ianagos said:
Very good point I just assumed the spindle was oriented. But one can make no assumptions. I could also be that he is able to put more force back and forth vs side to side.

Anyways to the op did you try what I told you with no pull stud? Does the taper match with blueing?

I did, pleaSe see post #6. Thanks.

I will try with moon clip in second groove first to see if that fixes issue, just didn’t want to mess something up without confirmation if it didn’t go there.

Diezul · Jan 31, 2020

Thanks, I saw that diagram too, but it still wasnt clear to me which groove the half moons (DRB-0014) sit. But it seems a few people have confirmed it should be on the second groove from top so I will try this now. Thanks.

Diezul · Jan 31, 2020

triumph406 said:
For whatever reason I don't think your pulling the tool holder into the taper. If you could borrow a tension gage that would tell you right away if you have any drawbar tension.

How does it sound when install a toolholder? there should be a 'thump' when the drawbar pulls the toolholder in to the taper. If it's pulled in with no noise or a distinct thump then it's not being pulled in enough

The crude (as used by some Fadal techs) method of checking drawbar tension is to use a crowbar between the spindle nose and toolholder. If it it can be moved then there's a problem with the Belleviles. Maybe the stack or quantity is wrong.

Where did you get the Bellviles from? If it's from a known Fadal source they'll be correct. If you measured what you had and ordered some from another source, maybe you have the wrong belleviles.

I do notice a 'thump' when the toolholder gets pulled in. Please see post #6 where I did a test mentioned and most likely means the toolholder is not getting pulled in enough. Next step is to try with the half moon locks on the second groove of the drawbar which should compress the belleville washers more and lead to stronger pull in force?

I bought the washers and floater from fadalcnc, so it should be the correct set.

Appreciate your help, I'm new to this whole world of machining (what did I get myself into?) with no prior experience, so even simple/obvious things to someone more experienced is very helpful to me.

Ianagos · Jan 31, 2020

Now from seeing your post number 6 that makes me feel better about your spindle taper. So then in that case it’s probably a drawbar not installed correctly or incorrect pullstuds possibly.

Diezul · Feb 1, 2020

Unfortunately, changing the half moon lock keys to the second groove of the drawbar did not affect anything in regards to the issue.

I tried wiggling the toolholder along the x-axis through the side panels, and did not notice any play. Seems to only be along y-axis and probably best described as a clicky sort of play without much effort at all, maybe ~5 ft/lb of force.

Another thing to note is that when the complete toolholder (with pullstud) is loaded into the spindle, if I push the toolholder slightly up into the spindle (again maybe with ~5 ft/lb of force), I cannot experience the issue and it seems solid. The pullstuds I'm using are SYIC-21003-C (CAT40 - ANSI - C) which I've checked and should be the correct dimensions based of the pull stud spec stickered on the machine.

Therefore, seems like it has something to do with the drawbar, ball bearings, floater ring, or some grooves in the spindle that may be slightly out of spec from being worn, which causes the toolholder to not sit correctly? I'm just worried that if I try to run it as-is, it may somehow damage the spindle taper in the long run? Also don't want to spend $300 on a new drawbar if it isn't related to the issue.

If I try adding another belleville washer to the stack (I'm at 47 already for the non-locking no TSC configuration), could it maybe help the issue? Anyone ever try using more belleville washers than specified (I may have read somewhere that someone did for additional force).

triumph406 · Feb 1, 2020

Diezul said:
I tried wiggling the toolholder along the x-axis through the side panels, and did not notice any play. Seems to only be along y-axis and probably best described as a clicky sort of play without much effort at all, maybe ~5 ft/lb of force.

If you rotate the spindle 90 degs, does it still only move in y-axis direction? If so, that’s down to how you are push/pulling on the toolholder

Diezul said:
Another thing to note is that when the complete toolholder (with pullstud) is loaded into the spindle, if I push the toolholder slightly up into the spindle (again maybe with ~5 ft/lb of force), I cannot experience the issue and it seems solid. The pullstuds I'm using are SYIC-21003-C (CAT40 - ANSI - C) which I've checked and should be the correct dimensions based of the pull stud spec stickered on the machine. .

The problem you have is the drawbar isn't pulling the tool all the way into the taper, your applying 5# to get the taper to seat, which is a fraction of the drawbar tension.
I suspect you have a problem with something in the assembly that’s not correctly orientated and not allowing the drawbar to pull up sufficently.

Diezul said:
Therefore, seems like it has something to do with the drawbar, ball bearings, floater ring, or some grooves in the spindle that may be slightly out of spec from being worn, which causes the toolholder to not sit correctly? I'm just worried that if I try to run it as-is, it may somehow damage the spindle taper in the long run? Also don't want to spend $300 on a new drawbar if it isn't related to the issue.

If you run it as is you’ll f’ the taper in a matter of minutes.
I don’t think a Belleville is hanging up on the drawbar, but it wouldn’t hurt to polish those marks off the shaft.
Are the ball bearing holes in the drawbar very elongated? Even if they are that’s not your problem.

Diezul said:
If I try adding another belleville washer to the stack (I'm at 47 already for the non-locking no TSC configuration), could it maybe help the issue? Anyone ever try using more belleville washers than specified (I may have read somewhere that someone did for additional force).

Again issue isn't the number of belleviles, I've added an extra belleviles on a locking drawbar and increased the drawbar tension a little, but that's not the way to do it with a locking drawbar.
Pull the drawbar out, with belleviles,balls, floater etc lay it out on a table in the order you have it assembled and post a picture of the assembly, it may be obvious to somebody very familiar with non-locking drawbars what’s going on.
Where are you in CA? If in So Cal competent Fadal techs are common, at some point might be worth calling one in.

Fadal - Slightly loose toolholder along Y-Axis

Plastic

Stainless

Plastic

Stainless

Stainless

Plastic

Plastic

Diamond

Stainless

Hot Rolled

Aluminum

Aluminum

Diamond

Diamond

Plastic

Plastic

Plastic

Stainless

Plastic

Diamond

Similar threads