Newbie- X2 drawbar rotating eccentric ...

[binky72]

OK, my first post on this forum ... and it might be a stupid one !

I just recevied my new X2 mill a few days ago.
When I turned it on for some testing I noticed that the drawbar nut was rotating eccentric, see video. Is this normal? It seems that the drawbar originally was tightened up quite firm. When I re-tightened the drawbar (a bit less) it was rotating much more centric. How much should the drawbar acctually by tightened? The spindle seems to be rotating just fine, but you will see that the spindle face is not 100% flat. I have allready ordered a Tormach tooling system for the X2, so I will be using that on my new machine. Which also means that I have to fix the spindle face.

YouTube - X2 spindle / drawbar

YouTube - X2 spindle / drawbar

Sorry for this. Thanks.

Eirik

[ataxy]

i dont think its bad i have a bf20 wich is different from a x2 but it also turn excentric a bit

[BobWarfield]

That's normal. If it annoys you, make a drop in bushing. Turn the bushing so its ID is a bit larger than the drawbar, just enough so the drawbar slides easily. Make the OD fit the inside of the spindle, and put a lip so the bushing will sit on top.

10 minute job on a lathe. I did one because I have a powered drawbar and need it to line up right on the nut.

Cheers,

BW

[skmetal7]

mine didd the same thing, i turned a taper on the drawbar, and a taper on the little bushing and now it lines up perfetly. With the belt drive that I am using, at high speed it would vibrate a lot, now its fine

[LeeWay]

I had a drawbar with two type threads on mine. It was perhaps a little worse than yours on top. I bought some good grade 7/16" -20 threaded rod and some nuts. I also turned a brass tapered bushing. The drawbar is now much smoother. I never had as much out of round on the lower spindle as you have though. I guess I may have been lucky. I did pull mine apart to replace a gear at one point, then reinstalled the bearings and it was still nice and smooth. I bought another spindle for a different project, but haven't powered it up yet. Not sure how smooth it runs.

I guess the outside of the lower spindle makes no real difference either way, if the collet will run close to true. You may not be able to run any small end mills on it. Of course I never had much luck with those when I was manual milling.

[philbur]

With the drawbar nut that far out the machine will vibrate at speed due to the imbalance. As said, make a bushing to align it.

Be careful about your assumptions regarding the spindle lower face. If there is a chamfer on the edge it may not be concentric, it can make it look like the whole face is wobbling. Put a DTI on the face. Of course if you are going to use the TTS system the face needs to be "perfectly" square with the taper axis. You may be able to just reface it with a lathe cutting tool in a vice on the table. This will make it square with the spindle bearing axis. However you also have to check if the internal taper axis is centred on, and parallel, to the spindle bearing axis. If this is out it could be more difficult to correct, depending on what equipment you have access to.

Phil

Originally Posted by LeeWay I had a drawbar with two type threads on mine. It was perhaps a little worse than yours on top. I bought some good grade 7/16" -20 threaded rod and some nuts. I also turned a brass tapered bushing. The drawbar is now much smoother. I never had as much out of round on the lower spindle as you have though. I guess I may have been lucky. I did pull mine apart to replace a gear at one point, then reinstalled the bearings and it was still nice and smooth. I bought another spindle for a different project, but haven't powered it up yet. Not sure how smooth it runs. I guess the outside of the lower spindle makes no real difference either way, if the collet will run close to true. You may not be able to run any small end mills on it. Of course I never had much luck with those when I was manual milling.

[binky72]

The video of the lower part of the spindle looks worse then it is, the small chamfer on the spindle plays you a trick :-) I will of course re-check it when I get the DTI that I have ordered. From what I have measured so far, it is the spindle face that is not square with the taper axis. The spindle side seems OK (will recheck with DTI). I have tested the chuck/spindle adding a drill bit in the chuck and it rotates perfectly centric. So it's just the drawbar that gets draged out of line when it is tightened up firm, I don't have a lathe so I will see what I can do to make a bushing.

As philbur said my plan is to use a lathe cutting tool to re-face the spindle, this is also the recommendation in the TTS operational manual. I will have to see how this goes. I am totally new into this type of machinery.

Thanks for all you helps. Really appreciate it.

Eirik

Originally Posted by philbur With the drawbar nut that far out the machine will vibrate at speed due to the imbalance. As said, make a bushing to align it. Be careful about your assumptions regarding the spindle lower face. If there is a chamfer on the edge it may not be concentric, it can make it look like the whole face is wobbling. Put a DTI on the face. Of course if you are going to use the TTS system the face needs to be "perfectly" square with the taper axis. You may be able to just reface it with a lathe cutting tool in a vice on the table. This will make it square with the spindle bearing axis. However you also have to check if the internal taper axis is centred on, and parallel, to the spindle bearing axis. If this is out it could be more difficult to correct, depending on what equipment you have access to. Phil

[_taz_]

my x2 does the same thing, I thought it was more the nuts that weren't cut exact and it just made it look like it was wobbling. I'm watched the center and it seemed to be concentric. I think I'll take th nuts off and run it slow and see.

I'll also look into these tips, thanks.

[philbur]

With a little bit of imagination you can use your mill as a lathe in order to make the bushing. Don't hold the bushing blank in a drill chuck though. Depending on what spindle taper you have you should be able to use a collet big enough to hold the workpiece/bushing blank.

Phil

PS: If you don't intend to buy a lathe then getting the mill set-up to do some simple turning is an extremely good idea in any case.

Originally Posted by binky72 I don't have a lathe so I will see what I can do to make a bushing. Eirik

[binky72]

If have actually thought about that, but I think I would like to get a bit familiar with the mini mill itself before "expanding" it to do some "lathe" work.

Thanks for the info and tips. Philbur, nice to see that there are other people from Norway on the forum even from the same town