X2 Mill Table and Saddle with linear rails

[shooter123456]

Alrighty, all the hardware is done for the X and Y axes. Thats 3 bearing blocks, 2 motor mounts, and 2 ball nut mounts. I also finished the machining on the base and saddle to get the hardware to fit right.

Here is a picture of all the mounting hardware I will be using:

Here is the base mounted up to cut a recess for the Y axis ballscrew bearing block to sit in.

A wee bit of cutting action.

I ordered some flexible couplers for the 2 axes to hopefully make it a bit easier to get everything aligned well. Once they get here, I can mount the ballscrews and motors, then drill and tap the current mill base to attach it. The end of the X and Y is in sight!

 

[shooter123456]

I got a little antsy and proceeded without the flex mounts. I got the X and Y axes aligned pretty well as far as I can measure. I lined up and drilled holes for the X ballscrew bearing block and ball nut block. The movement is a little loud so I need to shim the screw into alignment better. I found something odd with the Y axis ball screw. I needed to turn the nut around and I dropped a few balls while doing so. I had to take out one of the wipers and then the movement went from gritty and poor, to ridiculously smooth and frictionless. Initially, if you spun the nut, it would stop as soon as you let go. Without the wiper in, holding it vertically by the nut causes the screw to start to slide its way out under its own weight.

Here is the set up I used to get the tables movement aligned. I used a 1-2-3 block because it is supposed to be within .0002" square and its the most square thing I own. I secured it against a ground reference edge on the X axis linear bearings. Those are supposed to be exactly paralell to the movement of the axis. If you look at the bottom right bearing, there is a lip on the closest side that isn't on the bottom left bearing. That is the reference edge. Then I stuck a DTI onto a steel plate to hold it in place and tapped the Y axis around until it was running perfectly true. Then everything was snugged down. I had it well under .0005" over 2" of travel which at the very least is significantly more accurate than the dovetails I am currently using.

Here is the old table next to the new table. Upgrading from roughly 15"x3.5" to 22"x8". More than triple the surface area.

Here is the old saddle next to the new saddle/base. A lot beefier for sure.

I stuck it up onto the mill with the old table removed. I put the head as high up as it goes and stuck a tool in the spindle. With the new table, I have about 9.5" from the table to the spindle. I lost roughly 2.5" there. But I should get 5" back when I do the Z axis linear rails. Either way, I will have plenty of room. I will need to cut the back of the enclosure open to stick the column out so I can fit the Y axis motor inside the enclosure.

Almost there! This plus the 1.3 HP spindle motor pulleyed up to 7200 RPM with the new angular contact bearings should leave me with one nice metal remover. Then epoxy in the column and some extra support at the base should improve it even more so.

 

[shooter123456]

A little more progress here. I got everything all mounted up, including the motors, couplers, and ball screws. The new table assembly is ready now. The last thing for this is to drill and tap the mills base to bolt the table to the mill. I had to make an extension to get the Y axis motor to reach the ball screw, but that was just a couple minutes of uneventful turning. There also wasn't enough clearance for the couplers screws to rotate, so I just cut a little clearance for them using a dremel. As it stands now, the Y axis motor sticks out of the front of the enclosure by about 3 inches, but I hope to get that space back by sliding the column out the back of the enclosure. I also caught one of the glass doors with the corner of the table while I was lifting it in and it immediately shattered. I am going to use acrylic to replace it.

I also took apart the ball nut for the x axis and found that one of the races had seized up for some reason so 3 of the races were circulating, but one of them was stuck and just grinding. I used the ballnut from the old Y axis to replace it and I am getting smooth movement. When testing and aligning the ball nuts, I was able to get the table to move and the ballscrews to rotate by just pushing the table in either direction. There is also zero binding with any of the movement on either axis. I was able to get the table moving at 300 IPM, but any faster and it started to stall. I think I will turn it back to about 200 IPM to be safe. I also found that the Y axis screw and nut were filthy. It was packed with what was basically aluminum sludge. I need to come up with a way to protect the new screw and the rails better.

Here is the table with all the motors connected up and everything secured in place.

Closer view of the X axis motor and its mount.

The deal under the table.

Closer view of the Y axis.

I haven't decided how I will do table mounting quite yet. I think to start, I will just drill and tap a few holes to bolt a .5" aluminum plate to the table that I will drill and tap for pins and clamps. I have 6.5" of Y axis movement without any extension for the head. I was surprised by that, I figured I would have less since the factory travels were about 3.9". I am excited to see how it does with some cutting. The table is very heavy though. Probably at least 40 lbs. Significantly heavier than the stock assembly, but I am not sure how the rigidity will fair with linear rails and bearings over the dovetails. Once I get it cutting some, I will get the base extension cut and put into place to support the end of the Y axis and hopefully help keep vibrations to a minimum.

 

[shooter123456]

Brief update. I did some cutting to test it out and the results were a little bit disappointing. I was getting a lot of chatter with light cuts in aluminum and it is struggling to climb mill. With conventional, it does alright, but it still has trouble. I could manage a .375" DOC, .01" WOC, at 20 IPM with a 3 flute carbide end mill. Before, the machine could handle .375 DOC, .035" WOC, at 25 IPM while climb milling without trouble. Usually, the spindle would start struggling before the chatter would kick in.

There was significant backlash in the Y axis. I could move it .01" easily just pushing back and forth lightly. I thought this was because of the ball nut so I took the nut off to look around. First, I noticed it only had 3 races compared to the 4 races on the other nuts I was using. I also measured the balls and they were .1540" almost exactly, maybe a little higher like .15403" but that last digit is nothing more than a guess with my micrometer reading to .0001". I measured the balls on the nut I was using for my X axis before and found them to be .1545". I swapped the old X axis nut in with the slightly larger balls and that made a noticeable difference. I could no longer move the assembly easily by hand and the mill seemed to get a little bit of steam back. It still has trouble climb milling anything much more than .005" WOC and 10 IPM. Conventional milling, it could handle .375" DOC, .02" WOC, at 20 IPM. At .025" WOC and 25 IPM, it chattered like crazy. I tried pushing it a little more with other cutters and playing with feeds and speeds, and using a 3/4" insert end mill, I could do .2" DOC, .1" WOC, at 20 IPM pretty consistently. It struggles the most when cutting with the Y axis positioned closer to me (away from the column) which I think is because of the unsupported section there. I am guessing that with it floating the way it is and supported by nothing but the rigidity of the aluminum plate, vibrations are aplenty. I am going to take care of the support there next to see if that makes any improvement. For that, I have a large 8x29x.75" piece of aluminum that will sit under the mill base and be secured in 4 points to the base and 3 points at the far end of the new Y axis base.

The other thing I think causing problems is backlash in each axis. With the dovetails, there was a good deal of friction holding everything still when it was stationary so the backlash from the ballscrews and bearings at the ends wasn't as noticable. With the linear rails and bearings, there is very little friction when stationary so the ballscrews, nuts, bearings, and motors have to do a better job holding it. I am looking into making them both a double nut. I also want to replace the bearings in the bearing blocks. The deep groove ball bearings provided with the ballscrews aren't doing a great job. One of them is making a knocking sound when rotated and they seize up pretty easy when I try tightening the lock nut on the ballscrew. If I can't get it to cut better, I think the next step would be to add 2 more bearings to the Y axis and either replace the rails (meaning the base and saddle may need to be remade, no big deal there though) or lose about 2.3" of travel dropping it from 7.5" to 5.2".

I was able to get it to make some decent chips, albeit a little slower than I would like. It was cutting for a little over an hour with a 3 flute indexible end mill. I drilled and tapped 6 holes in the table to secure a sub plate that I used as a jig to secure the part.

 

[shooter123456]

Last update for this particular project. At this point, I think it is done. I added the large plate that the base was bolted to, then made a spacer and bolted the end of the Y axis rail base to it. Then the plate got bolted to the enclosure table. When testing that, I think its good enough now. It doesn't chatter with most cuts up to the point that the spindle motor stalls which tells me I should be back to at least the rigidity I had before. I tried a few different cutters to see how it does and got decent results. With my 3 flute .750 insert end mill, it does best with a shallow depth of cut and a wide width. At .01" depth and .750 width, I can run it to 60 IPM at 4300 RPM before the spindle motor starts to struggle. I can get it to .1" depth and .4" width at about 40 IPM before the spindle starts struggling. With a 3 flute carbide .375" end mill, I can do .5" depth at .025" width at 30 IPM just fine, which is about what I would do before the new table. I also tested the squareness of the X and Y axis and it was within .0005"/inch to the best of my ability to measure that. I am sure I could do better, both on rigidity and squareness, but I accomplished the goal for this task so I am going to move on to other projects. I will take a few more pictures soon and add them.

 

[DMLCV]

Very nice job,
I am doing an upgrade to my X2 mill too and going to use an X3 table on it with parallel rails too with ball screws. I am new at this and it has been a big learning curve. I am using my 8x12/14 lathe as my mill right now and that is a learning curve too. I am getting ready to mount the redesigned head in the next week. Install the motor and do a test and then install the spindle and motor.

When I did the mounting of the spindle head I forgot to compensate for the offset of the head to the lower part. I have installed the ball screw and had run a test and it all worked. The lower part shows the original position of the Y axis ball screw and that has now changed since I am going over to parallel rails. The lower part is around 240mm and the table is 720mm.
I wish there were some folks around Chino Valley AZ it would be nice to have some other insight into this. I have a friend in NV that has been helping me with some of my questions and would not have gotten this far without his help.

 

[shooter123456]

Very nice job,
I am doing an upgrade to my X2 mill too and going to use an X3 table on it with parallel rails too with ball screws. I am new at this and it has been a big learning curve. I am using my 8x12/14 lathe as my mill right now and that is a learning curve too. I am getting ready to mount the redesigned head in the next week. Install the motor and do a test and then install the spindle and motor.
View attachment 245839
When I did the mounting of the spindle head I forgot to compensate for the offset of the head to the lower part. I have installed the ball screw and had run a test and it all worked. The lower part shows the original position of the Y axis ball screw and that has now changed since I am going over to parallel rails. The lower part is around 240mm and the table is 720mm.
I wish there were some folks around Chino Valley AZ it would be nice to have some other insight into this. I have a friend in NV that has been helping me with some of my questions and would not have gotten this far without his help.

Its looking good! One of my favorite things about having the X2 is that it is nice enough to some good work, but not so nice that I would be afraid to hack it up to try to make it better.

Linear rails and ball screws are the way to go. I was able to get the steppers to run the X at 360 IPM and the Y at 420 IPM. With the original dovetailed table, I couldn't get it up too far past 100 before it stalled. I also put a 1 HP treadmill motor on it that helps with deeper cuts as well.

My X2 won't see any new improvements though. I am building a new machine that will replace it. Bigger table, bigger rails, stiffer frame, bigger spindle motor.

Let me know if I can help with your X2 at all. I wish there were some local people I knew as well. Having access to a bridgeport or something similar would have made a lot of problems go away.

 

[DMLCV]

Ok, I have the LMS long table on my X2 now and as I said I was new at this. Do I need to put a metal pad between the y-axis and the x-axis?? I am using an X3 table which will give me a bigger table I will send photos. From my photo you can see where I am going to put the y-axis ball screw will notch out the hole in front to allow a level area.....

 

[shooter123456]

Ok, I have the LMS long table on my X2 now and as I said I was new at this. Do I need to put a metal pad between the y-axis and the x-axis?? I am using an X3 table which will give me a bigger table I will send photos. From my photo you can see where I am going to put the y-axis ball screw will notch out the hole in front to allow a level area.....

Thats a tough question to answer since I am not familiar with your design. A few questions to clarify, then maybe I can help.

You mention you are using an X3 table, and an X2 base. Are you planning on putting the linear rails on the bottom of the table or flipped the way the machine I designed is?

Will you be using the X2 saddle, or are you adding rails to the Y axis as well?

What size rails are you using?

 

[DMLCV]

I am using HSR #20 parallel rails on the y axis and x axis.

the base is LMS long base and not the one that came with the X2.

I am not using the saddle.

Planning on cutting back the dovetails on the base and installing the parallel rails. From your drawing I am going to do the same thing with the lower parallel rails.

Parallel rails attached to the base and the blocks to the plate.

I was going to mount a aluminum bar plate, 228.6 mm x 228.6 mm x 25mm bar stock to the lower parallel rails and then attach the table parallel rails to that plate.

Going to attach the parallel rails to the bottom of the table, the blocks will be attached to the plate. Also was going to cut back the dovetails too.

I hope I am making since.

It should look pretty much like your drawing.