X2 CNC mill overhaul

[Brass_Machine]

So it is about time I start a project log. This one is going to take some time (as I don't have any time or the $$ needed).

What I am doing is taking my X2 that has been converted to CNC (X and Y only) and giving it an overhaul. The mill was originally converted using FigNoggle's CNC Plans. I wasn't happy with how the Z was in plans, so I had never finished the conversion. As it was, the mill got heavily used (for those not familiar, I was making and selling some bike bits). I also never did anything about the leadscrews. Stock they are*yoda voice*. Same with the nuts. I have just adjusted it out the best I could and used backlash comp in Mach3.

Accuracy has been going down hill for some time now. It is at the point of being, unacceptable.

The plans?

1. Replace the stock lead screws with some precision acme screws and acytal nuts. I already have the materials from another project that never happened. This way I don't waste anything... Going to have to extend the X screw to work with the design in my head...

2. Use the base from LMS high torque mill that has the longer Y axis. I can't afford the whole BASE & Table, but I should be able to get some benefits from the base alone.

3. Re-design the motor mounts from what I have now. I will go into more detail about that as I plod along.

4. Re cut the 55* dovetails to 60*. I have read on CNCzone about some people that have done this. Apparently it allows for a thicker brass gib. I am still up in the air if I am going to do this.

5. Design an actual Z axis that I am happy with. I have a spare column. I have the gas strut conversion kit. I also have the longer rack. I have ideas, but nothing concrete yet.

I started working on this last night. I will straighten out my picture hosting and then start posting what I am doing.

**I know some people will ask, why not just start with an X3 or a G0704. Well, I just don't have the cash and may not have the room for one soon. Got to keep my hands busy...

[raynerd]

Looking forward to watching this and get your pics posted!

Chris

[John Stevenson]

Interested in how you are going to CNC the head.
The fignoggle plans and the steele plans always look crude to me

John s.

[Brass_Machine]

Interested in how you are going to CNC the head.
The fignoggle plans and the steele plans always look crude to me

John s.

It's going to be a few weeks before I will get to that part. But I agree. I hope to change that...

[Brass_Machine]

Minor tool gloat... Picked one these up from ebay.



Was going to build Bog's version, but at the price of this one, $49 usd, I decided not too.

[Brass_Machine]

So, last night I cleaned up the mill. This is how she looks right now...



The first thing I am going to do is work on the Y bearing block. The stock "block" isn't really a bearing, more of a guide hole. I have already had on fail on me. I want to keep the existing motor mount. 



So what I am going to do, is build a bearing block to hold some thrust bearings. Sort of like what Hoss did on his conversion but with mine belt driven like it already is. So a chunk of aluminum went on the band saw to cut to a closer size.



A short while later, I had a smaller chunk. Tossed it on the mill, squared it up and cut it to size.



That little guy should fit perfectly into the spot of the old bearing. Hopefully tomorrow or Saturday I can finish drilling the mount holes and boring the bearing pockets.

Eric

[HS93]

Have you thought of reversing the steper motor at the same time , also when I did mine (But X1 ) I fited ball races and thrust bearings it made it so smooth and got rid of a lot of the slop, I also turned an adapter that fitted over the nut for ajustment to take a handle (folding ) so it could me used manualy,it is held on with 4 m3 cap screws not fitted in the pictures , the main thing is it makes it more compact so you can fit it in to a cabnet to stop the swarf and the noise when CNC'ing. it all worker well as a power feed but because I was unable to sort out the nut on the screw (it was cast iron) it had to much back lash, with what I know now it could probeley have been sorted but I sold it.

&feature=related

  Peter 

[tumutbound]

Excellent timing!
I just got my X2 out of the wooden crate where it's sat since I moved 9 months ago.
I planned to pull it apart to adjust/clean everything and then tram it but I might wait a little while to see how this thread pans out.

So hurry up and finish! 

[Brass_Machine]

Have you thought of reversing the steper motor at the same time...
 the main thing is it makes it more compact so you can fit it in to a cabnet to stop the swarf and the noise when CNC'ing....

I have. That is one of the reasons I am keeping the belt drive. I look at other conversions with the stepper just hanging off into space. Ascetically, it just kind of looks goofy. I don't know if I will be able to reverse the motor. I hadn't thought about doing that. Not sure if the table and other mount will get in the way. I am keeping it on the left side of the table.

... I fited ball races and thrust bearings it made it so smooth and got rid of a lot of the slop...

Looking at your pictures, I see both. I was wondering if I should as well. Looking at what Hoss did to his, he just used 2 sets of thrust bearings. I have the thrust bearings... but now I wonder if I should get a ball race to fit between the two. I may already have one. Will have to check my stock.

All good ideas. Thanks!

[HS93]

get a bearing with flanges if you have a thin plate then you can sandwich the bearing and have one thrust touching the bearing, mine has blocks the same as you to replace the original part not the block shown with the thrust race but one about the same size as you used then the plate just needs a through hole or steeped for bearing, the block shown in pic 0016 was for a directdrive for a mate, again it had bearings and thrusts.

  Peter 

[tumutbound]

I'd thought of reversing the stepper on the Y axis but using a piece of aluminium channel, say 80x40, for the mount , This would provide protection for the belt. Not sure what wall thickness would be required for rigidity.

[z3t4]

Thanks for putting this thread up. I would very much like to CNC my X3 (it's on this year's list) but have no relevant skill and there appear to be no 'conversion kits' here in Blighty. So your WIP will be very interesting...

Regards,

John

[Rob.Wilson]

   good to see you back in the shop Eric   


 Your post reminds me I have a CNC build  I should be getting on with


Rob

[DaveH]

Good start Eric 
 
DaveH

[Brass_Machine]

I ordered the larger base from LMS for their HiTorque mill.



This should give me more range in the Y axis. It is also a bit heavier. So, I am going to hold off on finishing up the Y bearing/motor mounts and start on the X. Going to see if I can start it tonight.

X axis will include; a longer acme screw, an acetyl nut and new motor mounts. I am going to gear the motor like the Y axis is.

Eric

[Brass_Machine]

Working on my design for the Z axis. Which would be better way of driving it? Motor directly attached to the screw or a geared solution?

Ideas anyone? All the other designs (Hoss, Fignoggle etc...) have it belt driven.

Eric

[tumutbound]

I can't remember seeing any direct drive X2 conversions on cnczome, all have used belt drive for greater torque.
In theory it could be done but you would (probably) need a NEMA 34 rather than a NEMA 23 motor.

[techonehundred]

I ordered the larger base from LMS for their HiTorque mill.



This should give me more range in the Y axis. It is also a bit heavier. So, I am going to hold off on finishing up the Y bearing/motor mounts and start on the X. Going to see if I can start it tonight.

X axis will include; a longer acme screw, an acetyl nut and new motor mounts. I am going to gear the motor like the Y axis is.

Eric

So what are the dimension differences between this base and the original x2 base. Especially what are the differences in the dovetail dimensions.  Not a chance that the original table will work with it is there?

[Brass_Machine]

So what are the dimension differences between this base and the original x2 base. Especially what are the differences in the dovetail dimensions.  Not a chance that the original table will work with it is there?

I have heard that the dovetails are the same and that you can get away with the original saddle and table. You will OFC, need a new feed screw.

That said, it is all hearsay. Until I have the base in my grubby little hands, we won't know for sure. If it doesn't I am OK with that as the initial measurements put it at very close. I plan to recut the ways anyway.

The X axis is longer. I think almost an inch?? Not sure. The HiTorque has an X of 5.1" while the HF mill is 4". It is also a little over 4 pounds heavier. The part should be here Weds. I will let you know then.

[Brass_Machine]

I can't remember seeing any direct drive X2 conversions on cnczome, all have used belt drive for greater torque.
In theory it could be done but you would (probably) need a NEMA 34 rather than a NEMA 23 motor.

I know I have seen at least 3 builds with direct drive on the Zone. CNCfusion's kit is direct drive as well.



Just trying to figure out which has the advantage.

[tumutbound]

I can't remember seeing any direct drive X2 conversions on cnczome, all have used belt drive for greater torque.
In theory it could be done but you would (probably) need a NEMA 34 rather than a NEMA 23 motor.

I know I have seen at least 3 builds with direct drive on the Zone. CNCfusion's kit is direct drive as well.


Just trying to figure out which has the advantage.

I was only looking at the home grown conversions not the kits - installing a kit would be cheating 

[Brass_Machine]

I was only looking at the home grown conversions not the kits - installing a kit would be cheating 

HAHA!    Yes it is! No worries, I won't be cheating! 

There was one guy who did a direct drive solution that I liked at one time. I was thinking of using his idea but belt driven instead of direct drive. But ofc, I want to do the best job possible. so I am looking at how everyone has been doing it.

But what is optimal gearing? A 2:1 ratio? I have no idea 

[tumutbound]

I did see one conversion where the Z axis was internal to the column. A slot was machined behind where the rack goes to allow the ballnut to connect to the mill head.
Despite a lot of browsing on cnczone and the Yahoo groups, I've been unable to find it again.

It looked like a good way of keeping swarf off the ballscrew.

Of course to do this would require a second mill...

[Brass_Machine]

...
Of course to do this would require a second mill...

Or a second column. I did mention I have a second column right? 

But I am not going inside the column. For some reason slotting the column doesn't sound like a good idea.

Eric

[tumutbound]

Wish I could buy things like a second column or base here.
The only way I'd be able to do that is to buy a second mill