[MetalBlade]

I am choosing optical for several reasons - price, size and durability. The industrial plunger limit switches are nice but can be big and are costly. My limits are about the size of a peanut, are solid state with no moving parts to break down or contacts to arc and degrade. I expect them to be very repetitive though speed will have an effect I think - it depends on which thread in EMC they are monitored under. They are in the slow thread by default which at a high traverse rate they'll go later than if I'm crawling at them such as during a homing sequence. I originally planned to use independent home switches but I am now planning that they will be shared limit/homes. I still have to figure out how I am going to read my spindle speed. I'm thinking a hall effect sensor will be in order so I can mount that all up under the top gear case cover. I don't want anything near the spindle nose if I can avoid it. I still have a desire to put a DRO on the quill to facilitate manual drilling with the quill.

Sounds like you're really putting some thought into it. Are you worried about dust getting on the optics? That's really my only reason for steering clear of optical switches. A Hall effect sensor sounds like just the ticket for what you are trying to do. That's definitely a little farther then I'm taking it.

I was thinking about eventually adding some sort of encoders to my steppers. You know, nothing to complex. Just something that would maybe give me a pulse 200 times every revolution. That would give some amount of feedback even with microstepping, and be compatible with my limited amount of inputs.

Something else I was thinking about that would be cool if I ever make that usb version with the stepper drivers included would be to have the controller shift from microstepping at low rpm to full stepping at high rpms to counter the inductive reactance at higher rpm. I'm sure it would be possible to program a pic processor to do that.

[HackMax]

OK I finally got to the OEM ACME nut today. The pins in the nut were obviously drilled and placed once the nut was bolted in and aligned. There is really no reason to retain them as they were probably used to help keep the mill square while being jostled around during shipment. One less machining op for me Now to put my mill back together to make the ballnut mount.

Spent half the day yesterday putting threads on the y ballscrew with the lathe. I don't remember having such a tough time doing it in high school. The lathe wanted to stall too easy and I could only take .001 cut at a time especially when it got down to the final cuts. I think I need a bigger lathe. No I KNOW I need a bigger lathe. LOL

Rick

[Crevice Reamer]

The lathe wanted to stall too easy and I could only take .001 cut at a time especially when it got down to the final cuts. I think I need a bigger lathe......Rick

Are you using low range?

CR.

[HackMax]

Are you using low range?

CR.

Yup. It has plenty of power because I grabbed a peice of stock I had chucked up in it and tried to stall it and it took quite a grip. But I've noticed it wants to stall pretty easy when its cold. The motor pulses when it runs instead of a constant motion which it stalls when not in the pulse. Another reason I need a bigger one though is I thought 7x10 would be long enough but after I chuck a drill chuck with a drill bit in the tail I don't have squat for room to put my stock. I was thinking about eventually getting the HF 9x20. $699 isn't too bad.

Rick

[Crevice Reamer]

Yeah! 7 x 10 is mis-sized. It's actually only 7 x 8 inches.

CR.

[cadmonkey]

I agree the 7x10 is tiny. It was enough to get the screws done though and I've done enough with it since that it's paid for itself. I stalled out and cracked a number of carbide tipped threading bits doing the threads, I did chase them all with dies.

I chose to leave the pins for 2 reasons - 1 they provided extra support - I chose not to put all my faith into the strength of the 2 SHCS when it comes to the cutting forces, and 2) if anything went wrong I could still go back to the ACME nuts.

I'm not worried about dust - in testing the switches require a very opaque flag to trip. A piece of cardboard packaging (from a Rat Shack diode I think) doesn't always trip the switch, but a piece of aluminum is 100%. With where they will be mounted, not much gets there (under the table and saddle) so if chips get there they'll need to get cleaned out anyway because they're probably on the screws too. Someday I will put encoders onto the screws - not gonna get closed loop operation but at least it will shorten the gap

Your step morphing proposal is, if I'm not mistaken, exactly what the Gecko G203's do as the pulse rate increases.

[Crevice Reamer]

Your step morphing proposal is, if I'm not mistaken, exactly what the Gecko G203's do as the pulse rate increases.

Yes, both the G203Vs and also the G540 morph.

CR.

[MetalBlade]

.

[HackMax]

Woohoo got the y axis done! I get 7.975" travel I used most of your ideas to extend the travel Greg. I did change a few items though for future changes. I would like to be able to add another ball nut for zero backlash without losing too much of the travel i have gained so I changed the mounting block a bit. I also was leary of why they put those pins in there so I added my own roll pins and removed the factory pins. I just used a punch to knock them out and when i looked at them they were taper pins. It only takes a few slight taps and the pins just fall out. I also put the rollpins in a different location - note the .160" holes in the drawing. Other than a few other minor time and money saving changes you have saved me so much work. Thank you.

Rick

[cadmonkey]

You're welcome! Glad you got it together. Keep us apprised of how it runs for you. Congrats!

[HackMax]

Greg,

I have drawings and Solidworks models of the parts I changed but I haven’t got them all together at this time. I will work on it tonight and see if I can’t have it to you tomorrow.

For the most part I changed the parts to compensate for the parts and tooling I already had available to me instead of buying new. It's not so much the cost of the parts as it is that nemesis shipping costs. Even though I have built the x, y parts with the extra holes in them I have not implemented them as of yet. I'm going to see how what is already available pans out for now. I hate drilling holes in metal with a hand drill. Even the holes in the column, I only drilled two on each side. If I had time I would have changed that so that it used the column mounting bolts to hold the motor bracket similar to the CNCFusion product saving the drilling. I'm a little leery of bolting the softer aluminum between the bolt heads and the column flange though. My thought is to replace the bolts with longer threaded studs and then use a nut to hold the column to the base and then the rest of the stud could hold the motor mounting bracket. The column cover may have to be modified to allow this... not sure. I would be trying to avoid that.

I also removed any radius cuts I deemed not necessary. I had a horizontal bandsaw and manual mill so the radius cuts were a little difficult on the Z motor mount brackets. Since I had built the rest of the mill using the ACME setup I had access to CNC the x and y brackets but I ended up doing the same to these only because I was trying to make the job cutting them simpler.

I could keep the y ball screw down to 12mm so I could make use of the existing bearings I had bought for the OEM cut ACME screw. Mind you the surface is not smooth and a little undersize but how the bearing fits on the shaft is really not important IMHO since the forces in question are not radial but lateral. As a matter of fact if you go a little overboard in boring for the bearing hole it would help a little in compensating for shaft misalignment. I used a 7/16-14 nut to hold the shaft in the bearings - had to Loclite it, I didn’t have any jam nuts that size on hand.

The y axis end plate was something I also wanted to do without - more drilling into the machine, more money, and less y travel. I just drilled a 10-32 hole in the end of the ball screw and made a washer that would allow a countersunk flathead socket screw to keep the ball nut from running off the screw. I want to keep the chips off the column as well as the base back there so I put a piece of plastic (temporary until I get the cut rubber mounted) back there between where the head meets the column and the table meets the saddle. I don’t know how well this will work but I’ve seen it done on other’s mills.

As I mentioned in an earlier post the y ball nut mount looked like it could take better advantage of the available space so I changed that. I also wanted it so that I could remove the whole y assembly with only a few easy to access screws. I was also considering adding another ball nut to the other side of the retainer holding the existing one like in your x axis double nut setup without losing too much y travel. I did the same thing to the x axis mainly to avoid having to go under the saddle and remove the ball nut mount screws to remove the assembly. When I get more money to double up the ball nuts I will have to redesign the retainer portion of the ball nut mounts to make use of them. Shouldn’t be too hard and will probably be an offshoot of what you have done. Looks good to me.

I only went with one bearing in the x support bracket and thinner aluminum stock. This end won’t see that much action IMHO so I chose not to beef it up that much. As a matter of fact I have a pair of inline skates that I robbed the bearings from. The bearing was considerably smaller but should be able to handle what action it may see.

Other than replacing the metric hardware where possible with ANSI stuff the most of the design and hard work of getting the measurements correct is all yours. I haven’t started on the z axis yet because I don’t have the tooling to modify what needs modified back there. I do have a boring bar and if I lock the head at the proper place I can use it to open up the bearing mount using the quill but in what I’m using the mill for the z has the least amount of importance and is pretty accurate for what I need. I would like a little more speed out of it though so when the money is available for the extra tooling I may need and small, minor parts (already have the ball screw and nut) I will work on that - maybe double nut that too.

I have to run the mill through a few parts to see how all this works out yet but right now I need to make an enclosure for it while I still have it up in the air. I have a catch tray under it now but coolant splashes all over the floor still and chips still find their way in the house. I also bought an aluminum sheet to make table covers to keep the chips out of the t-slots and coolant off the steppers. Heh a 24x36 piece should be more than enough and it’s only around $6 at Lowes.

I was going to wait until after I tested the system before I let you know what I have done but since you asked I see no reason not to comply. I will let you know of any findings that might be of concern and keep you updated on the progress.

Rick

[cadmonkey]

Sorry - Hadn't put 2 and 2 together and realized it was you that made the change and was posting in Matt's thread! Oops! No rush - I was looking for pics to show on the gallery (crediting the machine's owner of course) just to show there is flexibility with a little creativity, which if you're doing one of these you obviously already have so use it to your advantage.

I know there were radius cuts that weren't necessary - more to make things look nice and be more knuckle friendly if you later have to work on it. As to the Z mount - not wanting to clamp under the head of the column bolts is exactly why I did it to the side of the column, plus it minimizes the stock needed to make the support arms for the stepper. The stud idea is a good one, but tramming the column (which seems to be needed on a routine, albeit relatively long, basis) would require undoing the Z mount. I found drilling in all the cast iron to be much easier than I thought. Using 2 in the Z mount shouldn't be a problem - I doubt they see enough force to worry about pivoting on the back one and shearing the front one off. If you only used 2 on the X bearing mount be careful if you don't have limit switches installed - if you run with enough force into the hard limits too often you could snap them off. The rubber sheet will work well. I did that on mine. I also used it over the two steppers - works very nice to drape over and drip coolant off and allows you to lift up easily and oil the bearings, adjust bearing preload, etc. Don't worry about getting the drawings - I wouldn't have time to integrate them into the set for quite a while

[Teyber12]

hey!

im very interested in taking out the electronics from the mill but i am not extremely inclined.

would you recomend:

1) just trimming some wires to the switches/speed control, "extending them", and running cable to the control box?

or

2) doing what you did and taking all the electronics out of the mill?

thanks mate

[cadmonkey]

Depends on what you want to accomplish - I wanted two things - the controls off the column, and the control board out of the column cover since it's a b(&^$ to get to when the mill is mounted firmly to the floor and back against a wall and the sealing of the little compartment the board is in is crap (at least on mine).

So what is your motivation? The control leads can handle several feet of additional length, but that only gets the controls off the column. I might be worried about the motor leads though, the direction switch would mean the motor leads would be 2x the length of the new mounting position. If you move it all, then just the motor leads get long by the length you move the controls.

[Teyber12]

Depends on what you want to accomplish - I wanted two things - the controls off the column, and the control board out of the column cover since it's a b(&^$ to get to when the mill is mounted firmly to the floor and back against a wall and the sealing of the little compartment the board is in is crap (at least on mine).

So what is your motivation? The control leads can handle several feet of additional length, but that only gets the controls off the column. I might be worried about the motor leads though, the direction switch would mean the motor leads would be 2x the length of the new mounting position. If you move it all, then just the motor leads get long by the length you move the controls.

Alright thanks Ill problably just move it all out of the column.

cheers!

[cadmonkey]

I feel that is the best course and realistically takes less effort than extending all the control connections Just want you to understand what my motivation was and know what yours was.

The fwd/rev control can be kind of confusing so note labels and appropriate connections carefully when you disconnect to remove and remount. Took me a while to figure out how to reconfigure to use a contactor to handle spindle control from the computer (I have no need for reverse operation at this time but could add it later so there's just one contactor that is operated but there's a out of place lead on the switch that needs to close when the motor is switched on or nothing happens so I achieved it by using a 3 pole contactor - I got some great deals on eBay).

[Teyber12]

oops! forgot to mention-

in the "perfect world" i want a full enclosure for the x3 with a little box like rod did with the total e-stop(the estop wired into the bob not the mill e stop), on/off, for/reverse, and spindle speed.

Thanks for your help

[MetalBlade]

I just thought I would let everyone know that I have lost my desire to pursue manufacturing any type of table extensions or even finish the patent process. I've found this really great job repairing PLC's and just don't have time to pursue it anymore. I may in the future even post my designs like Cadmonkey did.

Also about the breakout board problem causing the steppers to stall out. It's not the breakout board pulling too much current from the laptop as I had thought; Rather, it's the geckos pulling way too much current. I had looked up the PDF for the Optical Coupler that is in the gecko 201 and it said that when the Optical Coupler is pulsed fast, it could draw up to 50ma! That's way more then the 16ma that the gecko documentation states, and more then most breakout boards can source. It makes sense too, because the motors are stalling at higher rpms. I'm not sure what quality the Optical Coupler in the Gecko 203s are, but if they are the same ones as the 201 model then the same problem applies to them too.

I noticed that even driving a gecko 201 from a desktop that there is still a slight stall, but not completely. A cheap fix that will help the problem if you're using a desktop computer is to buy this Optical Couple part number 630-HCPL-2231-000E from mouser that uses a little bit less current and replace the ones the controllers came with. There is probably even better couplers out there that use even less, but they will be a lot more expensive. Also on my breakout board I am using buffers that can source more current to driver the stepper controllers which is 595-SN74BCT25244DW from mouser. They can drive up to 188ma.

Now, there is still even more to the stalling problem. The Gecko 201 divers don't compensate for the high inductive reactance of the motor like the 203's do, so if you're going to be running from a laptop and expect your steppers to be able to do at least 1000rpm, you need the gecko 203's.

Good luck to everyone on their builds.

[hab82]

I've just finished reading the thread. I haven't looked at the drawings yet but most of the Ideas discussed seem similar to my own. I have an X2 that I converted and am now moving to an X3. I feel that an X3 will get me away from most of the problems that have me dissatisfied with the X2.

One question that I have is: Have any of changed or contemplated converting the stock spindle motor to a more powerful version such as 1.5Hp 3 phase with VFD drive?

I am very dissatisfied with the torque of My X2 and It doesn't look like the X3 offers a tremendous amount more. It also has the added advantage of moving the controls out of the rear column. Eventually I want to computer control the spindle speed as well and it looks various interfaces will work with a vfd.

Any pointer to another applicable thread would also be appreciated.

I also noted with interest the use of a 7X10 to machine the screws. I used a 7x12 on my X2 conversion and planned the same for this. I used a toolpost grinder to get below the hardened area then machined first with carbide and finished with HSS. I don't trust myself with lathe threading so I use a die,

Hubert

[HackMax]

I've just finished reading the thread. I haven't looked at the drawings yet but most of the Ideas discussed seem similar to my own. I have an X2 that I converted and am now moving to an X3. I feel that an X3 will get me away from most of the problems that have me dissatisfied with the X2.

One question that I have is: Have any of changed or contemplated converting the stock spindle motor to a more powerful version such as 1.5Hp 3 phase with VFD drive?

I am very dissatisfied with the torque of My X2 and It doesn't look like the X3 offers a tremendous amount more. It also has the added advantage of moving the controls out of the rear column. Eventually I want to computer control the spindle speed as well and it looks various interfaces will work with a vfd.

Any pointer to another applicable thread would also be appreciated.

I also noted with interest the use of a 7X10 to machine the screws. I used a 7x12 on my X2 conversion and planned the same for this. I used a toolpost grinder to get below the hardened area then machined first with carbide and finished with HSS. I don't trust myself with lathe threading so I use a die,

Hubert

Most of my machining is aluminum based and I don't have any issues with torque given the max spindle speed is 2k rpm. The only problem area about the mill for me IS the spindle speed. I need it 3x what it is to get quality finishes in the metal. As it is now I can only mill the aluminum at 4-6 IPM and get a half decent finish. It still requires plenty of sanding though.

As for using the lathe for the screws make sure you use a 4 jaw independent chuck. I didn't realize how much run out I had in the lathe and cut the ends of the screw about .015" out of concentricity. I haven't noticed any problems yet but I still don't like that much run out on the screws.

Rick