# My Cnc Conversion



## chevydyl (Sep 21, 2015)

Today I got my pc with mach3 to talk through my cnc breakout board to my allen bradley servo drives/motors, success I say. Next up is making the pulleys fit and custom motor mounts. Oh yeah, and 8 read a letter from my work saying we are all getting a cut in pay so the new set of ballscrews are off my shopping list for now. Gotta love oilfield work huh. I'm relatively safe being an operator as they still need me, just for alot less money.


----------



## chevydyl (Sep 23, 2015)

Made an adaptor to fit the tiny 16t motor pulley to the motors 19mm shaft, I also bored the pulley for the screw to fit, the adaptor still has a couple ops left, the big pulley also has a few ops, I need to make a flanged bushing that will Bolt to the pulley and be keyed to the screw to ensure it rotates with no backlash. The drive ratio is 3:1, so I will have about 12lb-ft of torque on the screw. Also it has the ability to rapid at like 330ipm, not that a knee mill should be moving that fast but it could lol. The servos are 2.8hp/2kw from Allen Bradley. The tooth profile is Gates GT2, 5mm pitch, 15mm wide


----------



## chevydyl (Oct 5, 2015)

Since my ball screws will arrive tomorrow, it was necessary to redo the pulley adapter, so I faced the hub off the pulley, and bored it to like .486, the motor shaft adapter was made much the same as the last one, the last one was for demonstration purpose only, two set screws will be torqued to the motors keyway, no actual key, broach a blind hole anyone? The pulley will be pinned at the face to the adapter, on the tangent of the two diameters. Then a shcs with a custom washer will keep the dowel pin in, and the pulley from being able to move. All the fit ups are pretty darn good, in the picture I haven't quite driven the pulley all the way on yet, but the pulley face and adapter face will be flush.


----------



## chevydyl (Oct 7, 2015)

Ball screws....check.
Problems....check. lol
The issue is the x screw isn't quite long enough, on the float bearing side, the bearing journal isnt in the bearing, so I will make an extention, before anyone cackles about that, Prototrak actually makes screw extentions for oddball tables, like a 48inch screw on a 49inch table. I also had to machine a 32tpi bastard nut, screw has a .735 minor and .777 major for preload of the left bearings, I bored a .740 hole in some steel and started cutting threads until the screw fit, nice wiggle free fit Also the screw extention may be fruitless once the motor mounts arrive. I think it shifts the left bearing under the table a little, which would extend the right end of the screw where it needs to be....we will see. Any way here's a couple pics. Oh yeah, and when I turn the screws, that table moves, no detectable backlash, very happy for $500 ground screws, I got a major discount, they were new takeout screws off new machines, one an anilam the other an acu-rite


----------



## chevydyl (Oct 12, 2015)

One more piece to the puzzle, these come off an older Bridgeport EZ-TRAK cnc machine, where Southwestern Industries made a ProtoTRAK control to bridgies specs, not my favorite flavor of motor mount style, the newer ProtoTRAK mounts look a little nicer, they kick the Y motor 40deg to the right, X mount is different looking also, little cleaner but for $300 shipped($40 priority, 2 boxes) they were all that I was able to find. Elrod machine wanted 965 plus shipping for JUST the castings and covers, these used ones at least include the correct 7204 AC bearings, and if I find that one pair is no Bueno I have a new pair, 30 bucks, SKF 7204 BECBP, retail 64 ea, so I did good on those too.


----------



## chevydyl (Oct 15, 2015)

The motor brackets are installed, I need to turn a couple screw extensions for both screws, and a bearing bushing for the x screw. Then some motor spacer/adapters out of 1x4 alum sorry the shop and the machine is in complete disarray because of this step in my conversion. I can use the mill at this point but not accurately because the handles and dial don't fit without an extension


----------



## Firestopper (Oct 15, 2015)

chevydyl, your servo conversion resembles the one on the Lagun. Looks like a fair amount of work too. Will you be using a Proto Trak and lastly 2 or 3 axis? 
Looking good!


----------



## chevydyl (Oct 15, 2015)

The motor mounts are from a bridgeport ez trak machine, I will be using a pc based controller, mach3, it's diy, 2 axis for now. The  breakout board is a cnc4pc gem the C62 24volt, and I'm using allen bradley AC servos and drives. 1000w each. PLC type wiring terminal blocks.


----------



## chevydyl (Oct 16, 2015)

Got the bearing bushing done last night, and started drawing out the screw extentions. Today the y axis belt and pulleys showed up, also yesterday I spent $20 on shcs for both motor mounts, I also have to do a little clearance work on the housings to clear the screw pulleys, Prototrak uses 44t driven pulleys and I got 48t, slightly larger diameter. Prototrak is 2.75:1 I'm using 3:1
Pulleys and belt were $70 from stock drive


----------



## chevydyl (Oct 17, 2015)

Screw extention for x screw


----------



## Firestopper (Oct 17, 2015)

Nice! making progress on the conversion.


----------



## chevydyl (Oct 17, 2015)

The main thing is getting it put back together so I can use the mill, I have to turn a spacer for the new bearings on the y housing, and grind it in to .120  these AC bearings are somewhat confusing to setup properly so I can get a little preload, the prototrak manual shows a different housing Tha I have, there lay the confusion lol, turns out the used housings I got have 6204 bearings.... and the y axis were a little loose. The x bearings were good so I roll with them for now. The 7204 AC bearings are .118 thinner so the bearing retainer doesn't retain the bearings.


----------



## chevydyl (Oct 17, 2015)

Y axis work, made a spacer to place the pulley an acceptable distance from the housing wall, then had to modify the dial holder, I took off as much as I could and still left something for the dial to push up against. Then I had to remove about .125 from the dials inside flange to get it as close to the cover plate as I wanted. The dial is cast iron, yuck. Now I just have to make the screw extention for the y screw and then the mill can be used to make the motor adapters. Still have to make room for the belt inside both housings. That will be Monday probably.


----------



## Firestopper (Oct 17, 2015)

Looking good chevydyl,
Are you going to use a nesting or folding type hand wheel for the Y axis?, your twins might appreciate it hahaha The Lagun's Y axis hand wheel is at crotch level.


----------



## JimDawson (Oct 17, 2015)

firestopper said:


> Looking good chevydyl,
> Are you going to use a nesting or folding type hand wheel for the Y axis?, your twins might appreciate it hahaha The Lagun's Y axis hand wheel is at crotch level.


:+1:  mine only got me once, just in the leg.  I forgot to fold the handle in.  Won't do that again, now its kind of like never leaving the chuck key in the the chuck.


----------



## chevydyl (Oct 17, 2015)

Thnks. For now no, a set of those handwheels is like 200 bucks. So in the future yes


----------



## Firestopper (Oct 17, 2015)

Folding hand wheels.... $200.00
Preserving the twins.....Priceless 
Hahah just busting your chops brother.
Can't wait to see your finished machine.


----------



## chevydyl (Oct 18, 2015)

Hahaha, I have enough kids already. Well wait, the wife wants another.....
The motor adapters are 4x4x1 alu, I will bore a hole on the mill, then face the motor pilot in on the lathe, 4jaw status. No rotab. All said and done I will have close to 3500 into the coversion, I'll tally it up later. Cost won't include all the time I put into 'making things work'


----------



## chevydyl (Oct 18, 2015)

More updates. Motor adapter. Annular cutter is a badass lol.
Then facing the pilot. So, the motor will Bolt to the adapter, then the from the other side the adapter gets bolted to the motor housing. The mill is still setup to do the other adapter, but maaaaan that was alot of boring on the mill, I'm gonna get the other adapter to this same stage and then will drill the holes and tap for fixing the motor to the adapter, the I will install the belt and mark the proper location for the housing bolts.


----------



## chevydyl (Oct 18, 2015)

Oh yeah here's more, the y axis extension finished, AND talk about luck, the knee crank just kisses the y crank if they are both in the perfect position.


----------



## brino (Oct 18, 2015)

chevydyl said:


> Cost won't include all the time I put into 'making things work'



somehow it almost never does.......if it was a business for me it would be in the red; luckily it's just a hobby and those are expected to cost money! 
-brino


----------



## chevydyl (Oct 18, 2015)

And some more. You get the idea, you can see where I have to make room in the last picture. Still gotta drill and tap the 1/4-20 bolts for the adapter to mount to the housing, gonna be another late night. Have to machine the x axis pulleys too


----------



## chevydyl (Oct 19, 2015)

Got the housings clearanced today, done on a 2 axis prototrak k4, the picture is of the x housing, the y was nothing special to look at. Firestopper, so I asked Gary if he could run the program over and over to make this cut, it was about 5 passes, he said no, that he had to change the cutter comp and run the program each time, just an FYI for you on your controller


----------



## Firestopper (Oct 19, 2015)

Interesting, I was able to make repeated passes to cut two bores (1.497") in 1/2" CR flat bar using a 3/8" end mill (cutter comp included) and manually advancing the Z between each pass, lock it down and hit go. Alternating between the two bores. I was nervous and programmed feed rate at 10 IPM. The pins and the callers you see are the bores mentioned. The pins are welded on the backside.
I was very cautious on the last pass so not to suck up the center (coupon) left by the end mill.  Perhaps he chose to advance the cut by adjusting only the cutter compensation between each pass? 
Looks great man!  
The sharpie calculations resemble my vise too hahah.


----------



## chevydyl (Oct 19, 2015)

He has an AGE2 controller that may be why, but I asked if he could run it continuous without having to stop between passes and have the controller just cut .015 per pass and have it repeat until say .075 was removed, he said he couldn't do that, maybe it was because of the part being machined and not knowing what exactly the end dimension needed was. We just cut it until 'looks good enough' pretty neat how he setup the y axis cuts, they were an angled cuts, he used a 18 inch ruler and set it at an angle offset to the pulley diameters and took some various measurements and programmed them in, then hit Look At program and there were two angled lines, he had picked up on the bore for the bearings as his zeros.

So he changed the cutter diameter to a smaller size in the program to make it cut .0125 each pass, hitting go each time, used a .75 cutter and ended telling the controller it was a .575, then lowered the z to cut the rest of the wall and told it It had a .580 cutter so it wouldn't rub on the shank, the cutter wasn't long enough to cut the entire wall depth.


----------



## Firestopper (Oct 19, 2015)

chevydyl said:


> He has an AGE2 controller that may be why, but I asked if he could run it continuous without having to stop between passes and have the controller just cut .015 per pass and have it repeat until say .075 was removed, he said he couldn't do that, maybe it was because of the part being machined and not knowing what exactly the end dimension needed was. We just cut it until 'looks good enough' pretty neat how he setup the y axis cuts, they were an angled cuts, he used a 18 inch ruler and set it at an angle offset to the pulley diameters and took some various measurements and programmed them in, then hit Look At program and there were two angled lines, he had picked up on the bore for the bearings as his zeros.
> 
> So he changed the cutter diameter to a smaller size in the program to make it cut .0125 each pass, hitting go each time, used a .75 cutter and ended telling the controller it was a .575, then lowered the z to cut the rest of the wall and told it It had a .580 cutter so it wouldn't rub on the shank, the cutter wasn't long enough to cut the entire wall depth.



Clever! Thats where I hope to be, I understand basic programming but not close to that level yet.


----------



## Firestopper (Oct 19, 2015)

chevydyl said:


> He has an AGE2 controller that may be why, but I asked if he could run it continuous without having to stop between passes and have the controller just cut .015 per pass and have it repeat until say .075 was removed, he said he couldn't do that, maybe it was because of the part being machined and not knowing what exactly the end dimension needed was. We just cut it until 'looks good enough' pretty neat how he setup the y axis cuts, they were an angled cuts, he used a 18 inch ruler and set it at an angle offset to the pulley diameters and took some various measurements and programmed them in, then hit Look At program and there were two angled lines, he had picked up on the bore for the bearings as his zeros.
> 
> So he changed the cutter diameter to a smaller size in the program to make it cut .0125 each pass, hitting go each time, used a .75 cutter and ended telling the controller it was a .575, then lowered the z to cut the rest of the wall and told it It had a .580 cutter so it wouldn't rub on the shank, the cutter wasn't long enough to cut the entire wall depth.



Clever! Thats where I hope to be, I understand basic programming but not close to that level yet.


----------



## chevydyl (Oct 20, 2015)

Well, she's all done, now it's time to bring the computer out and hooked all that part up. It will be trial cutting tomorrow. I need a couple set screws yet. I ended up having to make another pulley adapter, like 2.5hrs into just that piece, I used an end mill on the lathe to cut a square ended hole, well it tapered the walls somehow and overshot the dimension in the back of the hole by .005  double you tee eff. This project has so far been a ton of work, more than I had anticipated. However the experience to solve issues is well worth the effort and the tune of cash from buying turn key conversion kits. New meaning to assembly required. Not a single part was meant to work together, I still have one major issue to address, the y axis still won't move the saddle unless the dial slops out about .005, I tried numerous suggestions, including the AC bearings preloaded, nunya. So I have one last fix, oversized balls, so I'll have to take the screw apart, Mic out a ball or two and place an order. Anyway here's a parting shot of the x done. Oh yeah, my lathe head bearings starting rattlin after taking .080 cuts one after another for about .800 removed.


----------



## chevydyl (Oct 20, 2015)

All wires are hooked up, just have to hook up power 240v


----------



## chevydyl (Oct 20, 2015)

It's alive, pictures soon of a cut part


----------



## jrstech (Oct 20, 2015)

chevydyl said:


> It's alive,



Congratulations on your new baby!


----------



## chevydyl (Oct 21, 2015)

As promised, I did a little lettering of a friend's business name, the guy helped out alot. I had some grounding issues causing interference but it's worked out now.


----------



## chevydyl (Oct 21, 2015)

As of right now, I have $2650 into the cnc conversion. I still need a scale for the Z and new handles, nother $500, I also still need to add some limit switches and a cabinet, and other electrical buttons and switches and a monitor stand of sorts. So I could in reality spend another 800 bucks to have it totally done. Plus the 950 I paid for the mill, not bad for cnc. I do realize you can buy used cnc machines for about that same cost, 3-10k. But the experience of building, nothing like it.


----------



## bpratl (Oct 21, 2015)

Your are correct it does add up and can be quite expensive to convert to CNC but as you said, " the experience of building, nothing like it".
I really enjoyed converting my lathe to CNC and now I'm trying to find time to finishing my mill. It was a thrill to see the machine make your first part on it's own. Bob


----------



## chevydyl (Oct 21, 2015)

Here's one more, so I did a profile on the outside, not much to say it's not round, it's a few thou off because of the y screw. Then I ran a pocket with dimensions of 1.125 square. It mic'd out to 1.125x1.1233 again the y screw showing its shortcomings. Lame that I have to rebuild a brand new screw, but that will be a project for the next couple weeks. I'm not sure of any other reason it could be other than the screw has backlash, it has new AC bearings and the mounting is all solid.


----------



## chevydyl (Oct 21, 2015)

A thrill? Haha I couldn't stop grinning.
However, my ground issue caused both servos to run off, LUCKILY the drives faulted before it hit the travel limits, I wouldn't have been able to stop it in time. They ran right when I hit the switch to enable the drives, Mach was idle. Wow.


----------



## Firestopper (Oct 21, 2015)

Congrats on you conversion! It's been cool keeping up with it, thanks for posting.


----------



## JimDawson (Oct 21, 2015)

chevydyl said:


> It mic'd out to 1.125x1.1233 again the y screw showing its shortcomings.



Looking good!  Assuming you have single nut screws, I would say that the dimensions came out pretty good for the first run.  If you can put in double nuts, the backlash can be adjusted to zero by preloading the nuts.


----------



## TomS (Oct 21, 2015)

chevydyl said:


> As promised, I did a little lettering of a friend's business name, the guy helped out alot. I had some grounding issues causing interference but it's worked out now.
> 
> 
> 
> ...



I've been watching your conversion since the beginning.  It turned out nice!  Can you share some info on your engraving set up?  Did you use a small diameter end mill or an engraving bit?  What speeds and feeds did you use?  Depth of cut?  I'm working towards making a control panel cover for my mill with text for each of the function knobs and buttons.

Thanks,

Tom S


----------



## chevydyl (Oct 21, 2015)

Thanks for the kind replies.
The engraving was done with an accupro .250 60deg carbide blank, 4200rpm, 6.67ipm doc .010-.015  not enough spindle speed or too deep of cut, it  was pretty burry, rubbed on some scotch Brite and took em down. Not sure if this bit was actually made for this or not but it's what a friend had for me to use to test some text.
Jim, the x axis screw has no backlash, setup an indicator touch the screw the table moves, y axis.....005 dial movement before the saddle flicks the needle. I feel like there is room for improvement, the screws are from different manufactures, one is from an Anilam controller (y) the other from an acu-rite  (x) control. Both take out brand new, but the seller was calling them (old type) maybe anilam used to have their screws loose so they'd last longer idk. Do you have any suggestions on anything else it could be besides the bearings on the screw?


----------



## JimDawson (Oct 21, 2015)

The only other thing that comes to mind is to make sure the axial play is actually in the ball nut rather then in the lead screw support bearings.  The lead screw support bearings should be preloaded a bit.  Short of that, installing larger balls in the nut is the proper fix.  I'm surprised that the Anilam screw does not have double nuts.


----------



## chevydyl (Oct 21, 2015)

Neither screw has double nuts, and the anilam screw is made by RBC,  the overall nut length is longer than the x screw, it sticks out the back of the yoke almost 1/4". I'll have to do some bench testing on it before I tear it apart as well.


----------



## chevydyl (Oct 22, 2015)

finally figured out how to get my Rapids up with electronic gearing. I tried high kernel speeds and it just made things twitchy, so I asked on cnc zone how to do it, then it came to me. 120000 steps per inch, divide by 4 is 30,000 set in Mach 30k steps per inch, the. In the servo drives set them to follow 4 quad counts per step input pulse, my resolution becomes .0000067 so I could actually divide one more time for a 1:8 ratio and have a resolution of .000013 and I think my Rapids would double but 115ipm is plenty for this mill at the moment.


----------



## TomS (Oct 22, 2015)

chevydyl said:


> Thanks for the kind replies.
> The engraving was done with an accupro .250 60deg carbide blank, 4200rpm, 6.67ipm doc .010-.015  not enough spindle speed or too deep of cut, it  was pretty burry, rubbed on some scotch Brite and took em down. Not sure if this bit was actually made for this or not but it's what a friend had for me to use to test some text.
> Jim, the x axis screw has no backlash, setup an indicator touch the screw the table moves, y axis.....005 dial movement before the saddle flicks the needle. I feel like there is room for improvement, the screws are from different manufactures, one is from an Anilam controller (y) the other from an acu-rite  (x) control. Both take out brand new, but the seller was calling them (old type) maybe anilam used to have their screws loose so they'd last longer idk. Do you have any suggestions on anything else it could be besides the bearings on the screw?



Thanks for the engraving info.  It helps a lot to have a starting point.

Tom S


----------



## JimDawson (Oct 22, 2015)

chevydyl said:


> finally figured out how to get my Rapids up with electronic gearing. I tried high kernel speeds and it just made things twitchy, so I asked on cnc zone how to do it, then it came to me. 120000 steps per inch, divide by 4 is 30,000 set in Mach 30k steps per inch, the. In the servo drives set them to follow 4 quad counts per step input pulse, my resolution becomes .0000067 so I could actually divide one more time for a 1:8 ratio and have a resolution of .000013 and I think my Rapids would double but 115ipm is plenty for this mill at the moment.




Sounds like that would work.  115 ipm is about right, I have mine set at 100 max.  Plenty fast.  1/3 micron resolution is close enough for any home machine, and most full on industrial machines for that matter.  Once you get the Y-axis lead screw worked out you are going to have a very accurate machine.


----------



## chevydyl (Oct 22, 2015)

Jim I actually went back and retuned to 100 max. It runs pretty good right now.
I still gotta familiarize myself with bobcad, having trouble cutting a square extrusion on the end of round stock, the part ended up being oversize and it finished the program in the center of one of the flats leaving a little indention, so I'll have to hone my skillz to make sure it continues off the part for a seamless finish.
And on the engraving, doing it over I had MUCH better results with the same part at only .005 to .008 deep. Maybe try 10-20ipm feed, the part must be flat of course, factory alum finish won't do, must take a face skim or the letters will be different widths. I also did a different style text BobCAD default, with a .075 2fl ball nose, the letters were shiny and turned out great, I have read that others had great results using small center drills as well, they are much much stronger, and if your using high speed steel your spindle rpm limit really improves finish.


----------



## JimDawson (Oct 22, 2015)

chevydyl said:


> ........the part ended up being oversize.......



I just takes a bit of practice to get it right, you're almost there!  

One hint, mic your end mill, and plug that number into your CAM tool size value or into the cutter comp if you have it.  Most end mills are not on size, normally a few thou under, that will cut an oversize outside profile.


----------



## Firestopper (Oct 22, 2015)

JimDawson said:


> I just takes a bit of practice to get it right, you're almost there!
> 
> One hint, mic your end mill, and plug that number into your CAM tool size value or into the cutter comp if you have it.  Most end mills are not on size, normally a few thou under, that will cut an oversize outside profile.



True, I allways measure the endmill as I have some regrind's. The cutter comp works great when you plug in the correct size.


----------



## chevydyl (Oct 22, 2015)

Thanks for the advice, the issue was my tool path in bobcad, I did something wrong, I talked to tech about the program crashing and they also helped me figure out what I did wrong, I will start mic'ing my cutters, I choose a tool in cam but see no data about size in Mach for comp, I'll look into it, I explained to firestopper on an AGE2 control how a friend used cutter comp.


----------

