[swoolhead]

A quick question, what spec motors are you planning on using to drive the x&z axis?

[Adobe Machine]

Machine Tool Camp, series 32 ,672 in/oz servos with US Digital encoders. The total reduction ( both avis) will be 7.2 :1, so there will be plenty of torgue and at 3500 rpm max , 80 IPM . Considering the long Z axis is only 30 ", will cover Z+ to Z- in less than 30 seconds.I may have to limit G00 to 40-50 IPM cause I can"t think that fast anyway.


Adobe (old as dirt)

[Adobe Machine]

Finished turning and threading the the X ( Long ) axis ball shaft. I changed the thread type to a 7/16 -20 , as I did not like the supplied fastners..They are difficult to torque correctly, so on the X axis I will use grade 8 double nuts.
1st nut against the bearing spacer is for torgue, the second is to lock.

I have a couple of pictures of the tooling I use to turn and thread. Even with a marginal lathe, with the correct inserts and holders, you can do a very professional job while turning and threading hard alloy steels.The key is set up, feeds and speeds and the correct inserts. My threading kit has profiling inserts for all threads, 8 to 24 threads per inch.They are engineered to cut perfect threads, and using the last ( spring pass) eliminate burrs. In the "old days" we struggled to thread with 60 degree cutters, these newer type profile inserts certinley achieved excellent results at an economical price. I have had this kit for over 3 years, and only had to replace one insert, as I bumped it against the shoulder on the last pass. My son and I (mostly him ) are rebuilding a Travel Air Bi Plane ( 1929 ) and he had attempted to cut some threads on his mini lathe with disappointing results.We then used my profile inserts and the threads came out excellent, and this using some tough, hard round stock.Pass any FAA inspection.
The same is true on just regular turning. When we started using these Valenite MCLN holders with the CNMP type positive rake inserts, our product came out much better, and quicker ! You reduce the cutting forces with these cutters, so your not "pushing" the tool and the turned part away from each other, giving an excellent finish in alloy steel and believe it or not, Alum. With alum. I usually use these cutters and finish cutters, but have also used them ( when I got lazy, did not want to change tooling ) to hog..like .250 depth of cut..The only thing with these holders and inserts they are big at the working end and if you are using a live center, hard to get in to cut the last inch or so, so you would use a left handed cutter if that was the situation.
I did notice that EMCO and some of the other discount tool supplies had the same style holder and inserts ,real economical. I've never tried those Asian imports, but would think they would be ok. Most of Kennemetal and Valanite holders and some inserts are comming from Isreal and their quality is excellent.In fact I purchased a 3 insert end mill ( 3/4 ") from Iscar.I have to tell you, that thing will make some chips in a hurry !
Another industry going over seas , real sad.
After finishing the ball shaft, I milled the "Link" between the apron and X axis ball nut flange.As WALT @ SGS had suggested in another thread, I hand lapped the surfaces between the apron and link and the ball nut flange and link.
In order to determine where to locate the center hole to pass the shaft through, and subsequent taped holes for the ball nut flange, I made a "pilot" shaft and turned a centered point on it.This pilot shaft had the same O.D. as the fixed angular bearings I.D. less .0003. I assembled the link to the apron, and brought it as close to the Fixed end as I could.I inserted the pilot thru the bearings and used it to mark the center.
Using Vector CAD/CAM, and my Tree Mill, I started X0Y0 at center of the shaft hole and interpolated a hole @ .700, then drilled 4 ea .201 holes for a 1/4 20 tap, and hand tapped those holes.

Next is: reloading the ball nut and installation on the machine.

Picture 1 : Simple end turning is done.

Picture 2 : Z Axis "Link" long look

Picture 3 & 4 a look at the tooling used for threading and turning.

[Adobe Machine]

Even using double ball nuts, I still stuff the front ( fixed, the one with the flange ) baLL nut with oversize balls ( chrome steel, 52100, grade 25), and just use the factory balls in the tension nut ( the tension nut does not drive, it only puts tension on the ball nut and the shaft )
In the pictures below, you can see how I set up to reload ball nuts.
1st I set the shaft in the lathe, and clean the shaft. Next I empty the factory balls in one container. I measure at least 30% of the balls, to determine if they loaded with oversize or staggered. They did not, all factory balls measured .1248 to .1249..close enough. I then prepped 2 dishes for oversize balls (.1252 and .1253) and marked my table that I use under the shaft for tools and to have a "catcher" plastic dish in case one gets dropped ( only 2 today). Then I load the empty ball nuts and hardware on the shaft and remount on the lathe...I shift the lathe in neutral and turn off the electrical to the lathe OFF as a saftey item. I begin loading, one ball in each, turn the chuck while holding the nuts and watch the balls disappear, keep loading and turning the same direction. I do keep the nut wet with oil, putting a little in every 3-4 balls.Pretty soon you can see balls appearing in the other side of the circut, do not let them go past where the tubes go in, they will forever be in no mans land and not recirculate !Next, use vasoline ( if a cool day, grease if a hot day) and fill 1/2 of the split recirculating tube with balls, then press the 2 sides together and install on the nut.I do install fastners at this time. It is important to turn the ball nut through the entire range, see if binds or jumps, or is loose. This was not any of the above, no the next step is installation of the shaft on the machine.

Picture 1 : My way of settting up and organising to stuff balls.

Picture 2 & 3 : Unloaded nuts and hardware on the shaft.

Picture 4 : Containers and tools

Picture 5 : Almost done

Picture 6 : Done

Picture 7: After running up and down the shaft, now ready for install.

Next : Installation of the ballshaft, testing for backlash, torquing fastners,and running the Z axis through the full 33" inches.

Adobe (old as dirt)

[Adobe Machine]

Installation of the ball shaft to the machine : With everything machined and done , and if I have measured everything correctly, it will fit as planned. No proplems loading, then I installed the ball nut and flange on the link ( Note, one is a stud to guide together) then tighten down.The bolt pattern was right on, but there is no play even with the fastners not tightned. I then ran the carraige to the fixed end and slightly tightned the fixed end angular bearing mount to the machine ( 25 lbs torque only ). then ran the carriage to the simple end and repeated. I then ran the carriage back and forth to the limits of each end about a dozen time, using my battery powered drill. No binding, no heat . The with one hand I turned the carriage to both limits, no binds.
At this time I torqued all fastners (to specs.) involved in the Z axis and repeated turning by hand the full distance and back. I did lubricate the balls and shaft a couple of times, then used my battery powered drill, ran the axis back and forth untill both batteries were dead. No heat, no binds exceptionally smooth.
I set up my tenths indicator as shown, at this time there is NO BACKLASH. I even had a neighbor ( at least 240 lbs ) push against the apron and we could see no movement .Untill the machine is making chips and under a good load, it would not be right to say there is 0 backlash, just at this time there is none.

Next. Machining the mountings for the servos, belts, tensioners and covers.I ordered a bellows to protect the ball shaft, will have to engineer mounts.

Pictures 1 & 2 :Installed ball nuts and shafts. The lower left fastner is the guide stud.

Pictures 4 and 5 Dial indicator set up to measure backlash.

Picture 6& 7 : Link and simple end.

Picture 8 : Ballnuts, shaft and Fixed angular end ( my shorty 11/16 end wrench was used to determine backlash)

Picture 9: Battery powered drill motor as a driver to test the Z Axis.

Picture 10. Torquing all fastners and bearing mounts.

Next : A cervasa. ( hey, its Saturday, right ? )

Adobe (old as dirt )

[fomaz]

Hello.

I own a small company in Portugal, where we have 3 latches. They work all day long, and we do, as all others companys near us, small quantities pieces.

I already made a cnc plasma cutter and a router mostly for wood. I have a difficult time in obtain pieces for both machines, and they probably cost me 2 times the price for you guys in Canada or USA. Both machines are payed with the work that they done.

I am very interested in your project, and I would like to know if you have work for the machine after it is done. Simple question, but the most important to me.
This question is because, if I have a cnc latch in my workshop, I don't know if work will apper to work on it.
I also think (know) that there is not and cnc latch in a 300 Km (arround 200 miles). So this could mean a opportonity ...

What do you think, or what others think about it ?
Any sucess storys of a guy that both a cnc and got lots of work ? Doing what ?


Thanks

[Adobe Machine]

Well, I had an accident 3 1/2 years ago that put me in a wheel chair. I make parts for Hot Rods, street rods and some race cars ( 1/4 mile drags) We had already sold our business of 35 years.( Manufacturing and Machine shop ) I had planned on retiring, working part time in my home shop, but it is real hard to operate a manual machine from a wheel chair.I 1st converted an old Tree Mill to CNC (one in the pictures) and that was so much fun and worked so well , decided to convert my Pratt Whitney Lathe to CNC.
Would it be economical ? Including a DRO, all the electronics,servos, electronic cabnet, wiring , ball screws, double ball nuts and misc fastners, I will have spent about $ 3800.00.I have owned the lathe since new
( purchased in 1969 never used, but manufactured in the mid 50's ) and taken real good care of it..so the decision was pretty easy. I just did not want to buy a used NC or CNC lathe and retrofit, then find mechanical problems.
To evaluate your situation as income vs cost would be imposible..If you found a good manual lathe and did the retrofit your self it might be economical and make a good business decision.It also could be a big" boat anchor" taking up room in your shop.Most depends on your skill leval and determination to make an accurate piece of machinery.
There are a lot of people on the Forum who can help you on the electrical end, because my education was not in electrical, I bought a complete kit from Machine Tool Camp, that made it easy for me and it uses matched items.
Most of the material used was scrap 6061 t6 and 7073 t 6 alum that I have been scounging for years. All fastners are # 8, and I'm real particular on correct torque and assembly procedures.I purchased complete fixed angular bearing mounts and used premium Barden bearings, as opposed to trying to "re-invent the wheel"and make the housings myself. In reading this forumn and searching you can see that most backlash problems are created by poor bearing mounts and poor planning.
Let me say this , in being in business for myself for 35 years.... if you do quality work, are honest with your employees and customers and can do something no one else does in the area, you have a good chance of being sucessfull.If you retrofit a lathe to CNC you may have to go out and advertise your new capability, but you may find even your competitors will use you for hard to lathe items. ( Profiling, threading tapers etc ).
If you get to the point you have decided to go ahead with a conversion, I can give a list of parts and suppliers to help you get started.

Adobe (old as dirt)

[fomaz]

Thank you.

I think I can handle an entire retrofit. I am able to do the electrical part, machanical and if necessary I can write a program to output gcode (I am not trying to say that I am good, but I think I can). I have done this before to my plasma table and my router, that were done from scratch.

The most important is if it will be work for the machine and the limitation of the machine, 1,2,3 or more tools ?

For example to do a simple sphere. How many tools are needed ? One for the one half of the sphere and another to the back of the sphere. ?!

Thank you for your replay.

Filipe

[Adobe Machine]

Tooling : I only use carbide inserted tools, main tools are left and right hand
MCLN shanks and the CNMP or CNMP/E 80 degree diamond shaped inserts, some with negative and some with a little positive rake, I use profiled tools for internal and external threading, as the picture above shows. We have drawer fulls of boring bars, a lot we made from HSS years back for groving
( o rings) and special applications, but my favorites are SI-STFC (R &L) for internal boring. Frankley, a lot of the tooling I have are from years of collecting, but do not use many HSS tools any more.
In tooling one of the 1st considerations is ridgidness..and the ability to cut with out a lot of cutting force. Using the MCLN tools with the CNMP carbide inserts reduced cutting forces substantially, therefore able to increase cycle times.
The only limitations of an open bed CNC lathe will be your ability to program: I use a CAD/CAM program ( Vector) to draw the part and convert the G code, it has taken me awhile to get comfortable with using it, but I do not know how we ever got by with out this type of program..I also bought a threading,turning and groving program put together by Fred Smith at Im serv, this is just fill in the blanks, and presto the G code is spit out.Really nice, well thought out program, and the ISO G code is pretty standard .
The other draw back is right now I have no automatic tool changer, but have looked at some internet plans that seem pretty easy to fabricate and install. After all the bugs are sorted out , then I will get serious about an ATC.
This will not be a high dollar turning center, mearly a very accurate CNC open bed lathe, that is a lot more versital than a manual one. If I need a manual lathe, there is a 17X60 Le Blond sitting next to it.

Adobe (old as dirt )

[Adobe Machine]

Fabrication and trial fit of the X axis belt cover/ servo support.

I found A 10" piece of 6061-t6 round stock that I've been hording for years, has a little storage/moving damage on the O.D., but fills a need for the X axis pully/belt cover and servo mount.

Fabricated a 3/8 flat stock of 6061 t-6 for a spacer that also serves as a stiffner for the Z axis link to the X axis bearing mount, which is also the link to the Apron, this should stiffen all of the Z axis functions.

Will let the pictures do the talkin' as they say...

Picture 1: Hoggin out the X axis pully/belt/servo support cover.

Picture 2: This is my 1978 or 1979 Tree Mill ( originally 2 axis) converted to 3 axis . using a 3 insert, Iscar 3/4" mill..56 IPM X.100 doc @ (estm ) 4500 spindle RPM...just makin' lots of chips !

Picture 3: Buried deep and runnin' hard..( wish I could )

Picture 4: Almost done., if you can see my DRO indicates X at .00059, and Y
at .0000, The Desk CNC screen shows X @ .0000 and Y @ .0000 , heck after all that rockin' and rollin', the 27 (28?) year old mill is off maybe .0006 or so..not bad considering age eh ?
(next post)

Adobe (old as dirt)

[Adobe Machine]

More : Pictures 5 and 6 surfacing the back side with a 2 ", 3 insert cutter.

Picture : 7and 8 , pocket and both front and back sides finished.

Picture : Re-set up, intropolating a 3.2 inch center hole for the pully hub access.

Picture: Just truckin', this Insert mill is making chips like crazy !

Picture: 3.2" hole is done, measured out of round is less than .0003 if I measure correctly ( and I can measure correctly ) I did have to deburr the edges before I measured the circle ( 8 places). Gonna take me longer to clean the mess than the machine time ~!

Picture: You can see how all of the Z componets and X axis componets come together. The round plug you see in the middle is a piece I turned to locate the cover on the X axis..And make sure that the located drilled holes were correct to the center of the X shaft.

Picture: View front of lathe to rear.

Picture: You can see how the cover is located.

Picture: Long view with the locating plug removed

Picture: Closer view

More Pictures next.

[Adobe Machine]

OK some of the pics are not in order..I think most of you are intelligent enough to figure out how I fu..k..d the order..

any way these pictures are why I must, must have a CNC mill and Lathe !

Adobe (old as dirt )

[Kipper]

Keep em coming :drool:

[Adobe Machine]

Fomaz:Maybe this could help your questions on the spindle control:
go to http://www.cadcamcadcam.com-Lathe Encoder kit-40436, look at that then on the left side is Desk CNC, hit that and look at Desk CNC software and controller..They also have "lathe quick software" hit and open..
There are some limited free down loads that will give you an idea what can be done very economically..as far as a controller and software.
I'm just a real KLUTZ when it comes to computors and software, but these programs have made it real easy..did I say I still use a slide rule ? ( I do !)..my children really laugh when I pull it out and challenge them to solve math problems faster ( they beat me every time if they use this computor, O well )

Adobe (old as dirt)

[WayneHill]

Fomaz:Maybe this could help your questions on the spindle control:
go to http://www.cadcamcadcam.com-Lathe Encoder kit-40436, look at that then on the left side is Desk CNC, hit that and look at Desk CNC software and controller..They also have "lathe quick software" hit and open..
There are some limited free down loads that will give you an idea what can be done very economically..as far as a controller and software.
I'm just a real KLUTZ when it comes to computors and software, but these programs have made it real easy..did I say I still use a slide rule ? ( I do !)..my children really laugh when I pull it out and challenge them to solve math problems faster ( they beat me every time if they use this computor, O well )

Adobe (old as dirt)

Link is:
http://www.cadcamcadcam.com/index.as...ROD&ProdID=104

Thank you... I wrote the lathe software

Nice work Adobe Machine!!

[Adobe Machine]

Wow..Wayne I can not say enough good about that program...I took it over to a friend of mine that has a high dollar turning center with a Funac control..He was astounded, and a little bit bummed as he had just paid some big bucks for a program that was not as user friendly, and your program actually was faster.All we had to do was edit some G code for his particular machine.
Couple your program with a decent CAD CAM program ( I'm using Vector) and you essentially have what some have paid $ $ $ $ for and gotta kick in more every year.

From me and I'm sure a lot of people using your program, THANKS !

Adobe (old as dirt)

[Adobe Machine]

X axis servo mount, belt cover: I found some scrap 6061 T 6 that had the correct deminsions to duplicate the round portion and enough length. Cut to size using my Power Matic 24 inch verticle band saw ( I saw alum at 4600 SFM, medium table speed..get a real good , accurate cut, almost as good as machined ) and cleaned up an old piece of 1/4" non structual alum for a sacrificial bottom, as this big of piece could not be cut in the vice.( table mount )

Pictures 1-2-3-4 :Show the set up and machining, using my Iscar 3 insert, 74 IPM at 4600 spindle ( estm ) and .200 doc.

Picture 5 : you can see the scrap starting to come off.I actually machined the sacrifical alum about .001 to .002, The good material measured .425,that was my Z drop (-),so maybe the Z is off by .001, or I was .001 above when I touched off the tool, hard to tell, but if there is a mistake, its usually me.

Picture 6-7: After finishing the O.D. of the servo support, assembled to the belt cover on the machine so that I could drill, countersink and tap as one assembly. I used some witness marks so I could make sure the alingment was spot on.There are 9 fastner holes ( 5/16 allen ). I only countersunk .150, as I wanted good material for clamping.

Picture 8: Top view of unit.

Next:Machine servo mount. I "sink" the servo outer mount in .130, and counter sink the locating boss as much. The plate is flat mounted with the sacrificial 1/4 " junk alum. on the Tree Mill table,and the CAM program is ready, so 1st thing in the morining, get to push buttons.. ! Then assembly.

Adobe (old as dirt )

[Adobe Machine]

Machined the Servo mount, which includes a .130 recess for the square servo flange, the round locator and 4 ea .215 holes matching the servo flange. I like to recess the flange and make it tight so there is no possibility of the servo "walking" under high torque conditions. It was tight allright,the servo flange used a hickey radius on the four corners, so had to dress them to fit the 1/2" radius I had in Vector CAD CAM, O well, took an hour or so of filling and hand fitting.I also drilled and reamed one 1/2" hole, and slotted another for the guide and tensioner ( They are actually called "stud bearings" have a quality bearing 3/4 inches wide with a 1/2 -20 stud with provisions to lube..really nice for a tensioner and guide.) After I got every thing cleaned up, deburred and holes chamfered, installed the drive and driven pullys and loaded everything on the lathe..Everything fit, even the belt length was correct as I used very little of the milled slot to tension the belt.I used a little anti-seize on all the fastners, but have not torqued to specs yet, just brought to almost tight.
Ran the servo with the battery from my Hot Rod, and I was suprised how quick the X axis went with only 12 volts. The power supply for this is going to be 80 volts,so the limit switches are going to be necessary with that kind of speed.

Picture 1& 2: The completed, milled parts, ready for a trial fit. The 1/2 inch nuts you see on the servo mount are the stud ends of the tensioner and guide.Using Vector CAD program, I was able to determine an obtimal position for the guide and the tensioner so as to get at least a 50% wrap on the driving pully. You can also see the reccess for the servo flange at .130.

Picture 3: Servo mount backside, and here you can see the tensioner/guide and their locations.

Picture 4 :is a closer view of the servo mount / belt cover.

Picture 5:Trial assembly..hmm.. everything fit correctly the first time .

Picture 6: Assembly from above

Picture 7: X axis drive group is ready to go..

Next: A cold Bud, it is Saturday, right ?
Then start making parts for the Z axis drive group.

A couple of quick questions for the experts. Would you not wire all overtravel switches parallel ? By that I mean, if one is tripped it kills all axis ?

Thanks

Adobe (old as dirt )

[Adobe Machine]

Start of Z axis servo drive:Cut a piece of 6061 T-6 plate for the Servo motor support. Using Vector CAD CAM I machined the servo mount recess .130, the # 10 holes and the face circle, then machined all of the mount holes. I did not round the corners and trim the outside yet, will do that when the entire unit is assembled, then do a quick perimeter pass with a 3/4 endmill.

Next, cut and machined 4ea, 1 1/2 by 1 1/2 inch steel pieces that will stiffen the plate from "torque curl", drilled and tapped then assembled to the servo plate.

Using Vector CAD CAM again, I cut clearences for the large upper pully, belt, tensioner, guide and cut the adjusting groove for the tensioner..

Using the same set up, I surfaced the assembled steel blocks so as to have a clean,flat surface to mount the back plate.

During a trial fit on the lathe, I found that the end of the lathe had some casting bumps ( hey, if you were that old you might have some "bumps" too)
that I must leval before installation to insure that the servo support plate is 90 degrees to the Z axis ball screw.

I also ordered my Ingus support for the wiring that will move with apron and the Z axis DRO wiring, they said about 6 days on that. I'm watching Erics
( the Widgetmaster) installation of a new DRO on his lathe, for some good ideas on my installation of the DRO on my conversion. Even with CNC, I sure like a DRO that shows actual position. I find little , if any error on my Tree CNC retrofit, but find myself looking at the DRO as much as the screen position.

Next: cut, drill countersink and install the rear plate to the assembled servo mount plate.

Pictures 1,2 & 3 Servo mount plate, servo mount machined, holes drilled, 1 1/2 by 1 1/2 stiffners/ spacers machined, drilled and tapped. I have not cleaned up the edges or rounded the corners, as that will be done as one unit with the back plate installed.

Pictures 4,5 &6: Partially assembled, then milling for clearence on the large pully, for the tensioner, guide and belt. then the slot for tensioner.

Pictures 7&8: Surfacing the stiffner/spacer blocks for a clean, flat surface to mount the back plate.

Pictures 9& 10, Overall view, just a mock up too illustrate how the componets will fit when assembled to the lathe.

[Al_The_Man]

A couple of quick questions for the experts. Would you not wire all overtravel switches parallel ? By that I mean, if one is tripped it kills all axis ?

Depends on the logic, if they are normally-open then they would be wired in parallel (OR'd).
If normally-closed type then they would all be wired in series.
(AND'ed).
The normal method is the latter, N.C.
Al.