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Messages - metlcutr55

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21
General Mach Discussion / Multimeter info
« on: May 14, 2016, 12:59:45 AM »
if im going to redo my mill control (knee mill currently fed 240 single phase) im going to need a decent multimeter.  i copied a photo of a $20 one that looked pretty nice and showed it to the shop electrician.  he said uh uh, you need to get a cat 3 or cat 4 meter.  you guys are the ones who have installed servo and stepper controls with mach3.  what say you?

thanks!

ken

22
General Mach Discussion / Re: Bridgeport Knee Mill Conversion?
« on: May 13, 2016, 01:15:46 AM »
Dave, i have the ball screws and motors in place so i am fortunate, but as i read this thread, its Hoods post #2 page 1 that sticks out to me.  a 3 axis 1200 oz-in kit runs $900 USD, keep it simple & drive what you have, double that figure maybe to make mounts, get pulleys and cables, computer etc, you'd have a cnc bridgeport with backlash.  like those folk i spoke of with the great big machines (the one i spoke of was a planer mill) youd have a machine that could do a lot, but would have limitations.

so for $2000 or less USD, would you have a machine that you'd consider worth that amount?  would its size capabilities make it worth it over your more precise less powerful mini-mill?  if you built it and loved it but hated the restrictions, the flaws could go away one small project at a time, 1st the sloppy x-y acme screws (the z is less a problem, the weight of the knee cancels out the backlash, the knee is always in the most downward position, pulled by gravity.)  then maybe x-y servos, giving you the encoder display (tho most seem to think proper steppers will not skip)

there still seems to be some driven knee doubts.  i can only say mine went up and down for 11+ years, the only motor fail was due to coolant leaking into the motor.  the motor was the same size as the other 2, but the x-y could rapid at 150 ipm, the knee was at 100 ipm.  never a problem.  it does have a rolled ballscrew, but hand cranking it, seems to provide about the same resistance as the bridgeport at work, which is acme screwed but 1 size smaller.

and i must ask for some forgiveness.  in a previous post i made the claim of a 1/8" drill deep drilling some cast iron slides.  isnt true, i looked at the drills which i still have in the shop today.  the 1/8 holes were connector holes to the holes i actually deep drilled which were .218" dia.  big difference, i will attribute it the the 3 olives vodka with ocean spray blueberry drinks i was sipping on.  my bad.


23
General Mach Discussion / Re: Bridgeport Knee Mill Conversion?
« on: May 12, 2016, 01:17:09 AM »
Gary, i dont understand your point.  i also peck drilled when i needed to, easy with 15" of cnc "z" travel.  one job comes to mind 5/8" drill thru 6" of 8620 steel with multiple length drill changes, did a lot of these parts.  
another job 1/8" drill thru 12" of cast iron (6" from ea end, and parts held so they extended below the table) also with multiple drill changes made easily possible by the free quill and snapchange holder.  no chip wrapping took place.

when i bought my mill, bed mills were also available, but 25% more than the knee mill i bought.  if i had the $$ id have bought the bed mill, but i didnt have it.  so, like Dave, theres a knee mill project waiting for me in my garage.  im lucky enough to have ballscrews and axis motors in place and more, but from reading this community and looking back on my 40 yrs in all kinds of machine shops, imho a simple stepper mach 3 add on would be a huge improvement to any hand cranked machine, even with old acme screws with high backlash.  one of the reasons i chose the machine i did was it had handwheels.  after about a year, i dont think i ever used them again.  i was 12 years self employed before the $$ crash in 2008 forced me to take a factory job, had i chosen high end manual machinery for my start up, id have failed in a year or so.  cnc is so important.  you cant make a circle on a hand bridgeport or a .5 radius in a corner with a 1/4 endmill.  or cut a 43 deg line.  its harder if the machine is not optimized but its still possible.  cant do that with your hands.

24
General Mach Discussion / Re: Bridgeport Knee Mill Conversion?
« on: May 11, 2016, 01:06:18 AM »
$.02 more...

i ran my 10 x 50 Acra knee mill, knee driven, pc controlled and built by CNC Automation here in NH USA, for 11 years, with NO problems related to the knee driven part.  in fact having the spindle free was the best part.  position over a hole, and mdi hand tap holes small as #2-56 with the tap held in a drill chuck.  or lift the spindle and watch the program run with cutter above part.  also enables you to use a quick change tooling like ultron snapchange, or a power drawbar and TTS type tooling.  no its not a bed mill, but with high positive insert cutters, moderate cut depths and fairly high feed & speed, you can move metal, including steel, at a pretty impressive rate.  if i was doing a lot of tiny short move work, or engraving, id like the quill driven.  otherwise, no.  my acra has 15"+ of cnc Z

it has ballscrews, fat ones at that.  so i dont have to deal with a cnc with old acme screws.  but having said that, i worked with a company for years that only employed big clunky worn out machines.  one of these they retro'ed with an old clunky cnc system.  despite the large amounts of backlash and way slop, this machine never sat empty.  they found ways to program so the looseness wouldnt crash the machine.  of course it could not machine a 30" dia +/- .001 hole, but folks lined up to have that hole put in at +/- .015 tolerance.

and im lucky to have dc brush servo motors already mounted.  but i think 50 ipm of stepper bridgeport would be great, when hand cranking is the alternative.

i did say my acra has 15"+ of Z.  well no it doesnt.  it is electronically brain dead. old like me heh. but im working on it now with the help of a forum member, in a year or less i hope to see it uccnc guided, and using Mach too, and a better machine than when i bought it.  i did a lot of great stuff on her, hope to have her ready when i retire from working for the man which ive been doing for 6 yrs or so, the man has been kind enough, but working for me i like the boss a lot better.

then, after all this fun, theres the lathe in the corner.........
 










25
General Mach Discussion / Re: running mill and lathe?
« on: October 02, 2015, 01:52:17 PM »
regarding the swapping of cables, although the situation is not exactly the same, i have a lathe and a mill that share rs232 communication with the same

computer, i ran the computer output into a cheap but industrial grade A-B switch, turn the switch to A, the mill is connected, to B and the lathe is connected.

maybe this is a possible solution.

26
General Mach Discussion / Re: Mach3 Major Bug?
« on: June 23, 2015, 11:46:10 AM »
another thread about mach leaving me pulling my hair.

im just a guy with an old dos based knee mill cnc and an old fanuc engine lathe.  both controls down, too old, dont want to fool with them,
i want to go to mach and an external motion control device and modern computer with modern software.  something i can put
together thus learning the internals so i (with help) can maintain my own stuff rather than calling the $$ fanuc man.

every time i think im ready to move a little, i get cold feet.  i sense that most of the many many problems seen on these forums
come from someone wanting to couple a laptop to a $10 chinese bob, and drive steppers stolen from god knows where and
wired improperly.  so i get inspired, until i see a post like TP's above.

other very knowledgeable folk on this forum have seemingly incorporated mach3 into machine tools and are very satisfied.

leaves me very confused.  what version of mach3 is the least buggy, and what are those bugs?  can i at least depend on
one version to act in a stable manner if i am willing to avoid certain programming techniques?  is mach4 really better?  reading
the mach4 forum section leaves me pulling my hair too.  is there any mach version buttoned down and ready to roll, if the machine
is properly built from good quality components?  TP said "the competition zoomed right by..", TP, do you mean that systems
like Eding, usbcnc, others may be better alternatives than mach?

are there any threads i have missed that serve as a faq for all the above questions?

i welcome all input, in this thread, on this forum, or via pm.
thank you,
ken


27
Show"N"Tell ( Your Machines) / Re: Nice Router Build
« on: July 20, 2013, 09:15:59 PM »
jmho, ymmv, but i cant help but think that that design would be many fold more rigid if:

the builder had used rectangular tubing on the base of the gantry sides that extended to the top and bolted to it all the way.  even if the rect tubing was open on the back face to clear the stepper.  a pair of triangular gussets on both sides of the machine added now running from the tops of the rect tubing to the tops of the endplates would be much more rigid.  i might even tie the 2 backsides of the triangle hypotenuses together with 2 straps ea for more rigidity. an "x" shape would be better.

a sawcut aluminum "x" connecting the 4 corner edges of the alum endplates would help too.  even a solid plate but that would be more cumbersome.  a pair (front and back) would help even more so.  maybe the back not needed since it looks like the spindle mount hangs on extruded shaped tubing. i might put a brace in the middle of the extruded tubing linking them, and check that the distance from guide tube to guide tube is the same in the middle as it is on the ends.

id bet the machine would hog faster, be more accurate in corners finishing, and run quieter and give better tool life.  again, jmho, ymmv.  im not a machine builder, but i did stay in a holiday inn express.....heh....on a more serious note, i have a cnc bridgeport in the garage, not so rigid, and run a large horizontal workcenter for my day job, very rigid, trust me rigid is good.  perhaps your demands dont justify this, just trying to help.

ken










28
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hi Hood!

i am still leaning towards that kit as is, for a couple reasons.  1st being my lack of electronics knowledge, thinking a very plain mach install is within my capabilities, messing with servo drives and controllers with multiple parameter inputs may be too much for me.  i am happy with the dc brush motors on my mill and hope the kit motors would be comparable in quality.  second being cost.  id try stepper but i am not liking the motor noise i hear on various vids.  i see the kit as the next step above steppers, if i can just get this lathe cutting again, i can modify the system to use a motion controller instead of the parallel port, and/or add better motors/drivers later, after ive made a lil $$.

what penalties will i pay going this way, simple brush servos, parallel port control, no external controller, "basic" mach3, vs doing it up as you have described?

i am waiting to hear from my electronics guy about getting the non x-z motion items on my lathe rolling less the fanuc.

i see little input here on this board about vendors and their level of kit support.  i see mostly negative input on cnczone about this question.  i welcome pm's from folk about this question, tho myself, i tend to air such maters publicly, a good job deserves a pat on the back, and vise versa!

thanks all for reading.

ken

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29
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hope my previous post was not too wordy as to put people off.  the more i think about this, i see it as 2 separate issues.  control of all the non x-z motion items, and control of the x & z with mach3.  i believe i will get my electronics-electric guy over here and see what we can do about getting the spindle to turn, and the brake, coolant & oiler to work without the fanuc stuff in place, and see what i will need to convert the power for all these items and get them properly switched.

once my lathe is working again but without x & z motion, i will attempt (with help if needed) the basic install of a kit and mach3.  if i can accomplish this, i will have functionality again, i can always control the spindle, coolant etc manually, and use mach cnc and jog to move the x & z.

3 issues i guess, i will want the stuff to all work together but i can attack these issues one at a time, likely 1st an index for threading, then the mpgs, etc etc.

i took a few pics inside the cabinet, ill post them in case anyone has comment.  ill try to make them thumbs but im not exactly sure how.  hoping to reuse a lot of this stuff.


from shop 003 by metlcutr55, on Flickr


from shop 004 by metlcutr55, on Flickr


from shop 005 by metlcutr55, on Flickr


from shop 006 by metlcutr55, on Flickr


from shop 007 by metlcutr55, on Flickr

once again, im really interesting in anything anyone has to say, about the kit ive "chosen", about vendors, etc etc


thanks
ken

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30
i have had issues with sticky, imprecise homing switches on my mill at times.  by clamping a tooling ball in my rear table t slot far to the x+ side as possible (this puts the ball in the general direction where my x-y home on my machine) and leaving it there, i can always go to the ball, indicate it, and set x-y zero.  then by using a tool holder with a flat ended rod i can go to x-y zero and set a z zero using a flat block or a shim top of the ball to the flat rod face.  it should be simple from there to find a pseudo xyz home for your machine near the limits of travel. if you set the tooling ball xyz zero each time you start up, travel to the pseudo home and re-zero, then when using your work offsets g54 thru g58 and g59 p1 thru g59 p253 as your work coordinates, you will always have a known reference point on your machine to re-check to, and your work coords should always be valid after using this "rube goldberg" homing scheme.  do learn to use your work and tool offsets, they are what make cnc machining a precise repeatable process with minimum headache.  hope this helps.

i have also considered adding a bored hole to my table to fit a tooling ball with a ground stem and flange, so the tooling ball can be inserted, picked up, then removed.  have not done it yet.

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