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Messages - metlcutr55

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General Mach Discussion / Re: Bridgeport Knee Mill Conversion?
« on: February 10, 2018, 11:10:31 AM »
great thread Dave, been following with interest.  my knee mill has a bad control which I hope to get going with either mach or uccnc this spring when the garage thaws out.  just a comment which I hope will be helpful.  mine is a 10 x 50 acra mill with square ways, and it rapids at 70 ipm.  when I bought it, it was at 100 ipm, but I had some control issues and slowing it helped.  thought yours was moving slower than this, just a little input to help.  fwiw, mine has a rolled ballscrew driving the knee, with a pulley and belt where the knee handle would go.  worked great.

General Mach Discussion / Re: How to slow down on rounded corners?
« on: December 25, 2017, 03:23:07 PM »
corner chatter exists in the commercial machine shop world too.  we deal with it by reducing the feed by as much as 90% in the corner itself, ie, the g02 and g03 moves, then back to full feed for the straight lines, like this:


commercially, it is female corners that give the most troubles, with chatter.

yes I copped out on my I's and J's with the R command, I used to be able to easily do it mostly in my head, but its been a long time.  Merry Christmas.

General Mach Discussion / Re: General question about small CNC mills
« on: November 08, 2017, 03:22:11 PM »
a couple things on these "hobby" machines, at least as I see it.  to me they are just machines, and they are limited by their size to smaller cuts, but surface footage and feed per tooth should still be maintained.  I say this without having run a sherline.  but I have a large Bridgeport, and a round column gear head rong fu mill.  and I have run a 6" spindle cincinnati vertical with 6" spindle, a machine that id guess weighed in excess of 6 tons.

the Cincinnati would hold a 10" facemill, take a cut 3/16" deep the full width, and throw chips that actually made a clinking sound when they hit the floor.  moving to the Bridgeport 20 years later, I could run a 3" facemill on it, but was limited to cuts about .090" deep.  but I could still maintain the proper surface footage and chip load per tooth for the cutter being used.  running the rong fu, the round column is less rigid, and my depth of cut went to about .030", once again I still tried to maintain surface footage ands chip load.  the same applies to the lathes ive run, a 48" chuck engine lathe made chips that clunked, the 17" I have now is limited to about 1/8" depth of cut, and the 7" hobby lathe I have I limit to about .030 depth of cut roughing.  but I still set my surface feet and chip load to the tool, and also to the material being cut.

just a guess on my part but if I were cutting that "T" id start at 1000 rpm, .020 doc, and .004 feed/rev for a 4 flute carbide mill (4 ipm).  if it worked well, id increase the doc until the machine began to protest, then back off a little.  multiple roughing cuts leaving maybe .010 on the surface for a finish cut.  again this is a guess, others here have sherlines and may chip in.  and a couple other things, to minimize chatter, use a sharp end mill vs a radius corner one, and avoid the biggest sin I see often posted, the shortest mill extension possible makes the least chatter and vibration, so many times ive seen pics of a 1/4 end mill with 1" of flutes hanging out 2" when a stub end mill with 1/4 of flutes sticking out a half inch would have worked so much better.  theres a nice speed feed calculator on littlemachineshop.com.  start easy, bump up til you see a problem beginning, then back off one!  and good luck!

Mach4 General Discussion / Re: mach 3 to 4
« on: April 05, 2017, 02:00:57 PM »
thanks Tweakie.  can i ask you to once again address computers that are compatible but do not have a separate video card, having instead "integrated" video?

i have never run a router, but ive run many machines of various rigidity over 40 years of machining, and this should apply.....run the cutter at or near recommended speeds, say 75% to start.  run the cutter at or near recommended feed rate per tooth, say 75%.  start with a very shallow depth of cut, say .005 inch.  if you find success there, increase the depth parameter slowly, say 50% at a time.  when you find you are breaking the points of the teeth, back off a little.  you may need to spoil a few cutters to find optimal results, and of course if you really want to get the best cutting rates you can similarly play with the feed and speed rates youre using.  imho, air is better than nothing, and mist is better than air.  if you use nothing or air, you may want cutters with TiAlN coating, these are designed to run dry and hot.  check your tool rep, there may be even better coatings available these days.  oh and ive always preferred cutters with a small nose radius, but these will be more pricey and generate more pressure.  but in a word or two, you will need to experiment a lil for your best results.  good luck!

General Mach Discussion / Re: soldering iron info, please
« on: May 18, 2016, 12:02:30 AM »
ive been looking at analog units in the $40+ range, and digital units at about 2x that.  do you find the digital units are worth the extra$$$ ??

the x-tronic model is now out of stock, no idea when it will return.  and what about the Aoyue brand?

General Mach Discussion / Re: soldering iron info, please
« on: May 17, 2016, 01:08:54 AM »
well, this looks like be a nice tool, and hopefully the last soldering iron ill ever buy, and looks kinda sexy.....

X-Tronic Model #3020-XTS Digital LED Display Soldering Station

General Mach Discussion / soldering iron info, please
« on: May 16, 2016, 02:16:22 PM »
thank you all for your input on multimeters.  now its time to replace a very cheap old soldering iron.

i dont see myself replacing components on a board level.  i believe if i lose say a servo amp id be

just putting in a new one and sending the old one out for evaluation and possible repair.

looking for an iron to tin wires, join them, and any of the other requirements that will come

in replacing the old dead cnc control on my mill with a breakout board, motion controller, new vfd, etc.

pencil? gun? station?  other considerations?

thanks, you guys are great.

General Mach Discussion / Re: Multimeter info
« on: May 15, 2016, 10:48:02 AM »
thanks all.  i believe monday i am going to order this one:


gets decent reviews in a few places, should be suitable for my task i think.

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?



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