Messages

11

General Mach Discussion / Re: Diameter changes .001 every part.

« on: December 10, 2018, 01:52:41 PM »

don't know, maybe this will be helpful.  I had a fanuc driven engine lathe, start making parts in the morning and I would see a small change, maybe .0002 on each consecutive part.  a little worse if the shop was cold.  go to the shop a couple hours early in the morning, put the lathe in a warmup program, and go back in the house and watch the news and drink coffee.  after that, the parts would usually repeat perfectly.

12

Tangent Corner / Re: how to login my cash app account

« on: November 21, 2018, 01:10:35 AM »

send me your bank information, and a certified check for $10000 us dollars.  once the check clears, since your Nigerian dollars are 60% larger by size, I will send you 120000 Mexican peso vouchers, which in Nigeria can be converted 10 for 1 for grams of ganja from the followers of Fela Kuti.  this can be sent back to me, and we will work details for a similar but much larger exchange.  in the end I will send you 7 pairs of boxer underwear from the Duluth trading company, one for each month.  all in horizontal stripes of the flag of your country, no stink, no sweat, no pinch.  only xxl size available, you may need suspenders.  but in the end, it will be worth it.  remember, women go crazy for a sharp dressed man!

13

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.

14

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:


G1X0Y0F10
G1Y.75
G2Y1X.25F1R.25
G1X.75F10
G2X1.Y.75F1
G1Y.25F10
G2X.75Y0F1
G1X.25F10
G2X0Y.25F1
G1X0Y0

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.

15

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!

16

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?

17

General Mach Discussion / Re: Keen to learn mild steel with my CNC router!!

« on: May 29, 2016, 12:17:48 PM »

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!

18

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?

19

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
http://www.amazon.com/X-Tronic-3020-XTS-Digital-Display-Soldering/dp/B01DGZFSNE/ref=sr_1_1?s=hi&ie=UTF8&qid=1463461302&sr=1-1&keywords=soldering&refinements=p_36%3A1253529011

20

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.