# Adventures In Metal: Ongoing Questions



## Metal (Jan 14, 2016)

So I decided to start an ongoing thread, rather than keep going with my roughing bit thread with nonrelated questions.


Question1:  In mach3, when I tell the mill to go to zero, it zeros the Z axis first, which has nearly lead to disaster several times, it seems stupid to bring the bit down to the metal then rake across it and hope a clamp isnt in the way, is there a way to tell mach3 to zero the Z /LAST/ ?

//edit: also can someone correct the spelling in my thread title because I'm a moron?


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## RJSakowski (Jan 14, 2016)

If you are talking about referencing, the z axis homes first as the home position on the z axis is usually at the uppermost position (tool withdrawn from work).  How do you have your DRO set up? In the Tormach flavor of Mach 3, there was the option of referencing each axis individually.  

If you have set a work zero, you should zero each axis separately.  If you give the command, G0 X0 Yo Z0, the mill will move in a straight line to 0,0,0.  You will want to lift the Z axis to a safe distance before commanding G0 X0 Y 0 followed by Z0 on the next line of code.


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## Metal (Jan 14, 2016)

I probably worded that terribly, thanks though.

I have limit switches setup, I can reference the machine home at will, and it does the Z axis first, then the other two, great, this is fine because the Z home axis is always going to be above the work and it'll never hit anything.
I was talking about the work home, when I click on "go to zero" underneath the DRO within mach3, it goes to the Z axis zero first, I want it to do it last so that incase I had to move off of my work to replace the tool, I dont have to bring the mill back to the vicinity of the work before clicking on it, having the Z axis lower first and risk snagging the edge of my workholders as it returns to work zero.

@ billy: i'll be all over the place with this one, though the mill is a cnc I really dont have a ton of idea what i'm doing here, I'd appreciate it if you left it here as I dont want to keep creating threads on particular topics and pollute the whole board.


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## Bill Gruby (Jan 14, 2016)

I see your point. I won't move it. Your Title has been fixed and you are not a Moron, you have fat fingers like the rest of us.  LOL

"Billy G"


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## TomS (Jan 14, 2016)

RJSakowski said:


> If you are talking about referencing, the z axis homes first as the home position on the z axis is usually at the uppermost position (tool withdrawn from work).  How do you have your DRO set up? In the Tormach flavor of Mach 3, there was the option of referencing each axis individually.
> 
> If you have set a work zero, you should zero each axis separately.  If you give the command, G0 X0 Yo Z0, the mill will move in a straight line to 0,0,0.  You will want to lift the Z axis to a safe distance before commanding G0 X0 Y 0 followed by Z0 on the next line of code.



I hear what you are saying.  My work around is I have a DRO on my quill so I set the DRO to zero when I set my Z axis machine zero.  Before clicking the Go to Zero button I raise my quill with the manual feed wheel.  Before clicking Cycle Start I reset my quill back to zero on the DRO.  This may not be the proper way to do it but it works for me.  I'm interested to hear what the CNC gurus have to say.

Tom S.


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## Metal (Jan 14, 2016)

Yeah thats sort of where I am, without the quill, because I dont have much Z axis, I have to move the mill off the part, replace the tool, then I can move it back, it seems like best practice /should/ be "if zero is closer to the part, it should be done last" as there could be any number of extrusions and such between where it is and where it needs to be.


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## RJSakowski (Jan 14, 2016)

Metal said:


> Yeah thats sort of where I am, without the quill, because I dont have much Z axis, I have to move the mill off the part, replace the tool, then I can move it back, it seems like best practice /should/ be "if zero is closer to the part, it should be done last" as there could be any number of extrusions and such between where it is and where it needs to be.


Metal,
Take a look at the website.  Apparently, this problem has been discussed considerably before. 
https://www.machsupport.com/forum/index.php?topic=15381.0


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## JimDawson (Jan 14, 2016)

Metal said:


> I was talking about the work home, when I click on "go to zero" underneath the DRO within mach3, it goes to the Z axis zero first, I want it to do it last so that incase I had to move off of my work to replace the tool, I dont have to bring the mill back to the vicinity of the work before clicking on it, having the Z axis lower first and risk snagging the edge of my workholders as it returns to work zero.



I think you can set up a tool change position in Mach3.  Then use the Go To button to get there,  if it works right, it should park Z first then do the X-Y move.  Another option could be to put in a a couple of lines of G-code at the bottom that moves the tool to a tool change position, then just run that block of code using the Run From Here button.


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## Wreck™Wreck (Jan 14, 2016)

I have never used mach3 or any open source machine control software, however I would never dream of pushing a "Work Home" button with the tool in the spindle and the work piece mounted.

Does this machine not have a manual rapid jog feature?


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## rdean (Jan 14, 2016)

If I understand correctly when pressing "Go To Zero" you want the X & Y to move to their "0" position and then the Z last.

Setting  "Safe Z" is what you want set to work coordinates and a distance you want the Z to rise to before the X & Y moves.  I use this quite often.

Ray


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## derf (Jan 15, 2016)

Seems like the machine home zero's are mixed up with the part program zero's. When I tell my machine to Z.0, tool .0, it goes to the top , which is the machine home zero and tool change position. If I just told it to go to z.0, it goes to the part program zero.


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## Metal (Jan 15, 2016)

rdean said:


> If I understand correctly when pressing "Go To Zero" you want the X & Y to move to their "0" position and then the Z last.
> 
> Setting  "Safe Z" is what you want set to work coordinates and a distance you want the Z to rise to before the X & Y moves.  I use this quite often.
> 
> Ray


Thanks Ray, I'll try it out, I thought safe Z was how you prevented the mill from crashing not retracting the bit from the work.

A short update: I've been eying a clausing 8520 on craigslist, it looks to be in really good condition, but I'm not sure if the cost is worth the extra 5" of travel than the benchmaster I have, Ideally I'd want ~20" x travel which would envelope everything I could think of making without screwing around with refixturing and/or locating pins and such, and it has a power feed X axis which seems unneeded if I am going to CNC it, is there a market to resell the power feed bychance?


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## TomS (Jan 15, 2016)

Metal said:


> Thanks Ray, I'll try it out, I thought safe Z was how you prevented the mill from crashing not retracting the bit from the work.
> 
> A short update: I've been eying a clausing 8520 on craigslist, it looks to be in really good condition, but I'm not sure if the cost is worth the extra 5" of travel than the benchmaster I have, Ideally I'd want ~20" x travel which would envelope everything I could think of making without screwing around with refixturing and/or locating pins and such, and it has a power feed X axis which seems unneeded if I am going to CNC it, is there a market to resell the power feed bychance?



Ray has it right.  I checked the Allow Safe Z Moves and tested it.  X and Y move to 0,0 followed by Z.  I learn something new everyday on this site.

Tom S.


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## Metal (Jan 18, 2016)

Ah ha, that seems to work! thanks.


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## rdean (Jan 18, 2016)

I have used Mach3 for about 7 years and I am still learning new things it can do.

All welcome

Ray


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## Metal (Jan 19, 2016)

Hey here's a new one, how do I figure out how fast I am supposed to be plunging or ramping?  my z axis has some backlash, so at the start of a cut it wants to ride up the bit, which is obviously a big problem.


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## Metal (Feb 4, 2016)

So I picked up a few cheap 3 flute endmills off amazon to experiment with depth of cut and speeds, I plan on breaking all of them 

New question: before using my mill every once in a while, I bring the mill all the way down, wipe the ways with a paper towel, and then reapply vacta2 way oil, every time the "wipe off" phase comes off pretty dark grey, which makes me think that the ways might be wearing rather quickly, or is this normal?  I disassembled, cleaned the ways, reassembled and made way covers so that no chip has a chance of reaching them, but its still grey upon cleaning, should I be concerned?


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## TomS (Feb 4, 2016)

Metal said:


> So I picked up a few cheap 3 flute endmills off amazon to experiment with depth of cut and speeds, I plan on breaking all of them
> 
> New question: before using my mill every once in a while, I bring the mill all the way down, wipe the ways with a paper towel, and then reapply vacta2 way oil, every time the "wipe off" phase comes off pretty dark grey, which makes me think that the ways might be wearing rather quickly, or is this normal?  I disassembled, cleaned the ways, reassembled and made way covers so that no chip has a chance of reaching them, but its still grey upon cleaning, should I be concerned?



Is there any noticeable wear on the ways?  Do you have a one-shot oiling system on your mill?  I have a one-shot system which tends to flush the ways clean.  If you are squirting oil on your ways it may not be getting where it needs to be and the gray may be due to wear.

Tom S.


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## TomS (Feb 4, 2016)

Metal said:


> Hey here's a new one, how do I figure out how fast I am supposed to be plunging or ramping?  my z axis has some backlash, so at the start of a cut it wants to ride up the bit, which is obviously a big problem.



My CAM program calculates ramp rates for me.  I can't recall seeing any printed information on this.  You can change it by editing your g-code if you are so inclined.

Tom S.


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## Metal (Feb 4, 2016)

TomS: Thanks as always

Its a really old benchmaster, I don't have any sort of oiling system, I just rub the oil onto the ways, when I get a chance should I disassemble, degrease, strub, and reoil the ways until it comes out clean?  I just now thought maybe some ground up cast iron from the ways might be providing grit which could be causing the wear (if it is wear) what else could it be?

My cam software also calculates ramping, but I'm in the grey area of what I should be doing, and what the mill is capable of doing, I suppose learning by experimentation is possible but with all the harping about knowing speeds and feeds it seems odd that it completely disregards the depth of cut (!?)


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## TomS (Feb 4, 2016)

Metal said:


> TomS: Thanks as always
> 
> Its a really old benchmaster, I don't have any sort of oiling system, I just rub the oil onto the ways, when I get a chance should I disassemble, degrease, strub, and reoil the ways until it comes out clean?  I just now thought maybe some ground up cast iron from the ways might be providing grit which could be causing the wear (if it is wear) what else could it be?
> 
> My cam software also calculates ramping, but I'm in the grey area of what I should be doing, and what the mill is capable of doing, I suppose learning by experimentation is possible but with all the harping about knowing speeds and feeds it seems odd that it completely disregards the depth of cut (!?)



You really need to make sure you are getting oil between the sliding and stationary way surfaces.  Instead of a one-shot lube system you can install Gits oilers.  These are the spring loaded ball oil ports installed on most machinery where oiling is necessary.  You can get them from McMaster-Carr and they don't cost a lot of money.  Lack of oil may be contributing to what you are seeing with plunge rates.

Tom S


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## Metal (Feb 4, 2016)

I got ya, I'm just not sure how to go about it without damaging the ways, would drilling out the gib through the gib lock hole that I don't use anymore since cncing and installing into that spot work?  or do I have a bunch of googling to do with proper installation.


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## TomS (Feb 4, 2016)

Metal said:


> I got ya, I'm just not sure how to go about it without damaging the ways, would drilling out the gib through the gib lock hole that I don't use anymore since cncing and installing into that spot work?  or do I have a bunch of googling to do with proper installation.



That will work.  You need to have a way to get oil into each of the six dovetails.  And don't forget the ball nuts.

When you take your machine apart to drill for the oil ports you might want to think about putting in some distribution grooves.  Below is a picture of what I did.  Search the net and you will find quite a bit of information that will help you.

Tom S.


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