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bolt circle pattern problem
« on: April 04, 2015, 06:14:20 PM »
Can someone run a bolt circle pattern on their machine and see if it works for them please

Im trying to drill a 4 hole pattern at 10 inches useing mill wizard.  I drill 2 pieces and match them up to each other and the holes are in the same spot.  But when i turn one 90 degres or flip it over and try and match them up again the holes are always off. 

If someone could please try this and let me know how it works out, im pulling my hair out here trying to get this thing set up right

Offline BR549

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Re: bolt circle pattern problem
« Reply #1 on: April 04, 2015, 08:18:20 PM »
You may want to try the G16 method for bolt circles it will be as accurate as your machine is.

Just a thought, (;-) TP

Offline JTW

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Re: bolt circle pattern problem
« Reply #2 on: April 04, 2015, 08:24:45 PM »
Are the co-ordinates ok or is this a hard problem? Like backlash?
Re: bolt circle pattern problem
« Reply #3 on: April 04, 2015, 08:44:30 PM »
I dont know what the G16 method is ill do a serch on that in a min.

I dont know if the cordinates are ok Im useing mill wizard for the gcode .I dont know how to use any cad programs at the moment. Im trying to learn gsimple right now but Im an idiot haha

I dont think its a backlah issue. i keep checking for backlash with a dial indicator and its not there. ive tried setting backlash compesation at a couple thousandths and it just gets worse.

 Ive set steps per unit a ton of time out to 11 inches with a dial caliper.

Ive checked for loose machine parts and everythings tight.  Its a chinese machine but its pretty sturdy. 

Ive even tried to do 2 2 bolt hole circles and change the degree on 2 of the holes 0.5 or 1 degree off and cant get it to line up. 

Offline JTW

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Re: bolt circle pattern problem
« Reply #4 on: April 04, 2015, 09:11:49 PM »
I would make a test piece with co-ordinates that I calculated myself and see if the problem persists just to eliminate that possibility. Is the machine based on servos or steppers?
Re: bolt circle pattern problem
« Reply #5 on: April 04, 2015, 09:19:56 PM »
Im using stepper motors and a g540.  i did a list of bolt holes wizard once but it was still off.  I was doing a .406 hole with a .250 endmill so i tried a .250 hole and still has the same problem.  I dont think im looseing steps or my steps are off i hit go to zero and it go back to the same place and the holes are always in the same place.. 

Offline BR549

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Re: bolt circle pattern problem
« Reply #6 on: April 04, 2015, 09:40:06 PM »
how far off are the holes ? Are they off in the radial mode.  4hole mode = 4 holes 90 deg apart radially.

Have you tired drilling a test hole instead of milling ??

When you say mill wizard is that the one that comes standard with Mach3 or one of the NFW ones ?

(;-) TP
Re: bolt circle pattern problem
« Reply #7 on: April 04, 2015, 09:58:46 PM »
Not the nsf wizards. Im using the mill wizard addon.. The holes are off about .040 to .070.. I did try just drilling a plain hole and still having the same problem.  Ive even tried compansating with back lash and off setting the holes and still cant get them to line up when rotated or flipped over.. Im not saying i compansated correctly just saying I tried haha 

Thanks for your help guys

Offline BR549

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Re: bolt circle pattern problem
« Reply #8 on: April 04, 2015, 10:03:23 PM »
Here is a simple G16 routine where MACH3 does all the math. Try it. It drills a center hole and  a bolt circle of 5" radius 4 holes 90 deg apart.


G90
G0 X0.00 Y0.00
G0 X6.00 Y6.00 (move to center point of bolt circle)
G81 X6.00 Y6.00 Z-.250 R.250 F10   (drill the center point hole)
G16  (X will set a radius from the center point, Y sets the angle)
G81 X5.00 Y0 Z-.250 R.250 F10   ( Drill first drill point at 5.00"radius and at zero deg:3 oclock)
X5.000 Y90          ( rotate to 90 degress and drill hole)
X5.000 Y180        ( rotate to 180 deg)
X5.000 Y270         (rotate to 270 deg)
G80  (cancel cycle)
G15  ( cancel G16)
M30
%
Re: bolt circle pattern problem
« Reply #9 on: April 04, 2015, 10:07:07 PM »
Can I just copy and paste that code and run it.