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Author Topic: Wooden CNC Router -- Bed Level?  (Read 2514 times)

AtomicProf

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Wooden CNC Router -- Bed Level?
« on: April 07, 2013, 12:21:22 AM »
Hi All,


So -- one of the things that made my monitor project take way too long was the fact that the bed is not parallel to the cutter head.


I made a long post of this and that and what I was going to do to remedy that.  WELL Pat and I were talking about it, and what I was going to do was just plain WRONG.


WE SHOULD NOT CUT THE TOP OF THE BOARDS at this TIME. 


Pat pointed out that we can adjust the four corners that hold the end of the FRONT to BACK (Y) axis lead screws.  SO -- that is what needs to happen next. 


The table is easily .2 inches off in some places, and that points to the lead screws being out of quilter..


Good Call Pat.
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P47

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Re: Wooden CNC Router -- Bed Level?
« Reply #1 on: April 07, 2013, 10:07:53 AM »
I found a couple of my laser levels you could use to help level things out. I'll bring them in with me today. You'll just need to get some AA batteries, each one takes three.

Chorca

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Re: Wooden CNC Router -- Bed Level?
« Reply #2 on: April 07, 2013, 04:22:37 PM »
The lead screws being off should not affect the accuracy of the table; they only provide the linear motion. Constraints are provided by the V-bearings that each axis rides on. Those will need to be adjusted, not the leadscrews.

AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #3 on: April 07, 2013, 07:56:58 PM »
The lead screws being off should not affect the accuracy of the table; they only provide the linear motion. Constraints are provided by the V-bearings that each axis rides on. Those will need to be adjusted, not the leadscrews.


Right --  That occurred to me as I was thinking it through on this mornings bicycle ride. 
Pat -- The levels will be helpful thanks, Can you put them in my storage drawer next to the Laser cutter please?
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P47

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Re: Wooden CNC Router -- Bed Level?
« Reply #4 on: April 07, 2013, 10:49:30 PM »
Just read this now, sorry didn't put the lasers in your locker but will bring them tuesday if I'm not there sooner,
 
Looked at the cnc router with Rick today, and we saw it isn't the lead screw bolts that can help level this but the bolts on the sides of the y axis.
« Last Edit: April 07, 2013, 11:58:29 PM by P47 »

AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #5 on: April 07, 2013, 10:57:02 PM »
As long as there are bolts that we can adjust.  I'm glad we are going this route prior to cutting into the bed.
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tomlong74

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Re: Wooden CNC Router -- Bed Level?
« Reply #6 on: April 09, 2013, 12:28:54 AM »
And before we try to dial it in too much...
Notice that the CNC's actual shuttle is borked.
That needs a rebuild before we can dial it in.
Oh, and not for nothing... the router itself comes loose from the bolt down. DANGEROUS!

PockyBum522

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Re: Wooden CNC Router -- Bed Level?
« Reply #7 on: April 09, 2013, 11:14:47 AM »
Huh? Could you explain that last part? You mean the physical router motor comes loose from where it's mounted?

P47

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Re: Wooden CNC Router -- Bed Level?
« Reply #8 on: April 09, 2013, 11:26:10 AM »
There's only three screws holding the aluminum router mount when there should be four.
I suggested getting allen heads and locknuts.



AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #9 on: April 09, 2013, 01:01:52 PM »
And before we try to dial it in too much...
Notice that the CNC's actual shuttle is borked.
That needs a rebuild before we can dial it in.
Oh, and not for nothing... the router itself comes loose from the bolt down. DANGEROUS!


Is, borked, and the last line about it coming loose the same item?  The one Pat has described?

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AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #10 on: April 10, 2013, 02:19:17 PM »
1 --  There were three of four bolts holding the router mount onto the slide.  Now there are 4 of 4, replaced with cap screws, properly sized washers and lock washers were added.
2 -- One of two cap screws that holds the router into the mount was missing.  Now there are two.  There is no room for a lock washer in the design of the mount.  This will me a maintenance item that we will have to address with training and signage for now.


Next step -- Check the flatness of the floor where the machine lives.


-- Please be awesome to the Wooden CNC Router --
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AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #11 on: April 14, 2013, 09:29:35 PM »
So I took some readings at floor level with the help of Ben.  I measured the leg height to the cross beams.  They are pretty much the same hight.  Although the Right Front leg might be 0.5 or 1 mm shorter than the others.  I am going to call them close enough and not worry about that.

(my tables didn't import well from apple pages.  But the numbers are Left Front (LF), Right Front (RF), Left Back (LB) and then Right Back (RB).   

Height of legs from floor, floor to bottom of side beams.  Measured twice, once with an adjustable carpenter square, once with a digital caliper.


   

Method
 

LF
 

RF
 

LB
 

RB
 
square
 
79.0
 
79.5
 
80
 
81
 
caliper
 
81.4
 
78.6
 
79.9
 
80.3
 
   

Floor level readings using the laser from position on the floor to each leg.  The red card was placed against the bottom of the beam.  The number is the distance up from the middle of the card.
Position
  • 1 = Center of table
  • 2 = Back of table beyond the bed
   

Position
 

LF
 

RF
 

LB
 

RB
 
1
 
3.6
 
2.6
 
2.9
 
3.1
 
2
 
3.2
 
2.0
 
2.5
 
2.5
 
Delta from floor 6 - reading
 
1 delta
 
2.4
 
3.6
 
3.1
 
2.9
 
2 delta
 
2.8
 
4.0
 
3.5
 
3.5
 
   
Observations:
The height of the legs all increased compared to the position of the laser level from position 1 to position 1.
The increases were, 0.4, 0.4, 0.4 and 0.6 -- So, There must be a depression in the concrete of 0.4 spaces from position 1 to 2. 
One space = 1/4 inch.
The RF corner is significantly higher than the other 3 corners.
Reading 1 : 1.2, 0.5 and 0.6
Reading 2 : 1.2, 0.5 and 0.5

Also note that the RF corner leg is about 1 mm shorter, ie closer to the floor than the other three legs.  (let's ignore this)

Bottom Line
We need to shim both back legs ( at the floor) with a 1/8 inch shim.
We need to shim the Left Front leg  (at the floor) with 5/16 inch shim.

Somebody please review my findings.


I took base line readings at the table top.  So after we shim it we can check those again.  Hopefully this will take some twist out of the frame.


« Last Edit: April 14, 2013, 09:31:56 PM by AtomicProf »
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AtomicProf

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Re: Wooden CNC Router -- Bed Level?
« Reply #12 on: April 27, 2013, 09:22:27 PM »
UPDATE -- I put the shims under the feet.
I put a laser level on the bed.
the Laser hit the aluminum side rails and EVERYTHING LOOKED GREAT.
This was not the case before I shimmed the feet, EVERYTHING LOOKED CROOKED then.


I didn't have time to do any cuts.  I'm fairly confident that the cuts will come out great now.


Thanks to PAT for suggesting I check the level at the floor first.  Also thanks to PAT for providing the laser levels.



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