# Pm932m-y Tram Off .003 Over 4"-y Gib Adjustment?



## Gburgswmich (Sep 23, 2015)

Hello all, and thanks to those sharing their knowledge and experience be to help beginners like myself!
My PM932M is barely broken in, but I need to get everything square! I checked my column to spindle, and it is perfectly square. The spindle to table however is off .003" over 4". The front of the spindle is sagging the .003 over 4". Is this something that can be fixed without shimming the front of the column? Is there a particular gib adjustment anyone would recommend? Again, I'm as green as they come, and forgive me if I haven't come across the answer through searching. I'm hoping someone can answer me here. I thank you all in advance. Greg


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## tmarks11 (Sep 23, 2015)

You are not going to like this answer, but... you really need a DTI, some holder to keep it in the spindle (like a Noga), and a cylindrical square.

There are two different shims that you might have to do.
1. Column to base (I know you said this isn't the case, but I am doubtful of any measurement made that doesn't involve a DTI).
2. Head to column slider

The trick is to figure out which one.  For that, you need a cylindrical square. 

If the problem is #1, than with a DTI (Dial Test Indicator) in the spindle, as you raise the spindle, the DTI measurement against the vertical face of the cylindrical square will change.  If the problem is #2, the DTI measurement will be unchanged as you raise the spindle.

You can shim will aluminum foil, which is a convenient thickness.

I wouldn't mess with either adjustment until I knew for sure what it was.  And I don't know a good way to figure it out without a cylindrical square, since you have to measure for Y position change in the DTI as you raise the head.


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## Gburgswmich (Sep 23, 2015)

I followed Hossmachine's guidelines and use a magnetic base attached to the column to measure runout in a precision rod in the spindle. The runout in both the x and y ended up being 0 after adjustment. 
Using a spindle square, I came up with the spindle to table measurement. The above test should rule out the head to column I believe??.....


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## dave2176 (Sep 23, 2015)

Can't argue with Tim's answer. He's dead on. Make sure the Z gib is adjusted right so it doesn't add to your measurement. It's fairly common to need to shim the column to get it perfect.
Dave


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## Gburgswmich (Sep 23, 2015)

I'm Using a starrett magnetic with interrapid DTI reading the runout on the precision .5" carbide rod in the spindle. Took readings at the top and bottom of the rod and fixed it to zero runout.
I don't think I know how to properly adjust the Z gib. That's was my hope was to make my adjustment there to fix this Y deflection. Maybe I'll mess with this some more. Just when I thought I purchased all the tools I needed to tram properly, now there's a cylindrical square


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## Dan_S (Sep 23, 2015)

before you but a cylindrical square, try this first.

1. mount your carbide rod in the spindle.
2. extend the quill 4" and then lock the quill in-place with the quill lock.
3. lock head in-place 
4. take a dti or a good 0.0005" indicator and mount it to the column so you can indicate close to the spindle
5. indicate close to the spindle and note the highest & lowest value in the x direction 
6. loosen the head and carefully raise it (don't move the indicator)
7. lock the head down again and then carefully indicate  on the end of the shaft just like in step 5

Use rollie dad method  to calculate if the head is out of tram to the column .
Repeat 5, 6, & 7 in the y direction.

Once you know how far you are off from the above, you can either live with it of fix it.  


To check against the table  just sweep it like shown in a million you tube videos. If you haven't fixed the above, you can factor it out when sweeping the table.


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## Gburgswmich (Sep 23, 2015)

The Rollie dad method is exactly what I did to find out the head was square to the column. Hoss machine's video on his g704 tramming is what I followed. Sorry if I wasn't clear in saying that in my intro. 
The head is not square to the table, so methods other than shimming the column are what I was hoping to find here


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## Dan_S (Sep 23, 2015)

what video  did you follow, because several of his videos have errors in them.


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## tmarks11 (Sep 23, 2015)

Gburgswmich said:


> I followed Hossmachine's guidelines and use a magnetic base attached to the column to measure runout in a precision rod in the spindle.


Hoss' technique has some short comings, but in the absence of a cylindrical square (which isn't cheap), this should get you what you need.  The precision drill rod in the spindle to the column DTI tells you the head is aligned to the column (assuming you rotated it to ensure that measured values were not affected by run-out of the collet, which frequently can be 0.002"+).

That means that any error found after that when sweeping the table (or using your double indicator spindle square) should then be column to base tram.  This can be caused by grit or paint chips in the mating surface.  Take the column off, clean up the mating surfaces, vacuum out the casting (sucks when casting sand falls out of the column on the base when you start putting it back together and you find you are further out than when you started), use blue painters tape to pick-up any grit off the mating surfaces, re-mate them and measure again. Then take it apart again and start shimming.

Note about z-axis gibs. Head droop due to gibs too loose would have shown up on your head-to-column measurement.  So I would't tighten the gibs.


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## Dan_S (Sep 23, 2015)

tmarks11 said:


> Hoss' technique has some short comings.



That's an understatement. Telling people to not use the ball on a dti is unforgivable.


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## Gburgswmich (Sep 23, 2015)

I watched the tramming part 1 video on the g704. I also used a spindle square to verify. I feel pretty confident the column and head are square. I will concentrate on cleaning up the mating surface. Hope it's not a nightmare. I knew I kept my shop crane for a reason


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## tmarks11 (Sep 23, 2015)

Dan_S said:


> That's an understatement. Telling people to not use the ball on a dti is unforgivable.


haha.  I missed that.  I remember there were some other somewhat odd things.  Largely why I don't like the drill rod in the spindle is it introduces other possible errors into your measurement (collet run-out, more than one axis out of tram making erroneous readings while running a DTI up the length of a small diameter rod).

Cylindrical square on the table gives you a solid perpendicular surface to measure against as the head is raised and lowered, minimizing stack-up of errors.



Gburgswmich said:


> I will concentrate on cleaning up the mating surface. Hope it's not a nightmare.


Not that bad.

But cleanliness is everything.  Treat it like a clean-room operation. Slightest bit of grit will put you further off than you started.  Wipe the surfaces down with acetone when you think they are absolutely clean before you join them together.

But worth doing.  It sucks when you flycut a surface, and every pass of the mill leaves a 0.003" groove where it meets up with the previous path.


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## qualitymachinetools (Sep 24, 2015)

Yes its very common to need to shim the column on these types of mills to get them to be dead on. But as already mentioned, there are a lot of variables, but these guys are giving you good information.

It wont hurt to shim it, but also wont hurt to use it as is for a bit too just learning to mill. Its actually fairly easy to shim it. I did one for a local person here recently, on the same mill.  Are you .003 Total over the whole sweep? Or .006 total with it being low in the front?

This one was about .003 Total over the whole table, and we used about .002 shim and it was dead on after that. But it varies on the amount all the time. The bolt torque moves it a bit too. It wont take long though, you'll get it I am sure.


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## Gburgswmich (Sep 24, 2015)

So the .003 is the measured with s spindle square where the points of contact are 4" apart. The front of the head is closer to the table, so I'm assuming the front of the column will need to be shimmed. When I pull the left side of the spindle square down (contact point on the back side of the table) the square gets closer to dead on. That tells me the column needs to sit more upright. 

I've milled on it a bit already, and am getting comfortable with it, but I want to get it square. I need to mill some dead flat bearing pockets in titanium SOON for a folding knife project and just don't want that as a variable of error.


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## qualitymachinetools (Sep 24, 2015)

Ok, so when you turn the spindle 1/2 turn, its exactly the same that way too then right? (I apologize if you already said that, I just did not see it)

But yes if thats it, you would need to shim the front of the column. The one that is on 0 is towards the front of the machine right? 

 You'd notice it on a fly cutter, but probably not on an end mill. If your spindle is at .0015 high in the back and .0015 low in the front over 2" Each, and you have a 1/2" end mill in there, its a much much smaller difference.  But it is better to get it perfect, the closer it is the easier.


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## sanddan (Sep 29, 2015)

When I had this type of mill I also had to shim the column to get the tramming dead on. It's really not that hard to do, just tedious as the shim thickness you need under the column it not the same as the amount you are off when checking at the quill. My process was to loosen the bolts holding the column, don't remove them just loosen, and push on the head enough to slip the shim under the column. Then tighten the bolts and check tram. It took me several attempts with different shim thicknesses to get it within .001". Also, shimming one corner will throw off the alignment in other directions. I think I had shims under 3 of the 4 corners with all 3 being different thicknesses.


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## Gburgswmich (Sep 29, 2015)

This is exactly what I plan to do when I return from vacation. I was going to use compressed air to clean the mating surface while lifting the head and column with my shop crane. I'm going to be doing this myself so I figured I can loosen the bolts enough to create a gap when I lift the head and column. Clean the mating surface then shim and tram and repeat shimming as needed. Thanks for the post!



sanddan said:


> When I had this type of mill I also had to shim the column to get the tramming dead on. It's really not that hard to do, just tedious as the shim thickness you need under the column it not the same as the amount you are off when checking at the quill. My process was to loosen the bolts holding the column, don't remove them just loosen, and push on the head enough to slip the shim under the column. Then tighten the bolts and check tram. It took me several attempts with different shim thicknesses to get it within .001". Also, shimming one corner will throw off the alignment in other directions. I think I had shims under 3 of the 4 corners with all 3 being different thicknesses.


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## Gburgswmich (Sep 29, 2015)

I'll check this when I return from vacation. Appreciate your help with this.



qualitymachinetools said:


> Ok, so when you turn the spindle 1/2 turn, its exactly the same that way too then right? (I apologize if you already said that, I just did not see it)
> 
> But yes if thats it, you would need to shim the front of the column. The one that is on 0 is towards the front of the machine right?
> 
> You'd notice it on a fly cutter, but probably not on an end mill. If your spindle is at .0015 high in the back and .0015 low in the front over 2" Each, and you have a 1/2" end mill in there, its a much much smaller difference.  But it is better to get it perfect, the closer it is the easier.


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## Gburgswmich (Oct 2, 2015)

So I'm back getting ready to set this up so I can lift the head and column to insert shims. Anybody with experience recommend me doing anything different than when first assembling the unit? I'm going to move the gear head to the very bottom of the column because my ceiling and this crane have clearance that forces me to do so.  I'm putting a strap under the pivot of the gear head and lifting the strap with my shop crane from that point. I'm not going to fully remove the column bolts, only enough to get some clearance between the column and base. Because of the weight of the head, my concern is where I've got the gear head supported. Any recommendations? I'll take a pic and post....


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## Gburgswmich (Oct 2, 2015)

Pics attached. This is how I installed the base column head onto the blue base when I first got it without too much of an issue. Since the base is not going to be connected here, is there anything else I should worry about here? I'm not lifting it completely off, just trying to get some clearance for shimming. 
I'm a complete novice guys, so I know you guys see things that I don't because you've experienced the good bad and ugly. I don't want to ruin a 3k plus mill here


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## Muskt (Oct 2, 2015)

I may be over-simplifying things, but how about forgetting the lift and use a couple of wooden blocks on the table and a short chunk of 2x4.  Loosen the bolts a small amount and pry the front up--insert shims--lower back into position and tighten & check--rinse & repeat till done.  If the rear needs shimmed, you won't even need to lever it--should tilt forward with the weight alone.  It would appear that the bolts shouldn't need to be loosened much more than 1/2 -1 turn to insert shims.  I am going to need to do mine soon, also.

Jerry in Delaware


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## TomS (Oct 2, 2015)

Muskt said:


> I may be over-simplifying things, but how about forgetting the lift and use a couple of wooden blocks on the table and a short chunk of 2x4.  Loosen the bolts a small amount and pry the front up--insert shims--lower back into position and tighten & check--rinse & repeat till done.  If the rear needs shimmed, you won't even need to lever it--should tilt forward with the weight alone.  It would appear that the bolts shouldn't need to be loosened much more than 1/2 -1 turn to insert shims.  I am going to need to do mine soon, also.
> 
> Jerry in Delaware



A couple of weeks ago I shimmed my column using this process except for one slight deviation.  Instead of prying the head with a 2x4 I engaged the quill downfeed knob on the right side of the mill head and used the downfeed handle to raise the front of the column.  Same result, different approach.

Tom S


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## Gburgswmich (Oct 3, 2015)

Thanks guys. So you are saying the lowering the quill onto a block of wood will create enough force to push the column up? No risk of damaging the spindle doing that? Again, novice, but it seems that's a lot of weight to put directly on the spindle.


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## tmarks11 (Oct 3, 2015)

You are much less than a 1/10 of the design static load of a pair of angular contact bearings of that size.  

Of bigger concern is making sure you don't lose control of the column/head while you are doing this.  I am guess it is at least 400+ lbs, so the key is LOOSEN, not removing the column-base bolts while you are doing this.


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## Gburgswmich (Oct 3, 2015)

Same machine or smaller than the pm932? Seems like this would be ok for a smaller machine but the pm932 head is pretty heavy and my concern would be what effect this would have on the spin





TomS said:


> A couple of weeks ago I shimmed my column using this process except for one slight deviation.  Instead of prying the head with a 2x4 I engaged the quill downfeed knob on the right side of the mill head and used the downfeed handle to raise the front of the column.  Same result, different approach.
> 
> Tom S


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## Gburgswmich (Oct 3, 2015)

Ok guys I think I'm lost in how to team with my spindle square. Before I mess with the column shimming, im starting over making sure I've done everything else before resorting to shimming. 

In x, I am dead perfect when looking at the spindle square as I face the mill. I rotated the spindle square to face the column, and now I'm off .003. All I did was rotate 180 degrees. Help.

Does anyone have a good link on how to properly team using a spindle square? Thanks for the help.


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## tmarks11 (Oct 3, 2015)

That is because your spindle square isn't square.

How did you zero the dials on it?  That has to be done before use.

Traditionally, you "sweep" the surface with one DTI , and you zero it at +X, and rotate it to -X, and then tram the mill until +X and -X are the same.

The spindle square means you don't have to sweep the surface while doing the tramming, but you do have to zero it before use by sweeping it 180 degrees.


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## Gburgswmich (Oct 3, 2015)

I squared it on a brand new calibrated inspection plate prior to use. I'm taking it out and doing it again now but I don't believe that's the issue.


tmarks11 said:


> That is because your spindle square isn't square.
> 
> How did you zero the dials on it?  That has to be done before use.
> 
> ...


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## sanddan (Oct 3, 2015)

Are you sure you need a hoist? I was able to tilt mine enough to slip shims under the front of the column by pushing with my left hand and using my right to insert the shim. Not that hard just be sure you only loosen the bolts, not remove them. I backed the front bolts off a lot and the rear only enough to allow the head to tilt. You aren't lifting the head, just tilting so shouldn't require a ton of force.


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## tmarks11 (Oct 3, 2015)

Squaring it on an inspection plate won't work.  Regardless of what the instructions claim.

Put it in the spindle, put a gage block at the +Y extent.  Zero one indicator on the gage block, spin 180 degrees, and zero the second gage block.  That takes out any errors (such as slight alignment error in the spindle square shank).

See below at time 1:00






They use a magnet, but the gage block works just as well.  You can also go right against the table, but then you really need to hold both DTI up while rotating, which is a PIA.


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## Gburgswmich (Oct 3, 2015)

Apparently I did do something to get the spindle square out of calibration. Sorry about that you were correct. I'll be back. Hang tight please!





Gburgswmich said:


> I squared it on a brand new calibrated inspection plate prior to use. I'm taking it out and doing it again now but I don't believe that's the issue.


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## Gburgswmich (Oct 3, 2015)

Ok I've got it calibrated to the table now...ill be back with more soon thanks!


tmarks11 said:


> Squaring it on an inspection plate won't work.  Regardless of what the instructions claim.
> 
> Put it in the spindle, put a gage block at the +Y extent.  Zero one indicator on the gage block, spin 180 degrees, and zero the second gage block.  That takes out any errors (such as slight alignment error in the spindle square shank).
> 
> ...


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## Gburgswmich (Oct 3, 2015)

Thanks! I am not sure how much weight I'm moving. I think the hoist is a gradual way of moving the head and column where I can control it closely. It's good to know you could move it that way.



sanddan said:


> Are you sure you need a hoist? I was able to tilt mine enough to slip shims under the front of the column by pushing with my left hand and using my right to insert the shim. Not that hard just be sure you only loosen the bolts, not remove them. I backed the front bolts off a lot and the rear only enough to allow the head to tilt. You aren't lifting the head, just tilting so shouldn't require a ton of force.


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## Gburgswmich (Oct 3, 2015)

Is there something other than gage blocks that will serve the same purpose? Say a 1-2-3 block? I don't have a set of gage blocks yet, only gage pins.



tmarks11 said:


> Squaring it on an inspection plate won't work.  Regardless of what the instructions claim.
> 
> Put it in the spindle, put a gage block at the +Y extent.  Zero one indicator on the gage block, spin 180 degrees, and zero the second gage block.  That takes out any errors (such as slight alignment error in the spindle square shank).
> 
> ...


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## T Bredehoft (Oct 3, 2015)

1 2 3 block, yes, but use the same block, the same corner of it. It doesn't have to be anything special, just so that the same point on the block is used for each setting.

Reading the above discussion, re: a cylinder square, I realized that I had one, purchased at an auction, in the 1980's in Dayton. It has stamped on one end, Feb. 48, I have to imagine that was date of mfgr.  Its about 2 inches in diameter, 5 1/2 long, It was still cased in brown wax.  I'd never had occasion to use it before.  I cleaned my PM25, ditto the cyl square, and set it up at 0 0 0 0 at the top.  I moved the quill down 1.675 (as far as it would go) and circled around it.  Y was 0 0 , X was ±.003.  Thrilled to find that the spindle was square with the column, or at least the table, but I thought I'd fixed the X earlier. 

I broke down the Cyl Sq set up, cranked the head down so that the quill was up and the indicator would just clear the  table, and clamped the column and the quill. I got out a pair of .050 Jo blocks and with the indicator as far out as it would go (7" radius) got a .014 variation between left and right. It took three or four corrections, now its within (I hope) .005, that's the reading on the indicator, but it doesn't repeat as well as I would like.  Anyway, I can't complain on .005 in 14 inches.


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## Gburgswmich (Oct 3, 2015)

Well calibrating the spindle square off off of a 1-2-3 block on the table has me much closer than where I first believed. It looks like I'm only out .001-.0015 in Y over 4". I appreciate the info guys. There is as much bad info out there as good info so it's hard to know what to use as guidelines. I built a sweeper I'm going to try out to see if the results are consistent.


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## sanddan (Oct 3, 2015)

Well, I watched the video and couldn't wait till tomorrow. I used that method to calibrate my spindle square and re-trammed the head. It was off in the x direction about .002" so I adjusted the head and tightened up the bolts. I checked the Y direction and it was off .004". I got that back to zero and re-checked the X direction and it was still dead on. I then set the spindle square on the table to see how far it was or wasn't off. It was shifted off .0005" each direction for a total of .001" compared to the "magnet" version for calibrating. Now I have to figure out why the head was so off when the gage isn't that far out. I think it moved when I tightened the bolts last time I trammed it.


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## TomS (Oct 3, 2015)

Gburgswmich said:


> Same machine or smaller than the pm932? Seems like this would be ok for a smaller machine but the pm932 head is pretty heavy and my concern would be what effect this would have on the spin



It had no effect whatsoever.  The bearing load rating is much higher than a few hundred pounds, which is what the head weighs.

Tom S


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## tmarks11 (Oct 4, 2015)

sanddan said:


> Now I have to figure out why the head was so off when the gage isn't that far out. I think it moved when I tightened the bolts last time I trammed it.


And that is the part that makes tramming a mill frustrating... even on a bridgeport where you don't need shims.  Tighten the bolts a little at a time in a cross pattern, checking several times as you get the bolts near tight to make sure it doesn't shift.  Even more annoying is that adjusting the Y-axis tram can affect the X-axis tram.


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## Gburgswmich (Oct 13, 2015)

Well it turns out that after I squared up my X, I'm only nodding .001" over 6" in Y. Checked by sweeping and with a spindle square. That .001 bothers me but I'm not sure it's worth lifting the column to attempt getting it perfect, at least not right now. Thanks for the help all!


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## TomS (Oct 13, 2015)

Gburgswmich said:


> Well it turns out that after I squared up my X, I'm only nodding .001" over 6" in Y. Checked by sweeping and with a spindle square. That .001 bothers me but I'm not sure it's worth lifting the column to attempt getting it perfect, at least not right now. Thanks for the help all!



I would agree with you that chasing .001" over 6" is not worth chasing.  I got my mill to .0015" over the width of the table in both X and Y (9-1/2").  I probably couldn't measure what effect this would have on most of the parts I make. 

Tom S


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## slingshot (Dec 27, 2015)

sanddan said:


> Are you sure you need a hoist? I was able to tilt mine enough to slip shims under the front of the column by pushing with my left hand and using my right to insert the shim. Not that hard just be sure you only loosen the bolts, not remove them. I backed the front bolts off a lot and the rear only enough to allow the head to tilt. You aren't lifting the head, just tilting so shouldn't require a ton of force.




I agree with sanddan that is how I done mine.


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