# 5/8 precision chuck run out



## Driveslayer45 (Feb 1, 2020)

has anyone purchased one of these recently and if so what does your run out look like?  Just got mine from PM Thursday night, put it in the mill and put a TI on it to see about .004" run out using a 1/2 endmill.  tested at the nose taper and on an endmill.  The same endmill in a collet has no runout, at least not within the range for me to measure.  The specs on the PM site say .001, so .004 seems excessive.  i emailed PM Thursday evening but not heard back yet.  just wondering what everyone else's thoughts are.


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## ACHiPo (Feb 1, 2020)

Driveslayer45 said:


> has anyone purchased one of these recently and if so what does your run out look like?  Just got mine from PM Thursday night, put it in the mill and put a TI on it to see about .004" run out using a 1/2 endmill.  tested at the nose taper and on an endmill.  The same endmill in a collet has no runout, at least not within the range for me to measure.  The specs on the PM site say .001, so .004 seems excessive.  i emailed PM Thursday evening but not heard back yet.  just wondering what everyone else's thoughts are.


Seems really high to me, especially if you have <<0.001" TIR as a baseline.  What is the chuck mounted to?  Check the taper, etc.


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## middle.road (Feb 1, 2020)

Driveslayer45 said:


> has anyone purchased one of these recently and if so what does your run out look like?  Just got mine from PM Thursday night, put it in the mill and put a TI on it to see about .004" run out using a 1/2 endmill.  tested at the nose taper and on an endmill.  The same endmill in a collet has no runout, at least not within the range for me to measure.  The specs on the PM site say .001, so .004 seems excessive.  i emailed PM Thursday evening but not heard back yet.  just wondering what everyone else's thoughts are.



Are we talking a drill chuck here? A link would help.


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## ACHiPo (Feb 1, 2020)

I assumed PM's Precision keyless chuck, but that's an excellent question.


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## mikey (Feb 1, 2020)

Can you tell us where the run out is coming from? I know that sounds facetious but you are reporting 0.004" TIR on the shank of an end mill and there are numerous interfaces in between the spindle and that end mill.

Is this an integral chuck or is it a chuck with a Jacobs taper installed on an R8 arbor? This is two interfaces.
What is the run out inside your spindle taper, taken at and averaged over three separate spots in the taper? This is your baseline and without it you cannot attribute any deviation to a thing inserted in the spindle taper. This is another interface.
And then there is the effect of clamping something in a 3 jawed thing. This is the interface with the biggest potential for run out.
A drill chuck typically has 3 jaws. The way to look at this is like a 3 jaw chuck on your lathe. As we all know, putting something that is precision ground into a 3 jaw chuck will cause substantial run out simply because it is a second operation chucking. In order to have that precision part run true you must either dial it in with a 4 jaw independent chuck if accuracy is important or use a collet if accuracy must be close and fast.

Due to the nature of the beast, a drill chuck will tighten variably because it relies on a threaded spindle. Depending on the diameter of the thing being clamped, the jaws will locate on that threaded spindle at different spots and those spots will differ every time you clamp something in the jaws. The same thing happens with a lathe scroll chuck; different spots in the scroll causes the jaws to run out like crazy.

So, expecting low run out on a drill chuck is expecting a lot just based on the mechanics of the thing. Throw in all those interfaces and you have an even greater amount of uncertainty.

The other thing to understand about drill chucks is that not all chucks are made equal. The jaws of a 1/2" Albrecht chuck are ground and hardened. Each jaw is 0.195" thick and are accurately machined. The jaw guide is likewise machined and hardened and then ground. The spindle is a precision ground Acme leadscrew and the head of that spindle has slots to match the machined contours of each jaw. When the chuck is closed on a round thing, everything moves pretty precisely and repeatedly but even an Albrecht chuck will run out due to the nature of a 3 jawed thing; it has a run out of less than 0.04mm/0.0016".

Sorry, didn't actually intend to go off like this but drill chuck accuracy, while important, has to be tempered with the knowledge that a drill is not a precision tool. Just the drill alone will add thousandths of inches of run out all by itself so if the chuck is anywhere close to 0.002 TIR (and you're sure its the chuck and not something else) then I wouldn't be too concerned about it.


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## Driveslayer45 (Feb 1, 2020)

sorry i should have included a link but i was on my phone.. i am referring to the PM precision 5/8 keyless drill chuck. https://www.precisionmatthews.com/shop/58-high-precision-keyless-drill-chuck/

"What is the chuck mounted to?  Check the taper, etc." <-- it's mounted in the R8 spindle of my PM-727v, which when measured with the same test indicator (TI) has no measurable run-out (by me)

"Can you tell us where the run out is coming from?" <-- my initial response is 'if i knew that i might not be asking anything', but as that is probably a little to glib since you're trying to be helpful i'll say i am not sure.  i measured it at the top smooth section above the gripping surface and on the tapered nose, the smooth area. both show about the same. which also is close enough to the reading i get on the endmill to make me believe its something in the mount. 

I ordered this particular one because i wanted an integrated chuck and its advertised run out is .001"

"drill is not a precision tool." <-- so i recognize this as true, and everything else you said i accept as so.. when i use a collet (which i know is more accurate) and the same end mill shaft i get no readable runout I have to believe the chuck is out of spec .. but if you can tell me how i should check it i certainly will, perhaps I am completely wrong in my procedure and expectation.


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## middle.road (Feb 1, 2020)

mikey said:


> Can you tell us where the run out is coming from? I know that sounds facetious but you are reporting 0.004" TIR on the shank of an end mill and there are numerous interfaces in between the spindle and that end mill.
> 
> Is this an integral chuck or is it a chuck with a Jacobs taper installed on an R8 arbor? This is two interfaces.
> What is the run out inside your spindle taper, taken at and averaged over three separate spots in the taper? This is your baseline and without it you cannot attribute any deviation to a thing inserted in the spindle taper. This is another interface.
> ...


@mikey, this looks like another one of your well written guides that you might write up and we'll get it into the download section. 



Sent from my XT1635-01 using Tapatalk


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## darkzero (Feb 1, 2020)

middle.road said:


> @mikey, this looks like another one of your well written guides that you might write up and publish in your book.
> 
> 
> 
> Sent from my XT1635-01 using Tapatalk



FTFY


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## mikey (Feb 1, 2020)

Okay, that helps a lot. So, your PM-727 has zero spindle run out - that's very good, by the way! You are using an integral chuck so that eliminates two potential interfaces. Now we need to determine if that shank is accurate. If it is, then all other run out should be attributable to the chuck itself. 

Here's the part I'm not clear on. You said, _*"i measured it at the top smooth section above the gripping surface and on the tapered nose, the smooth area. both show about the same. which also is close enough to the reading i get on the endmill to make me believe its something in the mount." *_I think you're saying you checked the exposed part of the R8 shank, the nose of the chuck and the end mill shank and got the same reading of 0.004", is that right? If so, then that shank is not accurate and it might be time to return or exchange it since it clearly exceeds their stated run out specs.

If you do return it, it might be a good idea to tell them how you checked it and the method used; you checked static run out of the spindle and got zero, then checked the R8 shank mounted in that spindle and got 0.004", and so on. It will leave them no leg to stand on and they will have to work with you to resolve it.

Good luck.


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## mikey (Feb 1, 2020)

middle.road said:


> @mikey, this looks like another one of your well written guides that you might write up and we'll get it into the download section.



I thought about doing a "How to check concentricity in the hobby shop" once upon a time. Might be time to put that back on the radar because it is a source of frustration for our guys. Let me think on it for a bit. Then I have to find the time to do it. If I don't get something up inside of a month or so, remind me, Dan.


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## mksj (Feb 1, 2020)

I am not sure I would expect that level of accuracy from that particular chuck, but still should be within the +/-0.002" range would be reasonable. Most chucks are much worse.  You might also check it with a 3/8" end mill. It is difficult to get below 0.001" no matter how good they are they will vary a bit depending on what they are clamping. Since they are integrated chucks there is not taper interface that could be off.

If you want a bit better precesion then you might look at their ultra high precision which is just slightly more. I have used this 5/8" chuck on another persons mill and it was very smooth and worked well.


			https://www.precisionmatthews.com/shop/18-58-ultra-high-precision-keyless-drill-chuck/


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## ddickey (Feb 1, 2020)

Driveslayer45 said:


> I ordered this particular one because i wanted an integrated chuck and its advertised run out is .001"


+/- .001" which means .002" TIR. 
Try a 1/4" end mill and see if it shows the same run out.


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## Driveslayer45 (Feb 1, 2020)

Thanks for the feedback and suggestions. I will try a 3/8 and 1/4 end mill shafts tomorrow.


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## Chewy (Feb 2, 2020)

PM30-MV with same drill chuck.  1/2" drill rod at fully retracted is .0022.  Fully extended is .0032.  Fowler .0005 indicator on Shars magnetic base. Ran the mill for 30 seconds to warm up as it is 60 degrees in the shop.


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## T Bredehoft (Feb 2, 2020)

Quit trying to indicate end mills. use dowel pins. Or drill rod.

_Edit: _Correct Typo.


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## wrmiller (Feb 2, 2020)

mksj said:


> I am not sure I would expect that level of accuracy from that particular chuck, but still should be within the +/-0.002" range would be reasonable. Most chucks are much worse.  You might also check it with a 3/8" end mill. It is difficult to get below 0.001" no matter how good they are they will vary a bit depending on what they are clamping. Since they are integrated chucks there is not taper interface that could be off.
> 
> If you want a bit better precesion then you might look at their ultra high precision which is just slightly more. I have used this 5/8" chuck on another persons mill and it was very smooth and worked well.
> 
> ...



I have the small and large ultra-high chucks for my mill, and a large for the lathe. As you say, very smooth and work very well.


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## middle.road (Feb 2, 2020)

Chewy said:


> PM30-MV with same drill chuck.  1/2" drill rod at fully retracted is .0022.  Fully extended is .0032.  Fowler .0005 indicator on Shars magnetic base. Ran the mill for 30 seconds to warm up as it is 60 degrees in the shop.


Waiting for it to warm up over here.


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## rwm (Feb 2, 2020)

ddickey said:


> +/- .001" which means .002" TIR.



Is that correct? When a manufacturer indicates runout they don't mean TIR?
Robert


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## mikey (Feb 2, 2020)

rwm said:


> Is that correct? When a manufacturer indicates runout they don't mean TIR?
> Robert



"+/- whatever" is the range the seller hopes the chuck will hit using the testing method they do not specify. Gives them wiggle room to deny a return.


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## Driveslayer45 (Feb 2, 2020)

T Bredehoft said:


> Quit trying to indicate end mills. use dowel pins. Or drill rod.
> 
> _Edit: _Correct Typo.


Why not use end mills? I always understood endmills to be precision ground? I am thinking even if they're not since I am using the same endmill between the Chuck and a collet it should work well for a relative comparison.


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## T Bredehoft (Feb 2, 2020)

Driveslayer45 said:


> Why not use end mills?



Becauses you should check at the holder and some distance away to make sure your piece is parallel the spindle. You can't well do that with an end mill.


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## rwm (Feb 3, 2020)

Driveslayer45 said:


> Why not use end mills? I always understood endmills to be precision ground? I am thinking even if they're not since I am using the same endmill between the Chuck and a collet it should work well for a relative comparison.


Also I have been told that drill rod is not round due to the way it is manufactured. It can be tri-lobed. I would assume that a long end mill would be an excellent choice absent a dowel pin.
Robert


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## wrmiller (Feb 3, 2020)

Gauge pin?


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## mksj (Feb 3, 2020)

The runout specification varies by manufacturer, some like Llambrich do specify the conditions of measurement for each of their chucks. A gauge pin or precision ground rod is probably ideal if you want to measure the runout at different distance from a chuck, but otherwise and end mill is fine for measurement close to the chuck. The typical drill chucks are for holding drills and there runout can be significant, so a TIR of a few thousandth is not going the mean much. If you need high accuracy then use a collet system, I use to use an ER-32 system (before I had a power drawbar) and it was withing 0.0002". I have two Llambrich integrated R8 drill chucks and they are both around 0.001" which is their spec., similar to scroll chucks they can vary a bit over the clamping range. I have heard of a number of people returning their new Jacobs Super chucks ans also a few Albrecht because of excessive TIR (like 0.004"), so QC of the newer products seem to be more of an issue.


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## Driveslayer45 (Feb 3, 2020)

ok, so am i hearing not to worry about a .004x runout on a drill chuck?


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## ddickey (Feb 3, 2020)

If it is outside of the specs then a call to PM is in order.


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## T Bredehoft (Feb 3, 2020)

Driveslayer45 said:


> ok, so am i hearing not to worry about a .004x runout on a drill chuck?



As Mickey stated above, drill chucks are not absolute precision instruments. If  collet mounted drill runs out more than collet specs, call for, complain, if the drill chuck runs out, and you want precision, use a collet. If you want a precision drilled hole, drill it undersized and bore it to final size.


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## ptsmith (Feb 3, 2020)

The PM listing states: "High Precision, Maximum of +/-.001″ Runout"

If it's unreasonable to expect that level of accuracy out of a drill chuck, then PM should not make that claim.

Nothing at all unreasonable about Driveslayer45 expecting and demanding what was promised by PM.


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## Chewy (Feb 3, 2020)

Somebody give me a refreasher course.  Isn't a .001 run out equal to a .002 TIR? Isn't that why everybody started using TIR?

Confused---Lost & Wandering


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## ddickey (Feb 3, 2020)

Yes. But .001" looks better than .002".


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## mikey (Feb 3, 2020)

Chewy said:


> Somebody give me a refreasher course.  Isn't a .001 run out equal to a .002 TIR? Isn't that why everybody started using TIR?



Yes, you're essentially right. Run out is the amount a rotating thing is off from the true centerline. Since a run out of 0.001" is the actual offset, the TIR will be double that, or 0.002". 

The PM chuck under discussion has a stated max run out of +/- 0.001" so it has a TIR max of 0.002". If the chuck were to fall anywhere inside this range then it is within spec. If it falls outside that range then it is not in spec. The problem with this simple expectation is that it relies on the thing that is holding the rotating thing, in this case it is a drill chuck holding an end mill, being true to the centerline of the spindle and we do not know that for certain. As a result, saying the reading at the end mill is a true indication of how much the chuck runs out is not entirely correct because it does not account for stacking tolerances. 

This is why I asked how he is measuring this, what the spindle reading was and what the chuck reads. If the spindle itself has zero run out then it is true to the spindle centerline and will not contribute to what he sees further down the line. Now, if the integral R8 spindle also reads zero and the body of the chuck also reads zero then any run out seen at the end mill must be due to the jaws or chuck spindle thread or whatever is going on inside the chuck IF we assume the end mill is round and straight. 

So, if you are going to attest that the drill chuck is out of spec then you must be able to tell the seller how you measured it, from spindle bore to the end of the test bar. Then if the chuck is out they have nothing to say and must take the chuck back.


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## Chewy (Feb 3, 2020)

rwm said:


> Also I have been told that drill rod is not round due to the way it is manufactured. It can be tri-lobed. I would assume that a long end mill would be an excellent choice absent a dowel pin.
> Robert


The 3' O1 drill rod from KBC is as round as it can be.  I spot check the pieces some times.  The 3/8" that I used yesterday in an assembly was checked 6-8 times around the diameter.  It was .0001 oversize and did not vary at all in any of the readings.  I have a selection from .233 to 3/4" that I work with all the time and none of it has displayed any out of round.


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## mikey (Feb 3, 2020)

Drill rod is supposed to be round to within ~0.001", I think, but it does not have a straightness spec.


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## stupoty (Feb 3, 2020)

What sort of TIR do you get with the same end mill held in a collet ?

If it's very similar their may be a small burr or speck of dirt in the spindle taper that is causing an issue.

Also does the error repeat well if you pop it out of the spindle and put it back in ?  You can mark the end mill with a sharpy marker or similar to check.

Stu


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## ptsmith (Feb 3, 2020)

This was in the first post:



Driveslayer45 said:


> has anyone purchased one of these recently and if so what does your run out look like?  Just got mine from PM Thursday night, put it in the mill and put a TI on it to see about .004" run out using a 1/2 endmill.  tested at the nose taper and on an endmill.  *The same endmill in a collet has no runout, at least not within the range for me to measure.*  The specs on the PM site say .001, so .004 seems excessive.  i emailed PM Thursday evening but not heard back yet.  just wondering what everyone else's thoughts are.


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## stupoty (Feb 3, 2020)

ptsmith said:


> This was in the first post:



Sorry , not sure how I missed that  

Have you got anything long enough to check the runout at the same distance from the spindle noes as the drill chuck puts the end mill ?

(the chuck is adding a lot of extension which could magnafy a very slight error)

So if the error repeats and there are no burrs on the R8 on the chuck then I guess there is an out of spec issue with the chuck.

Only other thing I guess could be  a burr or grit in the internal jaw mechanism.  Disassembly might affect warranty, might be worth asking PM first.

Stu


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## rwm (Feb 4, 2020)

I agree guys. The drill rod I have seems round to less than .001" but this was posted earlier:
See post #2. It does seem to be round to within .001 when checked. 








						Ground Drill Rod
					

I got a hunk of 7/8" ground drill rod and a pillow block for an indexing stetup on my new HF round column mill. I was disappointed to find it straight but it wasn't round. It would jam in the bore of the pillow block jet still wiggle side to side. I spent an hour and a half stoning the rod to...




					www.hobby-machinist.com
				




Robert


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## middle.road (Feb 4, 2020)

mikey said:


> Drill rod is supposed to be round to within ~0.001", I think, but it does not have a straightness spec.


I seemed to recall the same thing from back in the day. I had a design similar to what Robert posted above but with a total of (4) shafts in the machine.
I ran the design past our senior tool maker and he red-lined it with a note saying to order 'Thompson'. That's when I found out what 'Thompson' was.

Just did a quick search though to satisfy my curiosity. (gotta learn something new every day...)
Straightness on a few sites is spec'd at *.005" TIR/12"* - Starrett & McMaster-Carr both have it spec'd at this also.
A few didn't even list a spec for straightness.
One site even shows it at [±.005″ max T.I.R. per 12″] (sic)

That being said I broke out my old _Jorgensen Stock List & Reference Book_ from 1981, and they don't even show a 'straightness' tolerance for drill rod.


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## mikey (Feb 4, 2020)

Yup, if you need round AND straight, better to go with Thompson's linear shafting. At least they spec round and straight. Best to keep in mind their shafting is case hardened.


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## middle.road (Feb 4, 2020)

mikey said:


> Yup, if you need round AND straight, better to go with Thompson's linear shafting. At least they spec round and straight. Best to keep in mind their shafting is case hardened.


Though you can get their 316 SS non-case hardened. $$$ 
I keep hoping some will pop up at a sale/auction and I could score it cheaply...


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## mikey (Feb 4, 2020)

Cheap Thompson's shafting is an oxymoron, Dan!


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## Driveslayer45 (Feb 4, 2020)

the amount of feed back and comment is amazing.. thank  you all.

I do have some 3/4 drill rod i could cut a length off and put in a collet to see what that TIR looks like.


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## qualitymachinetools (Feb 5, 2020)

Hey guys, great tips, but no need to put too much more thought in to it, I replied last week and asked if a video could be sent because he said he was measuring runout on the smooth taper O.D. and I was not quite sure what was meant (Something like that, I am going from memory)  And everyone is correct that .004 is still better than most chucks, no matter what the opinion on a drill chuck is, if its not within spec it would be replaced. Driveslayer just reply to the email when you have a chance if there is still a problem and we will figure it out.


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## middle.road (Feb 6, 2020)

mikey said:


> Cheap Thompson's shafting is an oxymoron, Dan!


Nah, just have to get lucky and hit it at a good estate sale or auction.
Like the box of 'wire' I scored over the summer, (4) packs of Harris Safety-Silv, some flux, pack of rod and other 'junque' for $5, along with the 12" rods of Bunting 3/4" 660 plus some misc brass for $10. BS0006-13BRZ BAR
Some oddball stuff pops up at these sales, just got to have hope and hit it right.
Need to watch out for those lots of miscellany at the auctions with a ton of dust all over them.


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## sc0ch (Feb 19, 2020)

Isn't this why it's good to center drill when using a drill chuck? You think the drill chuck has runout, certainly the drill bit has more.  Running an endmill in a drill chuck can obliterate the chuck.


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## mmcmdl (Feb 19, 2020)

mikey said:


> Cheap Thompson's shafting is an oxymoron, Dan!



I throw it out all the time Mike .  I'll start holding onto it from now on .


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## middle.road (Feb 19, 2020)

mmcmdl said:


> I throw it out all the time Mike .  I'll start holding onto it from now on .


 ....... say it isn't so.


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## mmcmdl (Feb 19, 2020)

We use a lot of it . When we break down the lines we replace it with new , nothing wrong with it but it goes into the dumpster .


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## Aukai (Feb 19, 2020)

Maybe some should be recycled


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