# QCTP vertical runout



## Watchwatch (Dec 3, 2020)

Vertical runout is out a few thou over 1.5 inches on a gage pin in an ER collet and boring bar holder.

3 hour old PM 1236T with the PM QCTP.

Here is what I’ve done to isolate the problem. 

Indicated the top of the QCTP body. Around .0005

Indicated the gage pin/boring bar holder on a surface plate. A couple tenths high spot to high spot on the pin.

Checked for squareness of the QCTP to the spindle. Under a .001

2 collar test to check way twist. Within a few tenths over 8 inches. 


Is the issue with the dovetails or gibs on QCTP? I’m having the same vertical runout issue on both toolpost locations. 


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## Tozguy (Dec 3, 2020)

Its not clear what the problem is and what you mean by vertical run out on the boring bar holder. I have never checked my QCTP to see if it holds tools perfectly level cause it does not seem critical to me.


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## benmychree (Dec 3, 2020)

What do you think makes it a problem?


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## MrWhoopee (Dec 3, 2020)

benmychree said:


> What do you think makes it a problem?



I'm sensing the hobbyist's obsession with perfection whether it's relevant or not. 

The toolpost holds a tool, which is stationary on the post when in use. From what you have described, the bottom of the toolpost is not perfectly perpendicular to the mounting dovetails. It doesn't matter.

Now get back to work.


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## benmychree (Dec 3, 2020)

MrWhoopee said:


> I'm sensing the hobbyist's obsession with perfection whether it's relevant or not.
> 
> The toolpost holds a tool, which is stationary on the post when in use. From what you have described, the bottom of the toolpost is not perfectly perpendicular to the mounting dovetails. It doesn't matter.
> 
> Now get back to work.


I second that motion!


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## tq60 (Dec 3, 2020)

2 coller test, how? Between centers or just in chuck?

Square to Chuck, how?

You are posting measurements but not clear how made.

Given all parts on the tool post are stationary to the compound, it is not really important they be perfectly square as they can be moved then fixed in whatever final position.

There may be an issue but you are not clear on what you are trying to state.

Make a sketch and show dimensional notation then it may be better understood.

Squareness of the cross slide to ways matter as does many other items, please provide a sketch and focus on one issue at a time so the focus is on single items.

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## Watchwatch (Dec 3, 2020)

benmychree said:


> I second that motion!



Alright. I’ll poke a hole and see what happens.


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## Mitch Alsup (Dec 4, 2020)

Watchwatch said:


> Vertical runout is out a few thou over 1.5 inches on a gage pin in an ER collet and boring bar holder.
> 
> 3 hour old PM 1236T with the PM QCTP.
> 
> ...



Put a indicator on the compound slide and measure the front and top of hte gauge pin over its held distance in the ER chuck.
If the pin is not reading true on its face the headstock is not pointing square with the ways.
If the pin is not reading true on its top the headstock is pointing up or down with respect to the ways.
If the pin is not square to the ways, it does not mater what the carriage, cross slide, and compound are doing.
{Also note: it might be  aproblem with the collet chuck getting you all flustered.}

Try putting some indicators on the variaous moving parts {cariage, cross slide, compound} measuring the distance to the ways {inside and out}.
Then grab the assembly and push and pull with all your might and see if the indicators measure any movement.
This test would point to gib tightness.
I like my gibs to have a just barely detectible amount of drag on the ways, but for the parts to move with utmost smoothness.

Secondly, I had to clean the crap out of everything on my 12×36 including taking the QCTP apart several times to find that last grain or 2 of machining crap.


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## pontiac428 (Dec 4, 2020)

I think it is the effect it's having on his boring bar being coaxial with the spindle that are his concern.  Luckily, a lot of the squaring and facing can be done on a lathe.


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## jmarkwolf (Dec 5, 2020)

Are you confusing the term "runout" with "tool flex"?


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## epanzella (Dec 7, 2020)

As I (think) I understand this, you put an ER collet into a tool holer and put it in your QCTP. Then a dowel placed in the collet is not parrallel to the ways by a few thou? If that's the case it really doesn't matter.  The height of the point of the tool (on center) and the angle that the cutting edge is presented (sufficient relief) are what's important.


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## rock_breaker (Dec 7, 2020)

Hi WatchWatch., and a belated welcome to the website. 
What I am understanding may have to do with the spindle vertical  alignment, A sketch of where the runout is would be helpful. Not having some of the tools described of makes it difficult for me to understand the problem. Many favorable comments have been made about PM's skill and willingness to help, may be worth a try. 
Have a good day
Ray


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## SLK001 (Dec 8, 2020)

Make sure your toolpost is locking down on the compound T-slot and NOT on the bottom of the holder.  A lot of times, the vertical gap on the T-slot is shorter than the tendon on the bottom nut.  If that happens, no matter how tight you tighten your post, it isn't "connected" to the lathe and will have vertical play.  To check, remove the toolpost and slip just the bottom nut into the T-slot of the compound.  If the nut sticks proud of the compound top surface, you have found your problem (wedge the nut up to simulate the pull from the top nut).  If that happens, just grind off some of the top of the nut (until it is below the surface).

And vertical play like this IS a big deal.


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## Watchwatch (Dec 9, 2020)

Thank you to everyone for the warm welcome and advice. I called PM and wasn’t able to get much help.

I’m going to check the T slot nut this morning before I head to work. 

How does the ole saying go? A picture is worth a 1000 words. I’ll snap a few of what’s going on.

Side note. I started working on some boring bar bushings yesterday. I was able to hold .0002 on the OD across 3 inches of 12L14. So I’m fairly confident there isn’t twist in the ways.


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## Watchwatch (Dec 9, 2020)

Here is the problem











Here is the same setup on a surface plate. The problem is I’m not referencing the dovetails.











Top of the QCTP 

















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## pontiac428 (Dec 9, 2020)

Since you have a surface and a height gauge, have you tried proofing the tool post block and dovetails on the bench?  Eliminate some confounding variables by isolating the part and inspecting it without the confusion of the complicated lathe/cross slide/t-slot assembly.  If your post measures square, then you can start looking at the lathe.


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## epanzella (Dec 9, 2020)

If your post measures square while it's attached to the lathe the problem is either the QC tool post dovetails or the holder itself. Two tests you could do to find out which. Take the height adjuster off the boring bar holder and remount it to the toolpost  up side down. If the runout goes the other way it's the toolholder. If the runout is in the same direction it's the dovetails on the QCTP. You can double check your findings by doing the same thing with another holder with a square tool mounted.


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## Tozguy (Dec 9, 2020)

Thanks for the photos, problem is very clear now. Do you have a particular job to do that requires precision using your tool post and ER collet chuck set up that way?


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## Watchwatch (Dec 9, 2020)

Tozguy said:


> Thanks for the photos, problem is very clear now. Do you have a particular job to do that requires precision using your tool post and ER collet chuck set up that way?




My concern is that QCTP is out of spec. .003 over an inch adds up with a long boring bar or a drill.


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## Watchwatch (Dec 9, 2020)

epanzella said:


> If your post measures square while it's attached to the lathe the problem is either the QC tool post dovetails or the holder itself. Two tests you could do to find out which. Take the height adjuster off the boring bar holder and remount it to the toolpost up side down. If the runout goes the other way it's the toolholder. If the runout is in the same direction it's the dovetails on the QCTP. You can double check your findings by doing the same thing with another holder with a square tool mounted.



Thank you! 


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## jaek (Dec 9, 2020)

I see the out-of-square condition you are talking about here. There are two effects that I can see.

1) the effective rake and clearance angles on your tool will be 0.17 degrees different than expected.
2) if you reposition a tool significantly within the tool holder, you will need to readjust the tool height to remain on center.

How much do either of these matter?


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## Larry$ (Dec 9, 2020)

What do you use a collet in a tool holder to hold and why? I need to learn something here.


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## DAT510 (Dec 9, 2020)

Since the QCT holders register off the top of the Tool Post and you've shown the top of the tool post to be parallel with the bottom, then as others have mentioned....  I'd check the Squareness QCTP Dovetails to its base, Squareness of the Tool Holder Dovetails to the bore the ER Collet holder is mounted in and lastly the parallelness of the ER Collet shank to the ER collet and pin gage.


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## mikey (Dec 9, 2020)

How level a bar/drill is in the QCTP is entirely dependent upon you and the flatness of the height adjustment washer on the tool holder. Every single time you place a holder on the post, it will be a tiny bit different. I've been using a QCTP for over 35 years and have not noticed a major impact from this provided I set the tool on center, and I've drilled and bored a few holes in that time. My suggestion is to not worry about it too much.


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## MrWhoopee (Dec 9, 2020)

Now that you have made the situation clear, it would appear that the issue is with the boring bar holder. Since it is a genuine Aloris, you can probably get a replacement. Have you rotated the collet adapter 180 º and tried a different collet and pin?

My response remains the same.  The boring bar will not care as long as the cutting edge is set at the correct height.


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## Weldingrod1 (Dec 9, 2020)

I've used an ER collet to hold a round tool bit with some extension, in case you wanted a reason why...
	

	
	
		
		

		
			





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## mikey (Dec 9, 2020)

When boring, you still have to raise the tool up about 0.005-0.010" above center height to allow for tangential cutting forces so getting it dead on center for boring is not necessary, nor is it necessary to have the boring bar precisely level.


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## Larry$ (Dec 9, 2020)

I can tell I'm out of my class here. I just use a $20 tool holder with a V to hold round tools including boring bars up to 5/8".  I've got a boring bar holder for 1" and a bushing for 3/4". With in my limited skill set they seem to work fine. I have used a boring bar to reach where my regular turning tools couldn't. Seems to work OK. The only round tool bits I use are those D bits I grind on the tool & cutter grinder. Rarely used on the lathe. I'm way to cheap to buy a nice Aloris collet tool holder when I can make due.


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## Watchwatch (Dec 9, 2020)

Flipped the toolpost and checked it at the tail stick end. Then flipped the ER32 collet holder and checked at the chuck end.

Chuck end:












Tailstock end:












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## jaek (Dec 9, 2020)

You have a lot of nice name-brand gear. Lyndex-Nikken ER Collet holders, Aloris boring bar holder, BesTest indicator, made-in-Taiwan  lathe. Why are you still using the cheap PM tool post?


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## Watchwatch (Dec 10, 2020)

jaek said:


> You have a lot of nice name-brand gear. Lyndex-Nikken ER Collet holders, Aloris boring bar holder, BesTest indicator, made-in-Taiwan lathe. Why are you still using the cheap PM tool post?



Ive spent too much money on tooling recently. Luckily, Ive had a lot of the stuff for years. I grew up in a machine shop. 

I’m going to send the pictures to PM tomorrow and see if the QCTP is in spec. If it is, then I’ll bite the bullet and buy a Phase 2 or Aloris QCTP.


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## mmcmdl (Dec 10, 2020)

Watchwatch said:


> I’m going to send the pictures to PM tomorrow and see if the QCTP is in spec. If it is, then I’ll bite the bullet and buy a Phase 2 or Aloris QCTP.



If the PM is in spec , why buy another post ?  The only time this would come to a hill of beans is if you ran a long drill in a tool post chuck . You would rub the drill which is not a big problem . The way you're sitting , the tool tip is always going to stay parallel with the ways . Pull your tool out a foot or so , reset the height , which you should be doing anyway .


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## Tozguy (Dec 10, 2020)

Opportunity knocks!
With a boring bar in the headstock it would be fun to bore the tool holder dead nuts straight. After all we are machinists eh.


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## mmcmdl (Dec 10, 2020)

Absolutely ! Bore it perp to the dovetail and be done with it .


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## MrWhoopee (Dec 11, 2020)

Did you try rotating the collet adapter in the tool holder and a different collet/pin combo? Either of these could be off too (and much more important).
Checking the tool slot on another holder (or a couple) will tell you if it's the holder or the post. The readings on the surface plate point to either the holder or the collet adapter/collet.

I can't help but wonder, what prompted you to check this to begin with?


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## Watchwatch (Dec 12, 2020)

Found the issue. My setup is a little janky, but that’s the best that I could come up with.
















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## pontiac428 (Dec 12, 2020)

@Watchwatch, I am not sure what you are measuring in the last two pics.  I'm still confounded by the idea of measuring the part on the lathe.  What you are trying to do would be easy and decisive on the granite surface.


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## Larry$ (Dec 12, 2020)

That's a tricky measurement. Even the slightest move in & out on the dovetail will have a big effect. Your reference surface, top of carriage, would have to be absolutely parallel to the axis of the spindle. Even the slightest variance would be magnified by the dovetail. The compound surface could be introducing some variance. So could the vertical accuracy of the grinds on the tool post relative to the compound/ carriage top. Does the fit of the gibbs on the compound also affect it's top parallelism to the main axis? Have you determined that it is the grind of the dovetail and not the rest of the tool post?
Pontiac replied while I was typing. He's correct.


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